Science.gov

Sample records for acceptable change lac

  1. Application of Zoning and ``Limits of Acceptable Change'' to Manage Snorkelling Tourism

    NASA Astrophysics Data System (ADS)

    Roman, George S. J.; Dearden, Philip; Rollins, Rick

    2007-06-01

    Zoning and applying Limits of Acceptable Change (LAC) are two promising strategies for managing tourism in Marine Protected Areas (MPAs). Typically, these management strategies require the collection and integration of ecological and socioeconomic data. This problem is illustrated by a case study of Koh Chang National Marine Park, Thailand. Biophysical surveys assessed coral communities in the MPA to derive indices of reef diversity and vulnerability. Social surveys assessed visitor perceptions and satisfaction with conditions encountered on snorkelling tours. Notably, increased coral mortality caused a significant decrease in visitor satisfaction. The two studies were integrated to prescribe zoning and “Limits of Acceptable Change” (LAC). As a biophysical indicator, the data suggest a LAC value of 0.35 for the coral mortality index. As a social indicator, the data suggest that a significant fraction of visitors would find a LAC value of under 30 snorkellers per site as acceptable. The draft zoning plan prescribed four different types of zones: (I) a Conservation Zone with no access apart from monitoring or research; (II) Tourism Zones with high tourism intensities at less vulnerable reefs; (III) Ecotourism zones with a social LAC standard of <30 snorkellers per site, and (IV) General Use Zones to meet local artisanal fishery needs. This study illustrates how ecological and socioeconomic field studies in MPAs can be integrated to craft zoning plans addressing multiple objectives.

  2. Host acceptance tests of parasitoids from Indian Paratachardina lobata on the invasive lobate lac scale in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The invasive lobate lac scale identified as Paratachardina lobata (Hemiptera: Keriidae), native to southern India and Sri Lanka, is a severe threat to native and economic plants in southern Florida. Four parasitoid species, from southern India associated with Paratachardina lobata, were tested in qu...

  3. The HC-LAC: a Platform for Modeling Hydrology and Climate Change in Latin America and the Caribbean

    NASA Astrophysics Data System (ADS)

    Moreda, F.; Wyatt, A.; Bruhn, M.; Wheaton, W.; Miralles-Wilhelm, F.; Muñoz-Castillo, R.; Rineer, J.

    2013-05-01

    This platform, called the Hydrology and Climate Change in Latin America and The Caribbean, or "HC-LAC", is an integrated quantitative simulation of hydrology and climate change. The HC-LAC is composed of two principal components: the Analytical Hydrography Dataset (AHD) and an enhanced version of the Generalized Watershed Loading Function (GWLF). The AHD is a spatially explicit surface water data layer of Central and South America derived from digital elevation data from the Shuttle Radar Topography Mission (SRTM) and modified by the USGS to provide more accurate flow between cells in the raster data. For the LAC area, AHD consists 230, 000 catchments and stream segments with an average area of 100 km2 and length of 10 km, respectively. The AHD data structure is patterned after the US National Hydrography Dataset Plus (NHDPlus), thus providing a proven structure for flexible data integration and analyses necessary for spatial models like the HC-LAC. The structure of the AHD enables the implementation of water balance modeling and general routing of flows through the stream network thus supporting a range of environmental models. GWLF is applied on each AHD catchment which is characterized by multiple land use and soil type. The response of each land use in a given catchment is modeled separately in generating stream flow as well as recharge to soil storage. The stream flows generated from each catchment are routed through stream networks, providing total flow at any point in the stream network. A pilot implementation of the HC-LAC was established for the Rio Grande basin in North West Argentina (drainage area 6,700 km2). The model was parameterized and calibrated using readily available data. Three stream flow time series were generated using a reference climate case and two climate change projections. The reference case was based on historical records and assumes no climate change. The two climate change projections were generated using the IPCC "A2" high

  4. Understanding BL Lacertae objects. Structural and kinematic mode changes in the BL Lac object PKS 0735+178

    NASA Astrophysics Data System (ADS)

    Britzen, S.; Witzel, A.; Gong, B. P.; Zhang, J. W.; Gopal-Krishna; Goyal, A.; Aller, M. F.; Aller, H. D.; Zensus, J. A.

    2010-06-01

    Context. We present evidence that parsec-scale jets in BL Lac objects may be significantly distinct in kinematics from their counterparts in quasars. We argued this previously for the BL lac sources 1803+784 and 0716+714 and report here a similar pattern for another well-known BL Lac object, PKS 0735+178, whose nuclear jet is found to exhibit kinematics atypical of quasars. Aims: By analyzing the pc-scale jet morphology and its changes in 0735+178 we seek to understand the emission processes in BL Lac objects and to decipher their differences from quasars. A detailed study of the jet components' motion reveals that the standard AGN paradigm of apparent superluminal motion does not always describe the kinematics in BL Lac objects. We study 0735+178 here to augment and improve the understanding of the peculiar motions in the jets of BL Lac objects as a class. Methods: We analyzed 15 GHz VLBA (Very Long Baseline Array) observations (2 cm/MOJAVE survey) performed at 23 epochs between 1995.27 and 2008.91. Multiple Gaussians were fitted to the derived VLBA data, to trace the kinematical and flux density evolution of the individual VLBI (Very Long Baseline Interferometry) components in the nuclear jet. We then compared the jet kinematics with the optical and radio light curves available for this BL Lac object and point out some striking correlations between the properties of the radio knots and the features in the light curves. Results: We found a drastic structural mode change in the VLBI jet of 0735+178, between 2000.4 and 2001.8 when its twice sharply bent trajectory turned into a linear shape. We further found that this jet had undergone a similar transition sometime between December 1981 and June 1983. A mode change, occurring in the reverse direction (between mid-1992 and mid-1995) has already been reported in the literature. These structural mode changes are found to be reflected in changed kinematical behavior of the nuclear jet, manifested as an apparent

  5. The lac repressor.

    PubMed

    Lewis, Mitchell

    2005-06-01

    Few proteins have had such a strong impact on a field as the lac repressor has had in Molecular Biology. Over 40 years ago, Jacob and Monod [Genetic regulatory mechanisms in the synthesis of proteins, J. Mol. Biol. 3 (1961) 318] proposed a model for gene regulation, which survives essentially unchanged in contemporary textbooks. It is a cogent depiction of how a set of 'structural' genes may be coordinately transcribed in response to environmental conditions and regulates metabolic events in the cell. In bacteria, the genes required for lactose utilization are negatively regulated when a repressor molecule binds to an upstream cis activated operator. The repressor and its operator together form a genetic switch, the lac operon. The switch functions when inducer molecules alter the conformation of the repressor in a specific manner. In the presence of a particular metabolite, the repressor undergoes a conformational change that reduces its affinity for the operator. The structures of the lac repressor and its complexes with operator DNA and effector molecules have provided a physical platform for visualizing at the molecular level the different conformations the repressor and the molecular basis for the switch. The structures of lac repressor, bound to its operator and inducer, have also been invaluable for interpreting a plethora of biochemical and genetic data. PMID:15950160

  6. Acceptance- versus Change-Based Pain Management: The Role of Psychological Acceptance

    ERIC Educational Resources Information Center

    Blacker, Kara J.; Herbert, James D.; Forman, Evan M.; Kounios, John

    2012-01-01

    This study compared two theoretically opposed strategies for acute pain management: an acceptance-based and a change-based approach. These two strategies were compared in a within-subjects design using the cold pressor test as an acute pain induction method. Participants completed a baseline pain tolerance assessment followed by one of the two…

  7. Developing a New Instrument for Assessing Acceptance of Change

    PubMed Central

    Di Fabio, Annamaria; Gori, Alessio

    2016-01-01

    This article focuses on the usefulness of going beyond the concept of resistance to change and capitalizing on the use of a model that includes positivity and acceptance of change. We first discuss the theoretical background of this new construct in the work and organizational fields and then evaluate the psychometric properties of a new measure for assessing acceptance of change. The results of exploratory factor analysis indicated a factor structure with five principal dimensions; besides confirmatory factor analysis (CFA) goodness of fit indices indicated a good fit of the model to the data. All the dimensions showed good values of internal consistency. The results of the present study indicate that the Acceptance of Change Scale (ACS) is a brief and easily administered instrument with good psychometric properties that can promote the development of clients' strengths and the growth of a sense of Self, thereby helping them choose their own way without losing any opportunities in their lives and their work. PMID:27303356

  8. Developing a New Instrument for Assessing Acceptance of Change.

    PubMed

    Di Fabio, Annamaria; Gori, Alessio

    2016-01-01

    This article focuses on the usefulness of going beyond the concept of resistance to change and capitalizing on the use of a model that includes positivity and acceptance of change. We first discuss the theoretical background of this new construct in the work and organizational fields and then evaluate the psychometric properties of a new measure for assessing acceptance of change. The results of exploratory factor analysis indicated a factor structure with five principal dimensions; besides confirmatory factor analysis (CFA) goodness of fit indices indicated a good fit of the model to the data. All the dimensions showed good values of internal consistency. The results of the present study indicate that the Acceptance of Change Scale (ACS) is a brief and easily administered instrument with good psychometric properties that can promote the development of clients' strengths and the growth of a sense of Self, thereby helping them choose their own way without losing any opportunities in their lives and their work. PMID:27303356

  9. Late Holocene paleoenvironmental changes in Equatorial Africa as reconstructed by a diatom-based study of Lac Divangui (Gabon) sediments

    NASA Astrophysics Data System (ADS)

    Ariztegui, Daniel; Anselmetti, Flavio; Zosso, Anouk

    2016-04-01

    In recent years, an increasing number of studies have focused on the role of the tropics and the Equator as triggers of changes in the climate system at different time scales. There is, however, a remarkable paucity of continuous paleoenvironmental records in these areas preventing a better understanding of their role as climate forcing mechanisms. Lac Divangui is located at 2° south of the Equator in the forest of Rabi-Kunga, Gabon. This 1-km diameter basin attains a maximum depth of 80 m and provides a unique site to obtain a continuous archive of environmental changes through time. Previous investigations have shown that these organic-rich sediments contains large amounts of gas that, from a seismic surveying perspective, has prevented penetration of the acoustic signal. A range-finding study of the total organic fraction using Rock-Eval pyrolysis in a sedimentary core from the center of the basin showed a stable total organic content that is very high in average (~10%). A more detailed look into both the total organic fraction and certain biological remains, however, have shown substantial changes in both the quality of the total organic matter as well as the dominant diatom assemblages since 4.2 kyrs. BP. Although wet conditions appear to dominate the studied interval, several periods of dryness were identified around 2.4, 1.5 and 0.75 kyrs. BP. Since this last date the prevailing environmental conditions appear to be similar than today. These data are in agreement with observations in other African regions and are interpreted as related to the north-south movement of the Intertropical Convergence Zone (ITCZ). Gabon has the highest biodiversity of tropical Africa and previous investigations have shown that the tropical rainforest has reacted to both climate and human-induced environmental changes throughout the Holocene. Our combined sedimentological and organic remains results allow reconstructing the tropical rainforest history through time, which can be in

  10. Intermediate BL Lac objects

    NASA Astrophysics Data System (ADS)

    Bondi, M.; Marchã, M. J. M.; Dallacasa, D.; Stanghellini, C.

    2001-08-01

    The 200-mJy sample, defined by Marchã et al., contains about 60 nearby, northern, flat-spectrum radio sources. In particular, the sample has proved effective at finding nearby radio-selected BL Lac objects with radio luminosities comparable to those of X-ray-selected objects, and low-luminosity flat-spectrum weak emission-line radio galaxies (WLRGs). The 200-mJy sample contains 23 BL Lac objects (including 6 BL Lac candidates) and 19 WLRGs. We will refer to these subsamples as the 200-mJy BL Lac sample and the 200-mJy WLRG sample, respectively. We have started a systematic analysis of the morphological pc-scale properties of the 200-mJy radio sources using VLBI observations. This paper presents VLBI observations at 5 and 1.6GHz of 14 BL Lac objects and WLRGs selected from the 200-mJy sample. The pc-scale morphology of these objects is briefly discussed. We derive the radio beaming parameters of the 200-mJy BL Lac objects and WLRGs and compare them with those of other BL Lac samples and with a sample of FR I radio galaxies. The overall broad-band radio, optical and X-ray properties of the 200-mJy BL Lac sample are discussed and compared with those of other BL Lac samples, radio- and X-ray-selected. We find that the 200-mJy BL Lac objects fill the gap between HBL and LBL objects in the colour-colour plot, and have intermediate αXOX as expected in the spectral energy distribution unification scenario. Finally, we briefly discuss the role of the WLRGs.

  11. The acceptability of climate change in agricultural communities: comparing responses across variability and change.

    PubMed

    Raymond, Christopher M; Spoehr, John

    2013-01-30

    This study examined how the terms used to describe climate change influence landholder acceptability judgements and attitudes toward climate change at the local scale. Telephone surveys were conducted with landholders from viticultural (n = 97) or cereal growing (n = 195) backgrounds in rural South Australia. A variety of descriptive and inferential statistics were used to examine the influence of human-induced climate change and winter/spring drying trend terms on adaptation responses and uncertainties surrounding climate change science. We found that the terms used to describe climate change leads to significant differences in adaptation response and levels of scepticism surrounding climate change in rural populations. For example, those respondents who accepted human induced climate change as a reality were significantly more likely to invest in technologies to sow crops earlier or increase the amount of water stored or harvested on their properties than respondents who accepted the winter/spring drying trend as a reality. The results have implications for the targeting of climate change science messages to both rural landholders and communities of practice involved in climate change adaptation planning and implementation. PMID:23246767

  12. Multiband Microvariability of BL Lac During Outburst

    NASA Astrophysics Data System (ADS)

    Clements, S. D.; Carini, M. T.; Noble, J. C.

    1998-01-01

    The blazar BL Lac recently underwent a major outburst. A search for microvariability was made with the 0.76 m telescope at the University of Florida's Rosemary Hill Observatory. Nearly 300 CCD observations in V and R were made over ten nights in July. During that time, BL Lac varied by more than 1.5 magnitudes and exhibited substantial microvariability. In fact, it exhibited microvariability each of the eight nights multiple exposures were made, being most active when brightest on July 29. On this night, four mini-flares were seen within 7 hours. During one of these flares, BL Lac brightened by more than 0.5 magnitude in less than 2.5 hours. The variations in V and R were simultaneous within the limits of the observations. However, the V and R magnitudes did not always change at the same rate. On July 3, BL Lac brightened in R faster than in V. Then on July 4, it dimmed in V faster than in R. Yet over the ten nights observed, BL Lac became bluer as it brightened. Another interesting difference between the V and R data was seen on July 4 when a mini-flare was seen in V but not in R. Clearly, while the V and R variations are highly correlated, there are compelling differences. Here we present these observations and discuss them in relation to models intended to explain microvariability. The authors gratefully acknowledge the support of NASA grant NCC5-228.

  13. The extent of co-metabolism of glucose and galactose by Lactococcus lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus.

    PubMed

    Solem, Christian; Koebmann, Brian; Jensen, Peter R

    2008-05-01

    The lactose transporter and beta-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium and only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed at intermediate beta-galactosidase activities of 2000-3000 Miller units. At higher expression levels, the flux decreased. These strains had a glycolytic flux comparable with those of reference strains with the standard lactococcal PTS(lac) (lactose phosphotransferase transport system) lactose transporter, which indicates that lactose transport is not rate-limiting for glycolysis in Lactococcus. Finally, an additional ATP drain was introduced into the fastest growing strain, CS2004, to test whether the ATP demand controlled glycolysis under these conditions, but in fact no increase in glycolytic flux was observed. PMID:17822381

  14. The Energy Landscape of Hyperstable LacI-DNA Loops

    NASA Astrophysics Data System (ADS)

    Kahn, Jason

    2009-03-01

    The Escherichia coli LacI protein represses transcription of the lac operon by blocking access to the promoter through binding at a promoter-proximal DNA operator. The affinity of tetrameric LacI (and therefore the repression efficiency) is enhanced by simultaneous binding to an auxiliary operator, forming a DNA loop. Hyperstable LacI-DNA loops were previously shown to be formed on DNA constructs that include a sequence-directed bend flanked by operators. Biochemical experiments showed that two such constructs (9C14 and 11C12) with different helical phasing between the operators and the DNA bend form different DNA loop shapes. The geometry and topology of the loops and the relevance of alternative conformations suggested by probable flexible linkers in LacI remain unclear. Bulk and single molecule fluorescence resonance energy transfer (SM-FRET, with D. English) experiments on a dual fluorophore-labeled 9C14-LacI loop demonstrate that it adopts a single, stable, rigid closed-form loop conformation. Here, we characterize the LacI-9C14 loop by SM-FRET as a function of inducer isopropyl-β,D-thiogalactoside (IPTG) concentration. Energy transfer measurements reveal partial but incomplete destabilization of loop formation by IPTG. Surprisingly, there is no change in the energy transfer efficiency of the remaining looped population. Models for the regulation of the lac operon often assume complete disruption of LacI-operator complexes upon inducer binding to LacI. Our work shows that even at saturating IPTG there is still a significant population of LacI-DNA complexes in a looped state, in accord with previous in vivo experiments that show incomplete induction (with J. Maher). Finally, we will report progress on characterizing the ``energy landscape'' for DNA looping upon systematic variation of the DNA linkers between the operators and the bending locus. Rod mechanics simulations (with N. Perkins) provide testable predictions on loop stability, topology, and FRET.

  15. Trust, Isolation, and Presence: The Virtual Work Environment and Acceptance of Deep Organizational Change

    ERIC Educational Resources Information Center

    Rose, Laurence Michael

    2013-01-01

    The primary focus of this research was to explore through the use of a grounded theory methodology if the human perceptions of trust, isolation, and presence affected the virtual workers ability to accept deep organizational change. The study found that the virtual workers in the sample defined their acceptance of deep organizational change by…

  16. Defining acceptable conditions in wilderness

    NASA Astrophysics Data System (ADS)

    Roggenbuck, J. W.; Williams, D. R.; Watson, A. E.

    1993-03-01

    The limits of acceptable change (LAC) planning framework recognizes that forest managers must decide what indicators of wilderness conditions best represent resource naturalness and high-quality visitor experiences and how much change from the pristine is acceptable for each indicator. Visitor opinions on the aspects of the wilderness that have great impact on their experience can provide valuable input to selection of indicators. Cohutta, Georgia; Caney Creek, Arkansas; Upland Island, Texas; and Rattlesnake, Montana, wilderness visitors have high shared agreement that littering and damage to trees in campsites, noise, and seeing wildlife are very important influences on wilderness experiences. Camping within sight or sound of other people influences experience quality more than do encounters on the trails. Visitors’ standards of acceptable conditions within wilderness vary considerably, suggesting a potential need to manage different zones within wilderness for different clientele groups and experiences. Standards across wildernesses, however, are remarkably similar.

  17. Physiological regulation of a decontrolled lac operon.

    PubMed Central

    Wanner, B L; Kodaira, R; Neidhardt, F C

    1977-01-01

    The expression of the lac operon was studied under a variety of growth conditions in induced and in constitutive cells of Escherichia coli that carried different catabolite-insensitive lac promoters. Use of such "decontrolled" lac operons permitted a study of the expression of an operon that was presumably subject only to passive control. Since the use of toluenized cells was demonstrated not to be completely reliable, all enzyme assays were performed on sonic supernatant fluids. The cells contained different catabolite-insensitive promoters, which included the L1 and UV5 lac promoters, as well as others isolated in this study. There were three major observations. First, small but real carbon source effects were seen. Second, there was only a small change in beta-galactosidase specific activity with changes in the growth rate. This result implies a limited transcription and/or translation capacity within the cell. Third, at rapid growth rates, most promoters exhibited a decreased expression. The UV5 promoter, which was the "strongest" promoter, was an exception. A mechanism to explain this promoter-dependent control is discussed. PMID:323228

  18. 77 FR 49003 - Notice of Proposed Information Collection for Public Comment: Request for Acceptance of Changes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT Notice of Proposed Information Collection for Public Comment: Request for Acceptance... also lists the following information: Title of Proposal: Request for Acceptance of Changes in...

  19. Acceptance and Commitment Therapy as a Unified Model of Behavior Change

    ERIC Educational Resources Information Center

    Hayes, Steven C.; Pistorello, Jacqueline; Levin, Michael E.

    2012-01-01

    The present article summarizes the assumptions, model, techniques, evidence, and diversity/social justice commitments of Acceptance and Commitment Therapy (ACT). ACT focused on six processes (acceptance, defusion, self, now, values, and action) that bear on a single overall target (psychological flexibility). The ACT model of behavior change has…

  20. Prior Learning Assessment: A Case Study of Acceptance of Innovation and Change.

    ERIC Educational Resources Information Center

    Wolfson, Gloria Krupnick

    This project investigated the acceptance of innovation and change as it related to a specific education change of prior learning assessment (PLA) at the University College of the Fraser Valley (UCFV) in British Columbia, Canada. The study explored the barriers that existed against students who wanted to have experiential and workplace learning…

  1. 20 CFR 418.2260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false What major life-changing event evidence will we not accept? 418.2260 Section 418.2260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE... Using A More Recent Tax Year's Modified Adjusted Gross Income § 418.2260 What major life-changing...

  2. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false What major life-changing event evidence will we not accept? 418.1260 Section 418.1260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE... Year's Modified Adjusted Gross Income § 418.1260 What major life-changing event evidence will we...

  3. 20 CFR 418.2260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false What major life-changing event evidence will we not accept? 418.2260 Section 418.2260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE... Using A More Recent Tax Year's Modified Adjusted Gross Income § 418.2260 What major life-changing...

  4. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false What major life-changing event evidence will we not accept? 418.1260 Section 418.1260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE... Year's Modified Adjusted Gross Income § 418.1260 What major life-changing event evidence will we...

  5. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false What major life-changing event evidence will we not accept? 418.1260 Section 418.1260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE... Year's Modified Adjusted Gross Income § 418.1260 What major life-changing event evidence will we...

  6. Use of change management theories in gaining acceptance of telemedicine technology.

    PubMed

    Rufo, Rebecca Zapatochny

    2012-01-01

    The success of telemedicine applications within health care begins with the process of implementing planned change. The attitudes of staff and their willingness to embrace new technology can be positively influenced in order to gain acceptance of new ways to perform tasks. Telemedicine applications have been designed to improve operational efficiency and obtain improved outcomes, but system designers and procurers are dependent upon the organization's leadership to effect attitudinal and behavioral changes that are essential for acceptance and usage of new technology. PMID:22948364

  7. 39 CFR 3050.11 - Proposals to change an accepted analytical principle applied in the Postal Service's annual...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Proposals to change an accepted analytical... accepted analytical principle applied in the Postal Service's annual periodic reports to the Commission. (a... issue a notice of proceeding to change an accepted analytical principle. In addition, any...

  8. LacR is a repressor of lacABCD and LacT is an activator of lacTFEG, constituting the lac gene cluster in Streptococcus pneumoniae.

    PubMed

    Afzal, Muhammad; Shafeeq, Sulman; Kuipers, Oscar P

    2014-09-01

    Comparison of the transcriptome of Streptococcus pneumoniae strain D39 grown in the presence of either lactose or galactose with that of the strain grown in the presence of glucose revealed the elevated expression of various genes and operons, including the lac gene cluster, which is organized into two operons, i.e., lac operon I (lacABCD) and lac operon II (lacTFEG). Deletion of the DeoR family transcriptional regulator lacR that is present downstream of the lac gene cluster revealed elevated expression of lac operon I even in the absence of lactose. This suggests a function of LacR as a transcriptional repressor of lac operon I, which encodes enzymes involved in the phosphorylated tagatose pathway in the absence of lactose or galactose. Deletion of lacR did not affect the expression of lac operon II, which encodes a lactose-specific phosphotransferase. This finding was further confirmed by β-galactosidase assays with PlacA-lacZ and PlacT-lacZ in the presence of either lactose or glucose as the sole carbon source in the medium. This suggests the involvement of another transcriptional regulator in the regulation of lac operon II, which is the BglG-family transcriptional antiterminator LacT. We demonstrate the role of LacT as a transcriptional activator of lac operon II in the presence of lactose and CcpA-independent regulation of the lac gene cluster in S. pneumoniae. PMID:24951784

  9. Conceptual Change in Psychology Students' Acceptance of the Scientific Foundation of the Discipline

    ERIC Educational Resources Information Center

    Amsel, Eric; Ashley, Aaron; Baird, Todd; Johnston, Adam

    2014-01-01

    Two studies explored conceptual change in undergraduate psychology students' acceptance of the scientific foundations of the discipline. In Study 1, Introductory Psychology students completed the Psychology as Science questionnaire (PAS) at the beginning and end of the semester and did so from their own (Self Condition) and their instructors'…

  10. 77 FR 30306 - Notice of Proposed Information Collection: Comment Request; Request for Acceptance of Changes in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT Notice of Proposed Information Collection: Comment Request; Request for Acceptance of Changes in Approved Drawings and Specifications AGENCY: Office of the Assistant Secretary for Housing,...

  11. ACT for Leadership: Using Acceptance and Commitment Training to Develop Crisis-Resilient Change Managers

    ERIC Educational Resources Information Center

    Moran, Daniel J.; Consulting, Pickslyde

    2010-01-01

    The evidence-based executive coaching movement suggests translating empirical research into practical methods to help leaders develop a repertoire of crisis resiliency and value-directed change management skills. Acceptance and Commitment Therapy (ACT) is an evidence-based modern cognitive-behavior therapy approach that has been and applied to…

  12. 75 FR 36153 - Surety Companies Acceptable On Federal Bonds-Change In Business Address: American Economy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ... Department Circular 570, 2009 Revision, published July 1, 2009, at 74 FR 31536. FOR FURTHER INFORMATION... Fiscal Service Surety Companies Acceptable On Federal Bonds--Change In Business Address: American Economy... Economy Insurance Company (NAIC 19690). BUSINESS ADDRESS: 500 North Meridian Street, Indianapolis,...

  13. 76 FR 22451 - Surety Companies Acceptable on Federal Bonds-Change in Business Address; American Economy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... No. 8 to the Treasury Department Circular 570, 2010 Revision, published July 1, 2010, at 75 FR 38192... Fiscal Service Surety Companies Acceptable on Federal Bonds--Change in Business Address; American Economy... Address'' as follows: American Economy Insurance Company (NAIC 19690). Business Address: 350 E....

  14. Effects of speaking rate on the acceptability of change in segmental duration within a phrase

    NASA Astrophysics Data System (ADS)

    Muto, Makiko; Kato, Hiroaki; Tsuzaki, Minoru; Sagisaka, Yoshinori

    2001-05-01

    To contribute to the naturalness criteria of speech synthesis, acceptability of changes in segment duration has been investigated. Previous studies showed context dependency of the acceptability evaluation such as intraphrase positional effect, where listeners were more sensitive to the phrase-initial segment duration than the phrase-final one. Such contextual effects were independent of the original durations of the segments tested [Kato et al., J. Acoust. Soc. Am. 104, 540-549 (1998)]. However, past studies used only normal-speed speech and temporal variation was limited. The current study, therefore, examined the contextual effect with a wide variety of speaking rates. The materials were three-mora phrases with either rising or falling accent that were spoken at three rates (fast, normal, and slow) with or without a carrier sentence. The duration of each vowel was either lengthened or shortened (10-50 ms) and listeners evaluated the acceptability of these changes. The results showed a clear speaking-rate effect in parallel with the intraphrase positional effect: the acceptability declined more rapidly as the speaking rate became faster. These results, along with those of Kato et al., suggest that acceptability is evaluated based on the speaking rate rather than on the original duration itself. [Work supported by TAO, Japan.] a)Currently at GITI, Waseda University.

  15. Fifty years fused to lac.

    PubMed

    Beckwith, Jonathan

    2013-01-01

    I recount the history of how I became interested in the use of gene fusions for studying biological problems. Initially, selections for mutations that would restore function to an inactivated lac operon unexpectedly yielded fusions in which lac was expressed from the controlling elements of upstream genes. Subsequently, by chance, I generated strains in which the lac operon was transposed from its normal position on the chromosome to a position close to the trp operon, thus facilitating sets of useful fusions of the two operons. The development of a more generalized technique for obtaining fusions by my student Malcolm Casadaban opened up a much broader set of biological problems that could be approached with fusions. Work on these problems included the study of protein translocation across membranes, the analysis of membrane protein topology, and the discovery of the pathway of electron transfer that leads to disulfide bond formation in proteins. PMID:24024632

  16. Substance Use in Muslim Culture: Social and Generational Changes in Acceptance and Practice in Jordan.

    PubMed

    Mauseth, Kira B; Skalisky, Jordan; Clark, Noël E; Kaffer, Ray

    2016-08-01

    Through narrative analysis, this paper explores the changes in acceptance of and response to substance use in Muslim culture by evaluating data collected in qualitative interviews in Jordan in 2013. What is known and unknown about substance use in Muslim culture throughout the Arab world from previous research findings provides a foundation from which to explore new perspectives and compare themes between younger and older generations in Jordan. Trends of social change and behavioral expression influenced by dramatic political and social upheaval in the Arab world in the last 5 years will also be evaluated for the way in which they may be influencing both substance use and its acceptance among young adults in this population. Recommendations for future research and work in this area are also provided based on these findings. PMID:25972289

  17. Specific point mutations in Lactobacillus casei ATCC 27139 cause a phenotype switch from Lac- to Lac+.

    PubMed

    Tsai, Yu-Kuo; Chen, Hung-Wen; Lo, Ta-Chun; Lin, Thy-Hou

    2009-03-01

    Lactose metabolism is a changeable phenotype in strains of Lactobacillus casei. In this study, we found that L. casei ATCC 27139 was unable to utilize lactose. However, when exposed to lactose as the sole carbon source, spontaneous Lac(+) clones could be obtained. A gene cluster (lacTEGF-galKETRM) involved in the metabolism of lactose and galactose in L. casei ATCC 27139 (Lac(-)) and its Lac(+) revertant (designated strain R1) was sequenced and characterized. We found that only one nucleotide, located in the lacTEGF promoter (lacTp), of the two lac-gal gene clusters was different. The protein sequence identity between the lac-gal gene cluster and those reported previously for some L. casei (Lac(+)) strains was high; namely, 96-100 % identity was found and no premature stop codon was identified. A single point mutation located within the lacTp promoter region was also detected for each of the 41 other independently isolated Lac(+) revertants of L. casei ATCC 27139. The revertants could be divided into six classes based on the positions of the point mutations detected. Primer extension experiments conducted on transcription from lacTp revealed that the lacTp promoter of these six classes of Lac(+) revertants was functional, while that of L. casei ATCC 27139 was not. Northern blotting experiments further confirmed that the lacTEGF operon of strain R1 was induced by lactose but suppressed by glucose, whereas no blotting signal was ever detected for L. casei ATCC 27139. These results suggest that a single point mutation in the lacTp promoter was able to restore the transcription of a fully functional lacTEGF operon and cause a phenotype switch from Lac(-) to Lac(+) for L. casei ATCC 27139. PMID:19246746

  18. Proton NMR study of a complex between the lac repressor headpiece and a 22 base pair symmetric lac operator

    SciTech Connect

    Lamerichs, R.M.J.N.; Boelens, R.; van der Marel, G.A.; van Boom, J.H.; Kaptein, R.; Buck, F.; Fera, B.; Rueterjans, H. )

    1989-04-04

    A complex between the lac repressor headpiece and a fully symmetric tight-binding 22 bp lac operator was studied by 2D NMR. Several 2D NOE spectra were recorded for the complex in both H{sub 2}O and {sup 2}H{sub 2}O. Many NOE cross-peaks between the headpiece and DNA could be identified, and changes in the chemical shift of the DNA protons upon complex formation were analyzed. Comparison of these data with those obtained for a complex between the headpiece and a 14 bp half-operator, studied previously, shows that two headpieces form a specific complex with the 22 bp lac operator in which each headpiece binds in the same way as found for the 14 bp complex. The orientation of the recognition helix in the major groove of DNA in these complexes is opposite with respect to the dyad axis to that found for other repressors.

  19. 76 FR 68124 - Television Broadcasting Services; Fond du Lac, WI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... reconsideration of an August 12, 2009 Report and Order changing the allotted channel for station WWAZ-TV, Fond du... 5 for channel 44 at Fond du Lac ] because it permitted WLS-TV, an ABC network affiliate in Chicago... network service to numerous viewers that had lost service after the transition of WLS-TV to...

  20. Gap Acceptance During Lane Changes by Large-Truck Drivers—An Image-Based Analysis

    PubMed Central

    Nobukawa, Kazutoshi; Bao, Shan; LeBlanc, David J.; Zhao, Ding; Peng, Huei; Pan, Christopher S.

    2016-01-01

    This paper presents an analysis of rearward gap acceptance characteristics of drivers of large trucks in highway lane change scenarios. The range between the vehicles was inferred from camera images using the estimated lane width obtained from the lane tracking camera as the reference. Six-hundred lane change events were acquired from a large-scale naturalistic driving data set. The kinematic variables from the image-based gap analysis were filtered by the weighted linear least squares in order to extrapolate them at the lane change time. In addition, the time-to-collision and required deceleration were computed, and potential safety threshold values are provided. The resulting range and range rate distributions showed directional discrepancies, i.e., in left lane changes, large trucks are often slower than other vehicles in the target lane, whereas they are usually faster in right lane changes. Video observations have confirmed that major motivations for changing lanes are different depending on the direction of move, i.e., moving to the left (faster) lane occurs due to a slower vehicle ahead or a merging vehicle on the right-hand side, whereas right lane changes are frequently made to return to the original lane after passing. PMID:26924947

  1. An Elaboration Likelihood Model Based Longitudinal Analysis of Attitude Change during the Process of IT Acceptance via Education Program

    ERIC Educational Resources Information Center

    Lee, Woong-Kyu

    2012-01-01

    The principal objective of this study was to gain insight into attitude changes occurring during IT acceptance from the perspective of elaboration likelihood model (ELM). In particular, the primary target of this study was the process of IT acceptance through an education program. Although the Internet and computers are now quite ubiquitous, and…

  2. Legitimization of regulatory norms: Waterfowl hunter acceptance of changing duck bag limits

    USGS Publications Warehouse

    Schroeder, Susan A.; Fulton, David C.; Lawrence, Jeffrey S.; Cordts, Steven D.

    2014-01-01

    Few studies have examined response to regulatory change over time, or addressed hunter attitudes about changes in hunting bag limits. This article explores Minnesota waterfowl hunters’ attitudes about duck bag limits, examining attitudes about two state duck bag limits that were initially more restrictive than the maximum set by the U.S. Fish and Wildlife Service (USFWS), but then increased to match federal limits. Results are from four mail surveys that examined attitudes about bag limits over time. Following two bag limit increases, a greater proportion of hunters rated the new bag limit “too high” and a smaller proportion rated it “too low.” Several years following the first bag limit increase, the proportion of hunters who indicated that the limit was “too high” had declined, suggesting hunter acceptance of the new regulation. Results suggest that waterfowl bag limits may represent legal norms that influence hunter attitudes and gain legitimacy over time.

  3. Cultural change in acceptance of LGBT people: lessons from social marketing.

    PubMed

    Witeck, Bob

    2014-01-01

    We are in a new era in American history. Showing a remarkable shift in attitudes toward gay, lesbian, bisexual, and transgender (LGBT) people, the United States appears to be embracing a new, more inclusive view of family life. With positive action in two landmark Supreme Court cases and a rapidly growing number of state legislatures, the trends are strong toward full legal recognition of marriages of same-sex partners and parenthood by both partners in committed gay couples rearing children. And, the trend is international. Many people are both astonished and cheered by the accelerating pace of change in acceptance of LGBT people. Surveys now show that about 60% of Americans support marriage equality so that gay couples may wed. Less than a decade ago, that proportion of Americans opposed gay weddings. This article looks at what has changed, and why, as well as how social marketing, among other forces, lifted the curtain on these unmistakable trends. PMID:24826822

  4. 39 CFR 3050.11 - Proposals to change an accepted analytical principle applied in the Postal Service's annual...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Proposals to change an accepted analytical principle applied in the Postal Service's annual periodic reports to the Commission. 3050.11 Section 3050.11 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change...

  5. 39 CFR 3050.11 - Proposals to change an accepted analytical principle applied in the Postal Service's annual...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Proposals to change an accepted analytical principle applied in the Postal Service's annual periodic reports to the Commission. 3050.11 Section 3050.11 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change...

  6. 39 CFR 3050.11 - Proposals to change an accepted analytical principle applied in the Postal Service's annual...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Proposals to change an accepted analytical principle applied in the Postal Service's annual periodic reports to the Commission. 3050.11 Section 3050.11 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change...

  7. 39 CFR 3050.11 - Proposals to change an accepted analytical principle applied in the Postal Service's annual...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Proposals to change an accepted analytical principle applied in the Postal Service's annual periodic reports to the Commission. 3050.11 Section 3050.11 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change...

  8. Transcriptional and functional analysis of galactooligosaccharide uptake by lacS in Lactobacillus acidophilus.

    PubMed

    Andersen, Joakim M; Barrangou, Rodolphe; Abou Hachem, Maher; Lahtinen, Sampo; Goh, Yong Jun; Svensson, Birte; Klaenhammer, Todd R

    2011-10-25

    Probiotic microbes rely on their ability to survive in the gastrointestinal tract, adhere to mucosal surfaces, and metabolize available energy sources from dietary compounds, including prebiotics. Genome sequencing projects have proposed models for understanding prebiotic catabolism, but mechanisms remain to be elucidated for many prebiotic substrates. Although β-galactooligosaccharides (GOS) are documented prebiotic compounds, little is known about their utilization by lactobacilli. This study aimed to identify genetic loci in Lactobacillus acidophilus NCFM responsible for the transport and catabolism of GOS. Whole-genome oligonucleotide microarrays were used to survey the differential global transcriptome during logarithmic growth of L. acidophilus NCFM using GOS or glucose as a sole source of carbohydrate. Within the 16.6-kbp gal-lac gene cluster, lacS, a galactoside-pentose-hexuronide permease-encoding gene, was up-regulated 5.1-fold in the presence of GOS. In addition, two β-galactosidases, LacA and LacLM, and enzymes in the Leloir pathway were also encoded by genes within this locus and up-regulated by GOS stimulation. Generation of a lacS-deficient mutant enabled phenotypic confirmation of the functional LacS permease not only for the utilization of lactose and GOS but also lactitol, suggesting a prominent role of LacS in the metabolism of a broad range of prebiotic β-galactosides, known to selectively modulate the beneficial gut microbiota. PMID:22006318

  9. Probing of electronic structures of La@C82 superatoms upon clustering realized using glycine nanocavities

    NASA Astrophysics Data System (ADS)

    Taninaka, Atsushi; Ochiai, Takahiro; Kanazawa, Ken; Takeuchi, Osamu; Shigekawa, Hidemi

    2015-12-01

    We have succeeded in the first direct probe of the change in the electronic structures of La@C82 superatoms upon clustering by scanning tunneling microscopy/spectroscopy (STM/STS). An array of ∼1.3-nm-diameter glycine nanocavities self-assembled on a Cu(111) surface was used as a template. Isolated La@C82 superatoms were stably observed on terraces without diffusion to step edges, which enabled us to observe the change in the electronic structures associated with single, dimer, and clustered La@C82. A cluster with four La@C82 superatoms showed electronic structures similar to those obtained for thin films in previous works.

  10. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... through 404.721 of this chapter. (b) We will not accept evidence of marriage that fails to meet the requirements in §§ 404.725 through 404.727 of this chapter. (c) We will not accept evidence that your...

  11. Comparative functional analysis of the lac operons in Streptococcus pyogenes.

    PubMed

    Loughman, Jennifer A; Caparon, Michael G

    2007-04-01

    Having no known environmental reservoir, Streptococcus pyogenes, a bacterium responsible for a wider variety of human diseases than any other bacterial species, must rely on its host for metabolic substrates. Although a streptococcal aldolase, LacD.1, has been adapted to virulence gene regulation, both LacD.1 and a paralogous protein, LacD.2, are predicted to function in the tagatose 6-phosphate pathway for lactose and galactose utilization. In order to gain insight into the mechanism of the LacD.1 regulatory pathway and the role of genome context in the emergence of LacD.1's novel regulatory functions, we compared the function and regulation of the Lac.1 and Lac.2 loci. The Lac.1 operon is not inducible, and regulation by LacD.1 is independent of a functional tagatose 6-phosphate pathway and enhanced by the conserved truncation of upstream Lac.1 genes. In contrast, Lac.2 expression is sensitive to environmental carbohydrates, and LacD.2, not LacD.1, contributes to growth on galactose. Thus, we conclude that the Lac.1 locus has been specialized to participate in regulation, leaving efficient utilization of carbohydrate sources to the Lac.2 locus. The adaptation of LacD for transcription regulation may be an underappreciated strategy among prokaryotes, as homologues of this multifaceted enzyme are present in a broad range of species. PMID:17371500

  12. Mutagenesis in the lacI gene target of E. coli: improved analysis for lacI(d) and lacO mutants.

    PubMed

    Swerdlow, Sarah J; Schaaper, Roel M

    2014-12-01

    The lacI gene of Escherichia coli has been a highly useful target for studies of mutagenesis, particularly for analysis of the specificity (spectrum) of mutations generated under a variety of conditions and in various genetic backgrounds. The gene encodes the repressor of the lac operon, and lacI-defective mutants displaying constitutive expression of the operon are readily selected. DNA sequencing of the lacI mutants has often been confined to the N-terminal region of the protein, as it presents a conveniently short target with a high density of detectably mutable sites. Mutants in this region are easily selected due to their dominance in a genetic complementation test (lacI(d) mutants). A potential complication in these studies is that constitutive expression of lac may also arise due to mutations in the lac operator (lacO mutants). Under some conditions, for example when analyzing spontaneous mutations, lacO mutants can comprise a very high fraction of the constitutive mutants due to a strong base-substitution hotspot in the lac operator. Such mutational hot spots diminish the return of the sequencing effort and do not yield significant new information. For this reason, a procedure to eliminate the lacO mutants prior to DNA sequencing is desirable. Here, we report a simple method that allows screening out of lacO mutants. This method is based on the lack of resistance of lacO mutants to kanamycin under conditions when the kan gene is expressed from a plasmid under control of the lac promoter-operator (lacPO). We show data validating the new approach with sets of known lacI(d) and lacO mutants, and further apply it to the generation of a new collection of spontaneous mutations, where lacO mutants have historically been a significant contributor. PMID:25771873

  13. lac repressor blocks in vivo transcription of lac control region DNA.

    PubMed Central

    Sellitti, M A; Pavco, P A; Steege, D A

    1987-01-01

    Transcription of the Escherichia coli lac repressor gene (lacI) in vivo produces monocistronic mRNAs with discrete 3' ends in the lac control region, although the DNA sequence of this region does not specify a strong termination signal of the traditional form. Direct analysis of lac transcripts was used to show that the DNA sequence alone does not provide the signal to end the repressor mRNA and to establish that of the proteins with specific binding sites on control region DNA only the lac repressor has a striking effect on the continuity of lacI gene transcription. RNAs with 3' ends in the control region sequence are major mRNA species produced from a repressor-bound template, reflecting as much as a 50-fold increase over their levels in the repressor's absence. Repressor binding to the operator thus has a dual function. In addition to blocking initiation of transcription from the lacZ promoter, repressor serves as a termination factor by setting the length of its own transcript and separating lacI and lacZYA into two distinct transcription units. Images PMID:3554233

  14. Optimized expression and purification of biophysical quantities of Lac repressor and Lac repressor regulatory domain.

    PubMed

    Stetz, Matthew A; Carter, Marie V; Wand, A Joshua

    2016-07-01

    The recombinant production of Lac repressor (LacI) in Escherichia coli is complicated by its ubiquitous use as a regulatory element in commercially-available expression vectors and host strains. While LacI-regulated expression systems are often used to produce recombinant LacI, the product can be heterogeneous and unsuitable for some studies. Alternative approaches include using unregulated vectors which typically suffer from low yield or vectors with promoters induced by metabolically active sugars which can dilute isotope labels necessary for certain biophysical studies. Here, an optimized expression system and isolation protocol for producing various constructs of LacI is introduced which eliminates these complications. The expression vector is an adaptation of the pASK backbone wherein expression of the lacI gene is regulated by an anhydrotetracyline inducible tetA promoter and the host strain lacks the lacI gene. Typical yields in highly deuterated minimal medium are nearly 2-fold greater than those previously reported. Notably, the new expression system is also able to produce the isolated regulatory domain of LacI without co-expression of the full-length protein and without any defects in cell viability, eliminating the inconvenient requirement for strict monitoring of cell densities during pre-culturing. Typical yields in highly deuterated minimal medium are significantly greater than those previously reported. Characterization by solution NMR shows that LacI constructs produced using this expression system are highly homogenous and functionally active. PMID:27064119

  15. BL Lac Objects at the highest redshifts

    NASA Astrophysics Data System (ADS)

    Ajello, Marco

    2013-10-01

    For a long time high-redshift BL Lac objects were deemed not to exist. Fermi showed us that there is relevant population of BL Lacs with redshift beyond 1.0. Some of them belong to the high-synchrotron peaked (HSP) class and are among the hardest gamma-ray sources detected by Fermi showing emission up and beyond 100 GeV. This makes them the most luminous BL Lacs ever detected and rates them among the most powerful accelerators in the Universe. We plan to observe 3 extreme BL Lacs simultaneously with XMM-Newton, GROND and Swift. This will provide unprecedented coverage of the synchrotron peak from IR to hard X-ray allowing us: to understand the nature and the energetic of these objects, to answer long-standing questions on the blazar sequence and to use them as probes of the EBL.

  16. 77 FR 12910 - Surety Companies Acceptable on Federal Bonds-Name Change: White Mountains Reinsurance Company of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ..., published July 1, 2011, at 76 FR 38892. FOR FURTHER INFORMATION CONTACT: Surety Bond Branch at (202) 874-6850. SUPPLEMENTARY INFORMATION: Notice is hereby given that White Mountains Reinsurance Company of... Fiscal Service Surety Companies Acceptable on Federal Bonds--Name Change: White Mountains...

  17. 78 FR 35360 - Surety Companies Acceptable on Federal Bonds: Name Change-Allied World Reinsurance Company (NAIC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

    ..., published July 2, 2012, at 77 FR 39322. FOR FURTHER INFORMATION CONTACT: Surety Bond Branch at (202) 874-6850. SUPPLEMENTARY INFORMATION: Notice is hereby given that Allied World Reinsurance Company (NAIC... Fiscal Service Surety Companies Acceptable on Federal Bonds: Name Change--Allied World...

  18. Synthesis of tetravalent LacNAc-glycoclusters as high-affinity cross-linker against Erythrina cristagalli agglutinin.

    PubMed

    Ogata, Makoto; Chuma, Yasushi; Yasumoto, Yoshinori; Onoda, Takashi; Umemura, Myco; Usui, Taichi; Park, Enoch Y

    2016-01-01

    Four kinds of tetravalent double-headed glycoclusters [(LacNAc)4-DHGs] were designed with linkers of varying lengths consisting of alkanedioic carboxyamido groups (C6, C12, C18 and C24) between two bi-antennary LacNAc-glycosides. These glycoclusters served as high-affinity cross-linking ligands for the LacNAc-binding lectin Erythrina cristagalli agglutinin (ECA). The binding activity and cross-linking between each ligand and ECA were characterized by a hemagglutination inhibition (HI) assay, isothermal titration calorimetry (ITC), a quantitative precipitation assay and dynamic light scattering (DLS). For the precipitation assay and DLS measurement, the synthesized (LacNAc)4-DHGs were found to be capable of binding and precipitating the ECA as multivalent ligands. ITC analysis indicated the binding of (LacNAc)4-DHGs was driven by a favorable enthalpy change. Furthermore, the entropy penalty from binding (LacNAc)4-DHGs clearly decreased in a spacer length-dependent manner. The binding affinities of flexible (LacNAc)4-DHGs (C18 and C24) with long spacers were found to be more favorable than those of the clusters having short spacers (C6 and C12). These results were supported by molecular dynamics simulations with explicit water molecules for the tetravalent glycoclusters with ECA. We concluded that the subtle modification in the epitope-presenting scaffolds exerts the significant effect in the recognition efficiency involved in the LacNAc moieties by ECA. PMID:26672510

  19. Modification of natural matrix lac-bagasse for matrix composite films

    NASA Astrophysics Data System (ADS)

    Nurhayati, Nanik Dwi; Widjaya, Karna; Triyono

    2016-02-01

    Material technology continues to be developed in order to a material that is more efficient with composite technology is a combination of two or more materials to obtain the desired material properties. The objective of this research was to modification and characterize the natural matrix lac-bagasse as composite films. The first step, natural matrix lac was changed from solid to liquid using an ethanol as a solvent so the matrix homogenly. Natural matrix lac was modified by adding citric acid with concentration variation. Secondly, the bagasse delignification using acid hydrolysis method. The composite films natural matrix lac-bagasse were prepared with optimum modified the addition citric acid 5% (v/v) and delignification bagasse optimum at 1,5% (v/v) in hot press at 80°C 6 Kg/cm-1. Thirdly, composite films without and with modification were characterized functional group analysis using FTIR spectrophotometer and mechanical properties using Universal Testing Machine. The result of research showed natural matrix lac can be modified by reaction with citric acid. FTIR spectra showed without and with modification had functional groups wide absorption 3448 cm-1 group -OH, C=O ester strong on 1712 cm-1 and the methylene group -CH2 on absorption 1465 cm-1. The mechanical properties showed tensile strength 0,55 MPa and elongation at break of 0,95 %. So that composite films natural matrix lac can be made with reinforcement bagasse for material application.

  20. Multiple LacI-mediated loops revealed by Bayesian statistics and tethered particle motion

    PubMed Central

    Johnson, Stephanie; van de Meent, Jan-Willem; Phillips, Rob; Wiggins, Chris H.; Lindén, Martin

    2014-01-01

    The bacterial transcription factor LacI loops DNA by binding to two separate locations on the DNA simultaneously. Despite being one of the best-studied model systems for transcriptional regulation, the number and conformations of loop structures accessible to LacI remain unclear, though the importance of multiple coexisting loops has been implicated in interactions between LacI and other cellular regulators of gene expression. To probe this issue, we have developed a new analysis method for tethered particle motion, a versatile and commonly used in vitro single-molecule technique. Our method, vbTPM, performs variational Bayesian inference in hidden Markov models. It learns the number of distinct states (i.e. DNA–protein conformations) directly from tethered particle motion data with better resolution than existing methods, while easily correcting for common experimental artifacts. Studying short (roughly 100 bp) LacI-mediated loops, we provide evidence for three distinct loop structures, more than previously reported in single-molecule studies. Moreover, our results confirm that changes in LacI conformation and DNA-binding topology both contribute to the repertoire of LacI-mediated loops formed in vitro, and provide qualitatively new input for models of looping and transcriptional regulation. We expect vbTPM to be broadly useful for probing complex protein–nucleic acid interactions. PMID:25120267

  1. Depressive Symptoms Anticipate Changes in the Frequency of Alcohol Intoxication Among Low-Accepted Adolescents

    PubMed Central

    Richmond, Ashley D.; Laursen, Brett; Kerr, Margaret; Stattin, Håkan

    2015-01-01

    Objective: There is strong evidence that depression anticipates later drinking problems among adults. These associations have not been consistently documented during adolescence, perhaps because little attention has been given to individual differences in peer relationships, which are the primary setting for adolescent alcohol consumption. This study investigated associations between depressive affect and alcohol misuse as moderated by peer group acceptance. Method: A community sample of 1,048 Swedish youth provided self-reports of depressive symptoms and intoxication frequency at annual intervals across the middle school years (seventh grade: M = 13.21 years old; eighth grade: M = 14.27 years old; ninth grade: M = 15.26 years old). Peer nominations provided a measure of individual acceptance. Results: Growth curve analyses revealed differences in the extent to which initial levels of depressive symptoms predicted the slope of increase in intoxication frequency. Higher levels of depressive symptoms at the outset anticipated sharp increases in intoxication frequency from seventh to ninth grades for low-accepted youth but not for average- or high-accepted youth. Conclusions: poor peer relations and depressive affect are vulnerabilities that set the stage for escalating adolescent alcohol misuse. Across the middle school years, when most youth have their first experiences with alcohol, peer difficulties exacerbated the tendency of depressed youth to drink to excess. PMID:26098034

  2. The Changing Face of Scientific Discourse: Analysis of Genomic and Proteomic Database Usage and Acceptance.

    ERIC Educational Resources Information Center

    Brown, Cecelia

    2003-01-01

    Discusses the growth in use and acceptance of Web-based genomic and proteomic databases (GPD) in scholarly communication. Confirms the role of GPD in the scientific literature cycle, suggests GPD are a storage and retrieval mechanism for molecular biology information, and recommends that existing models of scientific communication be updated to…

  3. Domain of the Gods: Do traditional beliefs hinder public acceptance of the human role in climate change?

    NASA Astrophysics Data System (ADS)

    Donner, S.

    2008-12-01

    Public acceptance of new scientific discoveries like natural selection, plate tectonics, or the human role in climate change naturally lags behind the pace of the discoveries. In the case of climate change, unease or outright rejection of the scientific evidence for the role of human activity in climate change has been a hindrance to mitigation and adaptation efforts. This skepticism is normally attributed to everything from the quality of science education, to disinformation campaigns by representatives of the coal and gas industry, to individual resistance to behavioral change, to the nature of the modern information culture. This skepticism of scientific evidence for climate change, though often inspired by politics, economics and the particular dynamics of climate change, may actually be rooted in ancient beliefs that the climate is beyond the influence of humans. In this presentation, I will outline how the notion that humans control or influence the weather runs contrary to thousands of years of belief in a separation between the earth - the domain of man - and sky - the domain of the gods. Evidence from religious history, traditional villages in the Pacific (Fjij and Kiribati) and from public discourse in North America all indicates that the millennia-old belief in an earth-sky separation hinders people's acceptance that human activity is affecting the climate. The human role in climate change therefore represents a substantial paradigm shift, similar to the role of natural selection in human evolution. These deep roots of climate change skepticism must be factored into public climate change education efforts.

  4. Lac Courte Oreilles Energy Analysis Project

    SciTech Connect

    Leslie Isham; Denise Johnson

    2009-04-01

    The Lac Courte Oreilles Tribe applied for first step funding in 2007 and was awarded in October of that year. We wanted to perform an audit to begin fulfilling two commitments we made to our membership and resolutions that we adopted. One was the Kyoto Protocol and reduce our carbon emissions by 25% and to produce 25% of our energy by sustainable means. To complete these goals we needed to begin with first assessing what our carbon emissions are and begin taking the steps to conserve on the energy we currently use. The First Step Grant gave us the opportunity to do this. Upon funding the Energy Project was formed under the umbrella of the LCO Public Works Department and Denise Johnson was hired as the coordinator. She quickly began fulfilling the objectives of the project. Denise began by contact the LCO College and hiring interns who were able to go to each Tribal entity and perform line logging to read and document the energy used for each electrical appliance. Data was also gathered for one full year from each entity for all their utility bills (gasoline, electric, natural gas, fuel oil, etc.). Relationships were formed with the Green Team and other Green Committees in the area that could assist us in this undertaking. The Energy Task Force was of great assistance as well recommending other committees and guidance to completing our project. The data was gathered, compiled and placed into spreadsheets that would be understandable for anyone who didn't have a background in Renewable Resources. While gathering the data Denise was also looking for ways to conserve energy usage, policies changes to implement and any possible viable renewable energy resources. Changes in the social behaviors of our members and employees will require further education by workshops, energy fairs, etc.. This will be looked into and done in coordination with our schools. The renewable resources seem most feasible are wind resources as well as Bio Mass both of which need further assessment

  5. Decoupling as a mechanism of change in mindfulness and acceptance: a literature review.

    PubMed

    Levin, Michael E; Luoma, Jason B; Haeger, Jack A

    2015-11-01

    A growing body of research within the acceptance and mindfulness-based therapies suggests that these treatments may function in part by reducing or eliminating (i.e., decoupling) the normative relationships between internal experiences and other internal/overt behavior. Examples of decoupling effects found in this review include reduced relationships between urges to smoke and smoking behavior, between dysphoric mood and depressive cognitions, and between pain intensity and persistence in a painful task. A literature review identified 44 studies on acceptance and mindfulness that demonstrated decoupling effects. Overall, preliminary evidence for decoupling effects were found across a broad range of problem areas, including substance abuse, depression, eating disorders, overeating, chronic pain, anxiety, relationships, anger, avoidance behavior, and self-harm, with the strongest evidence currently available in the area of substance abuse. However, the review also notes a general lack of replication studies on decoupling effects and the need for more well-powered and controlled research testing specific decoupling hypotheses. PMID:26349756

  6. Public acceptability of government intervention to change health-related behaviours: a systematic review and narrative synthesis

    PubMed Central

    2013-01-01

    Background Governments can intervene to change health-related behaviours using various measures but are sensitive to public attitudes towards such interventions. This review describes public attitudes towards a range of policy interventions aimed at changing tobacco and alcohol use, diet, and physical activity, and the extent to which these attitudes vary with characteristics of (a) the targeted behaviour (b) the intervention and (c) the respondents. Methods We searched electronic databases and conducted a narrative synthesis of empirical studies that reported public attitudes in Europe, North America, Australia and New Zealand towards interventions relating to tobacco, alcohol, diet and physical activity. Two hundred studies met the inclusion criteria. Results Over half the studies (105/200, 53%) were conducted in North America, with the most common interventions relating to tobacco control (110/200, 55%), followed by alcohol (42/200, 21%), diet-related interventions (18/200, 9%), interventions targeting both diet and physical activity (18/200, 9%), and physical activity alone (3/200, 2%). Most studies used survey-based methods (160/200, 80%), and only ten used experimental designs. Acceptability varied as a function of: (a) the targeted behaviour, with more support observed for smoking-related interventions; (b) the type of intervention, with less intrusive interventions, those already implemented, and those targeting children and young people attracting most support; and (c) the characteristics of respondents, with support being highest in those not engaging in the targeted behaviour, and with women and older respondents being more likely to endorse more restrictive measures. Conclusions Public acceptability of government interventions to change behaviour is greatest for the least intrusive interventions, which are often the least effective, and for interventions targeting the behaviour of others, rather than the respondent him or herself. Experimental studies

  7. 78 FR 8220 - Surety Companies Acceptable on Federal Bonds-Change In Business Address and Redomestication...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-05

    ..., 2012, at 77 FR 39322. FOR FURTHER INFORMATION CONTACT: Surety Bond Branch at (202) 874-6850... changed their ``BUSINESS ADDRESS'' to ``62 Maple Avenue, Keene, NH 03431'' effective immediately....

  8. 75 FR 37881 - Surety Companies Acceptable on Federal Bonds-Change in Business Address and Redomestication...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ..., published July 1, 2009, at 74 FR 31536. FOR FURTHER INFORMATION CONTACT: Surety Bond Branch at (202) 874... Company (NAIC 24759) formally changed its ``Business Address'' to ``62 Maple Avenue, Keene, NH...

  9. Considering the Role of "Need for Cognition" in Students' Acceptance of Climate Change & Evolution

    ERIC Educational Resources Information Center

    Kudrna, Jeremy; Shore, Marta; Wassenberg, Deena

    2015-01-01

    Anthropogenic climate change (ACC) and evolution are examples of issues that are perceived differently by scientists and the general public. Within the scientific community, there are clear consensuses that human activities are increasing global temperatures (ACC) and that evolutionary mechanisms have led to the biodiversity of life on Earth…

  10. Pseudorevertants of a lac promoter mutation reveal overlapping nascent promoters.

    PubMed Central

    Karls, R; Schulz, V; Jovanovich, S B; Flynn, S; Pak, A; Reznikoff, W S

    1989-01-01

    Four pseudorevertants of a -10 region lacP mutation were isolated. Three of these mutations were found to activate nascent promoters. These mutations were: a -2 G/C----A/T change (-2A) promoting transcription at position +11, a +1 A/T----T/A change (+1T) promoting transcription initiation at position +13, and a +10 C/G----A/T change (+10A) promoting transcription initiation at a complex series of positions. The fourth mutation [a -12 T/A----A/T change (-12A)] promotes transcription initiation at -1. The promoters activated by mutations -12A, -2A and +1T resembled the canonical sigma 70 promoter sequences. The +10A promoter activity is also dependent upon the sigma 70 holoenzyme but can not be readily assigned to a specific promoter sequence. Images PMID:2499870

  11. Lac repressor: Crystallization of intact tetramer and its complexes with inducer and operator DNA

    SciTech Connect

    Pace, H.C.; Lu, P. ); Lewis, M. Smith Kline and French Labs., King of Prussia, PA )

    1990-03-01

    The intact lac repressor tetramer, which regulates expression of the lac operon in Escherichia coli, has been crystallized in the native form, with an inducer, and in a ternary complex with operator DNA and an anti-inducer. The crystals without DNA diffract to better than 3.5 {angstrom}. They belong to the monoclinic space group C2 and have cell dimensions a = 164.7 {angstrom}, b = 75.6 {angstrom}, and c = 161.2 {angstrom}, with {alpha} = {gamma} = 90{degree} and {beta} = 125.5{degree}. Cocrystals have been obtained with a number of different lac operator-related DNA fragments. The complex with a blunt-ended 16-base-pair strand yielded tetragonal bipyramids that diffract to 6.5 {angstrom}. These protein-DNA cocrystals crack upon exposure to the gratuitous inducer isopropyl {beta}-D-thiogalactoside, suggesting a conformational change in the repressor-operator complex.

  12. Changes in operant behavior of rats exposed to lead at the accepted no-effect level.

    PubMed

    Gross-Selbeck, E; Gross-Selbeck, M

    1981-11-01

    After weaning, male and female Wistar rats were fed a daily diet containing 1 g lead acetate/kg food until a level of about 20 micrograms/100 mL blood was obtained. The male rats were subjected to the different behavioral tests, whereas the females were mated to untreated males and further exposed until weaning of the offspring. Behavioral testing of the male offspring was performed between 3 and 4 months of age. General behavior of both groups was tested in the open-field task including locomotion, local movements, and emotionality. The conditioned instrumental behavior was tested in the Skinner box from simple to more complex programs. The blood-lead level was measured by flameless atomic absorption spectrometry. No behavioral changes became apparent in the open-field task and in the preliminary operant training. In the more complex programs (DRH = Differential Reinforcement of High Rates), the rats exposed to lead after weaning showed slight changes of DRH performance. By contrast, in pre- and neonatally exposed animals, DRH performance was significantly increased, although blood-lead levels had returned to normal at the time of testing. A comparison of lead effects in animals to possible effects in man is discussed in this paper, and it is concluded that lead exposure to man at doses which presently are suggested to be innocuous may result in subclinical functional changes of the central nervous system. PMID:7341050

  13. Design of the lac gene circuit revisited.

    PubMed

    Savageau, Michael A

    2011-05-01

    The lactose (lac) operon of Escherichia coli serves as the paradigm for gene regulation, not only for bacteria, but also for all biological systems from simple phage to humans. The details of the systems may differ, but the key conceptual framework remains, and the original system continues to reveal deeper insights with continued experimental and theoretical study. Nearly as long lasting in impact as the pivotal work of Jacob and Monod is the classic experiment of Novick and Weiner in which they demonstrated all-or-none gene expression in response to an artificial inducer. These results are often cited in claims that normal gene expression is in fact a discontinuous bistable phenomenon. In this paper, I review several levels of analysis of the lac system and introduce another perspective based on the construction of the system design space. These represent variations on a theme, based on a simply stated design principle, that captures the key qualitative features of the system in a largely mechanism-independent fashion. Moreover, this principle can be readily interpreted in terms of specific mechanisms to make predictions regarding monostable vs. bistable behavior. The regions of design space representing bifurcations are compared with the corresponding regions identified through bifurcation analysis. I present evidence based on biological considerations as well as modeling and analysis to suggest that induction of the lac system in its natural setting is a monostable continuously graded phenomenon. Nevertheless, it must be acknowledged that the lac stability question remains unsettled, and it undoubtedly will remain so until there are definitive experimental results. PMID:21414326

  14. Design of the lac gene circuit revisited

    PubMed Central

    Savageau, Michael A.

    2011-01-01

    The lactose (lac) operon of Escherichia coli serves as the paradigm for gene regulation, not only for bacteria, but also for all biological systems from simple phage to humans. The details of the systems may differ, but the key conceptual framework remains, and the original system continues to reveal deeper insights with continued experimental and theoretical study. Nearly as long lasting in impact as the pivotal work of Jacob and Monod is the classic experiment of Novick and Weiner in which they demonstrated all-or-none gene expression in response to an artificial inducer. These results are often cited in claims that normal gene expression is in fact a discontinuous bistable phenomenon. In this paper, I review several levels of analysis of the lac system and introduce another perspective based on the construction of the system design space. These represent variations on a theme, based on a simply stated design principle, that captures the key qualitative features of the system in a largely mechanism-independent fashion. Moreover, this principle can be readily interpreted in terms of specific mechanisms to make predictions regarding monostable vs. bistable behavior. The regions of design space representing bifurcations are compared with the corresponding regions identified through bifurcation analysis. I present evidence based on biological considerations as well as modeling and analysis to suggest that induction of the lac system in its natural setting is a monostable continuously graded phenomenon. Nevertheless, it must be acknowledged that the lac stability question remains unsettled, and it undoubtedly will remain so until there are definitive experimental results. PMID:21414326

  15. Origin of bistability in the lac Operon.

    PubMed

    Santillán, M; Mackey, M C; Zeron, E S

    2007-06-01

    Multistability is an emergent dynamic property that has been invoked to explain multiple coexisting biological states. In this work, we investigate the origin of bistability in the lac operon. To do this, we develop a mathematical model for the regulatory pathway in this system and compare the model predictions with other experimental results in which a nonmetabolizable inducer was employed. We investigate the effect of lactose metabolism using this model, and show that it greatly modifies the bistable region in the external lactose (Le) versus external glucose (Ge) parameter space. The model also predicts that lactose metabolism can cause bistability to disappear for very low Ge. We have also carried out stochastic numerical simulations of the model for several values of Ge and Le. Our results indicate that bistability can help guarantee that Escherichia coli consumes glucose and lactose in the most efficient possible way. Namely, the lac operon is induced only when there is almost no glucose in the growing medium, but if Le is high, the operon induction level increases abruptly when the levels of glucose in the environment decrease to very low values. We demonstrate that this behavior could not be obtained without bistability if the stability of the induced and uninduced states is to be preserved. Finally, we point out that the present methods and results may be useful to study the emergence of multistability in biological systems other than the lac operon. PMID:17351004

  16. Physico-chemical changes during storage and sensory acceptance of low sodium probiotic Minas cheese added with arginine.

    PubMed

    Felicio, T L; Esmerino, E A; Vidal, V A S; Cappato, L P; Garcia, R K A; Cavalcanti, R N; Freitas, M Q; Conte Junior, C A; Padilha, M C; Silva, M C; Raices, R S L; Arellano, D B; Bollini, H M A; Pollonio, M A R; Cruz, A G

    2016-04-01

    The partial substitution of sodium chloride by potassium chloride (0%, 25%, and 50%) and addition of arginine (1% w/w) in probiotic Minas cheese was investigated. Microbiological (Lactococcus lactis and Lactobacillus acidophilus counts, and functionality of the prebiotics L. acidophilus), physicochemical (pH, proteolysis, organic acids, fatty acids, and volatile profiles), rheological (uniaxial compression) and sensory (hedonic test with 100 consumers) characterizations were carried out. The sodium reduction and addition of arginine did not constitute a hurdle to lactic and probiotic bacteria survival, with presented values of about 9 log CFU/g, ranging from 7.11 to 9.21 log CFU/g, respectively. In addition, lower pH values, higher proteolysis, and a decrease in toughness, elasticity and firmness were observed, as well as an increase in lactic, citric, and acetic acid contents. In contrast, no change was observed in the fatty acid profile. With respect to the sensory acceptance, the probiotic low-sodium Minas cheese presented scores above 6.00 (liked slightly) for the attributes flavor and overall acceptance. The addition of arginine can be a potential alternative for the development of probiotic dairy products with reduced sodium content. PMID:26593536

  17. Changes in the Factors Influencing Public Acceptance of Nuclear Power Generation in Japan Since the 2011 Fukushima Daiichi Nuclear Disaster.

    PubMed

    Tsujikawa, Norifumi; Tsuchida, Shoji; Shiotani, Takamasa

    2016-01-01

    Public support for nuclear power generation has decreased in Japan since the Fukushima Daiichi nuclear accident in March 2011. This study examines how the factors influencing public acceptance of nuclear power changed after this event. The influence factors examined are perceived benefit, perceived risk, trust in the managing bodies, and pro-environmental orientation (i.e., new ecological paradigm). This study is based on cross-sectional data collected from two online nationwide surveys: one conducted in November 2009, before the nuclear accident, and the other in October 2011, after the accident. This study's target respondents were residents of Aomori, Miyagi, and Fukushima prefectures in the Tohoku region of Japan, as these areas were the epicenters of the Great East Japan Earthquake and the locations of nuclear power stations. After the accident, trust in the managing bodies was found to have a stronger influence on perceived risk, and pro-environmental orientation was found to have a stronger influence on trust in the managing bodies; however, perceived benefit had a weaker positive influence on public acceptance. We also discuss the theoretical and practical implications of these findings. PMID:26224041

  18. Induction of the lac promoter in the absence of DNA loops and the stoichiometry of induction.

    PubMed

    Oehler, Stefan; Alberti, Siegfried; Müller-Hill, Benno

    2006-01-01

    In vivo induction of the Escherichia coli lactose operon as a function of inducer concentration generates a sigmoidal curve, indicating a non-linear response. Suggested explanations for this dependence include a 2:1 inducer-repressor stoichiometry of induction, which is the currently accepted view. It is, however, known for decades that, in vitro, operator binding as a function of inducer concentration is not sigmoidal. This discrepancy between in vivo and in vitro data has so far not been resolved. We demonstrate that the in vivo non-linearity of induction is due to cooperative repression of the wild-type lac operon through DNA loop formation. In the absence of DNA loops, in vivo induction curves are hyperbolic. In the light of this result, we re-address the question of functional molecular inducer-repressor stoichiometry in induction of the lac operon. PMID:16432263

  19. Folding LacZ in the periplasm of Escherichia coli.

    PubMed

    Dwyer, Robert S; Malinverni, Juliana C; Boyd, Dana; Beckwith, Jon; Silhavy, Thomas J

    2014-09-01

    Targeted, translational LacZ fusions provided the initial support for the signal sequence hypothesis in prokaryotes and allowed for selection of the mutations that identified the Sec translocon. Many of these selections relied on the fact that expression of targeted, translational lacZ fusions like malE-lacZ and lamB-lacZ42-1 causes lethal toxicity as folded LacZ jams the translocation pore. However, there is another class of targeted LacZ fusions that do not jam the translocon. These targeted, nonjamming fusions also show toxic phenotypes that may be useful for selecting mutations in genes involved in posttranslocational protein folding and targeting; however, they have not been investigated to the same extent as their jamming counterparts. In fact, it is still unclear whether LacZ can be fully translocated in these fusions. It may be that they simply partition into the inner membrane where they can no longer participate in folding or assembly. In the present study, we systematically characterize the nonjamming fusions and determine their ultimate localization. We report that LacZ can be fully translocated into the periplasm, where it is toxic. We show that this toxicity is likely due to LacZ misfolding and that, in the absence of the periplasmic disulfide bond catalyst DsbA, LacZ folds in the periplasm. Using the novel phenotype of periplasmic β-galactosidase activity, we show that the periplasmic chaperone FkpA contributes to LacZ folding in this nonnative compartment. We propose that targeted, nonjamming LacZ fusions may be used to further study folding and targeting in the periplasm of Escherichia coli. PMID:25002543

  20. Regulatory region of the divergent Klebsiella pneumoniae lac operon.

    PubMed Central

    Buvinger, W E; Riley, M

    1985-01-01

    The chromosomal DNA that lies between the lacI and lacZ genes of Klebsiella pneumoniae constitutes a 196-base pair intercistronic region that contains regulatory sequences for both genes. The probable locations of specific regulatory elements for both lacI and lacZ genes were determined by analogy with the corresponding Escherichia coli sequences. A recombinational event in ancestral DNA evidently has inverted the transcriptional direction of lacI in K. pneumoniae relative to the transcriptional direction of lacI in E. coli. One end of the inversion was located within a 19-base pair sequence in the K. pneumoniae regulatory region. Sequences partially homologous to these 19 base pairs were found in two locations on either side of the E. coli lacI gene. The nucleotide sequence of the lac regulatory region in K. pneumoniae exhibits more than one possibility for folded tertiary structures. The spatial relationships of transcriptional binding sites differ in two possible structures. Associations of regulatory and transcriptional proteins with the DNA might affect conformation of the regulatory sequences and, as a consequence, transcription of the lac genes. PMID:3897197

  1. High-Resolution Specificity from DNA Sequencing Highlights Alternative Modes of Lac Repressor Binding

    PubMed Central

    Zuo, Zheng; Stormo, Gary D.

    2014-01-01

    Knowing the specificity of transcription factors is critical to understanding regulatory networks in cells. The lac repressor–operator system has been studied for many years, but not with high-throughput methods capable of determining specificity comprehensively. Details of its binding interaction and its selection of an asymmetric binding site have been controversial. We employed a new method to accurately determine relative binding affinities to thousands of sequences simultaneously, requiring only sequencing of bound and unbound fractions. An analysis of 2560 different DNA sequence variants, including both base changes and variations in operator length, provides a detailed view of lac repressor sequence specificity. We find that the protein can bind with nearly equal affinities to operators of three different lengths, but the sequence preference changes depending on the length, demonstrating alternative modes of interaction between the protein and DNA. The wild-type operator has an odd length, causing the two monomers to bind in alternative modes, making the asymmetric operator the preferred binding site. We tested two other members of the LacI/GalR protein family and find that neither can bind with high affinity to sites with alternative lengths or shows evidence of alternative binding modes. A further comparison with known and predicted motifs suggests that the lac repressor may be unique in this ability and that this may contribute to its selection. PMID:25209146

  2. High-resolution specificity from DNA sequencing highlights alternative modes of Lac repressor binding.

    PubMed

    Zuo, Zheng; Stormo, Gary D

    2014-11-01

    Knowing the specificity of transcription factors is critical to understanding regulatory networks in cells. The lac repressor-operator system has been studied for many years, but not with high-throughput methods capable of determining specificity comprehensively. Details of its binding interaction and its selection of an asymmetric binding site have been controversial. We employed a new method to accurately determine relative binding affinities to thousands of sequences simultaneously, requiring only sequencing of bound and unbound fractions. An analysis of 2560 different DNA sequence variants, including both base changes and variations in operator length, provides a detailed view of lac repressor sequence specificity. We find that the protein can bind with nearly equal affinities to operators of three different lengths, but the sequence preference changes depending on the length, demonstrating alternative modes of interaction between the protein and DNA. The wild-type operator has an odd length, causing the two monomers to bind in alternative modes, making the asymmetric operator the preferred binding site. We tested two other members of the LacI/GalR protein family and find that neither can bind with high affinity to sites with alternative lengths or shows evidence of alternative binding modes. A further comparison with known and predicted motifs suggests that the lac repressor may be unique in this ability and that this may contribute to its selection. PMID:25209146

  3. Changes in Sleep Problems and Psychological Flexibility following Interdisciplinary Acceptance and Commitment Therapy for Chronic Pain: An Observational Cohort Study

    PubMed Central

    Daly-Eichenhardt, Aisling; Scott, Whitney; Howard-Jones, Matthew; Nicolaou, Thaleia; McCracken, Lance M.

    2016-01-01

    Aims: Cognitive and behavioral treatments (CBT) for sleep problems and chronic pain have shown good results, although these results could improve. More recent developments based on the psychological flexibility model, the model underlying Acceptance and Commitment Therapy (ACT) may offer a useful addition to traditional CBT. The aim of this study was to examine whether an ACT-based treatment for chronic pain is associated with improved sleep. Secondly, we examined the associations between changes on measures of psychological flexibility and sleep-related outcomes. Methods: The study used an observational cohort methodology. Participants were 252 patients (73.8% female) attending a 4-week, interdisciplinary, pain management program in London, United Kingdom. Participants completed standard self-report measures of pain and functioning, sleep outcomes, and processes of psychological flexibility. Pre- to post-treatment, and pre-treatment to follow-up measures were examined for statistically significant differences using paired samples t-tests. Secondarily, hierarchical multiple regression analyses were conducted to examine change in process measures in relation to change in treatment outcome. Results: Participants showed statistically significant improvements (all p < 0.001) at post-treatment on measures of insomnia severity (d = 0.45), sleep interference (d = 0.61), and sleep efficiency (d = 0.32). Significant improvements in insomnia severity and sleep interference were also observed at 9-month follow up. Small to medium effect sizes were observed across the sleep outcomes. Statistically significant changes were also observed on measures of psychological flexibility, and these improvements were significantly associated with improvements on sleep-related outcomes, independently contributing up to 19% of unique variance. Conclusion: This study supports the potential usefulness of ACT-based treatments for chronic pain for addressing co-occurring sleep difficulties

  4. Weak operator binding enhances simulated Lac repressor-mediated DNA looping.

    PubMed

    Colasanti, Andrew V; Grosner, Michael A; Perez, Pamela J; Clauvelin, Nicolas; Lu, Xiang-Jun; Olson, Wilma K

    2013-12-01

    The 50th anniversary of Biopolymers coincides closely with the like celebration of the discovery of the Escherichia coli (lac) lactose operon, a classic genetic system long used to illustrate the influence of biomolecular structure on function. The looping of DNA induced by the binding of the Lac repressor protein to sequentially distant operator sites on DNA continues to serve as a paradigm for understanding long-range genomic communication. Advances in analyses of DNA structures and in incorporation of proteins in computer simulations of DNA looping allow us to address long-standing questions about the role of protein-mediated DNA loop formation in transcriptional control. Here we report insights gained from studies of the sequence-dependent contributions of the natural lac operators to Lac repressor-mediated DNA looping. Novel superposition of the ensembles of protein-bound operator structures derived from NMR measurements reveals variations in DNA folding missed in conventional structural alignments. The changes in folding affect the predicted ease with which the repressor induces loop formation and the ways that DNA closes between the protein headpieces. The peeling of the auxiliary operators away from the repressor enhances the formation of loops with the 92-bp wildtype spacing and hints of a structural reason behind their weak binding. PMID:23818216

  5. Gamma-ray luminosity function of BL Lac objects

    NASA Astrophysics Data System (ADS)

    Zeng, Houdun; Yan, Dahai; Zhang, Li

    2014-06-01

    The gamma-ray luminosity function (GLF) of BL Lac objects is constructed by using a sample of BL Lac objects with redshifts selected from the Second LAT AGN catalog. The GLFs of BL Lacs in the frame of the pure density evolution (PDE), the pure luminosity evolution (PLE), and the luminosity-dependent density (LDDE) models are determined by using the Markov Chain Monte Carlo (MCMC) technique, respectively. Our results suggest that the PDE model can give best description for BL Lac GLF based on the combination of constraints of model parameters and good fits to the observed data of Fermi-Large Area Telescope (LAT) BL Lacs, but other two models (PLE and LDDE) cannot be excluded. Based on our constructed GLFs, the contribution to the extragalactic diffuse gamma-ray background (EGRB) from BL Lacs is estimated, and ˜1-5 per cent of the EGRB in the 0.1-100 GeV band is found to come from unresolved BL Lacs (including the cascade emission). In addition, it is found that the BL Lac GLF is very different from flat spectrum radio quasar GLF and then the contribution of blazars to the EGRB should be estimated separately.

  6. The lactose transporter in Leuconostoc lactis is a new member of the LacS subfamily of galactoside-pentose-hexuronide translocators.

    PubMed Central

    Vaughan, E E; David, S; de Vos, W M

    1996-01-01

    The gene encoding the lactose transport protein (lacS) of Leuconostoc lactis NZ6009 has been cloned from its native lactose plasmid, pNZ63, by functional complementation of lactose permease-deficient Escherichia coli mutants. Nucleotide sequence analysis revealed an open reading frame with the capacity to encode a protein of 639 amino acids which had limited but significant identity to the lactose transport carriers (LacS) of Streptococcus thermophilus (34.5%) and Lactobacillus bulgaricus (35.6%). This similarity was present both in the amino-terminal hydrophobic carrier domain, which is homologous to the E. coli melibiose transporter, and in the carboxy-terminal enzyme IIA-like regulatory domain. The flanking regions of DNA surrounding lacS were also sequenced. Preceding the lacS gene was a small open reading frame in the same orientation encoding a deduced 95-amino-acid protein with a sequence similar to the amino-terminal portion of beta-galactosidase I from Bacillus stearothermophilus. The lacS gene was separated from the downstream beta-galactosidase genes (lacLM) by 2 kb of DNA containing an IS3-like insertion sequence, which is a novel arrangement for lac genes in comparison with that in other lactic acid bacteria. The lacS gene was cloned in an E. coli-Streptococcus shuttle vector and was expressed both in a lacS deletion derivative of S. thermophilus and in a pNZ63-cured strain, L. lactis NZ6091. The role of the LacS protein was confirmed by uptake assays in which substantial uptake of radiolabeled lactose or galactose was observed with L. lactis or S. thermophilus plasmids harboring an intact lacS gene. Furthermore, galactose uptake was observed in NZ6091, suggesting the presence of at least one more transport system for galactose in L. lactis. PMID:8633855

  7. Intranight Variability During the 1997 Outburst of BL Lac

    NASA Astrophysics Data System (ADS)

    Clements, Sandra D.; Carini, Michael T.; Noble, John C.

    1998-02-01

    The blazar BL Lac underwent a major outburst this summer. To search for intranight variability during the outburst, observations of BL Lac were made with the 30 inch telescope at the University of Florida's Rosemary Hill Observatory. During ten nights in July, nearly 300 CCD observations were made. BL Lac was seen to vary by more than 1.5 magnitudes over those ten nights. Substantial intranight variability was also observed. For example, on July 29, BL Lac increased in brightness by more than 0.5 magnitude in less than 2.5 hours. The observations of BL Lac taken in July are reported here and discussed in relation to the models intended to explain intranight variability.

  8. Evidence that selected amplification of a bacterial lac frameshift allele stimulates Lac(+) reversion (adaptive mutation) with or without general hypermutability.

    PubMed Central

    Slechta, E Susan; Liu, Jing; Andersson, Dan I; Roth, John R

    2002-01-01

    In the genetic system of Cairns and Foster, a nongrowing population of an E. coli lac frameshift mutant appears to specifically accumulate Lac(+) revertants when starved on medium including lactose (adaptive mutation). This behavior has been attributed to stress-induced general mutagenesis in a subpopulation of starved cells (the hypermutable state model). We have suggested that, on the contrary, stress has no direct effect on mutability but favors only growth of cells that amplify their leaky mutant lac region (the amplification mutagenesis model). Selection enhances reversion primarily by increasing the mutant lac copy number within each developing clone on the selection plate. The observed general mutagenesis is attributed to a side effect of growth with an amplification-induction of SOS by DNA fragments released from a tandem array of lac copies. Here we show that the S. enterica version of the Cairns system shows SOS-dependent general mutagenesis and behaves in every way like the original E. coli system. In both systems, lac revertants are mutagenized during selection. Eliminating the 35-fold increase in mutation rate reduces revertant number only 2- to 4-fold. This discrepancy is due to continued growth of amplification cells until some clones manage to revert without mutagenesis solely by increasing their lac copy number. Reversion in the absence of mutagenesis is still dependent on RecA function, as expected if it depends on lac amplification (a recombination-dependent process). These observations support the amplification mutagenesis model. PMID:12136002

  9. Molecular phylogeny and biogeography of lac insects (Hemiptera: Kerriidae) inferred from nuclear and mitochondrial gene sequences.

    PubMed

    Chen, Hang; Chen, Xiaoming; Feng, Ying; Yang, Hui; He, Rui; Zhang, Wenfeng; Yang, Zixiang

    2013-10-01

    Lac insects are commercial scale insects with high economic value. The combined molecular phylogeny of 20 lac insect populations was generated using elongation factor 1 alpha, mitochondrial cytochrome c oxidase subunit I and the small subunit ribosomal RNA gene loci. The 20 populations of lac insects clustered into four distinct clades supported by high bootstrap values in maximum parsimony, maximum likelihood and Bayesian analyses. Clade A at the base of the dendrogram comprises Kerria ruralis and two populations of Kerria lacca and is the branch with most primitive species. Clade B includes K. lacca, Kerria sindica and the three populations P, V and Z from India. They clustered with high bootstrap support and have evolved later than those in Clade A. The three unidentified populations P, V and Z exhibited a close relationship with K. lacca and are the same species. In Clade C, three populations of Kerria yunnanensis (Ym, Yj and Yl), population Ys from Thailand and population H from India clustered as a group, in which population H clustered with Ym with 100 % bootstrap in all three analysis methods. In Clade D, Kerria chinensis, Kerria pusana and three populations of K. yunnanensis clustered together with strong support, and are located in the upper branches of the dendrogram and are recently evolved taxa. The majority of populations from the Indian subcontinent clade are more closely related to outgroup taxa from the primitive family Pseudococcidae, as compared to the Eurasian populations. Phylogenetic analysis reveals that the Indian subcontinent is the centre of original of lac insects which have translocated to the Eurasian Continent. Based on the theory of continental drift and existing fossil records, it is suggested that lac insect evolved from ancient scale insects during the late Cretaceous period when the Indian subcontinent drifted towards the Eurasian Continent. Changes in the global environment have impacted on the distribution and evolution of lac

  10. Natural LacI from E. coli yields faster response and higher level of expression than the LVA-tagged LacI.

    PubMed

    Andreassen, Patrick Rosendahl; Fredberg, Sofie; Horan, Mattias; Knudsen, Maria Højberg; Jacobsen, Kirstine; Kjær, Andreas; Krogh, Thøger Jensen; Kronborg, Tina; Mattsson, Nicky Cordua; Schmidt, Sissel Ida; Wille, Heidi; Andersen, Ann

    2014-12-19

    The lac promoter is one of the most commonly used promoters for expression control of recombinant genes in E. coli. In the absence of galactosides, the lac promoter is repressed by its repressor protein LacI. Since the lac promoter is regulated by a repressor, overexpression of LacI is necessary for regulation when the promoter is introduced on a high-copy plasmid. For that purpose, a modified variant of LacI, a LVA-tagged LacI, was submitted to the Registry of Standard Biological Parts and has been used for more than 500 constructs since then. We have found, however, that natural LacI is superior to the LVA-tagged LacI as controller of expression. PMID:25524095

  11. DNA supercoiling, a critical signal regulating the basal expression of the lac operon in Escherichia coli

    PubMed Central

    Fulcrand, Geraldine; Dages, Samantha; Zhi, Xiaoduo; Chapagain, Prem; Gerstman, Bernard S.; Dunlap, David; Leng, Fenfei

    2016-01-01

    Escherichia coli lac repressor (LacI) is a paradigmatic transcriptional factor that controls the expression of lacZYA in the lac operon. This tetrameric protein specifically binds to the O1, O2 and O3 operators of the lac operon and forms a DNA loop to repress transcription from the adjacent lac promoter. In this article, we demonstrate that upon binding to the O1 and O2 operators at their native positions LacI constrains three (−) supercoils within the 401-bp DNA loop of the lac promoter and forms a topological barrier. The stability of LacI-mediated DNA topological barriers is directly proportional to its DNA binding affinity. However, we find that DNA supercoiling modulates the basal expression from the lac operon in E. coli. Our results are consistent with the hypothesis that LacI functions as a topological barrier to constrain free, unconstrained (−) supercoils within the 401-bp DNA loop of the lac promoter. These constrained (−) supercoils enhance LacI’s DNA-binding affinity and thereby the repression of the promoter. Thus, LacI binding is superhelically modulated to control the expression of lacZYA in the lac operon under varying growth conditions. PMID:26763930

  12. DNA supercoiling, a critical signal regulating the basal expression of the lac operon in Escherichia coli.

    PubMed

    Fulcrand, Geraldine; Dages, Samantha; Zhi, Xiaoduo; Chapagain, Prem; Gerstman, Bernard S; Dunlap, David; Leng, Fenfei

    2016-01-01

    Escherichia coli lac repressor (LacI) is a paradigmatic transcriptional factor that controls the expression of lacZYA in the lac operon. This tetrameric protein specifically binds to the O1, O2 and O3 operators of the lac operon and forms a DNA loop to repress transcription from the adjacent lac promoter. In this article, we demonstrate that upon binding to the O1 and O2 operators at their native positions LacI constrains three (-) supercoils within the 401-bp DNA loop of the lac promoter and forms a topological barrier. The stability of LacI-mediated DNA topological barriers is directly proportional to its DNA binding affinity. However, we find that DNA supercoiling modulates the basal expression from the lac operon in E. coli. Our results are consistent with the hypothesis that LacI functions as a topological barrier to constrain free, unconstrained (-) supercoils within the 401-bp DNA loop of the lac promoter. These constrained (-) supercoils enhance LacI's DNA-binding affinity and thereby the repression of the promoter. Thus, LacI binding is superhelically modulated to control the expression of lacZYA in the lac operon under varying growth conditions. PMID:26763930

  13. The lac operon of Lactobacillus casei contains lacT, a gene coding for a protein of the Bg1G family of transcriptional antiterminators.

    PubMed Central

    Alpert, C A; Siebers, U

    1997-01-01

    The 5' region of the lac operon of Lactobacillus casei has been investigated. An open reading frame of 293 codons, designated lacT, was identified upstream of lacE. The gene product encoded by lacT is related to the family of transcriptional antiterminator proteins, which includes BglG from Escherichia coli, ArbG from Erwinia chrysanthemi, SacT, SacY, and LicT from Bacillus subtilis, and BglR from Lactococcus lactis. Amino acid sequence identities range from 35 to 24%, while similarities range from 56 to 47%. The transcriptional start site of the lac operon was identified upstream of lacT. The corresponding mRNA would contain in the 5' region a sequence with high similarity to the consensus RNA binding site of transcriptional antiterminators overlapping a sequence capable of folding into a structure that resembles a rho-independent terminator. LacT was shown to be active as an antiterminator in a B. subtilis test system using the sacB target sequence. lacT directly precedes lacEGF, the genes coding for enzyme IICB, phospho-beta-galactosidase, and enzyme IIA, and these genes are followed by a sequence that appears to encode a second rho-independent transcription terminator-like structure. Northern hybridizations with probes against lacT, lacE, and lacF revealed transcripts of similar sizes for the lac mRNAs of several L. casei strains. Since the length of the lac mRNA is just sufficient to contain lacTEGF, we conclude that the lac operon of L. casei does not contain the genes of the accessory tagatose-6-phosphate pathway as occurs in the lac operons of Lactococcus lactis, Streptococcus mutans, or Staphylococcus aureus. PMID:9045813

  14. Cost-benefit tradeoffs in engineered lac operons.

    PubMed

    Eames, Matt; Kortemme, Tanja

    2012-05-18

    Cells must balance the cost and benefit of protein expression to optimize organismal fitness. The lac operon of the bacterium Escherichia coli has been a model for quantifying the physiological impact of costly protein production and for elucidating the resulting regulatory mechanisms. We report quantitative fitness measurements in 27 redesigned operons that suggested that protein production is not the primary origin of fitness costs. Instead, we discovered that the lac permease activity, which relates linearly to cost, is the major physiological burden to the cell. These findings explain control points in the lac operon that minimize the cost of lac permease activity, not protein expression. Characterizing similar relationships in other systems will be important to map the impact of cost/benefit tradeoffs on cell physiology and regulation. PMID:22605776

  15. Functional Consequences of Exchanging Domains Between LacI and PurR are Mediated by the Intervening Linker Sequence

    PubMed Central

    Tungtur, Sudheer; Egan, Susan M.; Swint-Kruse, Liskin

    2007-01-01

    Homologue function can be differentiated by changing residues that affect binding sites or long-range interactions. LacI and PurR are two proteins that represent the LacI/GalR family (>500 members) of bacterial transcription regulators. All members have distinct DNA-binding and regulatory domains linked by ~18 amino acids. Each homologue has specificity for different DNA and regulatory effector ligands; LacI and PurR also exhibit differences in allosteric communication between DNA and effector binding sites. A comparative study of LacI and PurR suggested that alterations in the interface between the regulatory domain and linker are important for differentiating their functions. Four residues (equivalent to LacI positions 48, 55, 58, and 61) appear particularly important for creating a unique interface and were predicted to be necessary for allosteric regulation. However, nearby residues in the linker interact with DNA ligand. Thus, differences observed in interactions between linker and regulatory domain may be the cause of altered function or an effect of the two proteins binding different DNA ligands. To separate these possibilities, we created a chimeric protein with the LacI DNA-binding domain/linker and the PurR regulatory domain (LLhP). If the interface requires homologue-specific interactions in order to propagate the signal from effector binding, then LLhP repression should not be allosterically regulated by effector binding. Experiments show that LLhP is capable of repression from lacO1 and, contrary to expectation, allosteric response is intact. Further, restoring the potential for PurR-like interactions via substitutions in the LLhP linker tends to diminish repression. These effects are especially pronounced for residues 58 and 61. Clearly, binding affinity of LLhP for the lacO1 DNA site is sensitive to long-range changes in the linker. This result also raises the possibility that mutations at positions 58 and 61 co-evolved with changes in the DNA

  16. Expression of the human T-cell receptor V beta 5.3 in Escherichia coli by thermal induction of the trc promoter: nucleotide sequence of the lacIts gene.

    PubMed

    Adari, H; Andrews, B; Ford, P J; Hannig, G; Brosius, J; Makrides, S C

    1995-11-01

    We have constructed a vector, pKBi, for the high-level expression of the variable beta chain 5.3 (V beta 5.3) of the human T-cell receptor in Escherichia coli. This vector incorporates the trc promoter, a polylinker, two transcription terminators, and the tetracycline resistance gene. Furthermore, the vector contains the lacIts gene that encodes a temperature-sensitive (ts) lac repressor, thus obviating both the need to use IPTG as a transcriptional inducer, and bacterial strains that harbor either the lacI or lacIq genes. The sequence of the lacIts gene shows an open reading frame of 1,080 nucleotides encoding 360 amino acids, and differs from the lacI gene at nucleotide 559 (with reference to the first nucleotide of the start codon). This nucleotide changes from G to A, causing amino acid residue 187 to change from glycine (GGC) to serine (AGC). This mutation imparts thermal sensitivity to the lac repressor protein. This is the first time that a TCR V beta region has been expressed at high levels (up to 28 mg/liter of culture) without fusion partners. The availability of the lacIts gene for thermal induction of the trc promoter, and the presence of the tetracycline resistance gene should make the expression vector pKBi particularly attractive for the efficient production of human therapeutic proteins in bacteria. PMID:7576181

  17. Processes of Change in Acceptance and Commitment Therapy and Cognitive Therapy for Depression: A Mediation Reanalysis of Zettle and Rains

    ERIC Educational Resources Information Center

    Zettle, Robert D.; Rains, Jeanetta C.; Hayes, Steven C.

    2011-01-01

    Several articles have recently questioned the distinction between acceptance and commitment therapy (ACT) and traditional cognitive therapy (CT). This study presents a reanalysis of data from Zettle and Rains that compared 12 weeks of group CT with group ACT. For theoretical reasons, Zettle and Rains also included a modified form of CT that did…

  18. From traditional cognitive–behavioural therapy to acceptance and commitment therapy for chronic pain: a mixed-methods study of staff experiences of change

    PubMed Central

    Barker, Estelle

    2014-01-01

    Health care organizations, both large and small, frequently undergo processes of change. In fact, if health care organizations are to improve over time, they must change; this includes pain services. The purpose of the present study was to examine a process of change in treatment model within a specialty interdisciplinary pain service in the UK. This change entailed a switch from traditional cognitive–behavioural therapy to a form of cognitive–behavioural therapy called acceptance and commitment therapy. An anonymous online survey, including qualitative and quantitative components, was carried out approximately 15 months after the initial introduction of the new treatment model and methods. Fourteen out of 16 current clinical staff responded to the survey. Three themes emerged in qualitative analyses: positive engagement in change; uncertainty and discomfort; and group cohesion versus discord. Quantitative results from closed questions showed a pattern of uncertainty about the superiority of one model over the other, combined with more positive views on progress reflected, and the experience of personal benefits, from adopting the new model. The psychological flexibility model, the model behind acceptance and commitment therapy, may clarify both processes in patient behaviour and processes of staff experience and skilful treatment delivery. This integration of processes on both sides of treatment delivery may be a strength of acceptance and commitment therapy. PMID:26516541

  19. From traditional cognitive-behavioural therapy to acceptance and commitment therapy for chronic pain: a mixed-methods study of staff experiences of change.

    PubMed

    Barker, Estelle; McCracken, Lance M

    2014-08-01

    Health care organizations, both large and small, frequently undergo processes of change. In fact, if health care organizations are to improve over time, they must change; this includes pain services. The purpose of the present study was to examine a process of change in treatment model within a specialty interdisciplinary pain service in the UK. This change entailed a switch from traditional cognitive-behavioural therapy to a form of cognitive-behavioural therapy called acceptance and commitment therapy. An anonymous online survey, including qualitative and quantitative components, was carried out approximately 15 months after the initial introduction of the new treatment model and methods. Fourteen out of 16 current clinical staff responded to the survey. Three themes emerged in qualitative analyses: positive engagement in change; uncertainty and discomfort; and group cohesion versus discord. Quantitative results from closed questions showed a pattern of uncertainty about the superiority of one model over the other, combined with more positive views on progress reflected, and the experience of personal benefits, from adopting the new model. The psychological flexibility model, the model behind acceptance and commitment therapy, may clarify both processes in patient behaviour and processes of staff experience and skilful treatment delivery. This integration of processes on both sides of treatment delivery may be a strength of acceptance and commitment therapy. PMID:26516541

  20. Bistability of the lac operon during growth of Escherichia coli on lactose and lactose+glucose.

    PubMed

    Narang, Atul; Pilyugin, Sergei S

    2008-05-01

    The lac operon of Escherichia coli can exhibit bistability. Early studies showed that bistability occurs during growth on TMG/succinate and lactose+glucose, but not during growth on lactose. More recently, studies with lacGFP-transfected cells show bistability during growth on TMG/succinate, but not during growth on lactose and lactose+glucose. In the literature, these results are invariably attributed to variations in the destabilizing effect of the positive feedback generated by induction. Specifically, during growth on TMG/succinate, lac induction generates strong positive feedback because the permease stimulates the accumulation of intracellular TMG, which in turn, promotes the synthesis of even more permease. This positive feedback is attenuated during growth on lactose because hydrolysis of intracellular lactose by beta-galactosidase suppresses the stimulatory effect of the permease. It is attenuated even more during growth on lactose + glucose because glucose inhibits the uptake of lactose. But it is clear that the stabilizing effect of dilution also changes dramatically as a function of the medium composition. For instance, during growth on TMG/succinate, the dilution rate of lac permease is proportional to its activity, e, because the specific growth rate is independent of e (it is completely determined by the concentration of succinate). However, during growth on lactose, the dilution rate of the permease is proportional to e2 because the specific growth rate is proportional to the specific lactose uptake rate, which in turn, proportional to e. We show that: (a) This dependence on e2 creates such a strong stabilizing effect that bistability is virtually impossible during growth on lactose, even in the face of the intense positive feedback generated by induction. (b) This stabilizing effect is weakened during growth on lactose+glucose because the specific growth rate on glucose is independent of e, so that the dilution rate once again contains a term that

  1. On the magnetization of BL Lac jets

    NASA Astrophysics Data System (ADS)

    Tavecchio, F.; Ghisellini, G.

    2016-03-01

    The current paradigm foresees that relativistic jets are launched as magnetically dominated flows, whose magnetic power is progressively converted to kinetic power of the matter of the jet, until equipartition is reached. Therefore, at the end of the acceleration phase, the jet should still carry a substantial fraction (≈half) of its power in the form of a Poynting flux. It has been also argued that, in these conditions, the best candidate particle acceleration mechanism is efficient reconnection of magnetic field lines, for which it is predicted that magnetic field and accelerated relativistic electron energy densities are in equipartition. Through the modelling of the jet non-thermal emission, we explore if equipartition is indeed possible in BL Lac objects, i.e. low-power blazars with weak or absent broad emission lines. We find that one-zone models (for which only one region is involved in the production of the radiation we observe) the particle energy density is largely dominating (by 1-2 orders of magnitude) over the magnetic one. As a consequence, the jet kinetic power largely exceeds the magnetic power. Instead, if the jet is structured (i.e. made by a fast spine surrounded by a slower layer), the amplification of the inverse Compton emission due to the radiative interplay between the two components allows us to reproduce the emission in equipartition conditions.

  2. Chandra's First Decade Observing AR Lac

    NASA Astrophysics Data System (ADS)

    Ratzlaff, Peter; Drake, Jeremy J.; Durham, R. Nicholas; Kashyap, Vinay; Posson-Brown, Jennifer; Wargelin, Bradford J.

    2009-09-01

    X-ray observations of the eclipsing RS CVn-type binary AR Lacertae have been obtained every year from 1999 to 2008 with the Chandra High Resolution Camera imaging and spectroscopic detectors (HRC-I, HRC-S) as part of their gain and point spread function calibration. These represent the best quality data yet obtained on the long term variability of the X-ray emission of an RS CVn star, and are rendered especially valuable for the multi-epoch coverage of the AR Lac eclipses. The data are characterised by stochastic variability by factors of ˜2 on timescales of one to several ks, and by minor flaring events in which count rates are observed to be elevated by slightly larger factors. During primary eclipse, the X-ray count rate is generally observed at approximately 60% of its value outside of eclipse and during periods of relative quiescence. Little evidence for secondary eclipses is present in the data, reminiscent of earlier X-ray and EUV observations. The X-ray count rate modulation through the eclipses allow us to place an upper limit on the extent of a spherically symmetric coronae of about two stellar radii, the exact limit depending on the details of the coronal models and partition of emission between the component stars. We compare the observed Chandra count rates to earlier EUVE, EINSTEIN, EXOSAT and ROSAT observations and comment on the apparent lack of cyclic coronal activity on RS CVn-type binaries.

  3. The variable V381 Lac and its possible connection with the R CrB phenomenon

    NASA Astrophysics Data System (ADS)

    Rossi, C.; Dell'Agli, F.; Di Paola, A.; Gigoyan, K. S.; Nesci, R.

    2016-03-01

    We have performed new medium resolution spectroscopy, optical and near-infrared photometry to monitor the variability of the asymptotic giant branch (AGB) carbon star V 381 Lac. Our observations revealed rapid and deep changes in the spectrum and extreme variability in the optical and near-infrared bands. Most notably we observed the change of Na I D lines from deep absorption to emission, and the progressive growing of the [N II] doublet 6548-6584 Å emission, strongly related to the simultaneous photometric fading. V381 Lac occupies regions of Two Micron All-Sky Survey and Wide-field Infrared Survey Explorer colour-colour diagrams typical of stars with dust formation in the envelope. The general framework emerging from the observations of V381 Lac is that of a cool AGB carbon star undergoing episodes of high mass ejection and severe occultation of the stellar photosphere reminiscent of those characterizing the RCB phenomenon. Comparing the spectral energy distribution obtained with the theoretical model for AGB evolution with dust in the circumstellar envelope, we can identify V381 Lac as the descendant of a star of initial mass ˜2 M⊙, in the final AGB phases, evolved into a carbon star by repeated Third Dredge Up episodes. According to our model, the star is moderately obscured (τ10 ˜ 0.22) by dust, mainly formed by amorphous carbon (˜80 per cent) and SiC (˜20 per cent), with dust grain dimensions around ˜0.2 and 0.08 μm, respectively.

  4. Short Lesson Plan Associated with Increased Acceptance of Evolutionary Theory and Potential Change in Three Alternate Conceptions of Macroevolution in Undergraduate Students

    PubMed Central

    Abraham, Joel K.; Perez, Kathryn E.; Downey, Nicholas; Herron, Jon C.; Meir, Eli

    2012-01-01

    Undergraduates commonly harbor alternate conceptions about evolutionary biology; these alternate conceptions often persist, even after intensive instruction, and may influence acceptance of evolution. We interviewed undergraduates to explore their alternate conceptions about macroevolutionary patterns and designed a 2-h lesson plan to present evidence that life has evolved. We identified three alternate conceptions during our interviews: that newly derived traits would be more widespread in extant species than would be ancestral traits, that evolution proceeds solely by anagenesis, and that lineages must become more complex over time. We also attempted to measure changes in the alternate conceptions and levels of acceptance of evolutionary theory in biology majors and nonmajors after exposure to the lesson plan. The instrument used to assess understanding had flaws, but our results are suggestive of mixed effects: we found a reduction in the first alternate conception, no change in the second, and reinforcement of the third. We found a small, but significant, increase in undergraduate acceptance of evolutionary theory in two trials of the lesson plan (Cohen's d effect sizes of 0.51 and 0.19). These mixed results offer guidance on how to improve the lesson and show the potential of instructional approaches for influencing acceptance of evolution. PMID:22665588

  5. lac operon induction in Escherichia coli: Systematic comparison of IPTG and TMG induction and influence of the transacetylase LacA.

    PubMed

    Marbach, Anja; Bettenbrock, Katja

    2012-01-01

    Most commonly used expression systems in bacteria are based on the Escherichia coli lac promoter. Furthermore, lac operon elements are used today in systems and synthetic biology. In the majority of the cases the gratuitous inducers IPTG or TMG are used. Here we report a systematic comparison of lac promoter induction by TMG and IPTG which focuses on the aspects inducer uptake, population heterogeneity and a potential influence of the transacetylase, LacA. We provide induction curves in E. coli LJ110 and in isogenic lacY and lacA mutant strains and we show that both inducers are substrates of the lactose permease at low inducer concentrations but can also enter cells independently of lactose permease if present at higher concentrations. Using a gfp reporter strain we compared TMG and IPTG induction at single cell level and showed that bimodal induction with IPTG occurred at approximately ten-fold lower concentrations than with TMG. Furthermore, we observed that lac operon induction is influenced by the transacetylase, LacA. By comparing two Plac-gfp reporter strains with and without a lacA deletion we could show that in the lacA(+) strain the fluorescence level decreased after few hours while the fluorescence further increased in the lacA(-) strain. The results indicate that through the activity of LacA the IPTG concentration can be reduced below an inducing threshold concentration-an influence that should be considered if low inducer amounts are used. PMID:22079752

  6. Ultrafast force-clamp spectroscopy to probe lac repressor-DNA interactions

    NASA Astrophysics Data System (ADS)

    Monico, Carina; Capitanio, Marco; Belcastro, Gionata; Vanzi, Francesco; Pavone, Francesco S.

    2013-06-01

    We recently developed an ultrafast force-clamp laser trap capable to probe, under controlled force, bimolecular interactions with unprecedented temporal resolution. Here we present the technique in the framework of protein-DNA interactions, specifically on Lactose repressor protein (LacI). The high temporal resolution of the method reveals the kinetics of both short- and long-lived interactions of LacI along the DNA template (from ˜100 μs to tens of seconds), as well the dependence on force of such interaction kinetics. The two kinetically well-distinct populations of interactions observed clearly represent specific interactions with the operator sequences and a fast scanning of LacI along non-cognate DNA. These results demonstrate the effectiveness of the method to study the sequence-dependent affinity of DNA-binding proteins along the DNA and the effects of force on a wide range of interaction durations, including μs time scales not accessible to other single-molecule methods. This improvement in time resolution provides also important means of investigation on the long-puzzled mechanism of target search on DNA and possible protein conformational changes occurring upon target recognition.

  7. DNA looping increases the range of bistability in a stochastic model of the lac genetic switch.

    PubMed

    Earnest, Tyler M; Roberts, Elijah; Assaf, Michael; Dahmen, Karin; Luthey-Schulten, Zaida

    2013-04-01

    Conditions and parameters affecting the range of bistability of the lac genetic switch in Escherichia coli are examined for a model which includes DNA looping interactions with the lac repressor and a lactose analogue. This stochastic gene-mRNA-protein model of the lac switch describes DNA looping using a third transcriptional state. We exploit the fast bursting dynamics of mRNA by combining a novel geometric burst extension with the finite state projection method. This limits the number of protein/mRNA states, allowing for an accelerated search of the model's parameter space. We evaluate how the addition of the third state changes the bistability properties of the model and find a critical region of parameter space where the phenotypic switching occurs in a range seen in single molecule fluorescence studies. Stochastic simulations show induction in the looping model is preceded by a rare complete dissociation of the loop followed by an immediate burst of mRNA rather than a slower build up of mRNA as in the two-state model. The overall effect of the looped state is to allow for faster switching times while at the same time further differentiating the uninduced and induced phenotypes. Furthermore, the kinetic parameters are consistent with free energies derived from thermodynamic studies suggesting that this minimal model of DNA looping could have a broader range of application. PMID:23406725

  8. Engineering a portable riboswitch-LacP hybrid device for two-way gene regulation.

    PubMed

    Jin, Ye; Huang, Jian-Dong

    2011-10-01

    Riboswitches are RNA-based regulatory devices that mediate ligand-dependent control of gene expression. However, there has been limited success in rationally designing riboswitches. Moreover, most previous riboswitches are confined to a particular gene and only perform one-way regulation. Here, we used a library screening strategy for efficient creation of ON and OFF riboswitches of lacI on the chromosome of Escherichia coli. We then engineered a riboswitch-LacP hybrid device to achieve portable gene control in response to theophylline and IPTG. Moreover, this device regulated target expression in a 'two-way' manner: the default state of target expression was ON; the expression was switched off by adding theophylline and restored to the ON state by adding IPTG without changing growth medium. We showcased the portability and two-way regulation of this device by applying it to the small RNA CsrB and the RpoS protein. Finally, the use of the hybrid device uncovered an inhibitory role of RpoS in acetate assimilation, a function which is otherwise neglected using conventional genetic approaches. Overall, this work establishes a portable riboswitch-LacP device that achieves sequential OFF-and-ON gene regulation. The two-way control of gene expression has various potential scientific and biotechnological applications and helps reveal novel gene functions. PMID:21803790

  9. DNA looping increases the range of bistability in a stochastic model of the lac genetic switch

    NASA Astrophysics Data System (ADS)

    Earnest, Tyler M.; Roberts, Elijah; Assaf, Michael; Dahmen, Karin; Luthey-Schulten, Zaida

    2013-04-01

    Conditions and parameters affecting the range of bistability of the lac genetic switch in Escherichia coli are examined for a model which includes DNA looping interactions with the lac repressor and a lactose analogue. This stochastic gene-mRNA-protein model of the lac switch describes DNA looping using a third transcriptional state. We exploit the fast bursting dynamics of mRNA by combining a novel geometric burst extension with the finite state projection method. This limits the number of protein/mRNA states, allowing for an accelerated search of the model's parameter space. We evaluate how the addition of the third state changes the bistability properties of the model and find a critical region of parameter space where the phenotypic switching occurs in a range seen in single molecule fluorescence studies. Stochastic simulations show induction in the looping model is preceded by a rare complete dissociation of the loop followed by an immediate burst of mRNA rather than a slower build up of mRNA as in the two-state model. The overall effect of the looped state is to allow for faster switching times while at the same time further differentiating the uninduced and induced phenotypes. Furthermore, the kinetic parameters are consistent with free energies derived from thermodynamic studies suggesting that this minimal model of DNA looping could have a broader range of application.

  10. Integrated insights from simulation, experiment, and mutational analysis yield new details of LacI function.

    PubMed

    Swint-Kruse, Liskin; Zhan, Hongli; Matthews, Kathleen Shive

    2005-08-23

    Protein structural change underlies many signal transduction processes. Although end-state structures are known for various allosteric proteins, intermediates are difficult to observe. Recently, targeted molecular dynamics simulation (TMD) was used to examine the conformational transition and predict relevant intermediates for wild-type lactose repressor (LacI). A catalog of involved residues suggests that the transition of this homodimer is asymmetric and that K84 is a prominent participant in the dynamic N-subdomain interface. Previous experiments indicated that hydrophobic substitutions at position 84 engender slowed, biphasic inducer binding kinetics, which might reflect the same phenomena observed in TMD. Here, we report biochemical confirmation that DNA and inducer binding remain allosterically linked in K84A and K84L, albeit with a differential smaller than that found in wild-type LacI. Other features of these mutant proteins are consistent with an allosteric conformational shift that approximates that of the wild type. As a consequence, these repressors can be utilized to explore an unanswered question about LacI function: How many inducers (one or two per dimer) are required to diminish operator affinity? The biphasic natures of the K84L and K84A inducer association rates allow direct correlation between the two distinct inducer binding events and operator release. Indeed, the kinetics of operator release for the K84A and K84L closely parallel those for the second inducer binding event. Together with implications from previous equilibrium results for wild-type and mutant proteins, these kinetic data demonstrate that binding of two inducers per dimeric DNA binding unit is required to release the operator in these variant LacI proteins. PMID:16101304

  11. A computational study of λ-lac mutants

    NASA Astrophysics Data System (ADS)

    Werner, Maria; Aurell, Erik

    2009-12-01

    We present a comprehensive, computational study of the properties of bacteriophage λ mutants designed by Atsumi and Little (2006 Proc. Natl. Acad. Sci. 103 4558-63). These phages underwent a genetic reconstruction where Cro was replaced by a dimeric form of the Lac repressor. To clarify the theoretical characteristics of these mutants, we built a detailed thermodynamic model. The mutants all have a different genetic wiring than the wild-type λ. One group lacks regulation of PRM by the lytic protein. These mutants only exhibit the lysogenic equilibrium, with no transiently active PR. The other group lacks the negative feedback from CI. In this group, we identify a handful of bi-stable mutants, although the majority only exhibit the lysogenic equilibrium. The experimental identification of functional phages differs from our predictions. From a theoretical perspective, there is no reason why only 4 out of 900 mutants should be functional. The differences between theory and experiment can be explained in two ways. Either, the view of the λ phage as a bi-stable system needs to be revised, or the mutants have in fact not undergone a modular replacement, as intended by Atsumi and Little, but constitute instead a wider systemic change.

  12. Boolean models can explain bistability in the lac operon.

    PubMed

    Veliz-Cuba, Alan; Stigler, Brandilyn

    2011-06-01

    The lac operon in Escherichia coli has been studied extensively and is one of the earliest gene systems found to undergo both positive and negative control. The lac operon is known to exhibit bistability, in the sense that the operon is either induced or uninduced. Many dynamical models have been proposed to capture this phenomenon. While most are based on complex mathematical formulations, it has been suggested that for other gene systems network topology is sufficient to produce the desired dynamical behavior. We present a Boolean network as a discrete model for the lac operon. Our model includes the two main glucose control mechanisms of catabolite repression and inducer exclusion. We show that this Boolean model is capable of predicting the ON and OFF steady states and bistability. Further, we present a reduced model which shows that lac mRNA and lactose form the core of the lac operon, and that this reduced model exhibits the same dynamics. This work suggests that the key to model qualitative dynamics of gene systems is the topology of the network and Boolean models are well suited for this purpose. PMID:21563979

  13. Mechanism of promoter repression by Lac repressor-DNA loops.

    PubMed

    Becker, Nicole A; Peters, Justin P; Maher, L James; Lionberger, Troy A

    2013-01-01

    The Escherichia coli lactose (lac) operon encodes the first genetic switch to be discovered, and lac remains a paradigm for studying negative and positive control of gene expression. Negative control is believed to involve competition of RNA polymerase and Lac repressor for overlapping binding sites. Contributions to the local Lac repressor concentration come from free repressor and repressor delivered to the operator from remote auxiliary operators by DNA looping. Long-standing questions persist concerning the actual role of DNA looping in the mechanism of promoter repression. Here, we use experiments in living bacteria to resolve four of these questions. We show that the distance dependence of repression enhancement is comparable for upstream and downstream auxiliary operators, confirming the hypothesis that repressor concentration increase is the principal mechanism of repression loops. We find that as few as four turns of DNA can be constrained in a stable loop by Lac repressor. We show that RNA polymerase is not trapped at repressed promoters. Finally, we show that constraining a promoter in a tight DNA loop is sufficient for repression even when promoter and operator do not overlap. PMID:23143103

  14. Use of urea and glycine betaine to quantify coupled folding and probe the burial of DNA phosphates in lac repressor-lac operator binding.

    PubMed

    Hong, Jiang; Capp, Mike W; Saecker, Ruth M; Record, M Thomas

    2005-12-27

    Thermodynamic analysis of urea-biopolymer interactions and effects of urea on folding of proteins and alpha-helical peptides shows that urea interacts primarily with polar amide surface. Urea is therefore predicted to be a quantitative probe of coupled folding, remodeling, and other large-scale changes in the amount of water-accessible polar amide surface in protein processes. A parallel analysis indicates that glycine betaine [N,N,N-trimethylglycine (GB)] can be used to detect burial or exposure of anionic (carboxylate, phosphate) biopolymer surface. To test these predictions, we have investigated the effects of these solutes (0-3 m) on the formation of 1:1 complexes between lac repressor (LacI) and its symmetric operator site (SymL) at a constant KCl molality. Urea reduces the binding constant K(TO) [initial slope dlnK(TO)/dm(urea) = -1.7 +/- 0.2], and GB increases K(TO) [initial slope dlnK(TO)/dm(GB) = 2.1 +/- 0.2]. For both solutes, this derivative decreases with an increase in solute concentration. Analysis of these initial slopes predicts that (1.5 +/- 0.3) x 10(3) A2 of polar amide surface and (4.5 +/- 1.0) x 10(2) A2 of anionic surface are buried in the association process. Analysis of published structural data, together with modeling of unfolded regions of free LacI as extended chains, indicates that 1.5 x 10(3) A2 of polar amide surface and 6.3 x 10(2) A2 of anionic surface are buried in complexation. Quantitative agreement between structural and thermodynamic results is obtained for amide surface (urea); for anionic surface (GB), the experimental value is approximately 70% of the structural value. For LacI-SymL binding, two-thirds of the structurally predicted change in amide surface (1.0 x 10(3) A2) occurs outside the protein-DNA interface in protein-protein interfaces formed by folding of the hinge helices and interactions of the DNA binding domain (DBD) with the core of the repressor. Since urea interacts principally with amide surface, it is

  15. Effect of Low Salt Concentrations on Microbial Changes During Kimchi Fermentation Monitored by PCR-DGGE and Their Sensory Acceptance.

    PubMed

    Ahmadsah, Lenny S F; Min, Sung-Gi; Han, Seon-Kyeong; Hong, Yeun; Kim, Hae-Yeong

    2015-12-28

    Various salt concentrations (1.0%, 1.3%, 1.6%, 1.9%, and 2.1% labeled as sample A, B, C, D, and E, respectively) were investigated for microbial diversity, identification of Lactic Acid Bacteria (LAB) in salted kimchi cabbage, prepared under laboratory conditions. These samples were stored at 4°C for 5 weeks in proper aluminum-metalized pouch packaging with calcium hydroxide gas absorber. A culture-independent method known as polymerase chain reaction - denaturing gradient gel electrophoresis was carried out to identify LAB distributions among various salt concentration samples that had identified 2 Weissella (W. confusa and W. soli), 1 Lactobacillus (Lb. sakei), and 3 Leuconostoc (Lc. mesenteroides, Lc. lactis, and Lc. gelidum) in the overall kimchi samples. The pH, titratable acidity, viable cell counts, and coliform counts were not affected by salt variations. In order to assess sensory acceptance, the conducted sensory evaluation using a 9-point hedonic scale had revealed that samples with 1.3% salt concentration (lower than the manufacturer's regular salt concentration) was more preferred, indicating that the use of 1.3% salt concentration was acceptable in normal kimchi fermentation for its quality and safety. Despite similarities in pH, titratable acidity, viable cell counts, coliform counts, and LAB distributions among the various salt concentrations of kimchi samples, the sample with 1.3% salt concentration was shown to be the most preferred, indicating that this salt concentration was suitable in kimchi production in order to reduce salt intake through kimchi consumptions. PMID:26370801

  16. Gamma-ray observations of BL Lac objects

    NASA Technical Reports Server (NTRS)

    Hanlon, L.; McBreen, B.; OFlaherty, K.; Metcalfe, L.; Hunter, S.; Tashiro, M.; Wagner, S.; Bouchet, P.; Nicolson, G. D.; Smith, N. J.

    1997-01-01

    The results from observations of a sample of BL Lac objects by the Compton telescope (COMPTEL) and energetic gamma ray experiment telescope (EGRET) onboard the Compton Gamma Ray Observatory (CGRO) are presented. The main targets in the sample were selected on the basis of their X-ray brightness and apparent spectral hardening at hard X-ray energies. One of the targets, PKS 0521-365 was detected by EGRET, and these data are presented together with contemporaneous ground-based radio data. Subsequent X-ray observations of this source with the Advanced Satellite for Cosomology and Astrophysics (ASCA) demonstrated that, although originally classified as a BL Lac object, it is better described as a flat spectrum radio quasar. Upper limits on the gamma ray flux from all the non-detected BL lacs are presented.

  17. The disk-jet connection of Fermi 2LAC blazars

    NASA Astrophysics Data System (ADS)

    Du, L. M.; Xie, Zh. H.; Yi, T. F.; Xue, R.; Xu, Y. B.; Liu, W. G.; Wang, X. H.

    2016-07-01

    In this article, an estimator of the radiative power for blazars is proposed and is used in the study of the link between the accretion disk power and jet power. The results lend support to the disk-jet symbiosis. Since the blazars are strongly beamed sources, our results suggest that the Doppler enhancement of the sources needs to be removed to obtain physically reasonable results in the disk-jet connection study. The results after de-beaming suggest that FSRQs are accreting in the radiatively efficient regime, while the BL Lac population shows a flatter dependence between jet power and disk power, possibly due to a mixture of sources in the radiatively efficient (the broad lined BL Lacs) and inefficient (the bulk of the BL Lac population) regimes.

  18. Lack of evidence for horizontal transfer of the lac operon into Escherichia coli.

    PubMed

    Stoebel, Daniel M

    2005-03-01

    The idea that Escherichia coli gained the lac operon via horizontal transfer, allowing it to invade a new niche and form a new species, has become a paradigmatic example of bacterial nonpathogenic adaptation and speciation catalyzed by horizontal transfer. Surprisingly, empirical evidence for this event is essentially nonexistent. To see whether horizontal transfer occurred, I compared a phylogeny of 14 Enterobacteriaceae based on two housekeeping genes to a phylogeny of a part of their lac operon. Although several species in this clade appear to have acquired some or all of the operon via horizontal transfer, there is no evidence of horizontal transfer into E. coli. It is not clear whether the horizontal transfer events for which there is evidence were adaptive because those species which have acquired the operon are not thought to live in high lactose environments. I propose that vertical transmission from the common ancestor of the Enterobacteriaceae, with subsequent loss of these genes in many species can explain much of the patchy distribution of lactose use in this clade. Finally, I argue that we need new, well-supported examples of horizontal transfer spurring niche expansion and speciation, particularly in nonpathogenic cases, before we can accept claims that horizontal transfer is a hallmark of bacterial adaptation. PMID:15563718

  19. Apsidal motion in eclipsing binaries: FT Ori and MZ Lac

    NASA Astrophysics Data System (ADS)

    Bulut, A.; Bulut, I.; ćiçek, C.; Erdem, A.

    2016-03-01

    In this study, the apsidal motion analysis of two eccentric eclipsing binaries, FT Ori (P = 3.150 days, e = 0.397) and MZ Lac (P = 3.158 days, e = 0.399), have been presented. Their O - C diagrams were studied using all reliable times of minima found in the literature and new values for the elements of the apsidal motion for two systems have been computed. We found long periods of apsidal motion of 538 ± 12 years and 424 ± 6 years for FT Ori and MZ Lac, respectively.

  20. Dynamic model of gene regulation for the lac operon

    NASA Astrophysics Data System (ADS)

    Angelova, Maia; Ben-Halim, Asma

    2011-03-01

    Gene regulatory network is a collection of DNA which interact with each other and with other matter in the cell. The lac operon is an example of a relatively simple genetic network and is one of the best-studied structures in the Escherichia coli bacteria. In this work we consider a deterministic model of the lac operon with a noise term, representing the stochastic nature of the regulation. The model is written in terms of a system of simultaneous first order differential equations with delays. We investigate an analytical and numerical solution and analyse the range of values for the parameters corresponding to a stable solution.

  1. Structural explanation for allolactose (lac operon inducer) synthesis by lacZ β-galactosidase and the evolutionary relationship between allolactose synthesis and the lac repressor.

    PubMed

    Wheatley, Robert W; Lo, Summie; Jancewicz, Larisa J; Dugdale, Megan L; Huber, Reuben E

    2013-05-01

    β-Galactosidase (lacZ) has bifunctional activity. It hydrolyzes lactose to galactose and glucose and catalyzes the intramolecular isomerization of lactose to allolactose, the lac operon inducer. β-Galactosidase promotes the isomerization by means of an acceptor site that binds glucose after its cleavage from lactose and thus delays its exit from the site. However, because of its relatively low affinity for glucose, details of this site have remained elusive. We present structural data mapping the glucose site based on a substituted enzyme (G794A-β-galactosidase) that traps allolactose. Various lines of evidence indicate that the glucose of the trapped allolactose is in the acceptor position. The evidence includes structures with Bis-Tris (2,2-bis(hydroxymethyl)-2,2',2″-nitrilotriethanol) and L-ribose in the site and kinetic binding studies with substituted β-galactosidases. The site is composed of Asn-102, His-418, Lys-517, Ser-796, Glu-797, and Trp-999. Ser-796 and Glu-797 are part of a loop (residues 795-803) that closes over the active site. This loop appears essential for the bifunctional nature of the enzyme because it helps form the glucose binding site. In addition, because the loop is mobile, glucose binding is transient, allowing the release of some glucose. Bioinformatics studies showed that the residues important for interacting with glucose are only conserved in a subset of related enzymes. Thus, intramolecular isomerization is not a universal feature of β-galactosidases. Genomic analyses indicated that lac repressors were co-selected only within the conserved subset. This shows that the glucose binding site of β-galactosidase played an important role in lac operon evolution. PMID:23486479

  2. Lac du Flambeau Band of Lake Superior Chippewa Indians Strategic Energy Plan

    SciTech Connect

    Bryan Hoover

    2009-11-16

    This plan discusses the current energy use on the Lac du Flambeau Reservation, the current status of the Tribe's energy program, as well as the issues and concerns with energy on the reservation. This plan also identifies and outlines energy opportunities, goals, and objectives for the Tribe to accomplish. The overall goal of this plan is to address the energy situation of the reservation in a holistic manner for the maximum benefit to the Tribe. This plan is an evolving document that will be re-evaluated as the Tribe's energy situation changes.

  3. [Monopolization of honeydew sources by Crematogaster macaoensis and its effects on lac production].

    PubMed

    Wang, Si-Ming; Chen, You-Qing; Lu, Zhi-Xing; Liu, Chun-Ju; Zhang, Wei; Guo, Zu-Xue

    2011-01-01

    From October 2008 to May 2010, an investigation was made in a lac plantation in Yayi region of Mojiang County, Yunnan Province, China, aimed to understand the behavior of the monopolization of honeydew sources by ant Crematogaster macaoensis, and its effects on the sex ratio, mortality, fecundity, and lac production of Yunnan lac insect Kerria yunnanensis. The results showed that C. macaoensis fed and monopolized the honeydews around the clock during the whole life cycle of K. yunnanensis on the stick-lac, and the average number of visiting C. macaoensis ranged from 16.8 +/- 2.3 to 39.3 +/- 10.0 per 10 cm length of the stick-lac. C. macaoensis constructed shelters to prevent other animals from visiting the lac insect. C. macaoensis monopolization reduced the lac production of individual K. yunnanensi significantly, but had no significant effects on the lac production of whole lac insect colony. In addition, C. macaoensis monopolization reduced the mortality of K. yunnanensis significantly, and increased the percentage of K. yunnanensis females and the adult female fecundity. It was concluded that ant monopolization of the lac insect honeydew seemed to be beneficial to the lac production by the Yunnan lac insect. PMID:21548313

  4. Structure and bonding of superconducting LaC2.

    PubMed

    Babizhetskyy, V; Jepsen, O; Kremer, R K; Simon, A; Ouladdiaf, B; Stolovits, A

    2014-01-15

    We have synthesized polycrystalline samples of superconducting LaC2 and investigated them by x-ray and neutron powder diffraction, magnetic susceptibility and heat capacity measurements. Depending on the preparation conditions we find superconductivity below ~1.8 K. A comparison of the superconducting anomaly in the heat capacity with theoretical predictions indicates LaC2 to be a weak-coupling BCS-type superconductor. Evidence for a structural phase transition has not been found from the neutron powder diffraction experiments carried out down to 4 K. A negative thermal expansion of the c lattice parameter was observed below ~50 K. The electronic structure of LaC2 has been calculated ab initio and it is compared with that of YC2. The carbon-carbon distance of LaC2 has been determined from the neutron powder diffraction experiments and it is compared and discussed with respect to those observed in other superconducting binary and ternary La and Y carbides and carbide halides. PMID:24304506

  5. LUNSORT list of lunar orbiter data by LAC area

    NASA Technical Reports Server (NTRS)

    Hixon, S.

    1976-01-01

    Lunar orbiter (missions 1-5) photographic data are listed sequentially according to the number (1 to 147) LAC (Lunar Aeronautical Chart) areas by use of a computer program called LUNSORT. This listing, as well as a similar one from Apollo would simplify the task of identifying images of a given Lunar area. Instructions and sample case are included.

  6. Development of a Lac Operon Concept Inventory (LOCI)

    PubMed Central

    Stefanski, Katherine M.; Gardner, Grant E.; Seipelt-Thiemann, Rebecca L.

    2016-01-01

    Concept inventories (CIs) are valuable tools for educators that assess student achievement and identify misconceptions held by students. Results of student responses can be used to adjust or develop new instructional methods for a given topic. The regulation of gene expression in both prokaryotes and eukaryotes is an important concept in genetics and one that is particularly challenging for undergraduate students. As part of a larger study examining instructional methods related to gene regulation, the authors developed a 12-item CI assessing student knowledge of the lac operon. Using an established protocol, the authors wrote open-ended questions and conducted in-class testing with undergraduate microbiology and genetics students to discover common errors made by students about the lac operon and to determine aspects of item validity. Using these results, we constructed a 12-item multiple-choice lac operon CI called the Lac Operon Concept Inventory (LOCI), The LOCI was reviewed by two experts in the field for content validity. The LOCI underwent item analysis and was assessed for reliability with a sample of undergraduate genetics students (n = 115). The data obtained were found to be valid and reliable (coefficient alpha = 0.994) with adequate discriminatory power and item difficulty. PMID:27252300

  7. Development of a Lac Operon Concept Inventory (LOCI).

    PubMed

    Stefanski, Katherine M; Gardner, Grant E; Seipelt-Thiemann, Rebecca L

    2016-01-01

    Concept inventories (CIs) are valuable tools for educators that assess student achievement and identify misconceptions held by students. Results of student responses can be used to adjust or develop new instructional methods for a given topic. The regulation of gene expression in both prokaryotes and eukaryotes is an important concept in genetics and one that is particularly challenging for undergraduate students. As part of a larger study examining instructional methods related to gene regulation, the authors developed a 12-item CI assessing student knowledge of the lac operon. Using an established protocol, the authors wrote open-ended questions and conducted in-class testing with undergraduate microbiology and genetics students to discover common errors made by students about the lac operon and to determine aspects of item validity. Using these results, we constructed a 12-item multiple-choice lac operon CI called the Lac Operon Concept Inventory (LOCI), The LOCI was reviewed by two experts in the field for content validity. The LOCI underwent item analysis and was assessed for reliability with a sample of undergraduate genetics students (n = 115). The data obtained were found to be valid and reliable (coefficient alpha = 0.994) with adequate discriminatory power and item difficulty. PMID:27252300

  8. Are some BL Lacs artefacts of gravitational lensing?

    PubMed

    Ostriker, J P; Vietri, M

    1990-03-01

    WE suggested in 1985 that a significant fraction of BL Lacertae objects, a kind of lineless quasar, seen in nearby galaxies are in fact images, gravitationally lensed and substantially amplified by stars in the nearby galaxy, of background objects, optically violent variable (OVV) quasars at redshifts z > 1 (ref. 1). This hypothesis was made on the basis of certain general similarities between BL Lacs and O Ws, but for two recently observed BL Lacs(2,3) a strong case can be made that the accompanying elliptical galaxy is a foreground object. In addition, we argue that the distribution of BL Lac redshifts is hard to understand without gravitational lensing, unless we happen to be at a very local maximum of the spatial cosmic distribution of BL Lacs. Our analysis also indicates that the galaxies whose stars are likely to act as microlenses will be found in two peaks, one nearby, with redshift 0.05-0.10, and the other near the distant quasar. PMID:18278021

  9. Phosphorylation of Streptococcus salivarius Lactose Permease (LacS) by HPr(His∼P) and HPr(Ser-P)(His∼P) and Effects on Growth

    PubMed Central

    Lessard, Christian; Cochu, Armelle; Lemay, Jean-Dominique; Roy, Denis; Vaillancourt, Katy; Frenette, Michel; Moineau, Sylvain; Vadeboncoeur, Christian

    2003-01-01

    The oral bacterium Streptococcus salivarius takes up lactose via a transporter called LacS that shares 95% identity with the LacS from Streptococcus thermophilus, a phylogenetically closely related organism. S. thermophilus releases galactose into the medium during growth on lactose. Expulsion of galactose is mediated via LacS and stimulated by phosphorylation of the transporter by HPr(His∼P), a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS). Unlike S. thermophilus, S. salivarius grew on lactose without expelling galactose and took up galactose and lactose concomitantly when it is grown in a medium containing both sugars. Analysis of the C-terminal end of S. salivarius LacS revealed a IIA-like domain (IIALacS) almost identical to the IIA domain of S. thermophilus LacS. Experiments performed with purified proteins showed that S. salivarius IIALacS was reversibly phosphorylated on a histidine residue at position 552 not only by HPr(His∼P) but also by HPr(Ser-P)(His∼P), a doubly phosphorylated form of HPr present in large amounts in rapidly growing S. salivarius cells. Two other major S. salivarius PTS proteins, IIABLMan and IIABHMan, were unable to phosphorylate IIALacS. The effect of LacS phosphorylation on growth was studied with strain G71, an S. salivarius enzyme I-negative mutant that cannot synthesize HPr(His∼P) or HPr(Ser-P)(His∼P). These results indicated that (i) the wild-type and mutant strains had identical generation times on lactose, (ii) neither strain expelled galactose during growth on lactose, (iii) both strains metabolized lactose and galactose concomitantly when grown in a medium containing both sugars, and (iv) the growth of the mutant was slightly reduced on galactose. PMID:14617640

  10. 1984 Newbery Acceptance Speech.

    ERIC Educational Resources Information Center

    Cleary, Beverly

    1984-01-01

    This acceptance speech for an award honoring "Dear Mr. Henshaw," a book about feelings of a lonely child of divorce intended for eight-, nine-, and ten-year-olds, highlights children's letters to author. Changes in society that affect children, the inception of "Dear Mr. Henshaw," and children's reactions to books are highlighted. (EJS)

  11. Analysis and Remediation of the 2013 LAC-MÉGANTIC Train Derailment

    NASA Astrophysics Data System (ADS)

    Brunke, Suzanne; Aubé, Guy; Legaré, Serge; Auger, Claude

    2016-06-01

    On July 6, 2013 a train owned by Montréal, Maine & Atlantic Railway (MMA) Company derailed in Lac-Mégantic, Quebec, Canada triggering the explosion of the tankers carrying crude oil. Several buildings in the downtown core were destroyed. The Sûreté du Québec confirmed the death of 47 people in the disaster. Through the Canadian Space Agency (CSA) Rapid Information Products and Services (RIPS) program, MDA developed value-added products that allowed stakeholders and all levels of government (municipal, provincial and federal) to get an accurate picture of the disaster. The goal of this RIPS Project was to identify the contribution that remote sensing technology can provide to disasters such as the train derailment and explosion at Lac-Mégantic through response and remediation monitoring. Through monitoring and analysis, the Lac-Mégantic train derailment response and remediation demonstrated how Earth observation data can be used for situational awareness in a disaster and in documenting the remediation process. Both high resolution optical and RADARSAT-2 SAR image products were acquired and analyzed over the disaster remediation period as each had a role in monitoring. High resolution optical imagery provided a very clear picture of the current state of remediation efforts, however it can be difficult to acquire due to cloud cover and weather conditions. The RADARSAT-2 SAR images can be acquired in all weather conditions at any time of day making it ideal for mission critical information gathering. MDA's automated change detection processing enabled rapid delivery of advanced information products.

  12. Distinct signatures for mutator sensitivity of lacZ reversions and for the spectrum of lacI/lacO forward mutations on the chromosome of nondividing Escherichia coli.

    PubMed

    Bharatan, Shanti M; Reddy, Manjula; Gowrishankar, J

    2004-02-01

    A conditional lethal galE(Ts)-based strategy was employed in Escherichia coli, first to eliminate all growth-associated chromosomal reversions in lacZ or forward mutations in lacI/lacO by incubation at the restrictive temperature and subsequently to recover (as papillae) spontaneous mutations that had arisen in the population of nondividing cells after shift to the permissive temperature. Data from lacZ reversion studies in mutator strains indicated that the products of all genes for mismatch repair (mutHLS, dam, uvrD), of some for oxidative damage repair (mutMT), and of that for polymerase proofreading (dnaQ) are required in dividing cells; some others for oxidative damage repair (mutY, nth nei) are required in both dividing and nondividing cells; and those for alkylation damage repair (ada ogt) are required in nondividing cells. The spectrum of lacI/lacO mutations in nondividing cells was distinguished both by lower frequencies of deletions and IS1 insertions and by the unique occurrence of GC-to-AT transitions at lacO +5. In the second approach to study mutations that had occurred in nondividing cells, lacI/lacO mutants were selected as late-arising papillae from the lawn of a galE+ strain; once again, transitions at lacO +5 were detected among the mutants that had been obtained from populations initially grown on poor carbon sources such as acetate, palmitate, or succinate. Our results indicate that the lacO +5 site is mutable only in nondividing cells, one possible mechanism for which might be that random endogenous alkylation (or oxidative) damage to DNA in these cells is efficiently corrected by the Ada Ogt (or Nth Nei) repair enzymes at most sites but not at lacO +5. Furthermore, the late-arising papillae from the second approach were composed almost exclusively of dominant lacI/lacO mutants. This finding lends support to "instantaneous gratification" models in which a spontaneous lesion, occurring at a random site in DNA of a nondividing cell, is most

  13. Distinct signatures for mutator sensitivity of lacZ reversions and for the spectrum of lacI/lacO forward mutations on the chromosome of nondividing Escherichia coli.

    PubMed Central

    Bharatan, Shanti M; Reddy, Manjula; Gowrishankar, J

    2004-01-01

    A conditional lethal galE(Ts)-based strategy was employed in Escherichia coli, first to eliminate all growth-associated chromosomal reversions in lacZ or forward mutations in lacI/lacO by incubation at the restrictive temperature and subsequently to recover (as papillae) spontaneous mutations that had arisen in the population of nondividing cells after shift to the permissive temperature. Data from lacZ reversion studies in mutator strains indicated that the products of all genes for mismatch repair (mutHLS, dam, uvrD), of some for oxidative damage repair (mutMT), and of that for polymerase proofreading (dnaQ) are required in dividing cells; some others for oxidative damage repair (mutY, nth nei) are required in both dividing and nondividing cells; and those for alkylation damage repair (ada ogt) are required in nondividing cells. The spectrum of lacI/lacO mutations in nondividing cells was distinguished both by lower frequencies of deletions and IS1 insertions and by the unique occurrence of GC-to-AT transitions at lacO +5. In the second approach to study mutations that had occurred in nondividing cells, lacI/lacO mutants were selected as late-arising papillae from the lawn of a galE+ strain; once again, transitions at lacO +5 were detected among the mutants that had been obtained from populations initially grown on poor carbon sources such as acetate, palmitate, or succinate. Our results indicate that the lacO +5 site is mutable only in nondividing cells, one possible mechanism for which might be that random endogenous alkylation (or oxidative) damage to DNA in these cells is efficiently corrected by the Ada Ogt (or Nth Nei) repair enzymes at most sites but not at lacO +5. Furthermore, the late-arising papillae from the second approach were composed almost exclusively of dominant lacI/lacO mutants. This finding lends support to "instantaneous gratification" models in which a spontaneous lesion, occurring at a random site in DNA of a nondividing cell, is most

  14. Acceptance speech.

    PubMed

    Carpenter, M

    1994-01-01

    In Bangladesh, the assistant administrator of USAID gave an acceptance speech at an awards ceremony on the occasion of the 25th anniversary of oral rehydration solution (ORS). The ceremony celebrated the key role of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) in the discovery of ORS. Its research activities over the last 25 years have brought ORS to every village in the world, preventing more than a million deaths each year. ORS is the most important medical advance of the 20th century. It is affordable and client-oriented, a true appropriate technology. USAID has provided more than US$ 40 million to ICDDR,B for diarrheal disease and measles research, urban and rural applied family planning and maternal and child health research, and vaccine development. ICDDR,B began as the relatively small Cholera Research Laboratory and has grown into an acclaimed international center for health, family planning, and population research. It leads the world in diarrheal disease research. ICDDR,B is the leading center for applied health research in South Asia. It trains public health specialists from around the world. The government of Bangladesh and the international donor community have actively joined in support of ICDDR,B. The government applies the results of ICDDR,B research to its programs to improve the health and well-being of Bangladeshis. ICDDR,B now also studies acute respiratory diseases and measles. Population and health comprise 1 of USAID's 4 strategic priorities, the others being economic growth, environment, and democracy, USAID promotes people's participation in these 4 areas and in the design and implementation of development projects. USAID is committed to the use and improvement of ORS and to complementary strategies that further reduce diarrhea-related deaths. Continued collaboration with a strong user perspective and integrated services will lead to sustainable development. PMID:12345470

  15. Acceptance speech.

    PubMed

    Yusuf, C K

    1994-01-01

    I am proud and honored to accept this award on behalf of the Government of Bangladesh, and the millions of Bangladeshi children saved by oral rehydration solution. The Government of Bangladesh is grateful for this recognition of its commitment to international health and population research and cost-effective health care for all. The Government of Bangladesh has already made remarkable strides forward in the health and population sector, and this was recognized in UNICEF's 1993 "State of the World's Children". The national contraceptive prevalence rate, at 40%, is higher than that of many developed countries. It is appropriate that Bangladesh, where ORS was discovered, has the largest ORS production capacity in the world. It was remarkable that after the devastating cyclone in 1991, the country was able to produce enough ORS to meet the needs and remain self-sufficient. Similarly, Bangladesh has one of the most effective, flexible and efficient control of diarrheal disease and epidemic response program in the world. Through the country, doctors have been trained in diarrheal disease management, and stores of ORS are maintained ready for any outbreak. Despite grim predictions after the 1991 cyclone and the 1993 floods, relatively few people died from diarrheal disease. This is indicative of the strength of the national program. I want to take this opportunity to acknowledge the contribution of ICDDR, B and the important role it plays in supporting the Government's efforts in the health and population sector. The partnership between the Government of Bangladesh and ICDDR, B has already borne great fruit, and I hope and believe that it will continue to do so for many years in the future. Thank you. PMID:12345479

  16. VizieR Online Data Catalog: UBV photometry of V360 Lac (Hill+ 1997)

    NASA Astrophysics Data System (ADS)

    Hill, G.; Harmanec, P.; Pavlovski, K.; Bozic, H.; Hadrava, P.; Koubsky, P.; Ziznovsky, J.

    1997-03-01

    An analysis of an extensive collection of photometric and spectroscopic observations of the little studied bright Be star V360 Lac lead to the following main conclusions: (1) V360 Lac is a binary system consisting of a B3e primary and a F9IV secondary which probably fills the Roche lobe and losses mass towards the primary. Radial-velocity curves of both components were obtained. (2) The light variations arise from superposition of variations on at least three time scales: phase-locked orbital brightness and colour changes with two minima; sinusoidal variation with a 322.24d period and low-amplitude rapid changes with a possible period of 1.6738d. (3) A tentative solution of the B and V light curves which assumes the semi-detached configuration and presence of a disk around the primary, combined with the orbital solution, leads to preliminary basic physical elements of the system which are consistent with the radiative properties of the binary components. (1 data file).

  17. Expression of SofLAC, a new laccase in sugarcane, restores lignin content but not S:G ratio of Arabidopsis lac17 mutant.

    PubMed

    Cesarino, Igor; Araújo, Pedro; Sampaio Mayer, Juliana Lischka; Vicentini, Renato; Berthet, Serge; Demedts, Brecht; Vanholme, Bartel; Boerjan, Wout; Mazzafera, Paulo

    2013-04-01

    Lignin is a complex phenolic heteropolymer deposited in the secondarily thickened walls of specialized plant cells to provide strength for plants to stand upright and hydrophobicity to conducting cells for long-distance water transport. Although essential for plant growth and development, lignin is the major plant cell-wall component responsible for biomass recalcitrance to industrial processing. Peroxidases and laccases are generally thought to be responsible for lignin polymerization, but, given their broad substrate specificities and large gene families, specific isoforms involved in lignification are difficult to identify. This study used a combination of co-expression analysis, tissue/cell-type-specific expression analysis, and genetic complementation to correlate a sugarcane laccase gene, SofLAC, to the lignification process. A co-expression network constructed from 37 cDNA libraries showed that SofLAC was coordinately expressed with several phenylpropanoid biosynthesis genes. Tissue-specific expression analysis by quantitative RT-PCR showed that SofLAC was expressed preferentially in young internodes and that expression levels decrease with stem maturity. Cell-type-specific expression analysis by in situ hybridization demonstrated the localization of SofLAC mRNA in lignifying cell types, mainly in inner and outer portions of sclerenchymatic bundle sheaths. To investigate whether SofLAC is able to oxidize monolignols during lignification, the Arabidopsis lac17 mutant, which has reduced lignin levels, was complemented by expressing SofLAC under the control of the Arabidopsis AtLAC17 promoter. The expression of SofLAC restored the lignin content but not the lignin composition in complemented lac17 mutant lines. Taken together, these results suggest that SofLAC participates in lignification in sugarcane. PMID:23418623

  18. Direct observation of a 91 bp LacI-mediated, negatively supercoiled DNA loop by atomic force microscope.

    PubMed

    Fulcrand, Geraldine; Chapagain, Prem; Dunlap, David; Leng, Fenfei

    2016-03-01

    Escherichia coli lactose repressor (LacI), a tetrameric protein, is a paradigmatic transcriptional factor that controls the expression of lacZYA in the lac operon. It specifically binds to the O1, O2, and O3 operators of the lac promoter, forms DNA loops, and regulates transcription of the lac operon. In this article, utilizing combined techniques of DNA-nicking assay and AFM imaging, we directly observed a 91 bp LacI-mediated, negatively supercoiled DNA loop mimicking the DNA loop between the O1 and O3 operators in the lac promoter. PMID:26878689

  19. Evolution and Biophysics of the Escherichia coli lac Operon

    NASA Astrophysics Data System (ADS)

    Ray, J. Christian; Igoshin, Oleg; Quan, Selwyn; Monds, Russell; Cooper, Tim; Balázsi, Gábor

    2011-03-01

    To understand, predict, and control the evolution of living organisms, we consider biophysical effects and molecular network architectures. The lactose utilization system of E. coli is among the most well-studied molecular networks in biology, making it an ideal candidate for such studies. Simulations show how the genetic architecture of the wild-type operon attenuates large metabolic intermediate fluctuations that are predicted to occur in an equivalent system with the component genes on separate operons. Quantification of gene expression in the lac operon evolved in growth conditions containing constant lactose, alternating with glucose, or constant glucose, shows characteristic gene expression patterns depending on conditions. We are simulating these conditions to show context-dependent biophysical sources and costs of different lac operon architectures.

  20. Endless versatility in the biotechnological applications of Kluyveromyces LAC genes.

    PubMed

    Rubio-Texeira, Marta

    2006-01-01

    Most microorganisms adapted to life in milk owe their ability to thrive in this habitat to the evolution of mechanisms for the use of the most abundant sugar present on it, lactose, as a carbon source. Because of their lactose-assimilating ability, Kluyveromyces yeasts have long been used in industrial processes involved in the elimination of this sugar. The identification of the genes conferring Kluyveromyces with a system for permeabilization and intracellular hydrolysis of lactose (LAC genes), along with the current possibilities for their transfer into alternative organisms through genetic engineering, has significantly broadened the industrial profitability of lactic yeasts. This review provides an updated overview of the general properties of Kluyveromyces LAC genes, and the multiple techniques involving their biotechnological utilization. Emphasis is also made on the potential that some of the latest technologies, such as the generation of transgenics, will have for a further benefit in the use of these and related genes. PMID:16289464

  1. Wind Resource Assessment Report: Mille Lacs Indian Reservation, Minnesota

    SciTech Connect

    Jimenez, A. C.

    2013-12-01

    The U.S. Environmental Protection Agency (EPA) launched the RE-Powering America's Land initiative to encourage development of renewable energy on potentially contaminated land and mine sites. EPA collaborated with the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) and the Mille Lacs Band of Chippewa Indians to evaluate the wind resource and examine the feasibility of a wind project at a contaminated site located on the Mille Lacs Indian Reservation in Minnesota. The wind monitoring effort involved the installation of a 60-m met tower and the collection of 18 months of wind data at multiple heights above the ground. This report focuses on the wind resource assessment, the estimated energy production of wind turbines, and an assessment of the economic feasibility of a potential wind project sited this site.

  2. A Catalogue of XMM-Newton BL Lacs

    NASA Astrophysics Data System (ADS)

    Racero, E.; De la Calle, I.; Rouco Escorial, A.

    2015-05-01

    A catalogue of XMM-Newton BL Lac is presented based on a cross-correlation with the 1374 BL Lac objects listed in the 13th edition of the Veron-Cetty and Veron (2010) catalogue. X-ray counterparts were searched for in the field of view of more than 10000 pointed observations available in the XMM-Newton Archive (XSA) that were public before June 2012. The cross-correlation yielded around 250 XMM-Newton observations, which correspond to 162 different sources. X-ray data from the three EPIC cameras and Optical Monitor data were uniformly analyzed using the latest XMM-Newton Science Analysis System (SAS) version. The catalogue collects X-ray spectral properties, including flux variability, of the sample in the 0.2--10 KeV energy band. All the catalogue products will be made publicly available to the scientific community.

  3. A Catalogue of XMM-Newton BL Lacs

    NASA Astrophysics Data System (ADS)

    Rouco Escorial, A.; de la Calle, I.; Held, J.; Racero, E.

    2014-07-01

    A catalogue of XMM-Newton BL Lac is presented based on a cross-correlation with the 1374 BL Lac objects listed in the 13th edition of the Veron-Cetty and Veron (2010) catalogue. X-ray counterparts were searched for in the field of view of more than 10000 pointed observations available in the XMM-Newton Archive (XSA) that were public before June 2012. The cross-correlation yielded around 250 XMM-Newton observations, which correspond to 162 different sources. X-ray data from the three EPIC cameras and Optical Monitor data were uniformly analyzed using the latest XMMNewton Science Analysis System (SAS) version. The catalogue collects X-ray spectral properties, including flux variability, of the sample in the 0.2 - 10 keV energy band.

  4. Positive and Negative Control of the Lac Operon

    NASA Astrophysics Data System (ADS)

    Qaddour, Jihad S.; Werman, Steven D.; Misra, Prasanta K.

    1997-03-01

    We present a mathematical model for the positive and negative control of lac operon. We investigate a steady state solution for the coupled nonlinear differential equations representing the dynamic behaviors of the repressor-inducer components of negative control as well as the cyclic AMP receptor components of the positive control. A dimensionless derivation of the lac operon system is employed to produce singularly perturbed models. The first model represents the dynamical behavior of the operator while the slow model represents the dynamical behaviors of the inducer and the repressor. We use the singular perturbation theory to show that the behavior of the system can be described as a rapid on-off switch of structural gene transformation.

  5. Imaging redshift estimates for Fermi BL Lac objects

    SciTech Connect

    Stadnik, Matt; Romani, Roger W. E-mail: rwr@astro.stanford.edu

    2014-04-01

    We have obtained WIYN and SOAR i' images of BL Lacertae objects and used these to detect or constrain the flux of the host galaxy. Under common standard candle assumptions, these data provide estimates of, or lower bounds on, the redshift. Our targets are a set of flat-spectrum radio counterparts of high flux Fermi Large Area Telescope sources, with sensitive spectral observations showing them to be continuum-dominated BL Lac objects. In this sample, 5 of 11 BL Lac objects yielded significant host detections, with standard candle redshifts z = 0.13-0.58. Our estimates and lower bounds are generally in agreement with other redshifts estimates, although our z = 0.374 estimate for J0543–5532 implies a significantly sub-luminous host.

  6. Bistable behavior of the lac operon in E. coli when induced with a mixture of lactose and TMG.

    PubMed

    Díaz-Hernández, Orlando; Santillán, Moisés

    2010-01-01

    In this work we investigate multistability in the lac operon of Escherichia coli when it is induced by a mixture of lactose and the non-metabolizable thiomethyl galactoside (TMG). In accordance with previously published experimental results and computer simulations, our simulations predict that: (1) when the system is induced by TMG, the system shows a discernible bistable behavior while, (2) when the system is induced by lactose, bistability does not disappear but excessively high concentrations of lactose would be required to observe it. Finally, our simulation results predict that when a mixture of lactose and TMG is used, the bistability region in the extracellular glucose concentration vs. extracellular lactose concentration parameter space changes in such a way that the model predictions regarding bistability could be tested experimentally. These experiments could help to solve a recent controversy regarding the existence of bistability in the lac operon under natural conditions. PMID:21423364

  7. A highly sensitive and specific electrochemical sensing method for robust detection of Escherichia coli lac Z gene sequence.

    PubMed

    Li, Fengqin; Yu, Zhigang; Qu, Haichao; Zhang, Guiling; Yan, Hong; Liu, Xin; He, Xunjun

    2015-06-15

    Based on the interaction mode of capture probe-target-signal probe (CP-T-SP), a simple but efficient electrochemical sensing method is developed for robust detection of Escherichia coli (E. coli) lac Z gene sequence. The sensing system is simply composed of two probes with CP attached to the surface of gold electrode and methylene blue (MB)-labeled SP free in the detecting solution. Two duplexes are formed with the target DNA, an E. coli lac Z gene sequence, hybridizing with two ends of CP and SP separately. This structure can position the MB labels near to the electrode surface, thereby resulting in the change of detecting current. The proposed sensor exhibits a high sensitivity with a detection limit of ∼30 fM for target DNA and good mismatch discrimination ability (MDA). This method can also be applied to the construction of other sensors for the analysis of similar designated pathogenic bacteria gene sequence (PBGS). PMID:25562734

  8. Challenge of lightning detection with LAC on board Akatsuki spacecraft

    NASA Astrophysics Data System (ADS)

    Takahashi, Yukihiro; Sato, Mitsutero; Imai, Masataka; Yair, Yoav; Fischer, Georg; Aplin, Karen

    2016-04-01

    Even after extensive investigations with spacecraft and ground-based observations, there is still no consensus on the existence of lightning in Venus. It has been reported that the magnetometer on board Venus Express detected whistler mode waves whose source could be lightning discharge occurring well below the spacecraft. On the other hand, with an infrared sensor, VIRTIS of Venus Express, does not show the positive indication of lightning flashes. In order to identify the optical flashes caused by electrical discharge in the atmosphere of Venus, at least, with an optical intensity of 1/10 of the average lightning in the Earth, we built a high-speed optical detector, LAC (Lightning and Airglow Camera), on board Akatsuki spacecraft. The unique performance of the LAC compared to other instruments is the high-speed sampling rate at 32 us interval for all 32 pixels, enabling us to distinguish the optical lightning flash from other pulsing noises. Though, unfortunately, the first attempt of the insertion of Akatsuki into the orbit around Venus failed in December 2010, the second one carried out in December 7 in 2015 was quite successful. We checked out the condition of the LAC on January 5, 2016, and it is healthy as in 2010. Due to some elongated orbit than that planned originally, we have umbra for ~30 min to observe the lightning flash in the night side of Venus every ~10 days, starting on April 2016. Here we would report the instrumental status of LAC and the preliminary results of the first attempt to observe optical lightning emissions.

  9. Induction of the lac carrier and an associated membrane protein in Escherichia coli

    SciTech Connect

    Lagarias, D.M.

    1985-01-01

    Induction of the lac operon in wild type Escherichia coli strains results in synthesis of a 16 kilodalton inner membrane protein in addition to the known products of the lacZ, lacY and lacA genes. Cells carrying the lacY gene on a plasmid over produce this 16 kilodalton polypeptide as well as the Lac carrier, the membrane protein product of the lacY gene. However, (/sup 35/S)methionine labeling of minicells carrying the lacY plasmid shows that the 16 kDa protein is not synthesized from the plasmid DNA. The 16 kDa protein was purified and partially characterized. It is an acidic membrane protein of apparent molecular weight 15,800 whose amino terminal sequence (NH/sub 2/-Met-Arg-Asn-Phe-Asp-Leu-) does not correspond to any nucleotide sequence known in lac operon DNA. Using antibody prepared to the purified 16 kDa protein, a quantitative analysis of conditions under which this protein is made was accomplished, and reveals that the amount of 16 kDa protein which appears in the membrane is proportional to lac operon expression. Hybridization of a synthetic oligonucleotide probe complementary to the 5' end of 16 kDa protein mRNA shows that its synthesis is regulated at the level of transcription. A description of attempts to clone this gene is given. Possible functional roles for the 16 kDa protein are discussed.

  10. LacCore: Support for the terrestrial sediment core research community

    NASA Astrophysics Data System (ADS)

    Brady, K. L.; Noren, A. J.; Myrbo, A.; Ito, E.

    2009-12-01

    LacCore, the National Lacustrine Core Facility, has been funded by the US National Science Foundation and the University of Minnesota for the past decade as a public facility to support the terrestrial sediment core research community. LacCore provides free or low-cost access to an array of expensive equipment and instrumentation in the field and lab, training for a variety of procedures, and core and data curation. The user base has increased from perhaps 20 users and a handful of projects in the first year to 621 users and 250 projects in 2008. The community served is diverse, with topics including invasive species, eutrophication, salinization, tectonics, geomicrobiology, evolutionary biology, isostatic rebound, stream bank erosion, glaciology, hydrogeology, atmospheric chemistry, carbon cycling, and rock magnetics, as well as paleoenvironment and paleoclimate. The changing needs of projects drive innovation in procedures and equipment, all of which become available to subsequent researchers. Among the newest additions to the lab is a benchtop scanning electron microscope with electron-dispersive x-ray spectrometry (SEM-EDX or -EDS) capability for sediment characterization. This instrument allows rapid imaging of sedimentary components and determination of their elemental composition without substantial sample preparation, lead time, or user training. These images and data augment the initial core description process, filling a void between existing smear slide and scanning micro XRF capabilities.

  11. Computational modeling of leukocyte adhesion cascade (LAC)

    NASA Astrophysics Data System (ADS)

    Sarkar, Kausik

    2005-11-01

    In response to an inflammation in the body, leukocytes (white blood cell) interact with the endothelium (interior wall of blood vessel) through a series of steps--capture, rolling, adhesion and transmigration--critical for proper functioning of the immune system. We are numerically simulating this process using a Front-tracking finite-difference method. The viscoelastcity of the cell membrane, cytoplasm and nucleus are incorporated and allowed to change with time in response to the cell surface molecular chemistry. The molecular level forces due to specific ligand-receptor interactions are accounted for by stochastic spring-peeling model. Even though leukocyte rolling has been investigated through various models, the transitioning through subsequent steps, specifically firm adhesion and transmigration through endothelial layer, has not been modeled. The change of viscoelastic properties due to the leukocyte activation is observed to play a critical role in mediating the transition from rolling to transmigration. We will provide details of our approach and discuss preliminary results.

  12. Local elastic constants of LacI and implications for allostery.

    PubMed

    Ribeiro, Andre A S T; Ortiz, Vanessa

    2015-04-01

    Allostery connects subtle changes in a protein's potential energy surface, induced by perturbations like ligand-binding, to significant changes in its function. Understanding this phenomenon and predicting its occurrence are major goals of current research in biophysics and molecular biology. In this paper we introduce a novel approach for studying complex structural transformations such as those typical for allostery. We show that the calculation and analysis of atomic elastic constants of a known allosterically regulated protein, lac repressor, highlights regions that are particularly prone to suffer structural deformation and are experimentally linked to allosteric function. The calculations are based on a high resolution, all-atom description of the protein. We also show that, for the present system, modifying the description of the system from an all-atom forcefield to an elastic network model yields qualitatively different results, indicating the importance of adequately describing the local environment surrounding the different parts of the protein. PMID:25700189

  13. UGV acceptance testing

    NASA Astrophysics Data System (ADS)

    Kramer, Jeffrey A.; Murphy, Robin R.

    2006-05-01

    With over 100 models of unmanned vehicles now available for military and civilian safety, security or rescue applications, it is important to for agencies to establish acceptance testing. However, there appears to be no general guidelines for what constitutes a reasonable acceptance test. This paper describes i) a preliminary method for acceptance testing by a customer of the mechanical and electrical components of an unmanned ground vehicle system, ii) how it has been applied to a man-packable micro-robot, and iii) discusses the value of testing both to ensure that the customer has a workable system and to improve design. The test method automated the operation of the robot to repeatedly exercise all aspects and combinations of components on the robot for 6 hours. The acceptance testing process uncovered many failures consistent with those shown to occur in the field, showing that testing by the user does predict failures. The process also demonstrated that the testing by the manufacturer can provide important design data that can be used to identify, diagnose, and prevent long-term problems. Also, the structured testing environment showed that sensor systems can be used to predict errors and changes in performance, as well as uncovering unmodeled behavior in subsystems.

  14. Mathematical model of the lac operon: inducer exclusion, catabolite repression, and diauxic growth on glucose and lactose.

    PubMed

    Wong, P; Gladney, S; Keasling, J D

    1997-01-01

    A mathematical model of the lactose (lac) operon was developed to study diauxic growth on glucose and lactose. The model includes catabolite repression, inducer exclusion, lactose hydrolysis to glucose and galactose, and synthesis and degradation of allolactose. Two models for catabolite repression were tested: (i) cyclic AMP (cAMP) synthesis inversely correlated with the external glucose concentration and (ii) synthesis inversely correlated with the glucose transport rate. No significant differences in the two models were observed. In addition to synthesis, degradation and secretion of cAMP were also included in the model. Two models for the phosphorylation of the glucose produced from lactose hydrolysis were also tested: (i) phosphorylation by intracellular hexokinase and (ii) secretion of glucose and subsequent phosphorylation upon transport back into the cell. The latter model resulted in weak catabolite repression when the glucose produced from lactose was transported out of the cell, whereas the former model showed no catabolite repression during growth on lactose. Parameter sensitivity analysis indicates the importance of key parameters to lac operon expression and cell growth: the lactose and allolactose transformation rates by beta-galactosidase and the glucose concentrations that affect catabolite repression and inducer exclusion. Large values of the allolactose hydrolysis rate resulted in low concentrations of allolactose, low-level expression of the lac operon, and slow growth due to limited import and metabolism of lactose; small values resulted in a high concentration of allolactose, high-level expression of the lac operon, and slow growth due to a limiting concentration of glucose 6-phosphate formed from allolactose. Changes in the rates of all beta-galactosidase-catalyzed reactions showed similar behavior, but had more drastic effects on the growth rate. Changes in the glucose concentration that inhibited lactose transport could extend or contract

  15. Mapping DNA-Lac repressor interaction with ultra-fast optical tweezers

    NASA Astrophysics Data System (ADS)

    Monico, Carina; Tempestini, Alessia; Vanzi, Francesco; Pavone, Francesco S.; Capitanio, Marco

    2015-03-01

    The lac operon is a well-known example of gene expression regulation, based on the specific interaction of Lac repressor protein (LacI) with its target DNA sequence (operator). We recently developed an ultrafast force-clamp laser trap technique capable of probing molecular interactions with sub-ms temporal resolution, under controlled pN-range forces. With this technique, we tested the interaction of LacI with different DNA constructs. Based on position along the DNA sequence, the observed interactions can be interpreted as specific binding to operator sequences and transient interactions with nonspecific sequences.

  16. Lac operator repeats generate a traceable fragile site in mammalian cells.

    PubMed

    Jacome, Ariana; Fernandez-Capetillo, Oscar

    2011-10-01

    One limitation for the study of chromosomal fragile sites is that they must be studied on metaphase spreads, after the breakage. We show here that bacterial lac operator (lacO) repeats are prone to spontaneous breakage, which when combined with a fluorescent lac repressor (lacR) has allowed us to track a fragile site through the cell cycle. By using this system, we show that Plk1-interacting checkpoint helicase (PICH) is already present at fragile sites during interphase, suggesting roles for this helicase beyond mitosis. In addition, we report that the oncogene Myc promotes the formation of anaphase bridges and micronuclei containing fragile-site sequences. PMID:21836640

  17. CLUSTERING OF γ-RAY-SELECTED 2LAC FERMI BLAZARS

    SciTech Connect

    Allevato, V.; Finoguenov, A.; Cappelluti, N.

    2014-12-20

    We present the first measurement of the projected correlation function of 485 γ-ray-selected blazars, divided into 175 BL Lacertae (BL Lacs) and 310 flat-spectrum radio quasars (FSRQs) detected in the 2 year all-sky survey by the Fermi-Large Area Telescope. We find that Fermi BL Lacs and FSRQs reside in massive dark matter halos (DMHs) with log M{sub h} = 13.35{sub −0.14}{sup +0.20} and log M{sub h} = 13.40{sub −0.19}{sup +0.15} h {sup –1} M {sub ☉}, respectively, at low (z ∼ 0.4) and high (z ∼ 1.2) redshift. In terms of clustering properties, these results suggest that BL Lacs and FSRQs are similar objects residing in the same dense environment typical of galaxy groups, despite their different spectral energy distributions, power, and accretion rates. We find no difference in the typical bias and hosting halo mass between Fermi blazars and radio-loud active galactic nuclei (AGNs), supporting the unification scheme simply equating radio-loud objects with misaligned blazar counterparts. This similarity in terms of the typical environment they preferentially live in, suggests that blazars tend to occupy the center of DMHs, as already pointed out for radio-loud AGNs. This implies, in light of several projects looking for the γ-ray emission from DM annihilation in galaxy clusters, a strong contamination from blazars to the expected signal from DM annihilation.

  18. Peer Acceptance of Children with Language and Communication Impairments in a Mainstream Primary School: Associations with Type of Language Difficulty, Problem Behaviours and a Change in Placement Organization

    ERIC Educational Resources Information Center

    Laws, Glynis; Bates, Geraldine; Feuerstein, Maike; Mason-Apps, Emily; White, Catherine

    2012-01-01

    This research investigated peer acceptance of children with language and communication impairments attending a language resource base attached to a mainstream school. Compared to other children in their mainstream peer groups, peer acceptance was poor. Peer rejection was more common for children with profiles consistent with an autistic spectrum…

  19. Comparative genomics and evolution of regulons of the LacI-family transcription factors

    PubMed Central

    Ravcheev, Dmitry A.; Khoroshkin, Matvei S.; Laikova, Olga N.; Tsoy, Olga V.; Sernova, Natalia V.; Petrova, Svetlana A.; Rakhmaninova, Aleksandra B.; Novichkov, Pavel S.; Gelfand, Mikhail S.; Rodionov, Dmitry A.

    2014-01-01

    DNA-binding transcription factors (TFs) are essential components of transcriptional regulatory networks in bacteria. LacI-family TFs (LacI-TFs) are broadly distributed among certain lineages of bacteria. The majority of characterized LacI-TFs sense sugar effectors and regulate carbohydrate utilization genes. The comparative genomics approaches enable in silico identification of TF-binding sites and regulon reconstruction. To study the function and evolution of LacI-TFs, we performed genomics-based reconstruction and comparative analysis of their regulons. For over 1300 LacI-TFs from over 270 bacterial genomes, we predicted their cognate DNA-binding motifs and identified target genes. Using the genome context and metabolic subsystem analyses of reconstructed regulons, we tentatively assigned functional roles and predicted candidate effectors for 78 and 67% of the analyzed LacI-TFs, respectively. Nearly 90% of the studied LacI-TFs are local regulators of sugar utilization pathways, whereas the remaining 125 global regulators control large and diverse sets of metabolic genes. The global LacI-TFs include the previously known regulators CcpA in Firmicutes, FruR in Enterobacteria, and PurR in Gammaproteobacteria, as well as the three novel regulators—GluR, GapR, and PckR—that are predicted to control the central carbohydrate metabolism in three lineages of Alphaproteobacteria. Phylogenetic analysis of regulators combined with the reconstructed regulons provides a model of evolutionary diversification of the LacI protein family. The obtained genomic collection of in silico reconstructed LacI-TF regulons in bacteria is available in the RegPrecise database (http://regprecise.lbl.gov). It provides a framework for future structural and functional classification of the LacI protein family and identification of molecular determinants of the DNA and ligand specificity. The inferred regulons can be also used for functional gene annotation and reconstruction of sugar catabolic

  20. Comparative genomics and evolution of regulons of the LacI-family transcription factors.

    PubMed

    Ravcheev, Dmitry A; Khoroshkin, Matvei S; Laikova, Olga N; Tsoy, Olga V; Sernova, Natalia V; Petrova, Svetlana A; Rakhmaninova, Aleksandra B; Novichkov, Pavel S; Gelfand, Mikhail S; Rodionov, Dmitry A

    2014-01-01

    DNA-binding transcription factors (TFs) are essential components of transcriptional regulatory networks in bacteria. LacI-family TFs (LacI-TFs) are broadly distributed among certain lineages of bacteria. The majority of characterized LacI-TFs sense sugar effectors and regulate carbohydrate utilization genes. The comparative genomics approaches enable in silico identification of TF-binding sites and regulon reconstruction. To study the function and evolution of LacI-TFs, we performed genomics-based reconstruction and comparative analysis of their regulons. For over 1300 LacI-TFs from over 270 bacterial genomes, we predicted their cognate DNA-binding motifs and identified target genes. Using the genome context and metabolic subsystem analyses of reconstructed regulons, we tentatively assigned functional roles and predicted candidate effectors for 78 and 67% of the analyzed LacI-TFs, respectively. Nearly 90% of the studied LacI-TFs are local regulators of sugar utilization pathways, whereas the remaining 125 global regulators control large and diverse sets of metabolic genes. The global LacI-TFs include the previously known regulators CcpA in Firmicutes, FruR in Enterobacteria, and PurR in Gammaproteobacteria, as well as the three novel regulators-GluR, GapR, and PckR-that are predicted to control the central carbohydrate metabolism in three lineages of Alphaproteobacteria. Phylogenetic analysis of regulators combined with the reconstructed regulons provides a model of evolutionary diversification of the LacI protein family. The obtained genomic collection of in silico reconstructed LacI-TF regulons in bacteria is available in the RegPrecise database (http://regprecise.lbl.gov). It provides a framework for future structural and functional classification of the LacI protein family and identification of molecular determinants of the DNA and ligand specificity. The inferred regulons can be also used for functional gene annotation and reconstruction of sugar catabolic

  1. THERMAL CONDUCTIVITY AND ELEMENT FRACTIONATION IN EV Lac

    SciTech Connect

    Laming, J. Martin; Hwang, Una

    2009-12-10

    We present a 100 ks Suzaku observation of the dMe flare star EV Lac, in which the star was captured undergoing a moderate 1500 s flare. During the flare, the count rate increased by about a factor of 50 and the spectrum showed overall enhanced element abundances relative to quiescence. While the quiescent element abundances confirm the inverse first ionization potential (FIP) effect previously documented for EV Lac, with relatively higher depletions for low FIP elements, abundances during the flare spectra show a composition closer to that of the stellar photosphere. We discuss these results in the context of models that explain abundance fractionation in the stellar chromosphere as a result of the ponderomotive force due to Alfven waves. Stars with FIP or inverse FIP effects arising from differently directed ponderomotive forces may have quite different abundance signatures in their evaporated chromospheric plasma during flares, if the same ponderomotive force also affects thermal conduction downward from the corona. The regulation of the thermal conductivity by the ponderomotive force requires a level of turbulence that is somewhat higher than is normally assumed, but plausible in filamentary conduction models.

  2. Thermal Conductivity and Element Fractionation in EV Lac

    NASA Astrophysics Data System (ADS)

    Laming, J. Martin; Hwang, Una

    2009-12-01

    We present a 100 ks Suzaku observation of the dMe flare star EV Lac, in which the star was captured undergoing a moderate 1500 s flare. During the flare, the count rate increased by about a factor of 50 and the spectrum showed overall enhanced element abundances relative to quiescence. While the quiescent element abundances confirm the inverse first ionization potential (FIP) effect previously documented for EV Lac, with relatively higher depletions for low FIP elements, abundances during the flare spectra show a composition closer to that of the stellar photosphere. We discuss these results in the context of models that explain abundance fractionation in the stellar chromosphere as a result of the ponderomotive force due to Alfvén waves. Stars with FIP or inverse FIP effects arising from differently directed ponderomotive forces may have quite different abundance signatures in their evaporated chromospheric plasma during flares, if the same ponderomotive force also affects thermal conduction downward from the corona. The regulation of the thermal conductivity by the ponderomotive force requires a level of turbulence that is somewhat higher than is normally assumed, but plausible in filamentary conduction models.

  3. Conserved movement of TMS11 between occluded conformations of LacY and XylE of the Major Facilitator Superfamily suggests a similar hinge-like mechanism

    PubMed Central

    Västermark, Åke; Driker, Adelle; Li, Jiaqi; Saier, Milton H.

    2015-01-01

    Δ-distance maps can detect local remodeling that is difficult to accurately determine using superimpositions. TMSs 11 in both LacY and XylE of the Major Facilitator Superfamily (MFS) uniquely contribute the greatest amount of mobile surface area in the outward occluded state, and undergo analogous movements. The intracellular part of TMS11 moves away from the C-terminal domain and into the substrate cavity during the conformational change from the outward occluded to the inward occluded state. Upon releasing the substrate to the inside and assuming the inward open state, a difference was noted between LacY and XylE where TMS11 of LacY moved further into the substrate release space whereas in XylE, TMS11 slightly retracted into the C-terminal domain. Independent movement of the N-terminal half of TMS11 suggests that it is flexible in the middle. Repeat-swapped homology modeling was used to discover that a loop connecting TMSs 10 and 11 in LacY probably moves during the transition between the yet to be solved outward open state and the outward occluded state. TMSs 11 and the other elements displaying a notable domain-independent movement colocalize with the interdomain linker, suggesting that these elements could drive the alternating access movement between the domain halves. Preliminary evidence indicates that analogous movements occur in other members of the MFS. PMID:25586173

  4. Program Evaluation of Community College Learning Assistance Centers: What Do LAC Directors Think?

    ERIC Educational Resources Information Center

    Franklin, Doug; Blankenberger, Bob

    2016-01-01

    Objective: This study seeks to determine the nature of current program evaluation practices for learning assistance centers (LACs), the practices being used for program evaluation, and whether LAC directors believe their practices are appropriate for evaluating program effectiveness. Method: We conducted a survey (n = 61) of community college LAC…

  5. Radiocarbon measurements at LAC-UFF: Recent performance

    NASA Astrophysics Data System (ADS)

    Linares, Roberto; Macario, Kita D.; Santos, Guaciara M.; Carvalho, Carla; dos Santos, Hellen C.; Gomes, Paulo R. S.; Castro, Maikel D.; Oliveira, Fabiana M.; Alves, Eduardo Q.

    2015-10-01

    In 2012 a single stage accelerator mass spectrometer from NEC was installed at the Radiocarbon Laboratory of Universidade Federal Fluminense (LAC-UFF), Niterói, Brazil. Here, we present a status report of our facility. We discuss some modifications applied to our combustion protocol in an attempt to reduce our procedural blank, mostly to processed organic samples. Measurements of reference materials indicate low precision and accuracy that are partially related to beam optics through the acceleration tube. We observed that once the beam current intensity increases the measured 13C+/12C+ becomes erratic. Therefore, in order to maintain the AMS-δ13C values within reasonable values, so that fractionation corrections using the spectrometer 13C+/12C+ values does not affect the final 14C results, we are forced to limit the 12C- beam intensity to ⩽30 μA. This requirement was confirmed during our accuracy tests, when measuring selected annual tree-rings wood samples from a Parana pine (Araucaria angustifolia) between 1927 and 1997 previously measured at the Keck Carbon Cycle AMS Facility (KCCAMS), at the University of California, Irvine (UCI). At the LAC-UFF tree-ring wood samples were processed and measured in 4 different batches during a period of about 5 months. The 14C results were later compared to the high-precision data obtained at KCCAMS/UCI and reached a good agreement. Recently a problem associated with graphitization yield were finally identified and new measurements with secondary standards are promising.

  6. Mutation frequency and specificity with age in liver, bladder and brain of lacI transgenic mice.

    PubMed Central

    Stuart, G R; Oda, Y; de Boer, J G; Glickman, B W

    2000-01-01

    Mutation frequency and specificity were determined as a function of age in nuclear DNA from liver, bladder, and brain of Big Blue lacI transgenic mice aged 1.5-25 months. Mutations accumulated with age in liver and accumulated more rapidly in bladder. In the brain a small initial increase in mutation frequency was observed in young animals; however, no further increase was observed in adult mice. To investigate the origin of mutations, the mutational spectra for each tissue and age were determined. DNA sequence analysis of mutant lacI transgenes revealed no significant changes in mutational specificity in any tissue at any age. The spectra of mutations found in aging animals were identical to those in younger animals, suggesting that they originated from a common set of DNA lesions manifested during DNA replication. The data also indicated that there were no significant age-related mutational changes due to oxidative damage, or errors resulting from either changes in the fidelity of DNA polymerase or the efficiency of DNA repair. Hence, no evidence was found to support hypotheses that predict that oxidative damage or accumulation of errors in nuclear DNA contributes significantly to the aging process, at least in these three somatic tissues. PMID:10757770

  7. Yersinia pestis lacZ expresses a beta-galactosidase with low enzymatic activity.

    PubMed

    Bobrov, Alexander G; Perry, Robert D

    2006-02-01

    Although very little, if any, beta-galactosidase activity is detected in Yersinia pestis by a standard Miller assay, we found that Y. pestis KIM6+ cells formed blue colonies on plates containing 5-bromo-4-chloro-3-indolyl-beta-D-galactoside (X-gal). Searches of the Y. pestis genome databases revealed the presence of noncontiguous sequences highly homologous to Escherichia coli lacZ, lacY, and lacI. Yersinia pestis lacZ is predicted to encode a 1060 amino-acid protein with 62% identity and 72% similarity to beta-galactosidase from E. coli. A deletion in the Y. pestis lacZ gene caused the formation of white colonies on X-gal-containing plates and beta-galactosidase activity was at background levels in the KIM6+lacZ mutant, while the complemented strain expressed about 190 Miller units. The Y. pestis lacZ promoter was not regulated by isopropylthiogalactoside or glucose. Finally, uptake of lactose by Y. pestis may be impaired. PMID:16436060

  8. Single-Molecule Spectroscopic Determination of Lac Repressor-DNA Loop Conformation

    PubMed Central

    Morgan, Michael A.; Okamoto, Kenji; Kahn, Jason D.; English, Douglas S.

    2005-01-01

    The Escherichia coli lactose repressor protein (LacI) provides a classic model for understanding protein-induced DNA looping. LacI has a C-terminal four-helix bundle tetramerization domain that may act as a flexible hinge. In previous work, several DNA constructs, each containing two lac operators bracketing a sequence-induced bend, were designed to stabilize different possible looping geometries. The resulting hyperstable LacI-DNA loops exist as both a compact “closed” form with a V-shaped repressor and also a more “open” form with an extended hinge. The “9C14” construct was of particular interest because footprinting, electrophoretic mobility shift, and ring closure experiments suggested that it forms both geometries. Previous fluorescence resonance energy transfer (FRET) measurements gave an efficiency of energy transfer (ET) of 70%, confirming the existence of a closed form. These measurements could not determine whether open form or intermediate geometries are populated or the timescale of interconversion. We have now applied single-molecule FRET to Cy3, Cy5 double-labeled LacI-DNA loops diffusing freely in solution. By using multiple excitation wavelengths and by carefully examining the behavior of the zero-ET peak during titration with LacI, we show that the LacI-9C14 loop exists exclusively in a single closed form exhibiting essentially 100% ET. PMID:16085773

  9. Short Lesson Plan Associated with Increased Acceptance of Evolutionary Theory and Potential Change in Three Alternate Conceptions of Macroevolution in Undergraduate Students

    ERIC Educational Resources Information Center

    Abraham, Joel K.; Perez, Kathryn E.; Downey, Nicholas; Herron, Jon C.; Meir, Eli

    2012-01-01

    Undergraduates commonly harbor alternate conceptions about evolutionary biology; these alternate conceptions often persist, even after intensive instruction, and may influence acceptance of evolution. We interviewed undergraduates to explore their alternate conceptions about macroevolutionary patterns and designed a 2-h lesson plan to present…

  10. Nucleotide and deduced amino acid sequences of the lacR, lacABCD, and lacFE genes encoding the repressor, tagatose 6-phosphate gene cluster, and sugar-specific phosphotransferase system components of the lactose operon of Streptococcus mutans.

    PubMed Central

    Rosey, E L; Stewart, G C

    1992-01-01

    The complete nucleotide sequences of lacRABCDF and partial nucleotide sequence of lacE from the lactose operon of Streptococcus mutans are presented. Comparison of the streptococcal lac determinants with those of Staphylococcus aureus and Lactococcus lactis indicate exceptional protein and nucleotide identity. The deduced polypeptides also demonstrate significant, but lower, sequence similarity with the corresponding lactose proteins of Lactobacillus casei. Additionally, LacR has sequence homology with the repressor (DeoR) of the Escherichia coli deoxyribonucleotide operon, while LacC is similar to phosphokinases (FruK and PfkB) from E. coli. The primary translation products of the lacRABCDFE genes are polypeptides of 251 (M(r) 28,713), 142 (M(r) 15,610), 171 (M(r) 18,950), 310 (M(r) 33,368), 325 (M(r) 36,495), 104 (M(r) 11,401), and 123 (NH2-terminal) amino acids, respectively. As inferred from their direct homology to the staphylococcal lac genes, these determinants would encode the repressor of the streptococcal lactose operon (LacR), galactose-6-phosphate isomerase (LacA and LacB), tagatose-6-phosphate kinase (LacC), tagatose-1,6-bisphosphate aldolase (LacD), and the sugar-specific components enzyme III-lactose (LacF) and enzyme II-lactose (LacE) of the S. mutans phosphoenolpyruvate-dependent phosphotransferase system. The nucleotide sequence encompassing the S. mutans lac promoter appears to contain repeat elements analogous to those of S. aureus, suggesting that repression and catabolite repression of the lactose operons may be similar in these organisms. Images PMID:1400164

  11. Lac Repressor Mediated DNA Looping: Monte Carlo Simulation of Constrained DNA Molecules Complemented with Current Experimental Results

    PubMed Central

    Biton, Yoav Y.; Kumar, Sandip; Dunlap, David; Swigon, David

    2014-01-01

    Tethered particle motion (TPM) experiments can be used to detect time-resolved loop formation in a single DNA molecule by measuring changes in the length of a DNA tether. Interpretation of such experiments is greatly aided by computer simulations of DNA looping which allow one to analyze the structure of the looped DNA and estimate DNA-protein binding constants specific for the loop formation process. We here present a new Monte Carlo scheme for accurate simulation of DNA configurations subject to geometric constraints and apply this method to Lac repressor mediated DNA looping, comparing the simulation results with new experimental data obtained by the TPM technique. Our simulations, taking into account the details of attachment of DNA ends and fluctuations of the looped subsegment of the DNA, reveal the origin of the double-peaked distribution of RMS values observed by TPM experiments by showing that the average RMS value for anti-parallel loop types is smaller than that of parallel loop types. The simulations also reveal that the looping probabilities for the anti-parallel loop types are significantly higher than those of the parallel loop types, even for loops of length 600 and 900 base pairs, and that the correct proportion between the heights of the peaks in the distribution can only be attained when loops with flexible Lac repressor conformation are taken into account. Comparison of the in silico and in vitro results yields estimates for the dissociation constants characterizing the binding affinity between O1 and Oid DNA operators and the dimeric arms of the Lac repressor. PMID:24800809

  12. Improving Acceptance of Automated Counseling Procedures.

    ERIC Educational Resources Information Center

    Johnson, James H.; And Others

    This paper discusses factors that may influence the acceptance of automated counseling procedures by the military. A consensual model of the change process is presented which structures organizational readiness, the change strategy, and acceptance as integrated variables to be considered in a successful installation. A basic introduction to the…

  13. Sustaining the natural and economical resources of the Lac Courte Oreilles, Leslie Isham; Jason Weaver

    SciTech Connect

    Isham, Leslie; Weaver, Jason

    2013-09-30

    The Lac Courte Oreilles Band of Lake Superior Chippewa Indians, located in northwest Wisconsin has developed a project, entitled Sustaining the Natural and Economic Resources of the LCO Ojibwe. This technical report is a summary of the project.

  14. Photometric Analysis and Period Investigation of the EW Type Eclipsing Binary V441 Lac

    NASA Astrophysics Data System (ADS)

    Li, K.; Hu, S.-M.; Guo, D.-F.; Jiang, Y.-G.; Gao, D.-Y.; Chen, X.

    2016-09-01

    Four color light curves of the EW type eclipsing binary V441 Lac were presented and analyzed by the W-D code. It is found that V441 Lac is an extremely low mass ratio ( q = 0.093±0.001) semi-detached binary with the less massive secondary component filling the inner Roche lobe. Two dark spots on the primary component were introduced to explain the asymmetric light curves. By analyzing all times of light minimum, we determined that the orbital period of V441 Lac is continuously increasing at a rate of d P/d t = 5.874(±0.007) × 10-7 d yr-1. The semi-detached Algol type configuration of V441 Lac is possibly formed by a contact configuration destroyed shallow contact binary due to mass transfer from the less massive component to the more massive one predicted by the thermal relaxation oscillation theory.

  15. Can we respond mindfully to distressing voices? A systematic review of evidence for engagement, acceptability, effectiveness and mechanisms of change for mindfulness-based interventions for people distressed by hearing voices

    PubMed Central

    Strauss, Clara; Thomas, Neil; Hayward, Mark

    2015-01-01

    Adapted mindfulness-based interventions (MBIs) could be of benefit for people distressed by hearing voices. This paper presents a systematic review of studies exploring this possibility and we ask five questions: (1) Is trait mindfulness associated with reduced distress and disturbance in relation to hearing voices? (2) Are MBIs feasible for people distressed by hearing voices? (3) Are MBIs acceptable and safe for people distressed by hearing voices? (4) Are MBIs effective at reducing distress and disturbance in people distressed by hearing voices? (5) If effective, what are the mechanisms of change through which MBIs for distressing voices work? Fifteen studies were identified through a systematic search (n = 479). In relation to the five review questions: (1) data from cross-sectional studies showed an association between trait mindfulness and distress and disturbance in relation to hearing voices; (2) evidence from qualitative studies suggested that people distressed by hearing voices could engage meaningfully in mindfulness practice; (3) MBIs were seen as acceptable and safe; (4) there were no adequately powered RCTs allowing conclusions about effectiveness to be drawn; and (5) it was not possible to draw on robust empirical data to comment on potential mechanisms of change although findings from the qualitative studies identified three potential change processes; (i) reorientation of attention; (ii) decentring; and (iii) acceptance of voices. This review provided evidence that MBIs are engaging, acceptable, and safe. Evidence for effectiveness in reducing distress and disturbance is lacking however. We call for funding for adequately powered RCTs that will allow questions of effectiveness, maintenance of effects, mechanisms of change and moderators of outcome to be definitively addressed. PMID:26321980

  16. Can we respond mindfully to distressing voices? A systematic review of evidence for engagement, acceptability, effectiveness and mechanisms of change for mindfulness-based interventions for people distressed by hearing voices.

    PubMed

    Strauss, Clara; Thomas, Neil; Hayward, Mark

    2015-01-01

    Adapted mindfulness-based interventions (MBIs) could be of benefit for people distressed by hearing voices. This paper presents a systematic review of studies exploring this possibility and we ask five questions: (1) Is trait mindfulness associated with reduced distress and disturbance in relation to hearing voices? (2) Are MBIs feasible for people distressed by hearing voices? (3) Are MBIs acceptable and safe for people distressed by hearing voices? (4) Are MBIs effective at reducing distress and disturbance in people distressed by hearing voices? (5) If effective, what are the mechanisms of change through which MBIs for distressing voices work? Fifteen studies were identified through a systematic search (n = 479). In relation to the five review questions: (1) data from cross-sectional studies showed an association between trait mindfulness and distress and disturbance in relation to hearing voices; (2) evidence from qualitative studies suggested that people distressed by hearing voices could engage meaningfully in mindfulness practice; (3) MBIs were seen as acceptable and safe; (4) there were no adequately powered RCTs allowing conclusions about effectiveness to be drawn; and (5) it was not possible to draw on robust empirical data to comment on potential mechanisms of change although findings from the qualitative studies identified three potential change processes; (i) reorientation of attention; (ii) decentring; and (iii) acceptance of voices. This review provided evidence that MBIs are engaging, acceptable, and safe. Evidence for effectiveness in reducing distress and disturbance is lacking however. We call for funding for adequately powered RCTs that will allow questions of effectiveness, maintenance of effects, mechanisms of change and moderators of outcome to be definitively addressed. PMID:26321980

  17. The Changes in Dentists’ Perception and Patient’s Acceptance on Amalgam Restoration in Kurdistan-Iraq: A Questionnaire-based Cross-Sectional Study

    PubMed Central

    Mohammad, Hawzhen Masoud; Mohammad, Kale Masoud

    2015-01-01

    Background There has been considerable controversy concerning the health risks and benefits of utilizing mercury-containing amalgam. Across the developing countries, a reduction in the use of dental amalgam in oral health care provision is expected. Purpose Assessment of dentists’ and patient’s attitude of dental amalgam regarding attractiveness, perceived health, and treatment preferences in Kurdistan, Iraq. Materials and Methods A 4-page questionnaire comprised two parts, specific for dentist and patient were structured and delivered to each dentist oneself. Both open-ended and close-ended questions about the treatment needs of patients, uses of amalgam and its alternative, the properties and usefulness of different materials. Patient’s acceptance was assessed by means of structured questionnaire prepared based on commonly asked questions from routinely daily practice. Questions on the type of filling material in their mouth, previous knowledge of mercury in dental amalgam and disappointment due to mercury hazard and toxicity. They were to indicate their acceptance with filling their cavities by dental amalgam with or without prior information about its mercury content. This part was also accomplished by the dentists participated in this survey. Results Out of 185 dentists shared, only 39 (21.1%) indicated that amalgam presents no harm for the dentists and patients. While majority of dentists 85 (45.9%) were uncertain about this issue. Amalgam was selected most often 107 (57.8%) as the material of choice for restoring posterior teeth. About 94(50.8%) and 85(45.9%) of the practitioners primarily used glass ionomer/resin-reinforced glass ionomer and composite, respectively. Among 1850 patients received treatment, only 450 (24.32%) claimed to have heard about adverse reactions to dental amalgams. Those who believed it to be safe were 200 (10.82%).Acceptance towards amalgam was 62%. Conclusion While amalgam was the most common material used for posterior

  18. Genotype to Phenotype Mapping of the E. coli lac Promoter

    NASA Astrophysics Data System (ADS)

    Otwinowski, Jakub; Nemenman, Ilya

    2014-03-01

    Genotype-to-phenotype maps and the related fitness landscapes that include epistatic interactions are difficult to measure because of their high dimensional structure. Here we construct such a map using the recently collected corpora of high-throughput sequence data from the 75 base pairs long mutagenized E. coli lac promoter region, where each sequence is associated with induced transcriptional activity measured by a fluorescent reporter. We find that the additive (non-epistatic) contributions of individual mutations account for about two-thirds of the explainable phenotype variance, while pairwise epistasis explains about 7% of the variance for the full mutagenized sequence and about 15% for the subsequence associated with protein binding sites. Surprisingly, there is no evidence for third order epistatic contributions, and our inferred fitness landscape is essentially single peaked, with a small amount of antagonistic epistasis. We identify transcription factor (CRP) and RNA polymerase binding sites in the promotor region and their interactions. We conclude with a cautionary note that inferred properties of fitness landscapes may be severely influenced by biases in the sequence data. Funded in part by HFSP and James S. McDonnell Foundation.

  19. eLac - Conceptual Model for Flood Management

    NASA Astrophysics Data System (ADS)

    Rata, Marius; Florentin Draghia, Aurelian; Drobot, Radu; Matreata, Marius; Corbus, Ciprian

    2015-04-01

    This article reviews the conceptual model of the decision support system (DSS) for flood management activities introduced in the scope of e-LAC project. Following the general system architecture which has an emphasize on the water management decision processes, hydrologic and hydraulic models are introduced and discussed according to their specific DSS integration potential. Three directions are discussed in dedicated sections corresponding to the main modules defined in the conceptual model : the Water Basin Management Module (mainly implements the management decision flow, but manages also data exchange between hydrologic modeling module and hydraulic modeling module, allow real time visualization for hydrological data), the Hydrologic Modeling Module (manages all the modeling functionalities of rainfalls - runoff processes, providing continuous hydrologic forecasts with a variable time-step depending on the actual basin situation) and the Hydraulic Modeling Module (computes the flood's waves routing having as boundary upstream conditions the discharge hydrographs, generated both by catchment's upper area, river tributaries and inter-basins, respectively the rating curves, water level hydrograph or water surface slope as downstream condition). The GIS concepts are contextually reviewed based on their use as geospatial database for water management modeling, integration within hydrologic time courses, hydraulic modeling (from both software and management perspective), expert knowledge or mathematical modeling results (knowledge database, rules).

  20. On the hadronic cascade scenario for extreme BL Lacs

    NASA Astrophysics Data System (ADS)

    Tavecchio, Fabrizio

    2014-03-01

    The peculiar high-energy emission spectrum of the so-called extreme BL Lacs (EHBL) challenges the standard emission models of blazars. Among the possible solutions, the so-called hadronic cascade scenario assumes that the observed high-energy radiation is produced in the intergalactic space through photo-hadronic reactions by ultra-high energy cosmic rays (UHECR) with energies up to 1019-20 eV beamed by the blazar jet. Under the assumption - implicit in this model - that the intrinsic high-energy synchrotron self-Compton emission of the blazar does not substantially contribute to the observed γ-ray spectrum, we derive constraints to the basic physical quantities of the jet and we compare them with the requirements of the hadronic cascade scenario. We found that, for a plausible range of relativistic jet Doppler factors (δ = 10-50), the maximum achievable energy of the accelerated protons can exceed 2 × 1019 eV with jet powers of the order of ≈1044 erg s-1, parameters compatible with the requests of the hadronic scenario even if EHBL are embedded in magnetic fields of cosmic filaments. We also discuss the consequences of our results for the possibility that local EHBL contribute to the observed UHECR.

  1. Regulation of endothelial-specific transgene expression by the LacI repressor protein in vivo.

    PubMed

    Morton, Susan K; Chaston, Daniel J; Baillie, Brett K; Hill, Caryl E; Matthaei, Klaus I

    2014-01-01

    Genetically modified mice have played an important part in elucidating gene function in vivo. However, conclusions from transgenic studies may be compromised by complications arising from the site of transgene integration into the genome and, in inducible systems, the non-innocuous nature of inducer molecules. The aim of the present study was to use the vascular system to validate a technique based on the bacterial lac operon system, in which transgene expression can be repressed and de-repressed by an innocuous lactose analogue, IPTG. We have modified an endothelium specific promoter (TIE2) with synthetic LacO sequences and made transgenic mouse lines with this modified promoter driving expression of mutant forms of connexin40 and an independently translated reporter, EGFP. We show that tissue specificity of this modified promoter is retained in the vasculature of transgenic mice in spite of the presence of LacO sequences, and that transgene expression is uniform throughout the endothelium of a range of adult systemic and cerebral arteries and arterioles. Moreover, transgene expression can be consistently down-regulated by crossing the transgenic mice with mice expressing an inhibitor protein LacI(R), and in one transgenic line, transgene expression could be de-repressed rapidly by the innocuous inducer, IPTG. We conclude that the modified bacterial lac operon system can be used successfully to validate transgenic phenotypes through a simple breeding schedule with mice homozygous for the LacI(R) protein. PMID:24755679

  2. A quantitative understanding of lac repressor’s binding specificity and flexibility

    PubMed Central

    Zuo, Zheng; Chang, Yiming; Stormo, Gary D.

    2015-01-01

    Lac repressor, the first discovered transcriptional regulator, has been shown to confer multiple-modes of binding to its operator sites depending on the central spacer length. Other homolog members in the LacI/GalR family (PurR and YcjW) cannot bind their operator sites with similar structural flexibility. To decipher the underlying mechanism for this unique property, we used Spec-seq approach combined with site-directed mutagenesis to quantify the DNA binding specificity of multiple hybrids of lacI and PurR. We find that lac repressor’s recognition di-residues YQ and its hinge helix loop regions are both critical for its structural flexibility. Also, specificity profiling of the whole lac operator suggests that a simple additive model from single variants suffice to predict other multivariant sites’ energy reasonably well, and the genome occupancy model based on this specificity data correlates well with in vivo lac repressor binding profile. PMID:26752632

  3. Loss of the lac operon contributes to Salmonella invasion of epithelial cells through derepression of flagellar synthesis.

    PubMed

    Jiang, Lingyan; Ni, Zhiwei; Wang, Lei; Feng, Lu; Liu, Bin

    2015-03-01

    Salmonella, a genus that is closely related to Escherichia coli, includes many pathogens of humans and other animals. A notable feature that distinguishes Salmonella from E. coli is lactose negativity, because the lac operon is lost in most Salmonella genomes. Here, we expressed the lac operon in Salmonella enterica serovar Typhimurium and compared the virulence of the Lac(+) strain to that of the wild-type strain in a murine model, invasion assays, and macrophage replication assays. We showed that the Lac(+) strain is attenuated in vivo and the attenuation of virulence is caused by its defect in epithelial cell invasion. However, the invasion-defective phenotype is unrelated to lactose utilization. Through sequencing and the comparison of the transcriptome profile between the Lac(+) and wild-type strains during invasion, we found that most flagellar genes were markedly downregulated in the Lac(+) strain, while other genes associated with invasion, such as the majority of genes encoded in Salmonella pathogenicity island 1, were not differentially expressed. Moreover, we discovered that lacA is the major repressor of flagellar gene expression in the lac operon. In conclusion, these data demonstrate that the lac operon decreases Salmonella invasion of epithelial cells through repression of flagellar biosynthesis. As the ability to invade epithelial cells is a critical virulence determinant of Salmonella, our results provide important evidence that the loss of the lac operon contributes to the evolution of Salmonella pathogenicity. PMID:25362512

  4. Changes in the Redox Potential of Primary and Secondary Electron-Accepting Quinones in Photosystem II Confer Increased Resistance to Photoinhibition in Low-Temperature-Acclimated Arabidopsis1

    PubMed Central

    Sane, Prafullachandra Vishnu; Ivanov, Alexander G.; Hurry, Vaughan; Huner, Norman P.A.; Öquist, Gunnar

    2003-01-01

    Exposure of control (non-hardened) Arabidopsis leaves for 2 h at high irradiance at 5°C resulted in a 55% decrease in photosystem II (PSII) photochemical efficiency as indicated by Fv/Fm. In contrast, cold-acclimated leaves exposed to the same conditions showed only a 22% decrease in Fv/Fm. Thermoluminescence was used to assess the possible role(s) of PSII recombination events in this differential resistance to photoinhibition. Thermoluminescence measurements of PSII revealed that S2QA- recombination was shifted to higher temperatures, whereas the characteristic temperature of the S2QB- recombination was shifted to lower temperatures in cold-acclimated plants. These shifts in recombination temperatures indicate higher activation energy for the S2QA- redox pair and lower activation energy for the S2QB- redox pair. This results in an increase in the free-energy gap between P680+QA- and P680+Pheo- and a narrowing of the free energy gap between primary and secondary electron-accepting quinones in PSII electron acceptors. We propose that these effects result in an increased population of reduced primary electron-accepting quinone in PSII, facilitating non-radiative P680+QA- radical pair recombination. Enhanced reaction center quenching was confirmed using in vivo chlorophyll fluorescence-quenching analysis. The enhanced dissipation of excess light energy within the reaction center of PSII, in part, accounts for the observed increase in resistance to high-light stress in cold-acclimated Arabidopsis plants. PMID:12913169

  5. Changes in sensory properties and consumer acceptance of reduced fat pork Lyon-style and liver sausages containing inulin and citrus fiber as fat replacers.

    PubMed

    Tomaschunas, Maja; Zörb, Rebecca; Fischer, Jürgen; Köhn, Ehrhard; Hinrichs, Jörg; Busch-Stockfisch, Mechthild

    2013-11-01

    The effects of fat reduction in Lyon-style (25% fat) and liver sausages (30% fat) using inulin, citrus fiber and partially rice starch were studied in terms of sensory properties and consumer acceptance. Fat reduced Lyon-style sausages (3 to 17% fat) and liver sausages (3 to 20% fat) were respectively compared to the full-fat controls. Reducing fat in Lyon-style sausages decreased meat flavor, aftertaste meat flavor, greasiness and juiciness, and enhanced color intensity, spiciness, spicy aftertaste, raspy throat, coarseness and firmness scores. But adding inulin and citrus fiber led to sensory characteristics similar to the full-fat reference. Regarding liver sausages, attribute scores in greasiness, creaminess, lumpiness and foamy were decreased with fat reduction and simultaneous addition of fibers. Color intensity, spiciness, firmness and attribute furred tongue were increased. Consumer tests revealed acceptable fat reduced (32 to 90% less than control) and fiber enriched (1.0 to 5.6%) sausages. Drivers of liking were found to relate not only to high-fat but also to low-fat samples. PMID:23811098

  6. From requirements to acceptance tests

    NASA Technical Reports Server (NTRS)

    Baize, Lionel; Pasquier, Helene

    1993-01-01

    From user requirements definition to accepted software system, the software project management wants to be sure that the system will meet the requirements. For the development of a telecommunication satellites Control Centre, C.N.E.S. has used new rules to make the use of tracing matrix easier. From Requirements to Acceptance Tests, each item of a document must have an identifier. A unique matrix traces the system and allows the tracking of the consequences of a change in the requirements. A tool has been developed, to import documents into a relational data base. Each record of the data base corresponds to an item of a document, the access key is the item identifier. Tracing matrix is also processed, providing automatically links between the different documents. It enables the reading on the same screen of traced items. For example one can read simultaneously the User Requirements items, the corresponding Software Requirements items and the Acceptance Tests.

  7. Changes in the redox potential of primary and secondary electron-accepting quinones in photosystem II confer increased resistance to photoinhibition in low-temperature-acclimated Arabidopsis.

    PubMed

    Sane, Prafullachandra Vishnu; Ivanov, Alexander G; Hurry, Vaughan; Huner, Norman P A; Oquist, Gunnar

    2003-08-01

    Exposure of control (non-hardened) Arabidopsis leaves for 2 h at high irradiance at 5 degrees C resulted in a 55% decrease in photosystem II (PSII) photochemical efficiency as indicated by F(v)/F(m). In contrast, cold-acclimated leaves exposed to the same conditions showed only a 22% decrease in F(v)/F(m). Thermoluminescence was used to assess the possible role(s) of PSII recombination events in this differential resistance to photoinhibition. Thermoluminescence measurements of PSII revealed that S(2)Q(A)(-) recombination was shifted to higher temperatures, whereas the characteristic temperature of the S(2)Q(B)(-) recombination was shifted to lower temperatures in cold-acclimated plants. These shifts in recombination temperatures indicate higher activation energy for the S(2)Q(A)(-) redox pair and lower activation energy for the S(2)Q(B)(-) redox pair. This results in an increase in the free-energy gap between P680(+)Q(A)(-) and P680(+)Pheo(-) and a narrowing of the free energy gap between primary and secondary electron-accepting quinones in PSII electron acceptors. We propose that these effects result in an increased population of reduced primary electron-accepting quinone in PSII, facilitating non-radiative P680(+)Q(A)(-) radical pair recombination. Enhanced reaction center quenching was confirmed using in vivo chlorophyll fluorescence-quenching analysis. The enhanced dissipation of excess light energy within the reaction center of PSII, in part, accounts for the observed increase in resistance to high-light stress in cold-acclimated Arabidopsis plants. PMID:12913169

  8. A low-fat vegan diet elicits greater macronutrient changes, but is comparable in adherence and acceptability, compared with a more conventional diabetes diet among individuals with type 2 diabetes

    PubMed Central

    Barnard, Neal D.; Gloede, Lise; Cohen, Joshua; Jenkins, David J.A.; Turner-McGrievy, Gabrielle; Green, Amber A.; Ferdowsian, Hope

    2009-01-01

    Background Although therapeutic diets are critical to diabetes management, their acceptability to patients is largely unstudied. Objective To quantify adherence and acceptability for two types of diets for diabetes. Design Controlled trial conducted 2004 – 2006. Subjects/setting Individuals with type 2 diabetes (n = 99) at a community-based research facility. Intervention Participants were randomly assigned to a diet following 2003 American Diabetes Association (ADA) guidelines or a low-fat, vegan diet for 74 weeks. Main outcome measures Attrition, adherence, dietary behavior, diet acceptability, and cravings. Statistical analyses For nutrient intake and questionnaire scores, t-tests determined between-group differences. For diet-acceptability measures, the related samples Wilcoxon rank test assessed within-group changes; the independent samples Mann-Whitney U test compared the diet groups. Chi-square for independent samples compared the groups for changes in reported symptoms. Results All participants completed the initial 22 weeks; 90% (45/50) of ADA-group and 86% (42/49) of vegan-group participants completed 74 weeks. Fat and cholesterol intake fell more and carbohydrate and fiber intake increased more in the vegan group. At 22 weeks, group-specific diet adherence criteria were met by 44% (22/50) of ADA-group and 67% (33/49) of vegan-group participants (P=0.019); the ADA group reported a greater increase in dietary restraint; this difference was not significant at 74 weeks. Both groups reported reduced hunger and reduced disinhibition. Questionnaire responses rated both diets as satisfactory, with no significant differences between groups, except for ease of preparation, for which the 22-week ratings marginally favored the ADA group. Cravings for fatty foods diminished more in the vegan group at 22 weeks, with no significant difference at 74 weeks. Conclusions Despite its greater influence on macronutrient intake, a low-fat, vegan diet has an acceptability

  9. Mutagenesis by asbestos in the lung of lambda-lacI transgenic rats.

    PubMed

    Topinka, J; Loli, P; Georgiadis, P; Dusinská, M; Hurbánková, M; Kováciková, Z; Volkovová, K; Kazimírová, A; Barancoková, M; Tatrai, E; Oesterle, D; Wolff, T; Kyrtopoulos, S A

    2004-09-01

    In order to get more insight into the mechanism of asbestos-related lung cancer, the mutagenic potential of asbestos was examined in vivo in rat lung. Groups of five transgenic lambda-lacI (Big Blue) rats were intratracheally instilled with single doses of 1 or 2mg, or with four weekly doses of 2mg, per animal of the amosite asbestos. Sixteen weeks after instillation, the mutation frequency was found to be increased in lung DNA by 2-fold at doses of 2 mg (P = 0.035) and of 4 x 2 mg (P = 0.007) amosite. No significant changes were observed after 4 weeks of exposure. In separate experiments, wild-type F344 rats were treated by the same regimen as described above and markers of inflammation, genotoxicity, cell proliferation and lung tissue damage were analysed. Our results indicate a weak but persistent inflammation and cell proliferation which possibly plays a major role in the observed mutagenic effect. PMID:15288534

  10. Mass balance model of source apportionment, transport and fate of PAHs in Lac Saint Louis, Quebec.

    PubMed

    Mackay, D; Hickie, B

    2000-09-01

    A mass balance model has been developed and calibrated to describe the sources, transport and fate of seven polycyclic aromatic hydrocarbons (PAHs; anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, fluoranthene, phenanthrene, and pyrene) in the water and sediments of, and atmosphere over Lac Saint Louis, Quebec. The model uses specified input rates from background advective flows and emissions from the Alcan aluminum smelting facility at Beauharnois to deduce atmospheric concentrations and rates of wet and dry deposition to the three segment lake. Concentrations in water and sediment as well as relevant mass fluxes and residence times are computed and compared satisfactorily with monitoring data for five of the seven PAHs. Underestimation of concentrations for anthracene and phenanthrene is attributed to unquantified additional sources. The sources of the PAH burden in the lake are apportioned, and the implications of these results are discussed including likely response times to changes in loadings. It is suggested that this mass balance approach is more widely applicable to situations in which water bodies are impacted by a variety of contaminant sources. PMID:10834368

  11. [Alteration of Social Behaviors in Male Mice of CBA/Lac Strain under Agonistic Interactions].

    PubMed

    Kovalenko, I L; Kudryavtseva, N N

    2015-01-01

    Ability of people to communicate with each other is a necessary component of social behavior and normal development of individuals living in community. A pronounced impairment in communication may be the result of autism which is characterized by impaired socialization, low communication and restricted and/or repetitive behaviors. It is hypothesized that genes or rare mutations play a key role in the development of autism. However a multifold increase of the cases with autistic spectrum symptoms over the last years cannot be attributed exclusively to genetic mutations or heredity. Environmental contribution to the development of autistic symptoms has to be considered. The paper aimed to analyze the social behaviors of CBA/Lac mice with repeated experience of aggression or social defeats in daily agonistic interactions with accent on searches of associations with autistic symptoms in comparison with previously studied C57BL/6J animals. It has been shown that male mice of both strains with alternative social behaviors demonstrated the changes in social behaviors; however the expression of some form of behaviors was different. The data obtained to assert that long-term hostile social environment lead to development of disturbances in social behaviors, accompanying by autistic-like symptoms. PMID:26601507

  12. Aflatoxin B₁ and M₁ Degradation by Lac2 from Pleurotus pulmonarius and Redox Mediators.

    PubMed

    Loi, Martina; Fanelli, Francesca; Zucca, Paolo; Liuzzi, Vania C; Quintieri, Laura; Cimmarusti, Maria T; Monaci, Linda; Haidukowski, Miriam; Logrieco, Antonio F; Sanjust, Enrico; Mulè, Giuseppina

    2016-01-01

    Laccases (LCs) are multicopper oxidases that find application as versatile biocatalysts for the green bioremediation of environmental pollutants and xenobiotics. In this study we elucidate the degrading activity of Lac2 pure enzyme form Pleurotus pulmonarius towards aflatoxin B₁ (AFB₁) and M₁ (AFM₁). LC enzyme was purified using three chromatographic steps and identified as Lac2 through zymogram and LC-MS/MS. The degradation assays were performed in vitro at 25 °C for 72 h in buffer solution. AFB₁ degradation by Lac2 direct oxidation was 23%. Toxin degradation was also investigated in the presence of three redox mediators, (2,2'-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]) (ABTS) and two naturally-occurring phenols, acetosyringone (AS) and syringaldehyde (SA). The direct effect of the enzyme and the mediated action of Lac2 with redox mediators univocally proved the correlation between Lac2 activity and aflatoxins degradation. The degradation of AFB₁ was enhanced by the addition of all mediators at 10 mM, with AS being the most effective (90% of degradation). AFM₁ was completely degraded by Lac2 with all mediators at 10 mM. The novelty of this study relies on the identification of a pure enzyme as capable of degrading AFB₁ and, for the first time, AFM₁, and on the evidence that the mechanism of an effective degradation occurs via the mediation of natural phenolic compounds. These results opened new perspective for Lac2 application in the food and feed supply chains as a biotransforming agent of AFB₁ and AFM₁. PMID:27563923

  13. ATLAS ACCEPTANCE TEST

    SciTech Connect

    J.C. COCHRANE; J.V. PARKER; ET AL

    2001-06-01

    The acceptance test program for Atlas, a 23 MJ pulsed power facility for use in the Los Alamos High Energy Density Hydrodynamics program, has been completed. Completion of this program officially releases Atlas from the construction phase and readies it for experiments. Details of the acceptance test program results and of machine capabilities for experiments will be presented.

  14. Improved detection of lacZ reporter gene expression in transgenic epithelia by immunofluorescence microscopy.

    PubMed

    Mahony, Donna; Karunaratne, Seetha; Rothnagel, Joseph A

    2002-04-01

    The bacterial lacZ gene is commonly used as a reporter for the in vivo analysis of gene regulation in transgenic mice. However, several laboratories have reported poor detection of beta-galactosidase (the lacZ gene product) using histochemical techniques, particularly in skin. Here we report the difficulties we encountered in assessing lacZ expression in transgenic keratinocytes using classic X-gal histochemical protocols in tissues shown to express the transgene by mRNA in situ hybridization. We found that lacZ reporter gene expression could be reliably detected in frozen tissue sections by immunofluorescence analysis using a beta-galactosidase-specific antibody. Moreover, we were able to localize both transgene and endogenous gene products simultaneously using double-label immunofluorescence. Our results suggest that antibody detection of beta-galactosidase should be used to verify other assays of lacZ expression, particularly where low expression levels are suspected or patchy expression is observed. PMID:11994142

  15. Solving a discrete model of the lac operon using Z3

    NASA Astrophysics Data System (ADS)

    Gutierrez, Natalia A.

    2014-05-01

    A discrete model for the Lcac Operon is solved using the SMT-solver Z3. Traditionally the Lac Operon is formulated in a continuous math model. This model is a system of ordinary differential equations. Here, it was considerated as a discrete model, based on a Boolean red. The biological problem of Lac Operon is enunciated as a problem of Boolean satisfiability, and it is solved using an STM-solver named Z3. Z3 is a powerful solver that allows understanding the basic dynamic of the Lac Operon in an easier and more efficient way. The multi-stability of the Lac Operon can be easily computed with Z3. The code that solves the Boolean red can be written in Python language or SMT-Lib language. Both languages were used in local version of the program as online version of Z3. For future investigations it is proposed to solve the Boolean red of Lac Operon using others SMT-solvers as cvc4, alt-ergo, mathsat and yices.

  16. Does black hole spin play a key role in the FSRQ/BL Lac dichotomy?

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Debbijoy; Sreekumar, Parameswaran; Mukhopadhyay, Banibrata; Tomar, Ishan

    2016-04-01

    Blazars are characterized by large intensity and spectral variations across the electromagnetic spectrum It is believed that jets emerging from them are almost aligned with the line-of-sight. The majority of identified extragalactic sources in γ-ray catalogs of EGRET and Fermi are blazars. Observationally, blazars can be divided into two classes: flat spectrum radio quasars (FSRQs) and BL Lacs. BL Lacs usually exhibit lower γ-ray luminosity and harder power law spectra at γ-ray energies than FSRQs. We attempt to explain the high energy properties of FSRQs and BL Lacs from Fermi γ-ray space telescope observations. It was argued previously that the difference in accretion rates is mainly responsible for the large mismatch in observed luminosity in γ-ray. However, when intrinsic luminosities are derived by correcting for beaming effects, this difference in γ-ray luminosity between the two classes is significantly reduced. In order to explain this difference in intrinsic luminosities, we propose that spin plays an important role in the luminosity distribution dichotomy of BL Lacs and FSRQs. As the outflow power of a blazar increases with increasing spin of a central black hole, we suggest that the spin plays a crucial role in making BL Lac sources low luminous and slow rotators compared to FSRQ sources.

  17. Research on bodies of the executed in German anatomy: an accepted method that changed during the Third Reich. Study of anatomical journals from 1924 to 1951.

    PubMed

    Hildebrandt, Sabine

    2013-04-01

    While it is known that bodies of the executed were used for anatomical research in Germany during the Third Reich, it is unclear whether this type of work was unique to the time period or more common in Germany than elsewhere. The dissected persons and the anatomists involved have not been fully investigated. This study of anatomical journals from 1924 to 1951 shows that 166 out of 7,438 [2.2%] German language articles mentioned the use of "material" from the bodies of executed persons. In comparison, only 2 out of 4,702 English language articles explicitly mentioned bodies of the executed. From 1924 to1932, 33 of a total of 3,734 [1%] German articles listed the use of the executed. From 1933 to 1938 the number rose to 46 out of 2,265 [2%], and increased again from 1939 to 1945 to 73 out of 984 [7%]. After the war 15 out of 455 [3%] still dealt with "material" from the executed. German anatomists' familiarity with the use of the executed as a standard for healthy tissues even before 1933 may have contributed to the ease with which they accepted the "opportunities" (large-scale studies and research on women) presented to them by unlimited access to bodies of the executed provided by the abusive National Socialist (NS) legislation and continued using them for some years after the war. German postwar anatomy was built in part on the bodies of NS victims. Information given in some publications will help with further identification of these victims. PMID:22674739

  18. INFRARED SPECTRAL OBSERVATION OF EIGHT BL LAC OBJECTS FROM THE SPITZER INFRARED SPECTROGRAPH

    SciTech Connect

    Chen, P. S.; Shan, H. G.

    2011-05-01

    The Spitzer Infrared Spectrograph (IRS) low-resolution spectra for eight BL Lac objects are presented in this paper. It can be seen that the infrared spectrum of S5 0716+714 shows in the IRS region many emission features that would be from a nearby galaxy. It is also shown that, except for the silicate absorptions around 10 {mu}m for some sources, emission lines in the infrared spectra for the other seven BL Lac objects are indeed very weak or absent. In addition, ignoring the silicate feature, all spectra can be well fitted by a power-law distribution indicative of the emission mechanism of the synchrotron radiation for these BL Lac objects in the IRS region.

  19. Computing the period of light variability in BL Lac objects using the Jurkevich method.

    NASA Astrophysics Data System (ADS)

    Zhang, Xiong; Xie, Guangzhong; Bai, Jinming

    1998-07-01

    The authors present a method for finding the period of light variation in BL Lac objects. They find the long periods light variability in the BL Lac objects OJ 287, ON 231 and Mrk 421. Analysis and computing have shown that the data sample should span a very long time interval (about 100 years), covering at least six times the length of the periodicity being claimed, the possible period should refer to large amplitude variations and thus directly visible in the light curve. When the amplitude is low, far more than six times of the period length will be necessary to demonstrate its reality. The authors conclude that the method is the best way for period search in BL Lac objects.

  20. Period Variations of the Eclipsing Binary Systems T LMi and VX Lac

    NASA Astrophysics Data System (ADS)

    Yılmaz, M.; İzci, D. D.; Gümüş, D.; Özavci, İ.; Selam, S. O.

    2015-07-01

    We present a period analysis of the two Algol-type eclipsing binary systems T LMi and VX Lac using all available times of minimum in the literature, as well as new minima obtained at the Ankara University Kreiken Observatory. The period analysis of T LMi suggests mass transfer between the components and also a third body that is dynamically bound to the binary system. The analysis of VX Lac also suggests mass transfer between the components, and the presence of a third and a fourth body under the assumption of a Light-Time Effect. In addition, the periodic variation of VX Lac was examined under the hypothesis of magnetic activity, and the corresponding parameters were derived. We report here the orbital parameters for both systems, along with the ones related to mass transfer, and those for the third and fourth bodies.

  1. Spectroscopy of optically selected BL Lac objects and their γ-ray emission

    SciTech Connect

    Sandrinelli, A.; Treves, A.; Farina, E. P.; Landoni, M.; Falomo, R.; Foschini, L.; Sbarufatti, B.

    2013-12-01

    We present Very Large Telescope optical spectroscopy of nine BL Lac objects of unknown redshift belonging to the list of optically selected radio-loud BL Lac candidates. We explore their spectroscopic properties and possible link with gamma-ray emission. From the new observations we determine the redshifts of four objects from faint emission lines or from absorption features of their host galaxies. In three cases we find narrow intervening absorptions from which a lower limit to the redshift is inferred. For the remaining two featureless sources, lower limits to the redshift are deduced from the absence of spectral lines. A search for γ counterpart emission shows that six out of the nine candidates are Fermi γ-ray emitters and we find two new detections. Our analysis suggests that most of the BL Lac objects still lacking redshift information are most likely located at high redshifts.

  2. Detection of LacZ-Positive Cells in Living Tissue with Single-Cell Resolution.

    PubMed

    Doura, Tomohiro; Kamiya, Mako; Obata, Fumiaki; Yamaguchi, Yoshifumi; Hiyama, Takeshi Y; Matsuda, Takashi; Fukamizu, Akiyoshi; Noda, Masaharu; Miura, Masayuki; Urano, Yasuteru

    2016-08-01

    The LacZ gene, which encodes Escherichia coli β-galactosidase, is widely used as a marker for cells with targeted gene expression or disruption. However, it has been difficult to detect lacZ-positive cells in living organisms or tissues at single-cell resolution, limiting the utility of existing lacZ reporters. Herein we present a newly developed fluorogenic β-galactosidase substrate suitable for labeling live cells in culture, as well as in living tissues. This precisely functionalized fluorescent probe exhibited dramatic activation of fluorescence upon reaction with the enzyme, remained inside cells by anchoring itself to intracellular proteins, and provided single-cell resolution. Neurons labeled with this probe preserved spontaneous firing, which was enhanced by application of ligands of receptors expressed in the cells, suggesting that this probe would be applicable to investigate functions of targeted cells in living tissues and organisms. PMID:27400827

  3. Acceptance, values, and probability.

    PubMed

    Steel, Daniel

    2015-10-01

    This essay makes a case for regarding personal probabilities used in Bayesian analyses of confirmation as objects of acceptance and rejection. That in turn entails that personal probabilities are subject to the argument from inductive risk, which aims to show non-epistemic values can legitimately influence scientific decisions about which hypotheses to accept. In a Bayesian context, the argument from inductive risk suggests that value judgments can influence decisions about which probability models to accept for likelihoods and priors. As a consequence, if the argument from inductive risk is sound, then non-epistemic values can affect not only the level of evidence deemed necessary to accept a hypothesis but also degrees of confirmation themselves. PMID:26386533

  4. Newbery Medal Acceptance.

    ERIC Educational Resources Information Center

    Freedman, Russell

    1988-01-01

    Presents the Newbery Medal acceptance speech of Russell Freedman, writer of children's nonfiction. Discusses the place of nonfiction in the world of children's literature, the evolution of children's biographies, and the author's work on "Lincoln." (ARH)

  5. Newbery Medal Acceptance.

    ERIC Educational Resources Information Center

    Cleary, Beverly

    1984-01-01

    Reprints the text of Ms. Cleary's Newbery medal acceptance speech in which she gives personal history concerning her development as a writer and her response to the letters she receives from children. (CRH)

  6. Caldecott Medal Acceptance.

    ERIC Educational Resources Information Center

    Provensen, Alice; Provensen, Martin

    1984-01-01

    Reprints the text of the Provensens' Caldecott medal acceptance speech in which they describe their early interest in libraries and literature, the collaborative aspect of their work, and their current interest in aviation. (CRH)

  7. Determinants of bistability in induction of the Escherichia coli lac operon.

    PubMed

    Dreisigmeyer, D W; Stajic, J; Nemenman, I; Hlavacek, W S; Wall, M E

    2008-09-01

    The authors have developed a mathematical model of regulation of expression of the Escherichia coli lac operon, and have investigated bistability in its steady-state induction behaviour in the absence of external glucose. Numerical analysis of equations describing regulation by artificial inducers revealed two natural bistability parameters that can be used to control the range of inducer concentrations over which the model exhibits bistability. By tuning these bistability parameters, the authors found a family of biophysically reasonable systems that are consistent with an experimentally determined bistable region for induction by thio-methylgalactoside (TMG) (in Ozbudak et al. Nature, 2004, 427; p. 737). To model regulation by lactose, the authors developed similar equations in which allolactose, a metabolic intermediate in lactose metabolism and a natural inducer of lac, is the inducer. For biophysically reasonable parameter values, these equations yield no bistability in response to induction by lactose - only systems with an unphysically small permease-dependent export effect can exhibit small amounts of bistability for limited ranges of parameter values. These results cast doubt on the relevance of bistability in the lac operon within the natural context of E. coli, and help shed light on the controversy among existing theoretical studies that address this issue. The results also motivate a deeper experimental characterisation of permease-independent transport of lac inducers, and suggest an experimental approach to address the relevance of bistability in the lac operon within the natural context of E. coli. The sensitivity of lac bistability to the type of inducer emphasises the importance of metabolism in determining the functions of genetic regulatory networks. PMID:19045824

  8. A lacZ reporter gene expression atlas for 313 adult KOMP mutant mouse lines.

    PubMed

    West, David B; Pasumarthi, Ravi K; Baridon, Brian; Djan, Esi; Trainor, Amanda; Griffey, Stephen M; Engelhard, Eric K; Rapp, Jared; Li, Bowen; de Jong, Pieter J; Lloyd, K C Kent

    2015-04-01

    Expression of the bacterial beta-galactosidase reporter gene (lacZ) in the vector used for the Knockout Mouse Project (KOMP) is driven by the endogenous promoter of the target gene. In tissues from KOMP mice, histochemical staining for LacZ enzyme activity can be used to determine gene expression patterns. With this technique, we have produced a comprehensive resource of gene expression using both whole mount (WM) and frozen section (FS) LacZ staining in 313 unique KOMP mutant mouse lines. Of these, ∼ 80% of mutants showed specific staining in one or more tissues, while ∼ 20% showed no specific staining, ∼ 13% had staining in only one tissue, and ∼ 25% had staining in >6 tissues. The highest frequency of specific staining occurred in the brain (∼ 50%), male gonads (42%), and kidney (39%). The WM method was useful for rapidly identifying whole organ and some substructure staining, while the FS method often revealed substructure and cellular staining specificity. Both staining methods had >90% repeatability in biological replicates. Nonspecific LacZ staining occurs in some tissues due to the presence of bacteria or endogenous enzyme activity. However, this can be effectively distinguished from reporter gene activity by the combination of the WM and FS methods. After careful annotation, LacZ staining patterns in a high percentage of mutants revealed a unique structure-function not previously reported for many of these genes. The validation of methods for LacZ staining, annotation, and expression analysis reported here provides unique insights into the function of genes for which little is currently known. PMID:25591789

  9. A lacZ reporter gene expression atlas for 313 adult KOMP mutant mouse lines

    PubMed Central

    Pasumarthi, Ravi K.; Baridon, Brian; Djan, Esi; Trainor, Amanda; Griffey, Stephen M.; Engelhard, Eric K.; Rapp, Jared; Li, Bowen; de Jong, Pieter J.; Lloyd, K.C. Kent

    2015-01-01

    Expression of the bacterial beta-galactosidase reporter gene (lacZ) in the vector used for the Knockout Mouse Project (KOMP) is driven by the endogenous promoter of the target gene. In tissues from KOMP mice, histochemical staining for LacZ enzyme activity can be used to determine gene expression patterns. With this technique, we have produced a comprehensive resource of gene expression using both whole mount (WM) and frozen section (FS) LacZ staining in 313 unique KOMP mutant mouse lines. Of these, ∼80% of mutants showed specific staining in one or more tissues, while ∼20% showed no specific staining, ∼13% had staining in only one tissue, and ∼25% had staining in >6 tissues. The highest frequency of specific staining occurred in the brain (∼50%), male gonads (42%), and kidney (39%). The WM method was useful for rapidly identifying whole organ and some substructure staining, while the FS method often revealed substructure and cellular staining specificity. Both staining methods had >90% repeatability in biological replicates. Nonspecific LacZ staining occurs in some tissues due to the presence of bacteria or endogenous enzyme activity. However, this can be effectively distinguished from reporter gene activity by the combination of the WM and FS methods. After careful annotation, LacZ staining patterns in a high percentage of mutants revealed a unique structure-function not previously reported for many of these genes. The validation of methods for LacZ staining, annotation, and expression analysis reported here provides unique insights into the function of genes for which little is currently known. PMID:25591789

  10. High-energy cosmic neutrinos from spine-sheath BL Lac jets

    NASA Astrophysics Data System (ADS)

    Tavecchio, F.; Ghisellini, G.

    2015-08-01

    We recently proposed that structured (spine-sheath) jets associated with BL Lac objects could offer a suitable environment for the production of the extragalactic high-energy (E > 100 TeV) neutrino recently revealed by IceCube. Our previous analysis was limited to low-power BL Lac objects. We extend our preliminary study to the entire BL Lac population, assuming that the entire diffuse emission is accounted for by these sources. The neutrino output from a single source depends on a relatively large number of parameters. However, for several of them we have constraints coming from observations and previous application of the structured jet model to blazar and radiogalaxy emission. The observed neutrino spectrum then fixes the remaining free parameters. We assume that the power of cosmic rays as well as the radiative luminosity of the sheath depends linearly on the jet power. In turn, we assume that the latter is well traced by the γ-ray luminosity. We exploit the BL Lac γ-ray luminosity function and its cosmic evolution as recently inferred from Fermi-LAT data to derive the expected neutrino cumulative intensity from the entire BL Lac population. When considering only the low-power BL Lacs, a large cosmic ray power for each source is required to account for the neutrino flux. Instead, if BL Lacs of all powers produce neutrinos, the power demand decreases, and the required cosmic ray power becomes of the same order of the radiative jet power. In our scheme, the maximum energy of cosmic rays is constrained to be ≲ few PeV by the lack of events above few PeV. Although such a value is obtained through a fine-tuning with the data, we show that it could be possibly related to the equilibrium between cooling and acceleration processes for high-energy cosmic rays. We also discuss the prospects for the direct association of IceCube events with BL Lacs, providing an estimate of the expected counts for the most promising sources.

  11. Water resources of the Lac Qui Parle River Watershed, Southwestern Minnesota

    USGS Publications Warehouse

    Cotter, R.D.; Bidwell, L.E.

    1968-01-01

    The Lac qui Parle River watershed is underlain by thick water-bearing sections of glacial drift and Cretaceous rocks. Drainage is from the Coteau des Praries, a plateau in the southwest, to the Lac qui Parle reservoir, about 800 feet lower than the plateau. The term "watershed" as used in this report refers to that part of the drainage basin (767 square miles) within Minnesota. The total area of the drainage basin, including South Dakota, is 1110 square miles. Most waters from the watershed are of good quality.

  12. VizieR Online Data Catalog: CZ Lac multiperiodic Blazhko modulation (Sodor+, 2011)

    NASA Astrophysics Data System (ADS)

    Sodor, A.; Jurcsik, J.; Szeidl, B.; Varadi, M.; Henden, A.; Vida, K.; Hurta, Zs.; Posztobanyi, K.; Dekany, I.; Szing, A.

    2011-09-01

    CZ Lac was observed with a photometer attached to the 60-cm telescope of the Konkoly Observatory, Svabhegy, Budapest, through B and V filters on seven nights in 1967 (table A1), and 2 seasons between 2004 and 2005. We observed CZ Lac with the same, refurbished and automated 60-cm telescope equipped with a Wright Instruments 750x1100 CCD camera (field of view 17x24arcmin) in 2004 and 2005. About 29 000 frames were obtained in BV(RI)C bands. The data of the two seasons spanned 146 and 84d. (8 data files).

  13. Far-infrared photometry of compact extragalactic sources: OJ 187 and BL Lac

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Joy, M.; Lester, D. F.; Wilking, B. A.

    1984-01-01

    The 50 and 100 micron emissions of OJ 287 were detected and upper limits for BL Lac were obtained. These first measurements of two BL Lac objects in the far-infrared show them to be similar to the few quasars previously observed in the far-infrared. In particular, there is no evidence for significant dust emission, and the lambda approximately 100 micron flux density fits on a smooth line joining the near-infrared and millimeter continuum fluxes. The implications of the results for models of the sources are discussed briefly.

  14. Are BL Lac-type objects nearby black holes. [gas accretion model

    NASA Technical Reports Server (NTRS)

    Shapiro, S. L.; Elliot, J. L.

    1974-01-01

    It is pointed out that isolated black holes accreting interstellar gas can account for the characteristic properties of the Lacertids. Emission spectra for various interstellar gas densities and black hole masses are compared with the data plotted by Strittmatter et al. (1972) for the BL Lac-type objects. Rough estimates indicate that there may indeed be a finite number of stellar-mass black holes close to the earth as required by the theory. If it is determined that the BL Lac-type objects lie outside of the galactic disk a black hole accretion model may still apply if certain conditions are satisfied.

  15. Solvent H-bond accepting ability induced conformational change and its influence towards fluorescence enhancement and dual fluorescence of hydroxy meta-GFP chromophore analogue.

    PubMed

    Chatterjee, Tanmay; Mandal, Mrinal; Mandal, Prasun K

    2016-09-21

    The effect of structural rigidity towards enhancement of fluorescence quantum yield of GFP chromophore analogues has been documented. In the present study, a new way of enhancing the fluorescence quantum yield of two ortho-meta GFP chromophore analogues meta-methoxy-ortho-hydroxy-benzylimidazolidinone (abbreviated as mOMe-HBDI) and meta-diethylamino-ortho-hydroxyl imidazolidinone (abbreviated as MOHIM) has been reported. This enhancement is controlled by the H-bond accepting ability (denoted as β value) of the solvent and happens only in the case of GFP chromophore analogues having ortho (hydroxyl)-meta (electron donating group) and not in the case of analogues having a para electron donating group. The ground state (solid) conformation of mOMe-HBDI has been obtained from single crystal X-ray analysis, exhibiting the existence of strong intramolecular H-bonding. However, in solution phase, as the solvent β value increases, the strength of intramolecular H-bonding decreases. This process has strong influence on the relative conformational orientation of phenyl and imidazolidinone rings. For mOMe-HBDI, fluorescence quantum yield increases with increase in β value of the solvents. However, the effect of solvent polarity cannot be completely ruled out. The lower wavelength emission band (∼480 nm) has been assigned to the normal charge-transferred (CT) species, whereas the highly Stokes shifted emission band (∼660 nm) has been assigned to the proton-transferred (PT) tautomer species for mOMe-HBDI. In solvents of low β value (say hexane) only the PT band and in solvents of high β value (say DMSO) only the CT band is observed. Quite interestingly, in solvents of intermediate β value both CT and PT bands, thus dual emission, are observed. For mOMe-HBDI when fluorescence decay is monitored at the normal CT emission band, it is observed to be biexponential in nature. The short component increases from ∼0.2 ns to 0.6 ns and the long component increases from 1 to 3

  16. Program Evaluation: Outcomes of Participation in Lac Du Bois, the French Language Village of Concordia Language Villages

    ERIC Educational Resources Information Center

    Clementi, Donna L.

    2012-01-01

    The purpose of this study was to describe perceptions of stakeholders (leadership of Concordia Language Villages, staff members and villagers of "Lac du Bois", the French Language Village of Concordia Language Villages), related to achievement of the mission statement. The research question was: How do stakeholders in "Lac du…

  17. The Hinge Region Strengthens the Nonspecific Interaction between Lac-Repressor and DNA: A Computer Simulation Study

    PubMed Central

    Sun, Lili; Tabaka, Marcin; Hou, Sen; Li, Lin; Burdzy, Krzysztof; Aksimentiev, Aleksei; Maffeo, Christopher; Zhang, Xuzhu; Holyst, Robert

    2016-01-01

    LacI is commonly used as a model to study the protein-DNA interaction and gene regulation. The headpiece of the lac-repressor (LacI) protein is an ideal system for investigation of nonspecific binding of the whole LacI protein to DNA. The hinge region of the headpiece has been known to play a key role in the specific binding of LacI to DNA, whereas its role in nonspecific binding process has not been elucidated. Here, we report the results of explicit solvent molecular dynamics simulation and continuum electrostatic calculations suggesting that the hinge region strengthens the nonspecific interaction, accounting for up to 50% of the micro-dissociation free energy of LacI from DNA. Consequently, the rate of microscopic dissociation of LacI from DNA is reduced by 2~3 orders of magnitude in the absence of the hinge region. We find the hinge region makes an important contribution to the electrostatic energy, the salt dependence of electrostatic energy, and the number of salt ions excluded from binding of the LacI-DNA complex. PMID:27008630

  18. The Hinge Region Strengthens the Nonspecific Interaction between Lac-Repressor and DNA: A Computer Simulation Study.

    PubMed

    Sun, Lili; Tabaka, Marcin; Hou, Sen; Li, Lin; Burdzy, Krzysztof; Aksimentiev, Aleksei; Maffeo, Christopher; Zhang, Xuzhu; Holyst, Robert

    2016-01-01

    LacI is commonly used as a model to study the protein-DNA interaction and gene regulation. The headpiece of the lac-repressor (LacI) protein is an ideal system for investigation of nonspecific binding of the whole LacI protein to DNA. The hinge region of the headpiece has been known to play a key role in the specific binding of LacI to DNA, whereas its role in nonspecific binding process has not been elucidated. Here, we report the results of explicit solvent molecular dynamics simulation and continuum electrostatic calculations suggesting that the hinge region strengthens the nonspecific interaction, accounting for up to 50% of the micro-dissociation free energy of LacI from DNA. Consequently, the rate of microscopic dissociation of LacI from DNA is reduced by 2~3 orders of magnitude in the absence of the hinge region. We find the hinge region makes an important contribution to the electrostatic energy, the salt dependence of electrostatic energy, and the number of salt ions excluded from binding of the LacI-DNA complex. PMID:27008630

  19. Analysis of the spacer DNA between the cyclic AMP receptor protein binding site and the lac promoter.

    PubMed Central

    Flatow, U; Rajendrakumar, G V; Garges, S

    1996-01-01

    The role of the spacer region DNA between the cyclic AMP receptor protein (CRP) site and the RNA polymerase in the lac promoter was examined. We wanted to determine whether the wild-type DNA sequence of this region was an absolute requirement for CRP activation of lac transcription. The sequence of a 9-bp stretch of the spacer, from -41 to -49 relative to the start of transcription, was randomized, and the effect of randomization on lac expression was investigated in vitro and in vivo. We found that the spacer contains no specific sequence determinants for CRP activation of lac transcription; fewer than 1% of the mutants displayed greater than a 50% decrease in CRP activation of lac transcription. PMID:8636052

  20. Kepler Observations of Rapid Optical Variability in the BL Lac Object W2r192+42

    NASA Technical Reports Server (NTRS)

    R.Edelson; Mushotzky, R.; Vaughn, S.; Scargle, J.; Gandhi, P.; Malkan, M.; Baumgartner, W.

    2013-01-01

    We present the first Kepler monitoring of a strongly variable BL Lac, W2R1926+42. The light curve covers 181 days with approx. 0.2% errors, 30 minute sampling and >90% duty cycle, showing numerous delta-I/I > 25% flares over timescales as short as a day. The flux distribution is highly skewed and non-Gaussian. The variability shows a strong rms-flux correlation with the clearest evidence to date for non-linearity in this relation. We introduce a method to measure periodograms from the discrete autocorrelation function, an approach that may be well-suited to a wide range of Kepler data. The periodogram is not consistent with a simple power-law, but shows a flattening at frequencies below 7x10(exp -5) Hz. Simple models of the power spectrum, such as a broken power law, do not produce acceptable fits, indicating that the Kepler blazar light curve requires more sophisticated mathematical and physical descriptions than currently in use.

  1. Geology, petrography, geochemistry, and genesis of sulfide-rich pods in the Lac des Iles palladium deposits, western Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Duran, Charley J.; Barnes, Sarah-Jane; Corkery, John T.

    2016-04-01

    The Lac des Iles Pd deposits are known for their Pd-rich sulfide-poor mineralization. However, previously undocumented sulfide-rich pods also occur within the intrusion that hosts the deposits. Given the complex magmatic and hydrothermal history of the mineralization at Lac des Iles, the sulfide-rich pods could have crystallized from magmatic sulfide liquids or precipitated from hydrothermal fluids. Sulfide-rich pods occur throughout the stratigraphy, in all rock types, and along comagmatic shear zones, and contain net-textured to massive sulfides. They can be divided into four main groups based on the variation in mineral assemblages: (1) pyrrhotite-pentlandite ± pyrite-chalcopyrite-magnetite-ilmenite; (2) chalcopyrite ± pyrrhotite-pentlandite-pyrite-magnetite-ilmenite; (3) pyrite ± pentlandite-chalcopyrite-pyrrhotite-magnetite-ilmenite; and (4) magnetite ± ilmenite-pyrrhotite-pentlandite-pyrite-chalcopyrite. Whole rock metal contents and S isotopic compositions do not change with the amount of pyrite present, except for slight enrichments in As and Bi. The presence of an essentially magmatic sulfide mineral assemblage (pyrrhotite-pentlandite ± chalcopyrite) with pentlandite exsolution flames in pyrrhotite in some pods suggests that the pods crystallized from magmatic sulfide liquids. The very low Cu contents of the pods suggests that they are mainly cumulates of monosulfide solid solution (MSS). We propose a model whereby sulfide liquids were concentrated into dilation zones prior to crystallizing cumulus MSS. Intermediate solid solution crystallized from the fractionated liquids at the edges of some pods leaving residual liquids enriched in Pt, Pd, Au, As, Bi, Sb, and Te. These residual liquids are no longer associated with the pods. During subsequent alteration, pyrite replaced MSS/pyrrhotite, but this did not affect the platinum-group element contents of the pods.

  2. Can the KTP laser change the cementum surface of healthy and diseased teeth providing an acceptable root surface for fibroblast attachment?

    NASA Astrophysics Data System (ADS)

    Mailhot, Jason M.; Garnick, Jerry J.

    1996-04-01

    The purpose of our research is to determine the effects of KTP laser on root cementum and fibroblast attachment. Initial work has been completed in testing the effect of different energy levels on root surfaces. From these studies optimal energy levels were determined. In subsequent studies the working distance and exposure time required to obtain significant fibroblast attachment to healthy cementum surfaces were investigated. Results showed that lased cemental surfaces exhibited changes in surface topography which ranged from a melted surface to an apparent slight fusion of the surface of the covering smear layer. When the optimal energy level was used, fibroblasts demonstrate attachment on the specimens, resulting in the presence of a monolayer of cells on the control surfaces as well as on the surfaces lased with this energy level. The present study investigates the treatment of pathological root surfaces and calculus with a KTP laser utilizing these optimal parameters determine previously. Thirty single rooted teeth with advanced periodontal disease and ten healthy teeth were obtained, crowns were sectioned and roots split longitudinally. Forty test specimens were assigned into 1 of 4 groups; pathologic root--not lased, pathologic root--lased, root planed root and health root planed root. Human gingival fibroblasts were seeded on specimens and cultured for 24 hours. Specimens were processed for SEM. The findings suggest that with the KTP laser using a predetermined energy level applied to pathological root surfaces, the lased surfaces provided an unacceptable surface for fibroblast attachment. However, the procedural control using healthy root planed surfaces did demonstrate fibroblast attachment.

  3. 77 FR 27245 - Big Stone National Wildlife Refuge, Big Stone and Lac Qui Parle Counties, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-09

    ... Fish and Wildlife Service Big Stone National Wildlife Refuge, Big Stone and Lac Qui Parle Counties, MN... comprehensive conservation plan (CCP) and environmental assessment (EA) for Big Stone National Wildlife Refuge...: r3planning@fws.gov . Include ``Big Stone Draft CCP/ EA'' in the subject line of the message. Fax:...

  4. In silico evolved lac operons exhibit bistability for artificial inducers, but not for lactose.

    PubMed

    van Hoek, M J A; Hogeweg, P

    2006-10-15

    Bistability in the lac operon of Escherichia coli has been widely studied, both experimentally and theoretically. Experimentally, bistability has been observed when E. coli is induced by an artificial, nonmetabolizable, inducer. However, if the lac operon is induced with lactose, the natural inducer, bistability has not been demonstrated. We derive an analytical expression that can predict the occurrence of bistability both for artificial inducers and lactose. We find very different conditions for bistability in the two cases. Indeed, for artificial inducers bistability is predicted, but for lactose the condition for bistability is much more difficult to satisfy. Moreover, we demonstrate that in silico evolution of the lac operon generates an operon that avoids bistability with respect to lactose, but does exhibit bistability with respect to artificial inducers. The activity of this evolved operon strikingly resembles the experimentally observed activity of the operon. Thus our computational experiments suggest that the wild-type lac operon, which regulates lactose metabolism, is not a bistable switch. Nevertheless, for engineering purposes, this operon can be used as a bistable switch with artificial inducers. PMID:16877514

  5. Determining the bistability parameter ranges of artificially induced lac operon using the root locus method.

    PubMed

    Avcu, N; Alyürük, H; Demir, G K; Pekergin, F; Cavas, L; Güzeliş, C

    2015-06-01

    This paper employs the root locus method to conduct a detailed investigation of the parameter regions that ensure bistability in a well-studied gene regulatory network namely, lac operon of Escherichia coli (E. coli). In contrast to previous works, the parametric bistability conditions observed in this study constitute a complete set of necessary and sufficient conditions. These conditions were derived by applying the root locus method to the polynomial equilibrium equation of the lac operon model to determine the parameter values yielding the multiple real roots necessary for bistability. The lac operon model used was defined as an ordinary differential equation system in a state equation form with a rational right hand side, and it was compatible with the Hill and Michaelis-Menten approaches of enzyme kinetics used to describe biochemical reactions that govern lactose metabolism. The developed root locus method can be used to study the steady-state behavior of any type of convergent biological system model based on mass action kinetics. This method provides a solution to the problem of analyzing gene regulatory networks under parameter uncertainties because the root locus method considers the model parameters as variable, rather than fixed. The obtained bistability ranges for the lac operon model parameters have the potential to elucidate the appearance of bistability for E. coli cells in in vivo experiments, and they could also be used to design robust hysteretic switches in synthetic biology. PMID:25864166

  6. Catenation of carbon in LaC2 predicted under high pressure.

    PubMed

    Su, Chuanxun; Zhang, Jurong; Liu, Guangtao; Wang, Xin; Wang, Hui; Ma, Yanming

    2016-06-01

    Carbon has the capability of forming various bonding states that affect the structures and properties of transition metal carbides. In this work, structural search was performed to explore the structural diversity of LaC2 at pressures of 0.0-30.0 GPa. Five stable structures of LaC2 reveal a variety of carbon structural units ranging from a dimer to bent C3, zigzag C4 and armchair polymer chains. A series of pressure-induced structural transformations are predicted, I4/mmm (i.e. experimental α phase) →C2/c→Pnma→Pmma, which involve the catenation of carbon from a dimer to zigzag C4 units and further to armchair polymer chains. The bent C3 unit appears in a novel Immm structure. This structure is the theoretical ground state of LaC2 under ambient conditions, but is kinetically inaccessible from the experimental α phase. LaC2 becomes thermodynamically metastable relative to La2C3 + diamond above 17.1 GPa, and eventually decomposes into constituent elements above 35.6 GPa. The presented results indicate that catenation of carbon can be realized even in simple inorganic compounds under nonambient conditions. PMID:27166981

  7. SPECTROSCOPY OF THE LARGEST EVER {gamma}-RAY-SELECTED BL LAC SAMPLE

    SciTech Connect

    Shaw, Michael S.; Romani, Roger W.; Healey, Stephen E.; Michelson, Peter F.; Readhead, Anthony C. S.; Richards, Joseph L.; Max-Moerbeck, Walter; King, Oliver G.

    2013-02-20

    We report on spectroscopic observations covering most of the 475 BL Lacs in the second Fermi Large Area Telescope (LAT) catalog of active galactic nuclei (AGNs). Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic z-tilde from 0.23 to 0.33 and include redshifts as large as z = 2.471. Spectroscopic redshift minima from intervening absorbers have z-tilde = 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M {sub .} {approx} 10{sup 8.5} - 10{sup 9}, substantially larger than the mean of optical AGNs and LAT Flat Spectrum Radio Quasar samples. A slow increase in M {sub .} with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the {gamma}-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance.

  8. (Fond du Lac archeological resources within the Draft Area Recommendation Report)

    SciTech Connect

    Danz, D.L.

    1986-07-28

    Research into archaeological resources of the Fond du Lac Band within the DOE proposed high-level nuclear waste sites resulted in the discovery of four traditional ancestral sites. A number of ancestral sites that are located within other proposed repository sites were also discovered.

  9. The environment of x ray selected BL Lacs: Host galaxies and galaxy clustering

    NASA Technical Reports Server (NTRS)

    Wurtz, Ron; Stocke, John T.; Ellingson, Erica; Yee, Howard K. C.

    1993-01-01

    Using the Canada-France-Hawaii Telescope, we have imaged a complete, flux-limited sample of Einstein Medium Sensitivity Survey BL Lacertae objects in order to study the properties of BL Lac host galaxies and to use quantitative methods to determine the richness of their galaxy cluster environments.

  10. Elastic Rod Model of a DNA Loop in the Lac Operon

    NASA Astrophysics Data System (ADS)

    Balaeff, Alexander; Mahadevan, L.; Schulten, Klaus

    1999-12-01

    We use the theory of elasticity to compute the shape of the DNA loop bridging the gap in the crystal structure of the lac repressor-DNA complex. The Kirchhoff system of equations with boundary conditions derived from the crystal structure is solved using a continuation method. This approach can be applied effectively to find coarse-grained conformational minima of DNA loops.

  11. Lac repressor: a genetic and nuclear magnetic resonance study of structure and function

    SciTech Connect

    Jarema, M.A.C.; Lu, P.; Miller, J.H.

    1980-10-01

    The prototype gene control system, the lac operon of E. coli, has recently also become the best chemically characterized system to date. The complete primary sequence of both the gene and the protein reponsible for the regulation of this operon, the repressor, is known, along with the DNA sequence of its site of action, the operator. The lac repressor is a tetrametic protein with four identical subunits of 360 amino acids each, giving a total molecular weight of 154,000. The lac operator sequence is about 25 to 30 base pairs long. With the wealth of information about the primary structure the next question is one of geometry. This leads to the application of either x-ray diffraction or nuclear magnetic resonance (NMR) methods, since these are the only approaches that yield information about the geometry and environment of specific groups and atoms in these molecules. Since we are interested in the interaction of repressor with a variety of small molecular weight inducers and anti-inducers, as well as the operator sequence in aqueous solution, we chose the NMR approach. As of this writing, no useful crystals of the lac repressor or the repressor and any of its ligands have been reported. Because of our extensive genetic work with this system, we have a unique advantage in taking this approach as well.

  12. HOST PLANT RANGE OF LOBATE LAC SCALE, PARATACHARDINA LOBATA, IN FLORIDA.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The lobate lac scale (Paratacharidina lobata) is a serious pest of woody native and ornamental plants in Florida and the Bahamas. This insect, which is native to India and Sri Lanka, was known to attack many plants the number of plants it attacked in Florida was unknown. Field observation and field ...

  13. 77 FR 2774 - Notice of Intent To Prepare a Supplemental Environmental Impact Statement: Fond du Lac...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ...The FHWA is issuing this notice to advise the public that a limited scope Supplemental Environmental Impact Statement (SEIS) will be prepared for the proposed capacity improvements to Wisconsin Highway 23 from U.S. Highway 151 to County Highway P in Fond du Lac and Sheboygan Counties,...

  14. Accept or divert?

    PubMed

    Angelucci, P A

    1999-09-01

    Stretching scarce resources is more than a managerial issue. Should you accept the patient to an understaffed ICU or divert him to another facility? The intense "medical utility" controversy focuses on a situation that critical care nurses now face every day. PMID:10614370

  15. Approaches to acceptable risk

    SciTech Connect

    Whipple, C.

    1997-04-30

    Several alternative approaches to address the question {open_quotes}How safe is safe enough?{close_quotes} are reviewed and an attempt is made to apply the reasoning behind these approaches to the issue of acceptability of radiation exposures received in space. The approaches to the issue of the acceptability of technological risk described here are primarily analytical, and are drawn from examples in the management of environmental health risks. These include risk-based approaches, in which specific quantitative risk targets determine the acceptability of an activity, and cost-benefit and decision analysis, which generally focus on the estimation and evaluation of risks, benefits and costs, in a framework that balances these factors against each other. These analytical methods tend by their quantitative nature to emphasize the magnitude of risks, costs and alternatives, and to downplay other factors, especially those that are not easily expressed in quantitative terms, that affect acceptance or rejection of risk. Such other factors include the issues of risk perceptions and how and by whom risk decisions are made.

  16. Why was Relativity Accepted?

    NASA Astrophysics Data System (ADS)

    Brush, S. G.

    Historians of science have published many studies of the reception of Einstein's special and general theories of relativity. Based on a review of these studies, and my own research on the role of the light-bending prediction in the reception of general relativity, I discuss the role of three kinds of reasons for accepting relativity (1) empirical predictions and explanations; (2) social-psychological factors; and (3) aesthetic-mathematical factors. According to the historical studies, acceptance was a three-stage process. First, a few leading scientists adopted the special theory for aesthetic-mathematical reasons. In the second stage, their enthusiastic advocacy persuaded other scientists to work on the theory and apply it to problems currently of interest in atomic physics. The special theory was accepted by many German physicists by 1910 and had begun to attract some interest in other countries. In the third stage, the confirmation of Einstein's light-bending prediction attracted much public attention and forced all physicists to take the general theory of relativity seriously. In addition to light-bending, the explanation of the advance of Mercury's perihelion was considered strong evidence by theoretical physicists. The American astronomers who conducted successful tests of general relativity became defenders of the theory. There is little evidence that relativity was `socially constructed' but its initial acceptance was facilitated by the prestige and resources of its advocates.

  17. The transition between BL Lac objects and flat spectrum radio quasars

    NASA Astrophysics Data System (ADS)

    Ghisellini, G.; Tavecchio, F.; Foschini, L.; Ghirlanda, G.

    2011-07-01

    We study the BL Lac objects detected in the 1-year all-sky survey of the Fermi satellite, with an energy spectral slope αγ in the 0.1-100 GeV band greater than 1.2. In the αγ versus γ-ray luminosity plane, these BL Lacs occupy the region populated by flat spectrum radio quasars (FSRQs). Studying the properties of their spectral energy distributions (SEDs) and of their emitting lines, we find that several of these BL Lacs have an SED similar to FSRQs and that they do have broad lines of large equivalent width (EW), and should be reclassified as FSRQs even adopting the current phenomenological definition (i.e. EW of the emitting line greater than 5 Å). In other cases, even if the EW is small, the emitting lines can be as luminous as in quasars, and again their SED is similar to the SED of FSRQs. Sources classified as BL Lacs with an SED appearing as intermediate between BL Lacs and FSRQs also have relatively weak broad emission lines and small EW, and can be considered as transition sources. These properties are confirmed also by model fitting that allows us to derive the relevant intrinsic jet parameters and the jet power. This study leads us to propose a physical distinction between the two classes of blazars, based on the luminosity of the broad-line region measured in Eddington units. The dividing line is of the order of LBLR/LEdd˜ 5 × 10-4, in good agreement with the idea that the presence of strong emitting lines is related to a transition in the accretion regime, becoming radiatively inefficient below a disc luminosity of the order of 1 per cent of the Eddington one.

  18. Positive control of lac operon expression in vitro by guanosine 5'-diphosphate 3'-diphosphate.

    PubMed

    Primakoff, P; Artz, S W

    1979-04-01

    Maximal expression of the Escherichia coli lactose operon in a coupled in vitro transcription-translation system from a Salmonella typhimurium relA mutant was strongly dependent upon addition of guanosine 5'-diphosphate 3'-diphosphate (ppGpp). Without added ppGpp, at saturating 3',5'-cyclic AMP (cAMP) concentrations, synthesis of beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) was reproducibly only 5-7% of that which can be obtained with 0.5-0.8 mM ppGpp. Experiments in which transcription was uncoupled from translation indicated that this 14- to 20-fold stimulation by ppGpp occurred at the level of transcription. When coupled beta-galactosidase synthesis was primed with a template containing a well-characterized mutant lac promoter (lacP(r)L8UV5), the dependence on ppGpp was greatly reduced. This result provides an important experimental control previously unavailable for verifying the significance of ppGpp effects on gene regulation in vitro; it indicates that activation of lacP(+) expression by ppGpp is specifically an effect of increased transcription initiations. Furthermore, the large ppGpp stimulation of lacP(+) DNA enabled the level of expression of this template to approach that of lacP(r)L8UV5 DNA, an observation expected from results in vivo but not obtained with other transcription-translation systems in vitro. The importance of these results is considered with respect to previous ideas on the physiological role of ppGpp as a supercontrol molecule in bacterial regulation. PMID:109832

  19. Four therapeutic diets: adherence and acceptability.

    PubMed

    Berkow, Susan E; Barnard, Neal; Eckart, Jill; Katcher, Heather

    2010-01-01

    Many health conditions are treated, at least in part, by therapeutic diets. Although the success of any intervention depends on its acceptability to the patient, the acceptability of therapeutic diets and factors that influence it have been largely neglected in nutrition research. A working definition of acceptability is proposed and an examination and summary are provided of available data on the acceptability of common diet regimens used for medical conditions. The goal is to suggest ways to improve the success of therapeutic diets. The proposed working definition of "acceptability" refers to the user's judgment of the advantages and disadvantages of a therapeutic diet-in relation to palatability, costs, and effects on eating behaviour and health-that influence the likelihood of adherence. Very low-calorie, reduced-fat omnivorous, vegetarian and vegan, and low-carbohydrate diets all achieve acceptability among the majority of users in studies of up to one year, in terms of attrition and adherence rates and results of questionnaires assessing eating behaviours. Longer studies are fewer, but they suggest that vegetarian, vegan, and reduced-fat diets are acceptable, as indicated by sustained changes in nutrient intake. Few studies of this length have been published for very low-calorie or low-carbohydrate diets. Long-term studies of adherence and acceptability of these and other therapeutic diets are warranted. PMID:21144137

  20. Tethered particle motion reveals that LacI·DNA loops coexist with a competitor-resistant but apparently unlooped conformation.

    PubMed

    Revalee, Joel D; Blab, Gerhard A; Wilson, Henry D; Kahn, Jason D; Meiners, Jens-Christian

    2014-02-01

    The lac repressor protein (LacI) efficiently represses transcription of the lac operon in Escherichia coli by binding to two distant operator sites on the bacterial DNA and causing the intervening DNA to form a loop. We employed single-molecule tethered particle motion to observe LacI-mediated loop formation and breakdown in DNA constructs that incorporate optimized operator binding sites and intrinsic curvature favorable to loop formation. Previous bulk competition assays indirectly measured the loop lifetimes in these optimized DNA constructs as being on the order of days; however, we measured these same lifetimes to be on the order of minutes for both looped and unlooped states. In a range of single-molecule DNA competition experiments, we found that the resistance of the LacI-DNA complex to competitive binding is a function of both the operator strength and the interoperator sequence. To explain these findings, we present what we believe to be a new kinetic model of loop formation and DNA competition. In this proposed new model, we hypothesize a new unlooped state in which the unbound DNA-binding domain of the LacI protein interacts nonspecifically with nonoperator DNA adjacent to the operator site at which the second LacI DNA-binding domain is bound. PMID:24507611

  1. Enhanced bacterial protein expression during auto-induction obtained by alteration of lac repressor dosage and medium composition.

    PubMed

    Blommel, Paul G; Becker, Katie J; Duvnjak, Petar; Fox, Brian G

    2007-01-01

    The auto-induction method of protein expression in E. coli is based on diauxic growth resulting from dynamic function of lac operon regulatory elements (lacO and LacI) in mixtures of glucose, glycerol, and lactose. The results show that successful execution of auto-induction is strongly dependent on the plasmid promoter and repressor construction, on the oxygenation state of the culture, and on the composition of the auto-induction medium. Thus expression hosts expressing high levels of LacI during aerobic growth exhibit reduced ability to effectively complete the auto-induction process. Manipulation of the promoter to decrease the expression of LacI altered the preference for lactose consumption in a manner that led to increased protein expression and partially relieved the sensitivity of the auto-induction process to the oxygenation state of the culture. Factorial design methods were used to optimize the chemically defined growth medium used for expression of two model proteins, Photinus luciferase and enhanced green fluorescent protein, including variations for production of both unlabeled and selenomethionine-labeled samples. The optimization included studies of the expression from T7 and T7-lacI promoter plasmids and from T5 phage promoter plasmids expressing two levels of LacI. Upon the basis of the analysis of over 500 independent expression results, combinations of optimized expression media and expression plasmids that gave protein yields of greater than 1000 mug/mL of expression culture were identified. PMID:17506520

  2. Seeking to change while accepting the now.

    PubMed

    Baumann, Steven L

    2010-01-01

    The efforts of several nurse authors and Marsha Linehan to integrate diverse methods taken from philosophy, the human sciences, and spirituality with the biomedical model and natural science are discussed in relation to healthcare and nursing practice. PMID:20026733

  3. Regulation of nitrogen fixation in Klebsiella pneumoniae: isolation and characterization of strains with nif-lac fusions.

    PubMed Central

    MacNeil, D; Zhu, J; Brill, W J

    1981-01-01

    Strains with lac fused to each of the seven nif operons were isolated by two different methods. Repressing conditions prevented expression of all nif operons, whereas derepressing conditions led to the expression of all nif operons. No differences in Nif regulation were observed between Escherichia coli and Klebsiella pneumoniae with the same nif-lac fusions. Most derivatives of nif-lac fusion strains selected on lactose and NH4+ contained nif operator mutations. Some derivative contained deletions, which establishes that the direction of transcription of all seven nif operons is toward his Images PMID:7007318

  4. Acceptability of human risk.

    PubMed Central

    Kasperson, R E

    1983-01-01

    This paper has three objectives: to explore the nature of the problem implicit in the term "risk acceptability," to examine the possible contributions of scientific information to risk standard-setting, and to argue that societal response is best guided by considerations of process rather than formal methods of analysis. Most technological risks are not accepted but are imposed. There is also little reason to expect consensus among individuals on their tolerance of risk. Moreover, debates about risk levels are often at base debates over the adequacy of the institutions which manage the risks. Scientific information can contribute three broad types of analyses to risk-setting deliberations: contextual analysis, equity assessment, and public preference analysis. More effective risk-setting decisions will involve attention to the process used, particularly in regard to the requirements of procedural justice and democratic responsibility. PMID:6418541

  5. 7 CFR 54.1019 - Renewal of acceptance certification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Renewal of acceptance certification. 54.1019 Section..., Processing, and Packaging of Livestock and Poultry Products § 54.1019 Renewal of acceptance certification... acceptance of compliance shall resubmit the design and fabrication details of any change in materials...

  6. Age and Acceptance of Euthanasia.

    ERIC Educational Resources Information Center

    Ward, Russell A.

    1980-01-01

    Study explores relationship between age (and sex and race) and acceptance of euthanasia. Women and non-Whites were less accepting because of religiosity. Among older people less acceptance was attributable to their lesser education and greater religiosity. Results suggest that quality of life in old age affects acceptability of euthanasia. (Author)

  7. Quantitative approaches to the study of bistability in the lac operon of Escherichia coli.

    PubMed

    Santillán, Moisés; Mackey, Michael C

    2008-08-01

    In this paper, the history and importance of the lac operon in the development of molecular and systems biology are briefly reviewed. We start by presenting a description of the regulatory mechanisms in this operon, taking into account the most recent discoveries. Then we offer a survey of the history of the lac operon, including the discovery of its main elements and the subsequent influence on the development of molecular and systems biology. Next the bistable behaviour of the operon is discussed, both with respect to its discovery and its molecular origin. A review of the literature in which this bistable phenomenon has been studied from a mathematical modelling viewpoint is then given. We conclude with some brief remarks. PMID:18426771

  8. Diverse galactooligosaccharides consumption by bifidobacteria: implications of β-galactosidase--LacS operon.

    PubMed

    Akiyama, Takuya; Kimura, Kazumasa; Hatano, Hiroshi

    2015-01-01

    Galactooligosaccharides (GOS) possess prebiotic properties that specifically increase the number of bifidobacteria in the human intestine, thus giving health benefits to the host. Although the bifidogenic effect of GOS has been demonstrated in numerous studies, the utilization of GOS by specific bifidobacteria remains unclear. The goal of our study was to elucidate GOS consumption by specific bifidobacteria and gain insights into the mechanism. First, we examined GOS consumption by 14 bifidobacterial strains belonging to seven different species by comparing growth rate, carbohydrate consumption, and acid production. We then performed a transcription analysis in the case of one strong GOS consumer, Bifidobacterium adolescentis YIT 4011(T), to predict the operon contributing to GOS use. The study indicated the contribution of an operon consisted of LacS symporter and β-galactosidase to bifidobacterial GOS consumption. PMID:25483279

  9. Hot absorbers and the x-ray spectra of BL Lac objects

    NASA Technical Reports Server (NTRS)

    Urry, C. Megan

    1994-01-01

    This is the final report to the National Aeronautics and Space Administration (NASA) concerning NASA grant NAG5-1671. This grant was awarded to Dr. C. Megan Urry of the Space Telescope Science Institute in response to a proposal, entitled 'Hot Absorbers and the X-Ray Spectra of BL Lac Objects.' The grant was originally awarded in October 1991 and expired in February 1994. The purpose of this project was to detect spectral features in high signal-to-noise Rosat PSPC spectra of X-ray-bright BL Lac objects. We were granted observations of three targets: PKS2155-304, Mrk421, and Mrk501. All three were bright and yielded 5,000-30,000 photons in the good PSPC data.

  10. Skeletal Muscle Tissue Clearing for LacZ and Fluorescent Reporters, and Immunofluorescence Staining.

    PubMed

    Verma, Mayank; Murkonda, Bhavani Sr; Asakura, Yoko; Asakura, Atsushi

    2016-01-01

    Skeletal muscle is a highly ordered yet complex tissue containing several cell types that interact with each other in order to maintain structure and homeostasis. It is also a highly regenerative tissue that responds to damage in a highly intricate but stereotypic manner, with distinct spatial and temporal kinetics. Proper examination of this process requires one to look at the three-dimensional orientation of the cellular and subcellular components, which can be accomplished through tissue clearing. While there has been a recent surge of protocols to study biology in whole tissue, it has primarily focused on the nervous system. This chapter describes the workflow for whole mount analysis of murine skeletal muscle for LacZ reporters, fluorescent reporters and immunofluorescence staining. Using this technique, we are able to visualize LacZ reporters more effectively in deep tissue samples, and to perform fluorescent imaging with a depth greater than 1700 μm. PMID:27492170

  11. Baby-Crying Acceptance

    NASA Astrophysics Data System (ADS)

    Martins, Tiago; de Magalhães, Sérgio Tenreiro

    The baby's crying is his most important mean of communication. The crying monitoring performed by devices that have been developed doesn't ensure the complete safety of the child. It is necessary to join, to these technological resources, means of communicating the results to the responsible, which would involve the digital processing of information available from crying. The survey carried out, enabled to understand the level of adoption, in the continental territory of Portugal, of a technology that will be able to do such a digital processing. It was used the TAM as the theoretical referential. The statistical analysis showed that there is a good probability of acceptance of such a system.

  12. High acceptance recoil polarimeter

    SciTech Connect

    The HARP Collaboration

    1992-12-05

    In order to detect neutrons and protons in the 50 to 600 MeV energy range and measure their polarization, an efficient, low-noise, self-calibrating device is being designed. This detector, known as the High Acceptance Recoil Polarimeter (HARP), is based on the recoil principle of proton detection from np[r arrow]n[prime]p[prime] or pp[r arrow]p[prime]p[prime] scattering (detected particles are underlined) which intrinsically yields polarization information on the incoming particle. HARP will be commissioned to carry out experiments in 1994.

  13. A source of artifact in the lacZ reversion assay in Escherichia coli.

    PubMed

    Hoffmann, George R; Gray, Carol L; Lange, Paulina B; Marando, Christie I

    2015-06-01

    The lacZ reversion assay in Escherichia coli measures point mutations that occur by specific base substitutions and frameshift mutations. The tester strains cannot use lactose as a carbon source (Lac(-)), and revertants are easily detected by growth on lactose medium (Lac(+)). Six strains identify the six possible base substitutions, and five strains measure +G, -G, -CG, +A and -A frameshifts. Strong mutagens give dose-dependent increases in numbers of revertants per plate and revertant frequencies. Testing compounds that are arguably nonmutagens or weakly mutagenic, we often noted statistically significant dose-dependent increases in revertant frequency that were not accompanied by an absolute increase in numbers of revertants. The increase in frequency was wholly ascribable to a declining number of viable cells owing to toxicity. Analysis of the conditions revealed that the frequency of spontaneous revertants is higher when there are fewer viable cells per plate. The phenomenon resembles "adaptive" or "stress" mutagenesis, whereby lactose revertants accumulate in Lac(-) bacteria under starvation conditions in the absence of catabolite repression. Adaptive mutation is observed after long incubation and might be expected to be irrelevant in a standard assay using 48-h incubation. However, we found that elevated revertant frequencies occur under typical assay conditions when the bacterial lawn is thin, and this can cause increases in revertant frequency that mimic chemical mutagenesis when treatments are toxic but not mutagenic. Responses that resemble chemical mutagenesis were observed in the absence of mutagenic treatment in strains that revert by different frameshift mutations. The magnitude of the artifact is affected by cell density, dilution, culture age, incubation time, catabolite repression and the age and composition of media. Although the specific reversion assay is effective for quickly distinguishing classes of mutations induced by potent mutagens, its

  14. Separating the BL Lac and cluster X-ray emissions in Abell 689 with Chandra

    NASA Astrophysics Data System (ADS)

    Giles, P. A.; Maughan, B. J.; Birkinshaw, M.; Worrall, D. M.; Lancaster, K.

    2012-01-01

    We present the results of a Chandra observation of the galaxy cluster Abell 689 (z = 0.279). Abell 689 is one of the most luminous clusters detected in the ROSAT All Sky Survey (RASS), but was flagged as possibly including significant point source contamination. The small point spread function of the Chandra telescope allows us to confirm this and separate the point source from the extended cluster X-ray emission. For the cluster, we determine a bolometric luminosity of Lbol= (3.3 ± 0.3) × 1044 erg s-1 and a temperature of kT = 5.1+2.2- 1.3 keV when including a physically motivated background model. We compare our measured luminosity for A689 to that quoted in the RASS, and find L0.1-2.4 keV= 2.8 × 1044 erg s-1, a value ˜10 times lower than the ROSAT measurement. Our analysis of the point source shows evidence for significant pile-up, with a pile-up fraction of ≃60 per cent. Sloan Digital Sky Survey spectra and Hubble Space Telescope (HST) images lead us to the conclusion that the point source within Abell 689 is a BL Lac object. Using radio and optical observations from the Very Large Array and HST archives, we determine αro= 0.50, αox= 0.77 and αrx= 0.58 for the BL Lac, which would classify it as being of 'high-energy peak BL Lac' type. Spectra extracted of A689 show a hard X-ray excess at energies above 6 keV that we interpret as inverse-Compton emission from aged electrons that may have been transported into the cluster from the BL Lac.

  15. Comparison between TeV and non-TeV BL Lac Objects

    NASA Astrophysics Data System (ADS)

    Lin, Chao; Fan, Jun-Hui

    2016-07-01

    BL Lacertae objects (BL Lacs) are the dominant population of TeV emitting blazars. In this work, we investigate whether there are any special observational properties associated with TeV sources. To do so, we will compare the observational properties of TeV detected BL Lacs (TeV BLs) with non-TeV detected BL Lac objects (non-TeV BLs). From the 3rd Fermi/LAT source catalog (3FGL), we can obtain 662 BL Lacs, out of which 47 are TeV BLs and 615 are non-TeV BLs. Their multi-wavelength flux densities (F R, F O, F X and F γ), photon spectral indexes (αX ph and αph γ), and effective spectral indexes (αRO and αOX) are compiled from the available literature. Then the luminosities (log vL R, log vL O, log vL X, log vL γ) are calculated. From comparisons, we find that TeV BLs are different from low synchrotron peaked BLs and intermediate synchrotron peaked BLs, but TeV BLs show similar properties to high synchrotron peaked (HSP) BLs. Therefore, we concentrated on a comparison between TeV HSP BLs and non-TeV HSP BLs. Analysis results suggest that TeV HSP BLs and non-TeV HSP BLs exhibit some differences in their αRO and αγ ph, but their other properties are quite similar.

  16. Contemporaneous Broadband Observations of Three High-redshift BL LAC Objects

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; An, H.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bonino, R.; Bregeon, J.; Britto, R. J.; Bruel, P.; Buehler, R.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Costanza, F.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Di Mauro, M.; Di Venere, L.; Domínguez, A.; Drell, P. S.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Finke, J.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giordano, F.; Giroletti, M.; Green, D.; Grenier, I. A.; Guiriec, S.; Horan, D.; Jóhannesson, G.; Katsuragawa, M.; Kuss, M.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Manfreda, A.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mirabal, N.; Mitthumsiri, W.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Nuss, E.; Ohsugi, T.; Okada, C.; Orlando, E.; Paneque, D.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, O.; Rau, A.; Romani, R. W.; Schady, P.; Sgrò, C.; Simone, D.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Stern, D.; Takahashi, H.; Thayer, J. B.; Torres, D. F.; Tosti, G.; Troja, E.; Vianello, G.; Wood, K. S.; Wood, M.

    2016-03-01

    We have collected broadband spectral energy distributions (SEDs) of three BL Lac objects 3FGL J0022.1-1855 (z = 0.689), 3FGL J0630.9-2406 (z\\quad ≳ 1.239), and 3FGL J0811.2-7529 (z = 0.774), detected by Fermi with relatively flat gigaelectronvolt spectra. By observing simultaneously in the near-infrared to hard X-ray band, we can well characterize the high end of the synchrotron component of the SED. Thus, fitting the SEDs to synchro-Compton models of the dominant emission from the relativistic jet, we can constrain the underlying particle properties and predict the shape of the gigaelectronvolt Compton component. Standard extragalactic background light (EBL) models explain the high-energy absorption well, with poorer fits for high-ultraviolet models. The fits show clear evidence for EBL absorption in the Fermi spectrum of our highest-redshift source 3FGL J0630.9-2406. While synchrotron self-Compton models adequately describe the SEDs, the situation may be complicated by possible external Compton components. For 3FGL J0811.2-7529, we also discover a nearby serendipitous source in the X-ray data, which is almost certainly another lower synchrotron peak frequency ({ν }{{pk}}{{sy}}) BL Lac, that may contribute flux in the Fermi band. Since our sources are unusual high-luminosity, moderate {ν }{{pk}}{{sy}} BL Lacs, we compare these quantities and the Compton dominance, the ratio of peak inverse Compton to peak synchrotron luminosities ({L}{{pk}}{{IC}}/{L}{{pk}}{{sy}}), with those of the full Fermi BL Lac population.

  17. Model for the possible origin of anorthosite-syenite associations like the Laramie anorthosite complex (lac)

    SciTech Connect

    Lindsley, D.H.; Kolker, A.; Fuhrman, M.; Frost, B.R.

    1985-01-01

    Proterozoic massif anorthosites (ANT) have several unique attributes. Compared to typical tholeiitic layered mafic intrusions, they are distinctly evolved, with low mg numbers and high Ab/An ratios, and are also more potassic, with 1-2 wt% K/sub 2/O - 5-10% normative Or that occurs as antiperthite. They are closely associated in time and space with still more potassic rocks (MSY: monzonites, syenites, mangerites, etc.) considered by some to be comagmatic with the ANT and by others to be partial melts of the country rock. If the MSY are comagmatic, the parent magma is must be relatively potassic. Such a magma might pond and fractionate at the base of thin continental crust, with olivines and pyroxenes sinking and plagioclase floating, thereby depleting the magma in Mg and Eu. Crystal mushes of plagioclase would then intrude the crust diapirically to depths of 8-15 km, forming ANT. With continued fractionation the K- and Fe-enriched liquid would begin crystallizing ternary feldspars (as found at LAC); these too would float, forming crystal mushes (MSY) that would rise diapirically and intrude the ANT. The cumulate MSY would have no Eu anomaly (or a small positive one) as found at LAC; the liquid would have a strong negative Eu anomaly. Some contamination of the MSY suite by partial melts from the country rock is likely. This model can explain the virtual continuum in mineral compositions from ANT to MSY reported for LAC by Fuhrman and others (this volume). Parent magmas might be trachyandesitic; another candidate is the biotite gabbro found throughout the LAC.

  18. Influence of Catabolite Repression and Inducer Exclusion on the Bistable Behavior of the lac Operon

    PubMed Central

    Santillán, Moisés; Mackey, Michael C.

    2004-01-01

    A mathematical model of the lac operon which includes all of the known regulatory mechanisms, including external-glucose-dependent catabolite repression and inducer exclusion, as well as the time delays inherent to transcription and translation, is presented. With this model we investigate the influence of external glucose, by means of catabolite repression and the regulation of lactose uptake, on the bistable behavior of this system. PMID:14990461

  19. X-Ray Spectral Variability Signatures of Flares in BL Lac Objects

    NASA Technical Reports Server (NTRS)

    Boettcher, Markus; Chiang, James; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We are presenting a detailed parameter study of the time-dependent electron injection and kinematics and the self-consistent radiation transport in jets of intermediate and low-frequency peaked BL Lac objects. Using a time-dependent, combined synchrotron-self-Compton and external-Compton jet model, we study the influence of variations of several essential model parameters, such as the electron injection compactness, the relative contribution of synchrotron to external soft photons to the soft photon compactness, the electron- injection spectral index, and the details of the time profiles of the electron injection episodes giving rise to flaring activity. In the analysis of our results, we focus on the expected X-ray spectral variability signatures in a region of parameter space particularly well suited to reproduce the broadband spectral energy distributions of intermediate and low-frequency peaked BL Lac objects. We demonstrate that SSC- and external-Compton dominated models for the gamma-ray emission from blazars are producing significantly different signatures in the X-ray variability, in particular in the soft X-ray light curves and the spectral hysteresis at soft X-ray energies, which can be used as a powerful diagnostic to unveil the nature of the high-energy emission from BL Lac objects.

  20. Computational Analysis of Looping of a Large Family of Highly Bent DNA by LacI

    PubMed Central

    Lillian, Todd D.; Goyal, Sachin; Kahn, Jason D.; Meyhöfer, Edgar; Perkins, N. C.

    2008-01-01

    Sequence-dependent intrinsic curvature of DNA influences looping by regulatory proteins such as LacI and NtrC. Curvature can enhance stability and control shape, as observed in LacI loops formed with three designed sequences with operators bracketing an A-tract bend. We explore geometric, topological, and energetic effects of curvature with an analysis of a family of highly bent sequences, using the elastic rod model from previous work. A unifying straight-helical-straight representation uses two phasing parameters to describe sequences composed of two straight segments that flank a common helically supercoiled segment. We exercise the rod model over this two-dimensional space of phasing parameters to evaluate looping behaviors. This design space is found to comprise two subspaces that prefer parallel versus anti-parallel binding topologies. The energetic cost of looping varies from 4 to 12 kT. Molecules can be designed to yield distinct binding topologies as well as hyperstable or hypostable loops and potentially loops that can switch conformations. Loop switching could be a mechanism for control of gene expression. Model predictions for linking numbers and sizes of LacI-DNA loops can be tested using multiple experimental approaches, which coupled with theory could address whether proteins or DNA provide the observed flexibility of protein-DNA loops. PMID:18931251

  1. Comparison of Deterministic and Stochastic Models of the lac Operon Genetic Network

    PubMed Central

    Stamatakis, Michail; Mantzaris, Nikos V.

    2009-01-01

    The lac operon has been a paradigm for genetic regulation with positive feedback, and several modeling studies have described its dynamics at various levels of detail. However, it has not yet been analyzed how stochasticity can enrich the system's behavior, creating effects that are not observed in the deterministic case. To address this problem we use a comparative approach. We develop a reaction network for the dynamics of the lac operon genetic switch and derive corresponding deterministic and stochastic models that incorporate biological details. We then analyze the effects of key biomolecular mechanisms, such as promoter strength and binding affinities, on the behavior of the models. No assumptions or approximations are made when building the models other than those utilized in the reaction network. Thus, we are able to carry out a meaningful comparison between the predictions of the two models to demonstrate genuine effects of stochasticity. Such a comparison reveals that in the presence of stochasticity, certain biomolecular mechanisms can profoundly influence the region where the system exhibits bistability, a key characteristic of the lac operon dynamics. For these cases, the temporal asymptotic behavior of the deterministic model remains unchanged, indicating a role of stochasticity in modulating the behavior of the system. PMID:19186128

  2. Color Variations of Two Blazars: BL Lac and PKS 0736+017

    NASA Astrophysics Data System (ADS)

    Clements, S. D.

    2002-12-01

    Multi-night campaigns to monitor sources for microvariability were undertaken in the summer of 1997 for BL Lac and in early 2002 for PKS 0736+017. BL Lac was observed at Rosemary Hill Observatory in Bronson, Florida and PKS 0736+017 was observed with the SARA telescope on Kitt Peak in Arizona. Both sources underwent dramatic flares and exhibited substantial microvariability. During each campaign, the source was observed alternately through V and R filters so that color variations could be monitored as well. The most commonly reported behavior for such objects is that they become redder when fainter. This is observed in the BL Lac data. These data do not indicate that the point source varies in color however. Instead, they support the notion that the underlying host galaxy contributes a larger fraction of the total flux when the source is faint than when it is bright. More unusual was the observation that PKS 0736+017 was observed to be redder when brighter. The data support the notion that the observed color variation may be related more to the nature of the variation (flaring, subsiding, or quiescent) than to the flux level.

  3. GINGA LAC and Einstein SSS X-ray Spectral Evidence of Abundance Gradients in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    White, R. E., III; Day, C. S. R.; Hatsukade, I.; Hughes, J. P.

    1993-12-01

    We jointly analyzed the Ginga LAC and Einstein SSS spectra of four cooling flow clusters: A496, A1795, A2142 & A2199. We took advantage of the two instruments' different fields of view (6 arcmin diameter for the SSS, 1times 2 degrees for the LAC) to determine whether there were spatial gradients in temperature, abundances and X-ray absorbing column densities. Each cluster has firm evidence of a relatively cool central component. The inclusion of such cool components in the joint spectral analysis leads to somewhat higher global temperature determinations than are derived from the higher energy LAC data alone. The abundances appear to be centrally enhanced in at least two (A496, A2142) and possibly three (A2199) of the four clusters. In these cases, the central cool component typically has abundances which exceed solar values. We also confirm the presence of large amounts of cold absorbing matter in three of the four clusters (A496, A1795 & A2199) and show that it is likely to be intrinsic to the cluster cooling flows.

  4. In vivo expression of adenovirus-mediated lacZ gene in murine nasal mucosa.

    PubMed

    Arimoto, Yukiko; Nagata, Hiroshi; Isegawa, Naohisa; Kumahara, Keiichiro; Isoyama, Kyoko; Konno, Akiyoshi; Shirasawa, Hiroshi

    2002-09-01

    Adenovirus is a good tool for transferring exogenous genes into various organs because the virus has a wide spectrum of infection. In this report, we demonstrate that a recombinant adenovirus, Ax1CAlacZ, can transfer an exogenous lacZ gene into murine nasal mucosa in vivo. The efficiency of the exogenous gene expression varied for different cell types and was improved by optimizing the method of administration. In the olfactory region, the olfactory epithelia, sustentacular cells and olfactory nerve efficiently expressed lacZ gene transferred by Ax1CAlacZ using either of two administration methods, dripping or injecting. In contrast, in the respiratory region, the respiratory epithelia but not the subepithelial tissues expressed lacZ gene transferred by Ax1CAlacZ, and the efficiency of the gene transfer, which was low when the virus was administered by nasal drops, was improved when the virus was administered by injection. Our study demonstrated that gene transfer mediated by adenovirus is more efficient in the olfactory epithelia than in the respiratory epithelia, and may be applicable to nasal or paranasal diseases such as olfactory epithelial disturbances. PMID:12403125

  5. STRUCTURED JETS IN BL LAC OBJECTS: EFFICIENT PeV NEUTRINO FACTORIES?

    SciTech Connect

    Tavecchio, Fabrizio; Ghisellini, Gabriele; Guetta, Dafne

    2014-09-20

    The origin of high-energy neutrinos (0.1–1 PeV range) detected by IceCube remains a mystery. In this work, we explore the possibility that efficient neutrino production can occur in structured jets of BL Lac objects, characterized by a fast inner spine surrounded by a slower layer. This scenario has been widely discussed in the framework of the high-energy emission models for BL Lac objects and radio galaxies. One of the relevant consequences of a velocity structure is the enhancement of the inverse Compton emission caused by the radiative coupling of the two zones. We show that a similar boosting could occur for the neutrino output of the spine through the photo-meson reaction of high-energy protons scattering off the amplified soft target photon field of the layer. Assuming the local density and the cosmological evolution of γ-ray BL Lac object derived from Fermi Large Area Telescope data, we calculate the expected diffuse neutrino intensity, which can match the IceCube data for a reasonable choice of parameters.

  6. Monzonites (MZ) and monzosyenites (MSY) associated with the Laramie anorthoside complex (LAC), Wyoming

    SciTech Connect

    Fuhrman, M.; Kolker, A.; Lindsley, D.H.; Frost, B.R.

    1985-01-01

    The relationship between Proterozoic massif anorthosites and the associated syenitic rocks remains controversial. Unlike most such complexes, the LAC is unmetamorphosed and hence is ideally suited to petrologic and geochemical tests of a possible comagmatic origin. The authors detailed mapping and petrologic studies of the MZ and MSY show that these rocks were nearly anhydrous and crystallized at 3-5 kbar, 950-1050/sup 0/C, and oxygen fugacities several log units below FMQ buffer. They intrude the anorthosite, although the radiometric ages are identical within error. They have found strong petrologic evidence for a close genetic relationship between the anorthositic rocks and the MZ and MSY: mineral-chemical trends - as expressed by feldspars; augites, and low-Ca pyroxenes - are virtually continuous from the anorthosite through MZ to MSY. In contrast, recent geochemical studies of the LAC indicate that the MSY cannot represent a liquid complementary to the anorthosite. Their studies suggest a possible explanation: the MSY, like the anorthosite, may be a cumulate rather than a liquid. Fine-grained MZ that forms a border facies of the MSY probably represents a liquid. The authors are also considering several other highly evolved units as possible liquids residual to the MSY; such liquids should show strong negative Eu anomalies. Rare-earth studies on the fine-grained MZ and on other rocks are under way. A model for the possible comagmatic formation of the LAC is given by Lindsley and others.

  7. Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during the 2015 outburst

    SciTech Connect

    Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; Singh, K. P.; Bottcher, M.; Kaur, Navpreet; Baliyan, K. S.

    2015-08-17

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energy distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. Furthermore, the rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.

  8. Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during the 2015 outburst

    DOE PAGESBeta

    Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; Singh, K. P.; Bottcher, M.; Kaur, Navpreet; Baliyan, K. S.

    2015-08-17

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energymore » distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. Furthermore, the rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.« less

  9. Multi-wavelength Study of Flaring Activity in BL Lac Object S5 0716+714 during the 2015 Outburst

    NASA Astrophysics Data System (ADS)

    Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; Singh, K. P.; Bottcher, M.; Kaur, Navpreet; Baliyan, K. S.

    2015-08-01

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energy distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. The rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.

  10. Effect of DNA looping on the induction kinetics of the lac operon.

    PubMed

    Narang, Atul

    2007-08-21

    The induction of the lac operon follows cooperative kinetics. The first mechanistic model of these kinetics is the de facto standard in the modeling literature [Yagil, G., Yagil, E., 1971. On the relation between effector concentration and the rate of induced enzyme synthesis. Biophys. J. 11, 11-17]. Yet, subsequent studies have shown that the model is based on incorrect assumptions. Specifically, the repressor is a tetramer with four (not two) inducer-binding sites, and the operon contains two auxiliary operators (in addition to the main operator). Furthermore, these structural features are crucial for the formation of DNA loops, the key determinants of lac repression and induction. Indeed, the repression is determined almost entirely (>95%) by the looped complexes [Oehler, S., Eismann, E.R., Krämer, H., Müller-Hill, B., 1990. The three operators of the lac operon cooperate in repression. EMBO J. 9(4), 973-979], and the pronounced cooperativity of the induction curve hinges upon the existence of the looped complexes [Oehler, S., Alberti, S., Müller-Hill, B., 2006. Induction of the lac promoter in the absence of DNA loops and the stoichiometry of induction. Nucleic Acids Res. 34(2), 606-612]. Here, we formulate a model of lac induction taking due account of the tetrameric structure of the repressor and the existence of looped complexes. We show that: (1) The kinetics are significantly more cooperative than those predicted by the Yagil and Yagil model. The cooperativity is higher because the formation of looped complexes is easily abolished by repressor-inducer binding. (2) The model provides good fits to the repression data for cells containing wild-type tetrameric or mutant dimeric repressor, as well as the induction curves for 6 different strains of Escherichia coli. It also implies that the ratios of certain looped and non-looped complexes are independent of inducer and repressor levels, a conclusion that can be rigorously tested by gel electrophoresis. (3

  11. Outreach, Diversity, and Education Supported by NSF Facilities LacCore and the Continental Scientific Drilling Coordination Office (CSDCO), University of Minnesota

    NASA Astrophysics Data System (ADS)

    Myrbo, A.

    2015-12-01

    Climatic and environmental change are a powerful hook to engage students and the public with geoscience. Recent lake sediments often feature visual and compositional evidence of anthropogenic changes, which can pique curiosity and serve as a gateway for interest in more remote past changes. Cores provide an integrative, place-based geoscience education/outreach platform: lake dynamics incorporate principles of chemistry, physics, and biology; lake basin formation and sedimentary signals trace back to numerous geoscience subdisciplines. Lakes reflect local changes, and so are inherently place-based and relevant to both rural and urban populations. The esthetics of lakes in the landscape and sediments under the microscope spark the artistic sensibilities of those who do not consider themselves scientists: lakes are readymade for STEAM education. LacCore has exploited the magic of lake sediment cores in its 15 years as an NSF Facility, and now expands to additional environments as the NSF Continental Scientific Drilling Coordination Office. Part of scaling up is the formalization of major support for the Broader Impacts (BI) activities of Facility users. LacCore/CSDCO now musters its collaborative experiences in site REUs and other undergrad research projects, in-depth training of students, teachers, and faculty, a long list of informal education experiences, and common-good software development, to provide assistance to researchers seeking meaningful broader impacts and educators seeking extra- or co-curricular field and laboratory research experiences for their students. Outreach, diversity, and education support includes dissemination of best practices, as well as coordination, administration, and basic capacity for such activities in collaboration with project PIs and students, through no-cost support, or collaborative proposals or supplements from NSF where necessary for project scale. Community-driven research and broadening participation are central to the

  12. Hanford Site Solid Waste Acceptance Criteria

    SciTech Connect

    MCDOWELL, A.K.; TRINER, G.C.

    2002-03-28

    DOE Order 435.1 requires that each treatment, storage, and/or disposal facility (referred to in this document as TSD unit) that manages low-level or transuranic (TRU) waste (including mixed waste and TSCA PCB waste) maintain waste acceptance criteria. These criteria must address the various requirements to operate the TSD unit in compliance with applicable safety and environmental requirements. This document sets forth the baseline criteria for acceptance of waste at TSD units operated by WMP. The criteria for each TSD unit have been established to ensure that waste accepted can be managed in a manner that is within the operating requirements of the unit, including environmental regulations, DOE Orders, permits, technical safety requirements, waste analysis plans, performance assessments, and other applicable requirements. Revisions to the acceptance criteria document require an Unreviewed Safety Question review to document that the changes are consistent with current applicable safety analysis. Acceptance criteria apply to the following TSD units: the Low-Level Burial Grounds (LLBG) including both the nonregulated portions of the LLBG and trenches 31 and 34 of the 218-W-5 Burial Ground for mixed waste disposal; Central Waste Complex (CWC); Waste Receiving and Processing (WRAP) Facility; and T-Plant facility. Waste from all generators, both from the Hanford Site and from offsite facilities, must comply with these criteria. Exceptions can be granted as provided in Section 1.6. Specific waste streams could have additional requirements based on the identified TSD pathway. These requirements are communicated in the waste specification records (WSRds) and/or waste stream profile sheet approvals. The Hanford Site manages nonradioactive waste through direct shipments to offsite contractors. The waste acceptance requirements of the offsite TSD facility must be met for these nonradioactive wastes. This document does not address the acceptance requirements of these offsite

  13. Acceptance of School Integration: 1965-1969

    ERIC Educational Resources Information Center

    Alston, Jon P.; Knapp, Melvin J.

    1971-01-01

    This national study reports on the changing attitudes of white adults having school age children toward school integration during the period 1965-1969. Stresses the importance of regional and educational variables. With the exception of farmers, most non-Southern respondents accepted some form of school integration. (DM)

  14. Comparative efficacy and acceptability of psychotherapies for acute anxiety disorders in children and adolescents: study protocol for a network meta-analysis

    PubMed Central

    Zhang, Yuqing; Zhou, Xinyu; James, Anthony C; Qin, Bin; Whittington, Craig J; Cuijpers, Pim; Del Giovane, Cinzia; Liu, Yiyun; Cohen, David; Weisz, John R; Xie, Peng

    2015-01-01

    Introduction Anxiety disorders are associated with significant public health burden in young individuals. Cognitive-behavioural therapy (CBT) is the most commonly used psychotherapy for anxiety disorders in children and adolescents, but previous reviews were hindered by a limited number of trials with direct comparisons between different psychotherapies and their deliveries. Consequently, the main aim of this research was to investigate the comparative efficacy and acceptability of various types and deliveries of psychotherapies for anxiety disorders in children and adolescents. Methods and analysis We will systematically search PubMed, EMBASE, Cochrane, Web of Science, PsycINFO, CINAHL, ProQuest Dissertations and LiLACS for randomised controlled trials, regardless of whether participants received blinding or not, published from 1 January 1966 to 30 January 2015 (updated to 1 July 2015), that compared any psychotherapy with either a control condition or an active comparator with different types and/or different delivery formats for the acute treatment of anxiety disorders in children and adolescents. Data extraction, risk of bias and quality assessments will be independently extracted by two reviewers. The primary outcome for efficacy will be mean overall change scores in anxiety symptoms (self-rated or assessor-rated) from baseline to post-treatment between two groups. The acceptability of treatment will be measured as the proportion of patients who discontinued treatment during the acute phase of treatment. We will assess efficacy, based on the standardised mean difference (SMD), and acceptability, based on the OR, using a random-effects network meta-analysis within a Bayesian framework. Subgroup and sensitivity analyses will be conducted to assess the robustness of the findings. Ethics and dissemination No ethical issues are foreseen. The results will be published in a peer-reviewed journal and will be disseminated electronically and in print. The meta

  15. RegR, a Global LacI/GalR Family Regulator, Modulates Virulence and Competence in Streptococcus pneumoniae

    PubMed Central

    Chapuy-Regaud, Sabine; Ogunniyi, A. David; Diallo, Nicole; Huet, Yvette; Desnottes, Jean-François; Paton, James C.; Escaich, Sonia; Trombe, Marie-Claude

    2003-01-01

    The homolactic and catalase-deficient pathogen Streptococcus pneumoniae is not only tolerant to oxygen but requires the activity of its NADH oxidase, Nox, to develop optimal virulence and competence for genetic transformation. In this work, we show that the global regulator RegR is also involved in these traits. Genetic dissection revealed that RegR regulates competence and the expression of virulence factors, including hyaluronidase. In bacteria grown in vitro, RegR represses hyaluronidase. At neutral pH, it increases adherence to A549 epithelial cells, and at alkaline pH, it acts upstream of the CiaRH two-component signaling system to activate competence. These phenotypes are not associated with changes in antibiotic resistance, central metabolism, and carbohydrate utilization. Although the RegR0 (where 0 indicates the loss of the protein) mutation is sufficient to attenuate experimental virulence of strain 23477 in mice, the introduction of an additional hyl0 (where 0 indicates the loss of function) mutation in the RegR0 strain 23302 dramatically reduces its virulence. This indicates that residual virulence of the RegR0 Hyl+ derivative is due to hyaluronidase and supports the dual role of RegR in virulence. This LacI/GalR regulator, not essential for in vitro growth in rich media, is indeed involved in the adaptive response of the pneumococcus via its control of competence, adherence, and virulence. PMID:12704136

  16. Sonic boom acceptability studies

    NASA Astrophysics Data System (ADS)

    Shepherd, Kevin P.; Sullivan, Brenda M.; Leatherwood, Jack D.; McCurdy, David A.

    1992-04-01

    The determination of the magnitude of sonic boom exposure which would be acceptable to the general population requires, as a starting point, a method to assess and compare individual sonic booms. There is no consensus within the scientific and regulatory communities regarding an appropriate sonic boom assessment metric. Loudness, being a fundamental and well-understood attribute of human hearing was chosen as a means of comparing sonic booms of differing shapes and amplitudes. The figure illustrates the basic steps which yield a calculated value of loudness. Based upon the aircraft configuration and its operating conditions, the sonic boom pressure signature which reaches the ground is calculated. This pressure-time history is transformed to the frequency domain and converted into a one-third octave band spectrum. The essence of the loudness method is to account for the frequency response and integration characteristics of the auditory system. The result of the calculation procedure is a numerical description (perceived level, dB) which represents the loudness of the sonic boom waveform.

  17. Sonic boom acceptability studies

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Sullivan, Brenda M.; Leatherwood, Jack D.; Mccurdy, David A.

    1992-01-01

    The determination of the magnitude of sonic boom exposure which would be acceptable to the general population requires, as a starting point, a method to assess and compare individual sonic booms. There is no consensus within the scientific and regulatory communities regarding an appropriate sonic boom assessment metric. Loudness, being a fundamental and well-understood attribute of human hearing was chosen as a means of comparing sonic booms of differing shapes and amplitudes. The figure illustrates the basic steps which yield a calculated value of loudness. Based upon the aircraft configuration and its operating conditions, the sonic boom pressure signature which reaches the ground is calculated. This pressure-time history is transformed to the frequency domain and converted into a one-third octave band spectrum. The essence of the loudness method is to account for the frequency response and integration characteristics of the auditory system. The result of the calculation procedure is a numerical description (perceived level, dB) which represents the loudness of the sonic boom waveform.

  18. Construction and characterization of thermo-inducible vectors derived from heat-sensitive lacI genes in combination with the T7 A1 promoter.

    PubMed

    Chao, Yun-Peng; Chern, Jong-Tzer; Wen, Chin-Sheng; Fu, Hongyong

    2002-07-01

    The lack of stringency and the cost of induction are two major disadvantages of using lac-derived vectors for recombinant protein productions. To compensate for these drawbacks, a series of thermo-inducible vectors was developed by coupling heat-sensitive lacI (lacIts) with the T7 A1 promoter on a multiple-copynumber plasmid. The lacIts genes were created by the introduction of Gly187-->Ser substitution along with three alternative mutation sites, Leu233-->Lys, Ala241-->Thr, and Gly265-->Asp, generated by site-directed mutagenesis into the wild-type lacI gene. With the LacZ production as a model, the induction profiles for various vectors containing distinct lacIts exhibited a positive trend as the temperature increased. The fully induced level was achieved by applying the temperature shift from 30 degrees C to 42, 40, or 37 degrees C to the cells harboring the plasmid with the Gly187-->Ser, Ala241-->Thr, or Gly265-->Asp substitution in lacI, respectively. As a result, it produced the maximal LacZ production ranging between 46,000 and 54,000 Miller units, corresponding to a 100- to 400-fold amplification over the uninduced level. As a whole, these novel expression vectors are characterized as having tight regulation and facile inducibility, and their practical usefulness in industrial production of recombinant proteins appears promising. PMID:17590925

  19. The SOS-LUX-LAC-FLUORO-Toxicity-test on the International Space Station (ISS)

    NASA Astrophysics Data System (ADS)

    Rabbow, E.; Rettberg, P.; Baumstark-Khan, C.; Horneck, G.

    In the 21 st century, an increasing number of astronauts will visit the International Space Station (ISS) for prolonged times. Therefore it is of utmost importance to provide necessary basic knowledge concerning risks to their health and their ability to work on the station and during extravehicular activities (EVA) in free space. It is the aim of one experiment of the German project TRIPLE-LUX (to be flown on the ISS) to provide an estimation of health risk resulting from exposure of the astronauts to the radiation in space inside the station as well as during extravehicular activities on one hand, and of exposure of astronauts to unavoidable or as yet unknown ISS-environmental genotoxic substances on the other. The project will (i) provide increased knowledge of the biological action of space radiation and enzymatic repair of DNA damage, (ii) uncover cellular mechanisms of synergistic interaction of microgravity and space radiation and (iii) examine the space craft milieu with highly specific biosensors. For these investigations, the bacterial biosensor SOS-LUX-LAC-FLUORO-Toxicity-test will be used, combining the SOS-LUX-Test invented at DLR Germany (Patent) with the commercially available LAC-FLUORO-Test. The SOS-LUX-Test comprises genetically modified bacteria transformed with the pBR322-derived plasmid pPLS-1. This plasmid carries the promoterless lux operon of Photobacterium leiognathi as a reporter element under control of the DNA-damage dependent SOS promoter of ColD as sensor element. This system reacts to radiation and other agents that induce DNA damages with a dose dependent measurable emission of bioluminescence of the transformed bacteria. The analogous LAC-FLUORO-Test has been developed for the detection of cellular responses to cytotoxins. It is based on the constitutive expression of green fluorescent protein (GFP) mediated by the bacterial protein expression vector pGFPuv (Clontech, Palo Alto, USA). In response to cytotoxic agents, this system

  20. The SOS-LUX-LAC-FLUORO-Toxicity-test on the International Space Station (ISS).

    PubMed

    Rabbow, E; Rettberg, P; Baumstark-Khan, C; Horneck, G

    2003-01-01

    In the 21st century, an increasing number of astronauts will visit the International Space Station (ISS) for prolonged times. Therefore it is of utmost importance to provide necessary basic knowledge concerning risks to their health and their ability to work on the station and during extravehicular activities (EVA) in free space. It is the aim of one experiment of the German project TRIPLE-LUX (to be flown on the ISS) to provide an estimation of health risk resulting from exposure of the astronauts to the radiation in space inside the station as well as during extravehicular activities on one hand, and of exposure of astronauts to unavoidable or as yet unknown ISS-environmental genotoxic substances on the other. The project will (i) provide increased knowledge of the biological action of space radiation and enzymatic repair of DNA damage, (ii) uncover cellular mechanisms of synergistic interaction of microgravity and space radiation and (iii) examine the space craft milieu with highly specific biosensors. For these investigations, the bacterial biosensor SOS-LUX-LAC-FLUORO-Toxicity-test will be used, combining the SOS-LUX-Test invented at DLR Germany (Patent) with the commercially available LAC-FLUORO-Test. The SOS-LUX-Test comprises genetically modified bacteria transformed with the pBR322-derived plasmid pPLS-1. This plasmid carries the promoterless lux operon of Photobacterium leiognathi as a reporter element under control of the DNA-damage dependent SOS promoter of ColD as sensor element. This system reacts to radiation and other agents that induce DNA damages with a dose dependent measurable emission of bioluminescence of the transformed bacteria. The analogous LAC-FLUORO-Test has been developed for the detection of cellular responses to cytotoxins. It is based on the constitutive expression of green fluorescent protein (GFP) mediated by the bacterial protein expression vector pGFPuv (Clontech, Palo Alto, USA). In response to cytotoxic agents, this system

  1. High-level expression of Bacillus naganoensis pullulanase from recombinant Escherichia coli with auto-induction: effect of lac operator.

    PubMed

    Nie, Yao; Yan, Wei; Xu, Yan; Chen, Wen Bo; Mu, Xiao Qing; Wang, Xinye; Xiao, Rong

    2013-01-01

    Pullulanase plays an important role in specific hydrolysis of branch points in amylopectin and is generally employed as an important enzyme in starch-processing industry. So far, however, the production level of pullulanase is still somewhat low from wide-type strains and even heterologous expression systems. Here the gene encoding Bacillus naganoensis pullulanase was amplified and cloned. For expression of the protein, two recombinant systems, Escherichia coli BL21(DE3)/pET-20b(+)-pul and E. coli BL21(DE3)/pET-22b(+)-pul, were constructed, both bearing T7 promoter and signal peptide sequence, but different in the existance of lac operator and lacI gene encoding lac repressor. Recombinant pullulanase was initially expressed with the activity of up to 14 U/mL by E. coli BL21(DE3)/pET-20b(+)-pul with IPTG induction in LB medium, but its expression level reduced continually with the extension of cryopreservation time and basal expression was observed. However, E. coli BL21(DE3)/pET-22b(+)-pul , involving lac operator downstream of T7 promoter to regulate foreign gene transcription, exhibited pullulanase activity consistently without detected basal expression. By investigating the effect of lac operator, basal expression of foreign protein was found to cause expression instability and negative effect on production of target protein. Thus double-repression strategy was proposed that lac operators in both chromosome and plasmid were bound with lac repressor to repress T7 RNA polymerase synthesis and target protein expression before induction. Consequently, the total activity of pullulanase was remarkably increased to 580 U/mL with auto-induction by lac operator-involved E. coli BL21(DE3)/pET-22b(+)-pul. When adding 0.6% glycine in culture, the extracellular production of pullulanase was significantly improved with the extracellular activity of 502 U/mL, which is a relatively higher level achieved to date for extracellular production of pullulanase. The successful

  2. High-Level Expression of Bacillus naganoensis Pullulanase from Recombinant Escherichia coli with Auto-Induction: Effect of lac Operator

    PubMed Central

    Xu, Yan; Chen, Wen Bo; Mu, Xiao Qing; Wang, Xinye; Xiao, Rong

    2013-01-01

    Pullulanase plays an important role in specific hydrolysis of branch points in amylopectin and is generally employed as an important enzyme in starch-processing industry. So far, however, the production level of pullulanase is still somewhat low from wide-type strains and even heterologous expression systems. Here the gene encoding Bacillus naganoensis pullulanase was amplified and cloned. For expression of the protein, two recombinant systems, Escherichia coli BL21(DE3)/pET-20b(+)-pul and E. coli BL21(DE3)/pET-22b(+)-pul, were constructed, both bearing T7 promoter and signal peptide sequence, but different in the existance of lac operator and lacI gene encoding lac repressor. Recombinant pullulanase was initially expressed with the activity of up to 14 U/mL by E. coli BL21(DE3)/pET-20b(+)-pul with IPTG induction in LB medium, but its expression level reduced continually with the extension of cryopreservation time and basal expression was observed. However, E. coli BL21(DE3)/pET-22b(+)-pul , involving lac operator downstream of T7 promoter to regulate foreign gene transcription, exhibited pullulanase activity consistently without detected basal expression. By investigating the effect of lac operator, basal expression of foreign protein was found to cause expression instability and negative effect on production of target protein. Thus double-repression strategy was proposed that lac operators in both chromosome and plasmid were bound with lac repressor to repress T7 RNA polymerase synthesis and target protein expression before induction. Consequently, the total activity of pullulanase was remarkably increased to 580 U/mL with auto-induction by lac operator-involved E. coli BL21(DE3)/pET-22b(+)-pul. When adding 0.6% glycine in culture, the extracellular production of pullulanase was significantly improved with the extracellular activity of 502 U/mL, which is a relatively higher level achieved to date for extracellular production of pullulanase. The successful

  3. The effect of stochasticity on the lac operon: an evolutionary perspective.

    PubMed

    van Hoek, Milan; Hogeweg, Paulien

    2007-06-01

    The role of stochasticity on gene expression is widely discussed. Both potential advantages and disadvantages have been revealed. In some systems, noise in gene expression has been quantified, in among others the lac operon of Escherichia coli. Whether stochastic gene expression in this system is detrimental or beneficial for the cells is, however, still unclear. We are interested in the effects of stochasticity from an evolutionary point of view. We study this question in the lac operon, taking a computational approach: using a detailed, quantitative, spatial model, we evolve through a mutation-selection process the shape of the promoter function and therewith the effective amount of stochasticity. We find that noise values for lactose, the natural inducer, are much lower than for artificial, nonmetabolizable inducers, because these artificial inducers experience a stronger positive feedback. In the evolved promoter functions, noise due to stochasticity in gene expression, when induced by lactose, only plays a very minor role in short-term physiological adaptation, because other sources of population heterogeneity dominate. Finally, promoter functions evolved in the stochastic model evolve to higher repressed transcription rates than those evolved in a deterministic version of the model. This causes these promoter functions to experience less stochasticity in gene expression. We show that a high repression rate and hence high stochasticity increases the delay in lactose uptake in a variable environment. We conclude that the lac operon evolved such that the impact of stochastic gene expression is minor in its natural environment, but happens to respond with much stronger stochasticity when confronted with artificial inducers. In this particular system, we have shown that stochasticity is detrimental. Moreover, we demonstrate that in silico evolution in a quantitative model, by mutating the parameters of interest, is a promising way to unravel the functional

  4. Fusions of flagellar operons to lactose genes on a mu lac bacteriophage.

    PubMed Central

    Komeda, Y

    1982-01-01

    Previous studies have defined 29 genes necessary for synthesis of the Escherichia coli flagellar apparatus. This study analyzed the transcriptional control of flagellar genes, using Mu d (Apr lac) phage to generate flagellar mutants by insertion. These mutants contained operon fusions of flagellar genes to the lac genes of the Mu d phage and allowed the measurement of flagellar operon expression by detection of beta-galactosidase activity. These fusion mutants expressed the enzyme activity constitutively, and an autogenous regulation mechanism was not revealed. Lambda transducing phages carrying these chromosomal fla-lac fusions were also isolated and used to examine the effect of different fla mutations on expression of each flagellar operon. The results showed that flagellar operons are divided into six classes; (class 1) the flbB operon, which controls all of the other flagellar operons; (class 2) the flaU and flbC operons, which are controlled by the flbB operon gene products and are not required for the expression of other Fla operons; (class 3) the flbA, flaG, flaD, flaN, flaB, and flaA operons, which are under flbB operon control and are required for the expression of other fla operons; (class4) the flaZ operon, which is controlled by the gene products of the group 1 and 3 operons and is required for hag transcription; (class 5) the mocha and flaS operons, which are controlled by the gene products of the group 1 and 3 operons; and (class 6) the hag operon. These results are discussed with respect to the possible assembly sequence of the fla gene products. PMID:7037746

  5. Flexible Gates Generate Occluded Intermediates in the Transport Cycle of LacY☆

    PubMed Central

    Stelzl, Lukas S.; Fowler, Philip W.; Sansom, Mark S.P.; Beckstein, Oliver

    2014-01-01

    The major facilitator superfamily (MFS) transporter lactose permease (LacY) alternates between cytoplasmic and periplasmic open conformations to co-transport a sugar molecule together with a proton across the plasma membrane. Indirect experimental evidence suggested the existence of an occluded transition intermediate of LacY, which would prevent leaking of the proton gradient. As no experimental structure is known, the conformational transition is not fully understood in atomic detail. We simulated transition events from a cytoplasmic open conformation to a periplasmic open conformation with the dynamic importance sampling molecular dynamics method and observed occluded intermediates. Analysis of water permeation pathways and the electrostatic free-energy landscape of a solvated proton indicated that the occluded state contains a solvated central cavity inaccessible from either side of the membrane. We propose a pair of geometric order parameters that capture the state of the pathway through the MFS transporters as shown by a survey of available crystal structures and models. We present a model for the occluded state of apo-LacY, which is similar to the occluded crystal structures of the MFS transporters EmrD, PepTSo, NarU, PiPT and XylE. Our simulations are consistent with experimental double electron spin–spin distance measurements that have been interpreted to show occluded conformations. During the simulations, a salt bridge that has been postulated to be involved in driving the conformational transition formed. Our results argue against a simple rigid-body domain motion as implied by a strict “rocker-switch mechanism” and instead hint at an intricate coupling between two flexible gates. PMID:24513108

  6. The effect of LacI autoregulation on the performance of the lactose utilization system in Escherichia coli.

    PubMed

    Semsey, Szabolcs; Jauffred, Liselotte; Csiszovszki, Zsolt; Erdossy, János; Stéger, Viktor; Hansen, Sabine; Krishna, Sandeep

    2013-07-01

    The lactose operon of Escherichia coli is a paradigm system for quantitative understanding of gene regulation in prokaryotes. Yet, none of the many mathematical models built so far to study the dynamics of this system considered the fact that the Lac repressor regulates its own transcription by forming a transcriptional roadblock at the O3 operator site. Here we study the effect of autoregulation on intracellular LacI levels and also show that cAMP-CRP binding does not affect the efficiency of autoregulation. We built a mathematical model to study the role of LacI autoregulation in the lactose utilization system. Previously, it has been argued that negative autoregulation can significantly reduce noise as well as increase the speed of response. We show that the particular molecular mechanism, a transcriptional roadblock, used to achieve self-repression in the lac system does neither. Instead, LacI autoregulation balances two opposing states, one that allows quicker response to smaller pulses of external lactose, and the other that minimizes production costs in the absence of lactose. PMID:23658223

  7. What makes the lac-pathway switch: identifying the fluctuations that trigger phenotype switching in gene regulatory systems.

    PubMed

    Bhogale, Prasanna M; Sorg, Robin A; Veening, Jan-Willem; Berg, Johannes

    2014-10-01

    Multistable gene regulatory systems sustain different levels of gene expression under identical external conditions. Such multistability is used to encode phenotypic states in processes including nutrient uptake and persistence in bacteria, fate selection in viral infection, cell-cycle control and development. Stochastic switching between different phenotypes can occur as the result of random fluctuations in molecular copy numbers of mRNA and proteins arising in transcription, translation, transport and binding. However, which component of a pathway triggers such a transition is generally not known. By linking single-cell experiments on the lactose-uptake pathway in E. coli to molecular simulations, we devise a general method to pinpoint the particular fluctuation driving phenotype switching and apply this method to the transition between the uninduced and induced states of the lac-genes. We find that the transition to the induced state is not caused only by the single event of lac-repressor unbinding, but depends crucially on the time period over which the repressor remains unbound from the lac-operon. We confirm this notion in strains with a high expression level of the lac-repressor (leading to shorter periods over which the lac-operon remains unbound), which show a reduced switching rate. Our techniques apply to multistable gene regulatory systems in general and allow to identify the molecular mechanisms behind stochastic transitions in gene regulatory circuits. PMID:25245949

  8. Isolation and Structure Determination of a Missing Endohedral Fullerene La@C70 through In Situ Trifluoromethylation.

    PubMed

    Wang, Zhiyong; Aoyagi, Shinobu; Omachi, Haruka; Kitaura, Ryo; Shinohara, Hisanori

    2016-01-01

    D5h-symmetric fullerene C70 (D5h-C70) is one of the most abundant members of the fullerene family. One longstanding mystery in the field of fullerene chemistry is whether D5h-C70 is capable of accommodating a rare-earth metal atom to form an endohedral metallofullerene M@D5h-C70, which would be expected to show novel electronic properties. The molecular structure of La@C70 remains unresolved since its discovery three decades ago because of its extremely high instability under ambient conditions and insolubility in organic solvents. Herein, we report the single-crystal X-ray structure of La@C70(CF3)3, which was obtained through in situ exohedral functionalization by means of trifluoromethylation. The X-ray crystallographic study reveals that La@C70(CF3)3 is the first example of an endohedral rare-earth fullerene based on D5h-C70. The dramatically enhanced stability of La@C70(CF3)3 compared to La@C70 can be ascribed to trifluoromethylation-induced bandgap enlargement. PMID:26530527

  9. Crystal structure of VmoLac, a tentative quorum quenching lactonase from the extremophilic crenarchaeon Vulcanisaeta moutnovskia.

    PubMed

    Hiblot, Julien; Bzdrenga, Janek; Champion, Charlotte; Chabriere, Eric; Elias, Mikael

    2015-01-01

    A new representative of the Phosphotriesterase-Like Lactonases (PLLs) family from the hyperthermophilic crenarchaeon Vulcanisaeta moutnovskia has been characterized and crystallized. VmoLac is a native, proficient lactonase with promiscuous, low phosphotriesterase activity. VmoLac therefore represents an interesting candidate for engineering studies, with the aim of developing an efficient bacterial quorum-quenching agent. Here, we provide an extensive biochemical and kinetic characterization of VmoLac and describe the X-ray structures of the enzyme bound to a fatty acid and to its cognate substrate 3-oxo-C10 AHL (Acyl-Homoserine Lactone). The structures highlight possible structural determinants that may be involved in its extreme thermal stability (Tm = 128 °C). Moreover, the structure reveals that the substrate binding mode of VmoLac significantly differs from those of its close homologues, possibly explaining the substrate specificity of the enzyme. Finally, we describe the specific interactions between the enzyme and its substrate, and discuss the possible lactone hydrolysis mechanism of VmoLac. PMID:25670483

  10. Accepting Foreign Genes.

    PubMed

    Boto, Luis

    2016-05-01

    Three recent papers underline the importance of the host genomic background in allowing the stable maintenance of horizontally acquired genes. These studies suggest that post-transfer changes in both host genome and acquired genes contribute to the stable integration of foreign genes. PMID:27075565

  11. A proteomics platform combining depletion, multi-lectin affinity chromatography (M-LAC), and isoelectric focusing to study the breast cancer proteome.

    PubMed

    Zeng, Zhi; Hincapie, Marina; Pitteri, Sharon J; Hanash, Samir; Schalkwijk, Joost; Hogan, Jason M; Wang, Hong; Hancock, William S

    2011-06-15

    The discovery of breast cancer associated plasma/serum biomarkers is important for early diagnosis, disease mechanism elucidation, and determination of treatment strategy for the disease. In this study of serum samples, a multidimensional fractionation platform combined with mass spectrometric analysis were used to achieve the identification of medium to lower abundance proteins, as well as to simultaneously detect glycan and abundance changes. Immuno-affinity depletion and multi-lectin chromatography (M-LAC) were integrated into an automated HPLC platform to remove high abundance protein and fractionate glycoproteins. The collected glycoproteomes were then subjected to isoelectric focusing (IEF) separation by a digital ProteomeChip (dPC), followed by in-gel digestion and LC-MS analysis using an Orbitrap mass spectrometer. As a result, the total number of identified proteins increased significantly when the IEF fractionation step was included as part of the platform. Relevant proteins with biological and disease significance were observed and the dynamic range of the serum proteome measurement was extended. In addition, potential glycan changes were indicated by comparing proteins in control and cancer samples in terms of their affinity to the multi-lectin column (M-LAC) and the pI profiles in IEF separation. In conclusion, a proteomics platform including high abundance protein depletion, lectin affinity fractionation, IEF separation, and LC-MS analysis has been applied to discover breast cancer-associated proteins. The following candidates, thrombospondin-1 and 5, alpha-1B-glycoprotein, serum amyloid P-component, and tenascin-X, were selected as promising examples of the use of this platform. They show potential abundance and glycan changes and will be further investigated in future studies. PMID:21513341

  12. A Proteomics Platform Combining Depletion, Multi-lectin Affinity Chromatography (M-LAC) and Isoelectric Focusing to Study the Breast Cancer Proteome

    PubMed Central

    Zeng, Zhi; Hincapie, Marina; Pitteri, Sharon J.; Hanash, Samir; Schalkwijk, Joost; Hogan, Jason M.; Wang, Hon; Hancock, William S.

    2011-01-01

    The discovery of breast cancer associated plasma/serum biomarkers is important for early diagnosis, disease mechanism elucidation and determination of treatment strategy for the disease. In this study of serum samples, a multidimensional fractionation platform combined with mass spectrometric analysis were used to achieve the identification of medium to lower abundance proteins, as well as simultaneously detecting glycan and abundance changes. Immuno-affinity depletion and multi-lectin chromatography (M-LAC) were integrated into an automated HPLC platform to remove high abundance protein and fractionate glycoproteins. The collected glycoproteomes were then subjected to isoelectric focusing (IEF) separation by a digital ProteomeChip (dPC), followed by in-gel digestion and LC-MS analysis using an Orbitrap mass spectrometer. As a result, the total number of identified proteins increased significantly when the IEF fractionation step was included as part of the platform. Relevant proteins with biological and disease significance were observed and the dynamic range of the serum proteome measurement was extended. In addition, potential glycan changes were indicated by comparing proteins in control and cancer samples in terms of their affinity to the multi-lectin column (M-LAC) and the pI profiles in IEF separation. In conclusion, a proteomics platform including high abundance protein depletion, lectin affinity fractionation, IEF separation and LC-MS analysis has been applied to discover breast cancer associated proteins. The following candidates, thrombospondin-1 and 5, alpha-1B-glycoprotein, serum amyloid P-component and tenascin-X, were selected as promising examples of the use of this platform. They show potential abundance and glycan changes and will be further investigated in future studies. PMID:21513341

  13. Broad-band radio behaviour of flaring BL Lac (J2202+4216)

    NASA Astrophysics Data System (ADS)

    Angelakis, E.; Fuhrmann, L.; Nestoras, I.; Schmidt, R.; Zensus, J. A.; Krichbaum, T. P.; Ungerechts, H.; Sievers, A.; Riquelme, D.

    2011-05-01

    Responding to the ATels #3368, #3371, #3375 and #3377 reporting the recent activity of BL Lac (J2202+4216, RA= 22:02:43, DEC=+42:16:39 in J2000) at different high energy bands, we here report its behaviour in the cm-to-mm radio bands as observed by the F-GAMMA program. Recent activity: Observations performed with the Effelsberg 100-m and the IRAM 30-m telescope over the last months on May 1, 7, 20 and 25, show a persistent increase in the flux at all frequencies observed.

  14. Evaluation of critical indicators in the process of acquiring supplies and services LAC-UFPE

    NASA Astrophysics Data System (ADS)

    Caetano, V. F.; Ferreira, C. V.; dos Santos, M. J.; Honorato, F. A.

    2015-01-01

    In laboratories linked to public universities and accredited by the NBR ISO/IEC 17025, to meet efficiently item 4.6 (procurement of supplies and services) is a challenge that can be accomplished by programming based on historical purchases and services. In this study, we evaluated the critical procurement items to meet the quality management system of the LAC-UFPE: reagents, certified reference material, of equipment parts, maintenance and calibration of equipment and instruments. It was found that the most critical item is the certified reference material, the purchase or repair of which must be expedited within 125 days prior to the receipt to occur within the desired period.

  15. Characterization of lip expression in Salmonella typhimurium: analysis of lip::lac operon fusions.

    PubMed

    Smith, R L; Pelley, J W; Jeter, R M

    1991-10-01

    Strains of Salmonella typhimurium which have an auxotrophic requirement for lipoic acid were isolated by mutagenesis with the transposable element Mu dJ. The chromosomal location of these insertion mutations was determined to be at 14 map units by bacteriophage P22-mediated cotransduction. The lip gene is transcribed in the clockwise direction relative to the S. typhimurium genetic map. Strains with lip::lac operon fusions were used to characterize the transcriptional activity of the lip promoter. Transcription of the lip gene is not regulated by catabolite repression or lipoic acid concentration. The data indicate that the lip gene product is expressed constitutively at a low level. PMID:1663151

  16. The optical periodic analysis of BL Lac object AO 0235+164

    NASA Astrophysics Data System (ADS)

    Wang, Hongtao

    2014-05-01

    BL Lac object AO 0235+164 is a well-known object. We collect a large number of effective observation in B, V, R and I band from historical literatures. The possible periods are analyzed by means of discrete correlation function (DCF) method, structure function (SF) method and Jurkevich (J-K) method. The results show that there are possible periodic variations of 2.63-2.66 years in B band, 2.79-2.84 years in V band, 2.57-2.87 years in R band, 2.62-2.88 years in I band, respectively.

  17. The Long-term Light Variation of BL Lac Object 1ES 1959+650

    NASA Astrophysics Data System (ADS)

    Yuan, Y. H.; Liu, F. Q.

    2013-09-01

    In this paper, the long-term observations of Tuorla Observatory in Finland are collected. The power spectrum, the DCF (Discrete Correlation Function) method, and the Jurkevich method are used to analyze the periodicity. The results show that the periodicity of BL Lac Object 1ES 1959+650 is P=1.4±0.3 yr. Considering that there is a relation between the origin of periodicity and accretion disk, we use this periodicity to obtain the unstable region lying at R=9.65R_{g}}, where R_{g} represents the Schwarzschild radius.

  18. The Long-term Light Variation of BL Lac Object 1ES 1959+650

    NASA Astrophysics Data System (ADS)

    Yuan, Yu-hai; Liu, Fu-qing

    2014-07-01

    According to the data of optical observations of the Tuorla Observatory in Finland, using the power spectrum method, DCF (Discrete Correlation Function) method, and Jurkevich method, respectively, we analyzed the periodicity of the long-term light variation of the BL Lac object 1ES 1959+650, and obtained its light period to be P =1.4±0.3 yr. Assuming that the origin of the periodicity is concerned with the accretion disk, we obtained the region where the instability of this source occurs being R =9.65 Rg, here Rg represents the Schwarzschild radius.

  19. Analysis of LAC Observations of Clusters of Galaxies and Supernova Remnants

    NASA Technical Reports Server (NTRS)

    Hughes, J.

    1996-01-01

    The following publications are included and serve as the final report: The X-ray Spectrum of Abell 665; Clusters of Galaxies; Ginga Observation of an Oxygen-rich Supernova Remnant; Ginga Observations of the Coma Cluster and Studies of the Spatial Distribution of Iron; A Measurement of the Hubble Constant from the X-ray Properties and the Sunyaev-Zel'dovich Effect of Abell 2218; Non-polytropic Model for the Coma Cluster; and Abundance Gradients in Cooling Flow Clusters: Ginga LAC (Large Area Counter) and Einstein SSS (Solid State Spectrometer) Spectra of A496, A1795, A2142, and A2199.

  20. Fermi LAT Detection of a Gamma-ray Flare from the BL Lac Object ON 246

    NASA Astrophysics Data System (ADS)

    Becerra, Josefa

    2015-06-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux from a source positionally consistent with the BL Lac object ON 246 (RA=187.55871 deg, Dec=25.30198 deg, J2000, Beasley et al. 2002, ApJS, 141, 13; with redshift z=0.135, Nass et al. 1996, A&A, 309, 419), also known as S3 1227+25 and 3FGL J1230.3+2519 (3FGL; Acero et al. 2015, arXiv:1501.02003).

  1. The temporal dynamics of emotional acceptance: Experience, expression, and physiology.

    PubMed

    Dan-Glauser, Elise S; Gross, James J

    2015-05-01

    Emotional acceptance has begun to attract considerable attention from researchers and clinicians alike. It is not yet clear, however, what effects emotional acceptance has on early emotion response dynamics. To address this question, participants (N = 37) were shown emotional pictures and cued either to simply attend to them, or to accept or suppress their emotional responses. Continuous measures of emotion experience, expressive behavior, and autonomic responses were obtained. Results indicated that, compared to no regulation, acceptance led to more positive emotions, transiently enhanced expressivity, and lowered respiratory rate. Compared to suppression, acceptance led to more positive emotions, stronger expressivity, and smaller changes in heart rate, blood pressure, and pulse amplitude, as well as greater oxygenation. Acceptance and suppression thus have opposite effects on emotional response dynamics. Because acceptance enhances positive emotion experience and expression, this strategy may be particularly useful in facilitating social interactions. PMID:25782407

  2. Changes in the linear attenuation coefficient of canine appendicular bone following intravenous infusion of strontium lactate, measured using gamma-ray computed tomography.

    PubMed

    Overton, T R; Snyder, R E; Hangartner, T N; Girgis, S; Audette, R J; Secord, D C

    1992-04-01

    Changes in the average linear attenuation coefficient (LAC) within a fixed measurement volume in the proximal end of the dog tibia, which contains trabecular bone and associated soft tissues (the trabecular bone "space"), were monitored continuously using gamma-ray computed tomography (gamma-CT) prior to, during, and following intravenous infusion of strontium (Sr) lactate. An infusion of 1.3-4.7 g of Sr over a period of 110-160 minutes into 20-kg dogs resulted, within 6-8 hours, in an increase of 0.019-0.045 cm-1 (P less than 0.002) in the LAC. Calibration of the gamma-CT system showed that 0.44 mg/cm3 of Sr produced a change of 0.01 cm-1 in the LAC. Using this conversion factor, the Sr concentration in the trabecular bone space resulting from infusion, as measured by flame atomic absorption spectroscopy, agreed with that predicted by the change observed in the LAC. Sr present in the serum and urine was consistent with the changes observed in the LAC over the study period. Control dogs infused with mineral-free solutions showed no change in LAC. Calcium equivalents required to give the changes observed in the LAC using Sr indicate that variations in skeletal turnover in man can be monitored in the peripheral skeleton using gamma-CT. PMID:1571847

  3. Enhanced resistance of Saccharomyces cerevisiae to vanillin by expression of lacA from Trametes sp. AH28-2.

    PubMed

    Ji, Lei; Shen, Yu; Xu, Lili; Peng, Bingyin; Xiao, Yazhong; Bao, Xiaoming

    2011-09-01

    Saccharomyces cerevisiae is affected by the presence of certain phenolic compounds such as vanillin during fermentation of pretreated lignocellulosic hydrolysates. Since vanillin can be polymerized in the presence of laccase into compounds with lower toxicity, the laccase gene, lacA, from Trametes sp. AH28-2 was fused to the α-factor signal sequence and transferred into S. cerevisiae CEN.PK strains for secretory expression. Furthermore, the chaperone gene, KAR2, was overexpressed to promote the translocation of laccase. In the presence of 8 mmol/L vanillin, a shorter lag phase was observed in the lacA gene expressing strains. The vanillin-specific conversion rate of the lacA-expressing strain BSJX0A2 was 0.069 g g(-1)biomass h(-1), while it was 0.065 g g(-1)biomass h(-1) in the reference strain. PMID:21727001

  4. Crystallization and preliminary X-ray diffraction analysis of the lactonase VmoLac from Vulcanisaeta moutnovskia

    PubMed Central

    Hiblot, Julien; Gotthard, Guillaume; Champion, Charlotte; Chabriere, Eric; Elias, Mikael

    2013-01-01

    Phosphotriesterase-like lactonases (PLLs) are native lactonases that are capable of hydrolyzing lactones such as aliphatic lactones or acyl-homoserine lactones, which are involved in bacterial quorum sensing. Previously characterized PLLs are moreover endowed with a promiscuous phosphotriesterase activity and are therefore able to detoxify organophosphate insecticides. A novel PLL representative, dubbed VmoLac, has been identified from the hyperthermophilic crenarchaeon Vulcanisaeta moutnovskia. Because of its intrinsic high thermal stability, VmoLac may constitute an appealing candidate for engineering studies with the aim of producing an efficient biodecontaminant for organophosphorus compounds and a bacterial antivirulence agent. In combination with biochemical studies, structural information will allow the identification of the residues involved in substrate specificity and an understanding of the enzymatic catalytic mechanisms. Here, the expression, purification, crystallization and X-ray data collection at 2.4 Å resolution of VmoLac are reported. PMID:24192357

  5. Crystallization and preliminary X-ray diffraction analysis of the lactonase VmoLac from Vulcanisaeta moutnovskia.

    PubMed

    Hiblot, Julien; Gotthard, Guillaume; Champion, Charlotte; Chabriere, Eric; Elias, Mikael

    2013-11-01

    Phosphotriesterase-like lactonases (PLLs) are native lactonases that are capable of hydrolyzing lactones such as aliphatic lactones or acyl-homoserine lactones, which are involved in bacterial quorum sensing. Previously characterized PLLs are moreover endowed with a promiscuous phosphotriesterase activity and are therefore able to detoxify organophosphate insecticides. A novel PLL representative, dubbed VmoLac, has been identified from the hyperthermophilic crenarchaeon Vulcanisaeta moutnovskia. Because of its intrinsic high thermal stability, VmoLac may constitute an appealing candidate for engineering studies with the aim of producing an efficient biodecontaminant for organophosphorus compounds and a bacterial antivirulence agent. In combination with biochemical studies, structural information will allow the identification of the residues involved in substrate specificity and an understanding of the enzymatic catalytic mechanisms. Here, the expression, purification, crystallization and X-ray data collection at 2.4 Å resolution of VmoLac are reported. PMID:24192357

  6. Small-scale field test of the genetically engineered lacZY marker

    SciTech Connect

    Hattemer-Frey, H.A.; Brandt, E.J.; Travis, C.C. )

    1990-06-01

    Commercial genetic engineering is advancing into areas that require the small-scale introduction of genetically engineered microorganisms (GEMs) to better quantify variables that affect microorganism distribution and survival and to document potential long-term consequences. A recombinant DNA marker system, the lacZY marker, developed by the Monsanto Agricultural Co., enables the distribution and fate of marked fluorescent pseudomonad organisms to be monitored under actual field conditions. Critical evaluation of GEMs under field conditions is imperative if plant-beneficial effects are to be correlated with organism release. This paper evaluates the effectiveness of this marker system and its ability to facilitate the assessment of risks associated with deliberate environmental introductions of genetically engineered microorganisms. Results of prerelease contained growth chamber and field experiments demonstrated that: (1) the scientific risk assessment methodology adopted by Monsanto and approved by the U.S. Environmental Protection Agency was appropriate and comprehensive; (2) the deliberate introduction of a GEM did not pose unacceptable or unforeseen risks to human health or the environment; (3) the lacZY marker is an effective environmental tracking tool; and (4) regulatory oversight should reflect the expected risk and not be excessively burdensome for all GEMs.

  7. Dynamics and bistability in a reduced model of the lac operon.

    PubMed

    Yildirim, Necmettin; Santillan, Moises; Horike, Daisuke; Mackey, Michael C

    2004-06-01

    It is known that the lac operon regulatory pathway is capable of showing bistable behavior. This is an important complex feature, arising from the nonlinearity of the involved mechanisms, which is essential to understand the dynamic behavior of this molecular regulatory system. To find which of the mechanisms involved in the regulation of the lac operon is the origin of bistability, we take a previously published model which accounts for the dynamics of mRNA, lactose, allolactose, permease and beta-galactosidase involvement and simplify it by ignoring permease dynamics (assuming a constant permease concentration). To test the behavior of the reduced model, three existing sets of data on beta-galactosidase levels as a function of time are simulated and we obtain a reasonable agreement between the data and the model predictions. The steady states of the reduced model were numerically and analytically analyzed and it was shown that it may indeed display bistability, depending on the extracellular lactose concentration and growth rate. PMID:15189056

  8. Bistable behavior in a model of the lac operon in Escherichia coli with variable growth rate.

    PubMed

    Santillán, M

    2008-03-15

    This work is a continuation from another study previously published in this journal. Both the former and the present works are dedicated to investigating the bistable behavior of the lac operon in Escherichia coli from a mathematical modeling point of view. In the previous article, we developed a detailed mathematical model that accounts for all of the known regulatory mechanisms in this system, and studied the effect of inducing the operon with lactose instead of an artificial inducer. In this article, the model is improved to account, in a more detailed way, for the interaction of the repressor molecules with the three lac operators. A recently discovered cooperative interaction between the CAP molecule (an activator of the lactose operon) and Operator 3 (which influences DNA folding) is also included in this new version of the model. The growth rate dependence on the rate of energy entering the bacteria (in the form of transported glucose molecules and of metabolized lactose molecules) is also considered. A large number of numerical experiments is carried out with this improved model. The results are discussed in regard to the bistable behavior of the lactose operon. Special attention is paid to the effect that a variable growth rate has on the system dynamics. PMID:18065471

  9. Dynamics and bistability in a reduced model of the lac operon

    NASA Astrophysics Data System (ADS)

    Yildirim, Necmettin; Santillán, Moisés; Horike, Daisuke; Mackey, Michael C.

    2004-06-01

    It is known that the lac operon regulatory pathway is capable of showing bistable behavior. This is an important complex feature, arising from the nonlinearity of the involved mechanisms, which is essential to understand the dynamic behavior of this molecular regulatory system. To find which of the mechanisms involved in the regulation of the lac operon is the origin of bistability, we take a previously published model which accounts for the dynamics of mRNA, lactose, allolactose, permease and β-galactosidase involvement and simplify it by ignoring permease dynamics (assuming a constant permease concentration). To test the behavior of the reduced model, three existing sets of data on β-galactosidase levels as a function of time are simulated and we obtain a reasonable agreement between the data and the model predictions. The steady states of the reduced model were numerically and analytically analyzed and it was shown that it may indeed display bistability, depending on the extracellular lactose concentration and growth rate.

  10. Veritas Observations of Relativistic Outflows in - and Intermediate-Frequency BL Lac Objects

    NASA Astrophysics Data System (ADS)

    Prokoph, Heike

    2014-03-01

    The majority of blazars detected at very high energies (VHE; E > 100 GeV) are high-frequency-peaked BL Lac objects (HBLs). Low- and intermediate-frequency-peaked BL Lacs (LBLs/IBLs with synchrotron-peak frequencies in the infrared and optical regime) are generally more powerful, more luminous, and have a richer jet environment than HBLs. However, only a handful of these IBL and LBLs have been detected by ground-based gamma-ray telescopes, typically during high-flux states. The VERITAS array has been monitoring five known VHE LBLs/IBLs since 2009: 3C 66A, W Comae, PKS 1424+240, S5 0716+714 and BL Lacertae, with typical exposures of 5-10 hours per year. The results of these long-term observations are presented, including a bright, subhour-scale VHE flare of BL Lacertae in June 2011, the first low-state detections of 3C 66A and W Comae, and the detection and characterization of the IBL B2 1215+30.

  11. POWERFUL HIGH-ENERGY EMISSION OF THE REMARKABLE BL Lac OBJECT S5 0716+714

    SciTech Connect

    Vittorini, V.; Chen, A. W.; Ferrari, A.; Tavani, M.; D'Ammando, F.; Donnarumma, I.; Pacciani, L.; Pucella, G.; Bulgarelli, A.; Colafrancesco, S.; Giommi, P.

    2009-12-01

    BL Lac objects of the intermediate subclass (IBLs) are known to emit a substantial fraction of their power in the energy range 0.1-10 GeV. Detecting gamma-ray emission from such sources provides therefore a direct probe of the emission mechanisms and of the underlying powerhouse. The gamma-ray satellite, AGILE, detected the remarkable IBL S5 0716+714 (z approx = 0.3) during a high state in the period from 2007 September-October, marked by two very intense flares reaching peak fluxes of 200 x 10{sup -8} photons cm{sup -2} s{sup -1} above 100 MeV, with simultaneous optical and X-ray observations. We present here a theoretical model for the two major flares and discuss the overall energetics of the source. We conclude that 0716+714 is among the brightest BL Lac's ever detected at gamma-ray energies. Because of its high power and lack of signs for ongoing accretion or surrounding gas, the source is an ideal candidate to test the maximal power extractable from a rotating supermassive black hole via the pure Blandford-Znajek (BZ) mechanism. We find that during the 2007 gamma-ray flares 0716+714 approached or just exceeded the upper limit set by BZ for a black hole of mass 10{sup 9} M{sub sun}.

  12. Lightning Detection by LAC Onboard the Japanese Venus Climate Orbiter, Planet-C

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Yoshida, J.; Yair, Y.; Imamura, T.; Nakamura, M.

    Lightning activity in Venus has been a mystery for a long period, although many studies based on observations both by spacecraft and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). Planet-C will be launched in 2010 by JAXA. To distinguish an optical lightning flash from other pulsing noises, high-speed sampling at 50 kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not the first priority. For this purpose we developed a new type of APD (avalanche photo diode) array with a format of 8×8. A narrow band interference filter at wavelength of 777.4 nm (OI), which is the expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth's lightning or less at a distance of 3 Rv. In this paper, firstly we describe the background of the Venus lightning study to locate our spacecraft project, and then introduce the mission details.

  13. Lightning Detection by LAC Onboard the Japanese Venus Climate Orbiter, Planet-C

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Yoshida, J.; Yair, Y.; Imamura, T.; Nakamura, M.

    2008-06-01

    Lightning activity in Venus has been a mystery for a long period, although many studies based on observations both by spacecraft and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). Planet-C will be launched in 2010 by JAXA. To distinguish an optical lightning flash from other pulsing noises, high-speed sampling at 50 kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not the first priority. For this purpose we developed a new type of APD (avalanche photo diode) array with a format of 8×8. A narrow band interference filter at wavelength of 777.4 nm (OI), which is the expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth’s lightning or less at a distance of 3 Rv. In this paper, firstly we describe the background of the Venus lightning study to locate our spacecraft project, and then introduce the mission details.

  14. Induction of lacZ Mutations in Muta™Mouse Primary Hepatocytes

    PubMed Central

    Chen, Guosheng; Gingerich, John; Soper, Lynda; Douglas, George R; White, Paul A

    2010-01-01

    We have developed an in vitro mutation assay using primary hepatocytes from the transgenic Muta™Mouse. Primary hepatocytes were isolated using a two-step perfusion method with purification by Percoll, cultured, and treated with benzo[a]pyrene (BaP), 2-amino-1-methyl-6-phenyl- imidazo[4,5-b]pyridine (PhIP), 3-nitrobenzoanthrone (3-NBA), and cigarette smoke condensate (CSC). The mean lacZ mutant frequency (MF) for the solvent control was approximately twofold greater than the spontaneous MF observed in liver tissue. A concentration-dependent increase in MF (up to 3.7-fold above control) was observed following exposure to BaP. Fourfold and twofold increases in mutant frequency were observed for 3-NBA and PhIP exposures, respectively, without the addition of any exogenous metabolic activation. A slight but statistically significant increase in lacZ MF was observed for CSC, but only at the lowest concentration. This is the first report demonstrating that mutations can be detected in cultured primary hepatocytes from Muta™Mouse. The preliminary results presented suggest that the Muta™Mouse primary hepatocyte mutagenicity assay can be used as a cost-effective tool for screening of environmental mutagens and therapeutic products. Environ. Mol. Mutagen. 51:330–337, 2010. © 2009 Wiley-Liss, Inc. PMID:19953605

  15. An extracellular laccase with potent dye decolorizing ability from white rot fungus Trametes sp. LAC-01.

    PubMed

    Ling, Zhuo-Ren; Wang, Shan-Shan; Zhu, Meng-Juan; Ning, Ying-Jie; Wang, Shou-Nan; Li, Bing; Yang, Ai-Zhen; Zhang, Guo-Qing; Zhao, Xiao-Meng

    2015-11-01

    A novel laccase was purified from fermentation broth of white rot fungus Trametes sp. LAC-01 using an isolation procedure involving three ion-exchange chromatography steps on DEAE-cellulose, SP-Sepharose, and Q-Sepharose, and one gel-filtration step. The purified enzyme (TSL) was proved as a monomeric protein with a Mr of 59kDa based on SDS-PAGE and FPLC. Partial amino acid sequences were obtained by LC-MS/MS sharing considerably high sequence similarity with that of other laccases. It possessed optimal pH of 2.6 and temperature of 60°C using ABTS as the substrate. The Km of the laccase toward ABTS was estimated to 30.28μM at pH 2.6 and 40°C. TSL manifested considerably high oxidizing activity toward ABTS, but was avoid of degradative activity toward benzidine, caftaric acid, etc. It was effective in the decolorization of phenolic dyes - Bromothymol Blue and Malachite Green with decolorization rate higher than 60% after 24h of incubation. Adjunction of Cu(2+) with the final concentration of 2.0mmol/L significantly activated laccase production with a steady high level of 275.8-282.2U/mL in 96-144h. The high yield and short production period makes Trametes sp. LAC-01 and TSL potentially useful for industrial and environmental application and commercialization. PMID:26361865

  16. An Analysis of Periodic Components in BL Lac Object S5 0716 +714 with MUSIC Method

    NASA Astrophysics Data System (ADS)

    Tang, J.

    2012-01-01

    Multiple signal classification (MUSIC) algorithms are introduced to the estimation of the period of variation of BL Lac objects.The principle of MUSIC spectral analysis method and theoretical analysis of the resolution of frequency spectrum using analog signals are included. From a lot of literatures, we have collected a lot of effective observation data of BL Lac object S5 0716 + 714 in V, R, I bands from 1994 to 2008. The light variation periods of S5 0716 +714 are obtained by means of the MUSIC spectral analysis method and periodogram spectral analysis method. There exist two major periods: (3.33±0.08) years and (1.24±0.01) years for all bands. The estimation of the period of variation of the algorithm based on the MUSIC spectral analysis method is compared with that of the algorithm based on the periodogram spectral analysis method. It is a super-resolution algorithm with small data length, and could be used to detect the period of variation of weak signals.

  17. Northern hemisphere mid-latitude geomagnetic anomaly revealed from Levantine Archaeomagnetic Compilation (LAC).

    NASA Astrophysics Data System (ADS)

    Shaar, R.; Tauxe, L.; Agnon, A.; Ben-Yosef, E.; Hassul, E.

    2015-12-01

    The rich archaeological heritage of Israel and nearby Levantine countries provides a unique opportunity for archaeomagnetic investigation in high resolution. Here we present a summary of our ongoing effort to reconstruct geomagnetic variations of the past several millennia in the Levant at decadal to millennial resolution. This effort at the Southern Levant, namely the "Levantine Archaeomagnetic Compilation" (LAC), presently consists of data from over 650 well-dated archaeological objects including pottery, slag, ovens, and furnaces. In this talk we review the methodological challenges in achieving a robust master secular variation curve with realistic error estimations from a large number of different datasets. We present the current status of the compilation, including the southern and western Levant LAC data (Israel, Cyprus, and Jordan) and other published north-eastern Levant data (Syria and southern Turkey), and outline the main findings emerging from these data. The main feature apparent from the new compilation is an extraordinary intensity high that developed over the Levant region during the first two millennia BCE. The climax of this event is a double peak intensity maximum starting at ca. 1000 BCE and ending at ca. 735 BCE, accompanied with at least two events of geomagnetic spikes. Paleomagnetic directions from this period demonstrate anomalies of up to 20 degrees far from the averaged GAD field. This leads us to postulate that the maximum in the intensity is a manifestation of an intense mid-latitude local positive geomagnetic anomaly that persisted for over two centuries.

  18. Photopolarimetric Monitoring of the Blazar BL Lac in the Optical and Near-Infrared Bands: Decay of the Long-Lived Component

    NASA Astrophysics Data System (ADS)

    Sakimoto, Kiyoshi; Uemura, Makoto; Sasada, Mahito; Kawabata, Koji S.; Fukazawa, Yasushi; Yamanaka, Masayuki; Itoh, Ryosuke; Ohsugi, Takashi; Yoshida, Michitoshi; Akitaya, Hiroshi; Sato, Shuji; Kino, Masaru

    2013-04-01

    We report on the results of optical-near-infrared photopolarimetric observations of BL Lac conducted from 2008 to 2011. Our observations are consistent with past studies in which the behavior of the polarization of BL Lac could be understood with two components: short flares whose polarization angles randomly change, and a long-lived component. In addition, we detected a gradually decreasing trend in the total flux, the polarized flux, and the polarization degree without a large variation in the polarization angle from 2008 to mid-2009. These results suggest that the long-lived component decayed from 2008 to mid-2009. We propose that the long-lived component is not stationary, but is probably variable with a time-scale of years. We found no change in the activity of the short flares in 2008 and 2009, when the long-lived component was strong and weak, respectively. Furthermore, there were no clear differences in the mean color and the distribution of the polarization angle of the short flares from 2008 to 2009. These facts indicate that the emitting region of the long-term component was physically disconnected to that of the short flares. The color of the long-term component was bluer than that of the short flares, indicating a higher synchrotron peak-frequency. This could be due to a low efficiency of synchrotron and/or Compton cooling in the emitting region of the long-lived component. The long-term component is possibly originated from a relatively downstream region in the jet where the electron density is low, or the external radiation field is weak.

  19. Accepters and Rejecters of Counseling.

    ERIC Educational Resources Information Center

    Rose, Harriett A.; Elton, Charles F.

    Personality differences between students who accept or reject proffered counseling assistance were investigated by comparing personality traits of 116 male students at the University of Kentucky who accepted or rejected letters of invitation to group counseling. Factor analysis of Omnibus Personality Inventory (OPI) scores to two groups of 60 and…

  20. Cone penetrometer acceptance test report

    SciTech Connect

    Boechler, G.N.

    1996-09-19

    This Acceptance Test Report (ATR) documents the results of acceptance test procedure WHC-SD-WM-ATR-151. Included in this report is a summary of the tests, the results and issues, the signature and sign- off ATP pages, and a summarized table of the specification vs. ATP section that satisfied the specification.

  1. A KPC-scale X-ray jet in the BL LAC Source S5 2007+777

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita; Maraschi, Laura; Tavecchio, Fabrizio

    2008-01-01

    The BL Lac S3 2007++777, a classical radio-selected BL Lac from the sample of Stirkel et al. exhibiting an extended (19") radio jet. was observed with Chandra revealing an X-ray jet with simi1ar morphology. The hard X-ray spectrum and broad band SED is consistent with an IC/CMB origin for the X-ray emission, implying a highly relativistic flow at small angle to the line of sight with an unusually large deprojected length, 300 kpc. A structured jet consisting of a fast spine and slow wall is consistent with the observations.

  2. A series of vectors to construct lacZ fusions for the study of gene expression in Schizosaccharomyces pombe.

    PubMed

    Lafuente, M J; Petit, T; Gancedo, C

    1997-12-22

    We have constructed a series of plasmids to facilitate the fusion of promoters with or without coding regions of genes of Schizosaccharomyces pombe to the lacZ gene of Escherichia coli. These vectors carry a multiple cloning region in which fission yeast DNA may be inserted in three different reading frames with respect to the coding region of lacZ. The plasmids were constructed with the ura4+ or the his3+ marker of S. pombe. Functionality of the plasmids was tested measuring in parallel the expression of fructose 1,6-bisphosphatase and beta-galactosidase under the control of the fbp1+ promoter in different conditions. PMID:9450546

  3. Manoomin: place-based research with Native American students on wild rice lakes on the Fond du Lac Band of Lake Superior Chippewa Reservation, northern Minnesota

    NASA Astrophysics Data System (ADS)

    Ito, E.; Myrbo, A.; Dalbotten, D. M.; Pellerin, H.; Greensky, L.; Howes, T.; Wold, A.; McEathron, M. A.; Shanker, V.

    2010-12-01

    The manoomin project is a collaboration between Fond du Lac Tribal and Community College (Cloquet, MN), the Reservation’s Resource Management Division, and the University of Minnesota funded by the NSF GEO-OEDG Program. It builds on a successful seven-year history of collaboration between these parties, including regular science camps (gidaakiimanaanimigawig, Our Earth Lodge) for students of a wide range of ages. We are working as a team with Native students to study the history of wild rice (manoomin; Zizania palustris), a culturally important resource, growing on Reservation lakes. The joint project takes two main approaches: study of sediment core samples collected from Reservation lakes; and the collection of traditional knowledge about wild rice from the Elders. Science campers collect lake cores during winter with the assistance of the U of MN’s LacCore (National Lacustrine Core Facility) and Resource Management and visit LacCore to log, split and describe cores soon thereafter. Academic mentors with a range of specialties (phytoliths, pollen, plant macrofossils, sedimentology, geochemistry, magnetics) spend 1-2 weeks during the summer with small groups of college-age (>18, many nontraditional) student interns working on a particular paleoenvironmental proxy from the sediment cores. Younger students (middle and high school) also work in small teams in half day units with the same mentors. All campers become comfortable in an academic setting, gain experience working in research labs learning and practicing techniques, and jointly interpret collective results. The continuation of the project over five years (2009-2014) will allow these students to develop relationships with scientists and to receive mentoring beyond the laboratory as they make transitions into 2- and 4-year colleges and into graduate school. Their research provides historical and environmental information that is relevant to their own land that will be used by Resource Management which is

  4. Escherichia coli Fis and DnaA proteins bind specifically to the nrd promoter region and affect expression of an nrd-lac fusion.

    PubMed Central

    Augustin, L B; Jacobson, B A; Fuchs, J A

    1994-01-01

    The Escherichia coli nrd operon contains the genes encoding the two subunits of ribonucleoside diphosphate reductase. The regulation of the nrd operon has been observed to be very complex. The specific binding of two proteins to the nrd regulatory region and expression of mutant nrd-lac fusions that do not bind these proteins are described. A partially purified protein from an E. coli cell extract was previously shown to bind to the promoter region and to regulate transcription of the nrd operon (C. K. Tuggle and J. A. Fuchs, J. Bacteriol. 172:1711-1718, 1990). We have purified this protein to homogeneity by affinity chromatography and identified it as the E. coli factor for inversion stimulation (Fis). Cu-phenanthroline footprinting experiments showed that Fis binds to a site centered 156 bp upstream of the start of nrd transcription. Mutants with deletion and site-directed mutations that do not bind Fis at this site have two- to threefold-lower expression of an nrd-lac fusion. The previously reported negative regulatory nature of this site (C. K. Tuggle and J. A. Fuchs, J. Bacteriol. 172:1711-1718, 1990) was found to be due to a change in polarity in the vectors used to construct promoter fusions. Two nine-base sequences with homology to the DnaA consensus binding sequence are located immediately upstream of the nrd putative -35 RNA polymerase binding site. Binding of DnaA to these sequences on DNA fragments containing the nrd promoter region was confirmed by in vitro Cu-phenanthroline footprinting. Footprinting experiments on fragments with each as well as both of the mutated 9-mers suggests cooperativity between the two sites in binding DnaA. Assay of in vivo expression from wild-type and DnaA box-mutated nrd promoter fragments fused to lacZ on single-copy plasmids indicates a positive effect of DnaA binding on expression of nrd. Images PMID:8288532

  5. A cloning vector for creation of Escherichia coli lacZ translational fusions and generation of linear template for chromosomal integration.

    PubMed

    Uhlich, Gaylen A; Chen, Chin-Yi

    2012-05-01

    A novel cloning vector to aid in the construction of single copy β-galactosidase reporter systems for gene expression studies in lactose metabolizing Escherichia coli strains, including STEC, is described. The plasmid allows construction of translational fusions of cloned gene promoters to a short segment of E. coli lacZ. A selectable spectinomycin resistance marker flanked by a short lacI segment is positioned 5' to the cloning site. PCR amplification using opposing primers complementary to the upstream lacI fragment and the downstream lacZ fragment generates a linear template suitable for integration using pRedET recombination. Integration of linear template derived from the recombinant plasmid into host strains replaces the entire native lacZ promoter and fuses the promoter of interest in-frame with the lacZ gene, thus simultaneously producing a single-copy, chromosomal reporter system and eliminating background lacZ expression. Studies comparing ahpC expression from a chromosomal fusion in the lac open with that on a plasmid in E. coli strain EDL933 are shown. PMID:22197962

  6. Individual and Sex Differences in the Zone of Acceptable Alternatives.

    ERIC Educational Resources Information Center

    Leung, S. Alvin; Harmon, Lenore W.

    1990-01-01

    Examined zone of acceptable alternatives construct from Gottfredson's theory of career aspiration. College students' (N=246) responses to Occupations List were coded with measurements of sex type and prestige, and indicators of zone of acceptable alternatives for subjects' were computed. Found changes over time and differences related to gender…

  7. Self-Reported Acceptance of Social Anxiety Symptoms: Development and Validation of the Social Anxiety-Acceptance and Action Questionnaire

    ERIC Educational Resources Information Center

    MacKenzie, Meagan B.; Kocovski, Nancy L.

    2010-01-01

    Mindfulness and acceptance-based interventions have been used in social anxiety treatments with initial success. Further research requires the psychometrically sound measurement of mechanisms of change associated with these treatments. This research was conducted to develop and evaluate such a measure, the Social Anxiety-Acceptance and Action…

  8. A fire history derived from Pinus resinosa Ait. for the Islands of Eastern Lac La Croix, Minnesota, USA.

    PubMed

    Johnson, Lane B; Kipfmueller, Kurt F

    2016-06-01

    We reconstructed fire occurrence near a fur-trade era canoe travel corridor (used ca. 1780-1802) in the Quetico-Superior region west of Lake Superior to explore the possibility of human influence on pre-fire suppression rates of fire occurrence. Our research objectives were to (1) examine the spatial and temporal patterns of fire in the study area, (2) test fires' strength of association with regional drought, and (3) assess whether reconstructed fire frequencies could be explained by observed rates of lightning fire ignition over the modern period of record. We developed a 420-year fire history for the eastern portion of Lac La Croix in the Boundary Waters Canoe Area Wilderness (BWCAW). Seventy-one fire-scarred samples were collected from remnant Pinus resinosa Ait. (red pine) stumps and logs from thirteen distinct island and three mainland forest stands. Collectively these samples contained records of 255 individual fire scars representing 79 fire events from 1636 to 1933 (study area mean fire intervals [MFI] 3.8 yr). Reconstructed fires were spatially and temporally asynchronous and not strongly associated with regional drought (P > 0.05). When compared to the conservative, tree-ring reconstructed estimate of historical fire occurrence and modern lightning-caused fires (1929-2012), a noticeable change in the distribution and frequency of fires within the study area was evident with only two lightning-ignited island fires since 1934 in the study area. Our results suggest a high likelihood that indigenous land use contributed to surface fire ignitions within our study area and highlights the importance of examining the potential effects of past indigenous land use when determining modern approaches to fire and wilderness management in fire-adapted ecosystems. PMID:27509746

  9. A 33 yr constancy of the X-ray coronae of AR Lac and eclipse diagnosis of scale height

    SciTech Connect

    Drake, Jeremy J.; Ratzlaff, Peter; Kashyap, Vinay; Wargelin, Bradford J.; Huenemoerder, David P.; Pease, Deron O.

    2014-03-01

    Extensive X-ray and EUV photometric observations of the eclipsing RS CVn system AR Lac were obtained over the years 1997-2013 with the Chandra X-Ray Observatory Extreme-Ultraviolet Explorer (EUVE). During primary eclipse, High Resolution Camera count rates decrease by ∼40%. A similar minimum is seen during one primary eclipse observed by EUVE but not in others owing to intrinsic source variability. Little evidence for secondary eclipses is present in either the X-ray or EUV data, reminiscent of earlier X-ray and EUV observations. Primary eclipses allow us to estimate the extent of a spherically symmetric corona on the primary G star of about 1.3 R {sub ☉}, or 0.86 R {sub *}, and indicate that the G star is likely brighter than the K component by a factor of 2-5. Brightness changes not attributable to eclipses appear to be dominated by stochastic variability and are generally non-repeating. X-ray and EUV light curves cannot therefore be reliably used to reconstruct the spatial distribution of emission assuming that only eclipses and rotational modulation are at work. Moderate flaring is observed, where count rates increase by up to a factor of three above quiescence. Combined with older ASCA, Einstein, EXOSAT, ROSAT, and BeppoSAX observations, the data show that the level of quiescent coronal emission at X-ray wavelengths has remained remarkably constant over 33 yr, with no sign of variation due to magnetic cycles. Variations in base level X-ray emission seen by Chandra over 13 yr are only ∼10%, while variations back to pioneering Einstein observations in 1980 amount to a maximum of 45% and more typically about 15%.

  10. 78 FR 3911 - Big Stone National Wildlife Refuge, Big Stone and Lac Qui Parle Counties, MN; Final Comprehensive...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-17

    ... Fish and Wildlife Service Big Stone National Wildlife Refuge, Big Stone and Lac Qui Parle Counties, MN... (CCP) and finding of no significant impact (FONSI) for the environmental assessment (EA) for Big Stone.../FONSI on the planning Web site at http://www.fws.gov/midwest/planning/BigStoneNWR/index.html . A...

  11. Accepted scientific research works (abstracts).

    PubMed

    2014-01-01

    These are the 39 accepted abstracts for IAYT's Symposium on Yoga Research (SYR) September 24-24, 2014 at the Kripalu Center for Yoga & Health and published in the Final Program Guide and Abstracts. PMID:25645134

  12. L-286 Acceptance Test Record

    SciTech Connect

    HARMON, B.C.

    2000-01-14

    This document provides a detailed account of how the acceptance testing was conducted for Project L-286, ''200E Area Sanitary Water Plant Effluent Stream Reduction''. The testing of the L-286 instrumentation system was conducted under the direct supervision

  13. Acceptance test procedure MICON software exhaust fan control modifications

    SciTech Connect

    SILVAN, G.R.

    1999-05-21

    This acceptance test verifies the MICON program changes for the new automatic transfer switch ATS-2 alarms, the Closed Loop Cooling isolator status, the CB-3 position alarm, and the alarms for the new emergency fan damper backup air compressor.

  14. VizieR Online Data Catalog: Optically selected BL Lac candidates polarimetry (Heidt+, 2011)

    NASA Astrophysics Data System (ADS)

    Heidt, J.; Nilsson, K.

    2011-03-01

    195 polarimetric measurements of 182 BL Lac candidates from the SDSS taken with 3 different telescopes are presented. For each candidate the J2000 coordinates, its redshift, whether a source is listed in NED, the SDSS r-mag, the telescope for the observations used, the date of the observations, the exposure time for an individual exposure per position angle, the measured degree of polarization, the position angle and references to previous measurements of the sources are given. 13 objects have been observed twice. Here no entry for the coordinates is given. The redshifts, NED-listing and SDSS r-mags have been taken from Collinge et al. (2005, Cat. J/AJ/129/2542). (1 data file).

  15. Mechanism of negative thermal expansion in LaC2 from first-principles prediction

    NASA Astrophysics Data System (ADS)

    Liu, Yaming; Jia, Yu; Sun, Qiang; Liang, Erjun

    2015-01-01

    Based on density functional theory and quasiharmonic approximation, the coefficients of thermal expansion (CTE) and negative thermal expansion (NTE) mechanism of tetragonal LaC2 are studied. Numerical results show that there is an obvious NTE parallel to c-axis, and the CTE is approximately αc = - 1.67 ×10-6K-1, which coincides with the experimental data - 1.0 ×10-6K-1. In particular, a tiny NTE phenomenon along a-axis below 10 K has been predicted. The vibrational modes Eu and Eg at Γ (0 , 0 , 0), and other three modes at M (0.5 , 0.5 , 0) and Z (0 , 0 , 0.5), give rise to negative Grüneisen parameters and therefore contribute to the NTE along a- and c-axis. Additionally, the bulk CTE was calculated to be positive, our CTE values and temperature intervals agree well with the presented experiments.

  16. Mouthparts and stylet penetration of the lac insect Kerria lacca (Kerr) (Hemiptera:Tachardiidae).

    PubMed

    Ahmad, Ayashaa; Kaushik, Sandeep; Ramamurthy, V V; Lakhanpaul, Suman; Ramani, R; Sharma, K K; Vidyarthi, A S

    2012-09-01

    Hitherto less known aspects on mouthpart morphology and penetration mechanism of the lac insect Kerria lacca have been explored. Unique details of the mouthparts, i.e. morphology of labium and stylets and salivary sheath have been brought out. The gross morphology of the mouthparts though resembled other plant sucking homopterans; a two-segmented labium with symmetrically distributed six pairs of contact-chemoreceptors on its surface was distinct; the mandibular stylets had serrations on its extreme apical region, while the maxillary stylets had their external surface smooth with parallel longitudinal grooves on their inner surface. Formation of flanges, salivary sheath and penetration pathway observed along with probing and penetration of the stylets intracellularly up to the phloem cells, as illustrated herein, are the addition to the existing knowledge on the structural details of the mouthparts and the feeding behavior thereupon. PMID:22531548

  17. Nutrient status of the lowbush blueberry, Lac-Saint-Jean area, Quebec, Canada. [Vaccinium angustifolium

    SciTech Connect

    Bouchard, A.R.; Gagnon, M.J.

    1987-01-01

    The lowbush blueberry (Vaccinium angustifolium Ait.) is an important commercial crop of the Lac-Saint-Jean area (Quebec, Canada). The major blueberry fields are located on sandy soils relatively poor in available mineral nutrients. The nutrients originate from a thin organic layer found on the top of these sandy soils. The leaf mineral contents (N, P, K, Mg, Ca, Mn, Fe, Cu, Zn and B) were measured in five blueberry fields during 1984 and 1985. Soil pH and soil available P, K, and Mg were also assessed. The results show that the leaf mineral contents are generally adequate. However, K and Zn might be occasionally deficient when compared to the actual established standards. The available Mg in soil was significantly correlated with the leaf Mg concentration. The data also suggest that the influence of the pH following the burn pruning seems to influence the nutrition of this species.

  18. Surface Brightness Variation of the Contact Binary SW Lac: Clues From Doppler Imaging

    NASA Astrophysics Data System (ADS)

    Şenavcı, Hakan Volkan

    2012-04-01

    In this study, we present the preliminary light curve analysis of the contact binary SW Lac, using B, V light curves of the system spanning 2 years (2009 - 2010). During the spot modeling process, we used the information coming from the Doppler maps of the system, which was performed using the high resolution and phase dependent spectra obtained at the 2.1m Otto Struve Telescope of the McDonald Observatory, in 2009. The results showed that the spot modeling from the light curve analysis are in accordance with the Doppler maps, while the non-circular spot modeling technique is needed in order to obtain much better and reliable spot models.

  19. The flare star EV Lac. II - Relations between the characteristics of the flares

    NASA Astrophysics Data System (ADS)

    Avgoloupis, S.

    1986-07-01

    Characteristics of the four types of flares observed during the 184 events that were observed on the flare star EV Lac in the period 1967-1980 are analyzed. The data include the duration and magnitude of each event, the mean rate of luminosity and apparent magnitude increases, the integrated flare intensity over the whole event, and time histograms of intensity levels of the events. The flares were distributed into 49 type IV events, 71 type III events, 38 type II events and 25 type I events. Intensities were highest in type II events, and the extremes of other distinguishing characteristics were distributed among the other events, with some having correlations exceeding the 95 percent level. The differences were sufficiently pronounced to conclude that the individual type of flare event must be considered in future analyses, rather than considering all flare events as a uniform database.

  20. Development of a LacZ-based transcriptional reporter system for use with Moraxella catarrhalis.

    PubMed

    Evans, Amanda S; Pybus, Christine; Hansen, Eric J

    2013-03-01

    The lack of a transcriptional reporter system for use in Moraxella catarrhalis has hindered studies of gene regulation in this pathogen. PCR and recombinant DNA methods were used to insert a multicloning site (MCS) and promoterless full-length Escherichia coli lacZ gene, flanked by transcriptional terminators both immediately upstream and downstream, into the M. catarrhalis recombinant plasmid pWW115. Insertion into the MCS in the newly constructed plasmid pASE222 of M. catarrhalis promoter regions controlled by either a repressor (i.e., NsrR) or activator (i.e., PhoB) yielded transcriptional fusion constructs that were appropriately responsive to signal inputs dependent on the host strain genotype, as measured quantitatively by means of a Miller β-galactosidase assay. The transcriptional reporter plasmid pASE222 should prove to be a useful tool for rapid screening of factors affecting gene expression in M. catarrhalis. PMID:23219721

  1. Analysis of Optical Variations of BL Lac Object AO 0235+164

    NASA Astrophysics Data System (ADS)

    Hong-tao, Wang

    2014-03-01

    Historical optical BVRI band data are combined on the BL Lac object AO 0235 + 164. In order to examine the possible existence of lags and correlations between variations in different optical bands from this source, a statistical analysis is performed through the Discrete Correlation Function (DCF) method. Monte Carlo simulations called Flux Redistribution/Random Subset Selection (FR/RSS) are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with no or very weak lag within the errors. Long term variability of color indices are also analysed. No color variabilities are found.

  2. Unidentified Active Galactic Nuclei in the Fermi-2LAC catalogue: identification of candidate sources

    NASA Astrophysics Data System (ADS)

    Klindt, L.; van Soelen, B.; Meintjes, P. J.

    Blazars constitute the most violent astronomical objects with jet emitting radiation at all frequencies. In order to fully understand and model blazars and in particular the accretion-black hole system and superluminal jet structure, multi-wavelength observations are required. In the search for Very High Energy (VHE) sources a target sample of twenty unidentified sources with possible blazar characteristics has been constructed from sources listed in the Fermi-2LAC catalogue. The selected targets are all at high galactic latitude (|b| > 10°) with optical/radio counterparts within the Fermi 95% error circle. The selection criteria, which are based on source properties including radio brightness, photon spectral indices, undetermined redshifts, observability and variability, are presented along with the twenty identified sources.

  3. Spatial Diagnostics of Potential X-ray Remnants in Old Novae T Aur and DK Lac

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy

    2013-09-01

    We propose 5 and 3 ks ACIS-S snapshots of potentially extended X-ray remnants of two old classical novae, T Aur and DK Lac. They are the likely counterparts of X-ray sources discovered in our Swift survey of old classical novae, and each target has a spatially-resolved optical remnant with a size of order arcseconds. The additional short Chandra snapshots will confirm or reject the tentative Swift identifications through pinpoint astrometry, and will distinguish between extended remnant emission or rejuvenated accretion. Both are important for understanding binary evolution and also potential post-outburst hibernation, while detection of extended emission will represent extremely rare additions to the exclusive club of X-ray emitting classical nova remnants.

  4. 4U1722 + 11 - The discovery of an X-ray selected BL Lac object

    NASA Technical Reports Server (NTRS)

    Griffiths, R. E.; Wilson, A. S.; Ward, M. J.; Tapia, S.; Ulvestad, J. S.

    1989-01-01

    The Uhuru X-ray source 4U1722 + 11 was observed using the microchannel-plate detector (High Resolution Imager) on the Einstein Observatory, and its coordinates measured to a precision of about 5 arcsec. A 16th-magnitude stellar object within the error circle was observed spectroscopically at CTIO, and at the AAT, and found to have a featureless continuum. Subsequent radio observations at the VLA have established that the object is a radio source at the level of 60 mJy, and optical polarization measurements have determined that the source exhibits variable polarization at the level of 10 percent. On the basis of these observations, it is concluded that 4U1722 + 11 is a member of the class of objects known as X-ray selected blazars of BL Lac objects.

  5. A hadronic origin for ultra-high-frequency-peaked BL Lac objects

    NASA Astrophysics Data System (ADS)

    Cerruti, M.; Zech, A.; Boisson, C.; Inoue, S.

    2015-03-01

    Current Cherenkov telescopes have identified a population of ultra-high-frequency peaked BL Lac objects (UHBLs), also known as extreme blazars, that exhibit exceptionally hard TeV spectra, including 1ES 0229+200, 1ES 0347-121, RGB J0710+591, 1ES 1101-232, and 1ES 1218+304. Although one-zone synchrotron-self-Compton (SSC) models have been generally successful in interpreting the high-energy emission observed in other BL Lac objects, they are problematic for UHBLs, necessitating very large Doppler factors and/or extremely high minimum Lorentz factors of the emitting leptonic population. In this context, we have investigated alternative scenarios where hadronic emission processes are important, using a newly developed (lepto-)hadronic numerical code to systematically explore the physical parameters of the emission region that reproduces the observed spectra while avoiding the extreme values encountered in pure SSC models. Assuming a fixed Doppler factor δ = 30, two principal parameter regimes are identified, where the high-energy emission is due to: (1) proton-synchrotron radiation, with magnetic fields B ˜ 1-100 G and maximum proton energies Ep; max ≲ 1019 eV; and (2) synchrotron emission from p-γ-induced cascades as well as SSC emission from primary leptons, with B ˜ 0.1-1 G and Ep; max ≲ 1017 eV. This can be realized with plausible, sub-Eddington values for the total (kinetic plus magnetic) power of the emitting plasma, in contrast to hadronic interpretations for other blazar classes that often warrant highly super-Eddington values.

  6. Multiple Ant Species Tending Lac Insect Kerria yunnanensis (Hemiptera: Kerriidae) Provide Asymmetric Protection against Parasitoids

    PubMed Central

    Li, Qiao; Hoffmann, Benjamin D.; Zhang, Wei

    2014-01-01

    This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the

  7. [Coexistence mechanism of ant community in lac plantation under habitat heterogeneity].

    PubMed

    Wang, Si-ming; Chen, You-qing; Lu, Zhi-xing; Liu, Chun-ju; Guo, Zu-xue

    2010-10-01

    In order to reveal the coexistence mechanism of ant community in lac plantation, an investigation was made on the ant community composition and the ability of ant species in discovering and holding food resources in a lac plantation in Yayi Town of Mojiang County, Yunnan Province, with the relationships between ant body size and its ability of finding food under habitat heterogeneity probed. There were six dominant ant species in the plantation, i. e., Tetraponera allaborans (Walker), Crematogaster macaoensis Wheeler, Crematogasterferrarii Emery, Dolichoderus thoracicus (Smith), Polyrhachis proxima Roger, and Camponotus parius Emery. The hind leg length (y) of the six ant species increased allometrically with their head width (x), and the regression equation was y = 0.56 + 1.02x + 5.97x2 - 10.85x3. Different ant species had significant differences in their actual and relative frequency in discovering food resources in different habitats, but habitat type had no significant effects on the actual frequency in holding food resources by the ant species. The ant species with bigger head width and bigger body size index could discover more food resources in simple habitat. In contrast, the ant species with smaller head width, shorter hind leg length, and smaller body size index could discover more food resources in complex habitat. The heterogeneity of habitat caused the coexistence of ants: the smaller ant species lived in complex habitat, while the larger ones lived in simple habitat. In addition, numerically dominant ant species were unable to possess all resources, and thereby, could provide the opportunity to other ant species for resources acquisition, making the species coexistence come true. PMID:21328961

  8. Multiple ant species tending lac insect Kerria yunnanensis (Hemiptera: Kerriidae) provide asymmetric protection against parasitoids.

    PubMed

    Chen, Youqing; Lu, Zhixing; Li, Qiao; Hoffmann, Benjamin D; Zhang, Wei

    2014-01-01

    This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the

  9. HESS J1943+213: A Non-classical High-frequency-peaked BL Lac Object

    NASA Astrophysics Data System (ADS)

    Straal, S. M.; Gabányi, K. É.; van Leeuwen, J.; Clarke, T. E.; Dubner, G.; Frey, S.; Giacani, E.; Paragi, Z.

    2016-05-01

    HESS J1943+213 is an unidentified TeV source that is likely a high-frequency-peaked BL Lac (HBL) object, but that is also compatible with a pulsar wind nebula (PWN) nature. Each of these enormously different astronomical interpretations is supported by some of the observed unusual characteristics. In order to finally classify and understand this object, we took a three-pronged approach, through time-domain, high angular resolution, and multi-frequency radio studies. First, our deep time-domain observations with the Arecibo telescope failed to uncover the putative pulsar powering the proposed PWN. We conclude with ˜70% certainty that HESS J1943+213 does not host a pulsar. Second, long-baseline interferometry of the source with e-MERLIN at 1.5 and 5 GHz shows only a core, that is, a point source at ˜ 1–100 mas resolution. Its 2013 flux density is about one-third lower than that detected in the 2011 observations with similar resolution. This radio variability of the core strengthens the HBL object hypothesis. Third, additional evidence against the PWN scenario comes from the radio spectrum we compiled. The extended structure follows a power-law behavior with spectral index α \\=\\-0.54+/- 0.04 while the core component displays a flat spectrum (α \\=\\-0.03+/- 0.03). In contrast, the radio synchrotron emission of PWNe predicts a single power-law distribution. Overall, we rule out the PWN hypothesis and conclude that the source is a BL Lac object. The consistently high fraction (70%) of the flux density from the extended structure then leads us to conclude that HESS J1943+213 must be a non-classical HBL object.

  10. HESS J1943+213: A Non-classical High-frequency-peaked BL Lac Object

    NASA Astrophysics Data System (ADS)

    Straal, S. M.; Gabányi, K. É.; van Leeuwen, J.; Clarke, T. E.; Dubner, G.; Frey, S.; Giacani, E.; Paragi, Z.

    2016-05-01

    HESS J1943+213 is an unidentified TeV source that is likely a high-frequency-peaked BL Lac (HBL) object, but that is also compatible with a pulsar wind nebula (PWN) nature. Each of these enormously different astronomical interpretations is supported by some of the observed unusual characteristics. In order to finally classify and understand this object, we took a three-pronged approach, through time-domain, high angular resolution, and multi-frequency radio studies. First, our deep time-domain observations with the Arecibo telescope failed to uncover the putative pulsar powering the proposed PWN. We conclude with ∼70% certainty that HESS J1943+213 does not host a pulsar. Second, long-baseline interferometry of the source with e-MERLIN at 1.5 and 5 GHz shows only a core, that is, a point source at ∼ 1–100 mas resolution. Its 2013 flux density is about one-third lower than that detected in the 2011 observations with similar resolution. This radio variability of the core strengthens the HBL object hypothesis. Third, additional evidence against the PWN scenario comes from the radio spectrum we compiled. The extended structure follows a power-law behavior with spectral index α \\=\\-0.54+/- 0.04 while the core component displays a flat spectrum (α \\=\\-0.03+/- 0.03). In contrast, the radio synchrotron emission of PWNe predicts a single power-law distribution. Overall, we rule out the PWN hypothesis and conclude that the source is a BL Lac object. The consistently high fraction (70%) of the flux density from the extended structure then leads us to conclude that HESS J1943+213 must be a non-classical HBL object.

  11. Merging a Terrain-Based Parameter and Snow Particle Counter Data for the Assessment of Snow Redistribution in the Col du Lac Blanc Area

    NASA Astrophysics Data System (ADS)

    Schön, Peter; Prokop, Alexander; Naaim-Bouvet, Florence; Vionnet, Vincent; Guyomarc'h, Gilbert; Heiser, Micha; Nishimura, Kouichi

    2015-04-01

    Wind and the associated snow drift are dominating factors determining the snow distribution and accumulation in alpine areas, resulting in a high spatial variability of snow depth that is difficult to evaluate and quantify. The terrain-based parameter Sx characterizes the degree of shelter or exposure of a grid point provided by the upwind terrain, without the computational complexity of numerical wind field models. The parameter has shown to qualitatively predict snow redistribution with good reproduction of spatial patterns. It does not, however, provide a quantitative estimate of changes in snow depths. The objective of our research was to introduce a new parameter to quantify changes in snow depths in our research area, the Col du Lac Blanc in the French Alps. The area is at an elevation of 2700 m and particularly suited for our study due to its consistently bi-modal wind directions. Our work focused on two pronounced, approximately 10 m high terrain breaks, and we worked with 1 m resolution digital snow surface models (DSM). The DSM and measured changes in snow depths were obtained with high-accuracy terrestrial laser scan (TLS) measurements. First we calculated the terrain-based parameter Sx on a digital snow surface model and correlated Sx with measured changes in snow-depths (Δ SH). Results showed that Δ SH can be approximated by Δ SHestimated = α * Sx, where α is a newly introduced parameter. The parameter α has shown to be linked to the amount of snow deposited influenced by blowing snow flux. At the Col du Lac Blanc test side, blowing snow flux is recorded with snow particle counters (SPC). Snow flux is the number of drifting snow particles per time and area. Hence, the SPC provide data about the duration and intensity of drifting snow events, two important factors not accounted for by the terrain parameter Sx. We analyse how the SPC snow flux data can be used to estimate the magnitude of the new variable parameter α . To simulate the development

  12. Risk comparisons, conflict, and risk acceptability claims.

    PubMed

    Johnson, Branden B

    2004-02-01

    Despite many claims for and against the use of risk comparisons in risk communication, few empirical studies have explored their effect. Even fewer have examined the public's relative preferences among different kinds of risk comparisons. Two studies, published in this journal in 1990 and 2003, used seven measures of "acceptability" to examine public reaction to 14 examples of risk comparisons, as used by a hypothetical factory manager to explain risks of his ethylene oxide plant. This study examined the effect on preferences of scenarios involving low or high conflict between the factory manager and residents of the hypothetical town (as had the 2003 study), and inclusion of a claim that the comparison demonstrated the risks' acceptability. It also tested the Finucane et al. (2000) affect hypothesis that information emphasizing low risks-as in these risk comparisons-would raise benefits estimates without changing risk estimates. Using similar but revised scenarios, risk comparison examples (10 instead of 14), and evaluation measures, an opportunity sample of 303 New Jersey residents rated the comparisons, and the risks and benefits of the factory. On average, all comparisons received positive ratings on all evaluation measures in all conditions. Direct and indirect measures showed that the conflict manipulation worked; overall, No-Conflict and Conflict scenarios evoked scores that were not significantly different. The attachment to each risk comparison of a risk acceptability claim ("So our factory's risks should be acceptable to you.") did not worsen ratings relative to conditions lacking this claim. Readers who did or did not see this claim were equally likely to infer an attempt to persuade them to accept the risk from the comparison. As in the 2003 article, there was great individual variability in inferred rankings of the risk comparisons. However, exposure to the risk comparisons did not reduce risk estimates significantly (while raising benefit estimates

  13. Lactosylated Gramicidin-based lipid nanoparticles (Lac-GLN) for targeted delivery of anti-miR-155 to hepatocellular carcinoma

    PubMed Central

    Zhang, Mengzi; Zhou, Xiaoju; Wang, Bo; Yung, Bryant C.; Lee, Ly J.; Ghoshal, Kalpana; Lee, Robert J.

    2013-01-01

    Lactosylated gramicidin-containing lipid nanoparticles (Lac-GLN) were developed for delivery of anti-microRNA-155 (anti-miR-155) to hepatocellular carcinoma (HCC) cells. MiR-155 is an oncomiR frequently elevated in HCC. The Lac-GLN formulation contained N-lactobionyl-dioleoyl phosphatidylethanolamine (Lac-DOPE), a ligand for the asialoglycoprotein receptor (ASGR), and an antibiotic peptide gramicidin A. The nanoparticles exhibited a mean particle diameter of 73 nm, zeta potential of +3.5 mV, anti-miR encapsulation efficiency of 88%, and excellent colloidal stability at 4°C. Lac-GLN effectively delivered anti-miR-155 to HCC cells with a 16.1- and 4.1-fold up-regulation of miR-155 targets C/EBPβ and FOXP3 genes, respectively, and exhibited significant greater efficiency over Lipofectamine 2000. In mice, intravenous injection of Lac-GLN containing Cy3-anti-miR-155 led to preferential accumulation of the anti-miR-155 in hepatocytes. Intravenous administration of 1.5 mg/kg anti-miR-155 loaded Lac-GLN resulted in up-regulation of C/EBPβ and FOXP3 by 6.9- and 2.2- fold, respectively. These results suggest potential application of Lac-GLN as a liver-specific delivery vehicle for anti-miR therapy. PMID:23567045

  14. gidakiimanaaniwigamig (gidaa) science camps for 3-12 students at Fond du Lac Band of Lake Superior Chippewa

    NASA Astrophysics Data System (ADS)

    Ito, E.; Kowalczak, C.; Dalbotten, D. M.; Pellerin, H.; Greensky, L.

    2015-12-01

    Gidaa informal science camps have been held in various formats and emphases for over 10 years at Fond du Lac (FDL). These camps provided a safe place for young people to be "nerds" but did not have specific focus. In the last 5 years the camp themes became more focused on environmental issues facing the reservation. From 2009 to 2014 the camps focused on issues surrounding the health of wild rice plants. Since September 2014, we are focusing on climate literacy and how climate changes are affecting tribal environment. We learned from our wild rice themed activities that students are more focused and interested in topics that affect them and their reservation and traditional activities.Each camp has a presentation by a staff from the FDL Resource Management Division. These presentations are sometimes given on Friday evenings after dinner and yet students remain alert, respectful, and actively take notes. The presentation topic is known in advance and camp teachers (local middle and high school teachers who have been with us for 5 to 10 years) plan lessons around that topic. In addition, college students, some of them past camp participants, are on hand to assist the teachers and to provide role models. Students have investigated, for example, possible effects of climate change on the timing of rising of sugar maple sap and whether sugar maple tress will continue to thrive in their area, efforts to bring back sturgeon to local rivers and how the changes in water temperature may affect that effort, possible climate connection to decline of moose and walleye pike population at 5 weekend camps during the last academic year. We have conducted 2 surveys by an outside evaluator and will have the results before the next round of camps starts in fall 2015 to help us tweak the format if necessary. Teachers and planners (PIs) are happy with the way camps are running this year; there is a good balance of camp activities that allow teachers to translate and adapt the

  15. KDR-LacZ-expressing cells are involved in ovarian and testis-specific vascular development, suggesting a role for VEGFA in the regulation of this vasculature.

    PubMed

    Bott, Rebecca C; Clopton, Debra T; Fuller, Anna M; McFee, Ryann M; Lu, Ningxia; McFee, Renee M; Cupp, Andrea S

    2010-10-01

    Our objectives were to evaluate kinase insert domain protein receptor (KDR)-β-galactosidase (LacZ) expression as a marker for vascular development during gonadal morphogenesis and to determine whether any novel non-angiogenic KDR-LacZ expression was present in mouse testes or ovaries. Gonads were collected from mice expressing LacZ driven by the Kdr promoter (KDR-LacZ) from embryonic day 11 (E11) through postnatal day 60 (P60). At E11.5, mesonephric cells expressing KDR-LacZ seemed to migrate into the developing testis and surrounded developing seminiferous cords. Cells expressing KDR-LacZ appeared in the ovary with no apparent migration from the adjacent mesonephros, suggesting a different origin of endothelial cells. Testis organ cultures from E11 mice were treated with 8 μM VEGFR-TKI, a vascular endothelial growth factor A signal transduction inhibitor; subsequently, the amount of KDR-LacZ staining was reduced by 66%-99% (P<0.002), and the ability of KDR-expressing cells to form a densely organized vascular network was inhibited. Novel non-angiogenic KDR-LacZ staining was detected in the testis on specific subsets of germ cells at E16, E17, P4, P20, P30, and P60. In ovaries, staining was present on oocytes within oocyte cysts at E17 and within late secondary follicles of postnatal mice. Thus, KDR is an excellent marker for analyzing vascular development in the gonads. Inhibition of VEGFA signal transduction prevents the development of testis-specific vasculature. Furthermore, non-vascular KDR-LacZ staining suggests that KDR directly affects both spermatogenesis and somatic-oocyte interactions during gametogenesis. PMID:20848132

  16. Microbicide acceptability research: current approaches and future directions.

    PubMed

    Mantell, Joanne E; Myer, Landon; Carballo-Diéguez, Alex; Stein, Zena; Ramjee, Gita; Morar, Neetha S; Harrison, Polly F

    2005-01-01

    With growing recognition of the potential value of microbicides for HIV/STI prevention, the importance of the acceptability of this brand-new technology has been widely acknowledged. We review the current body of microbicide acceptability research, characterize the limitations in assessment approaches, and suggest strategies for improvement. Electronic databases and abstracts of recent meetings were searched for acceptability data regarding vaginal and rectal products that may be used for HIV prevention. Of the 61 studies reviewed, more than half assessed acceptability based primarily on the description of a hypothetical microbicide, or with the demonstration of a spermicide or lubricant. Physical characteristics of microbicidal products, their effects after insertion, and their effects on sensation during intercourse (for both partners) were the dimensions most frequently assessed (measured in 77%, 49% and 49% of studies, respectively). Attention to the social context of use was inadequate. As acceptability is likely to be a key determinant in the use-effectiveness of microbicides, in-depth understanding of the social processes that shape microbicide acceptability across diverse populations will become increasingly valuable. This includes exploring the effects that sexual partners, health care providers, and key opinion leaders have on the acceptability of microbicides among women and men, including youth and people living with HIV. Future research will benefit from studies of the acceptability of other contraceptive-barrier methods (especially the female condom), use of an agreed-upon operationalization of acceptability, use of acceptability assessments within clinical trials, expansion of measurement domains, and assessment of changes in perceptions of acceptability and use over time. Failure to understand the key factors associated with microbicide acceptability is likely to hinder the adoption and continued use of products that are effective in preventing HIV

  17. The MAGNEX large acceptance spectrometer

    SciTech Connect

    Cavallaro, M.; Cappuzzello, F.; Cunsolo, A.; Carbone, D.; Foti, A.

    2010-03-01

    The main features of the MAGNEX large acceptance magnetic spectrometer are described. It has a quadrupole + dipole layout and a hybrid detector located at the focal plane. The aberrations due to the large angular (50 msr) and momentum (+- 13%) acceptance are reduced by an accurate hardware design and then compensated by an innovative software ray-reconstruction technique. The obtained resolution in energy, angle and mass are presented in the paper. MAGNEX has been used up to now for different experiments in nuclear physics and astrophysics confirming to be a multipurpose device.

  18. Tumour progression of human neuroblastoma cells tagged with a lacZ marker gene: earliest events at ectopic injection sites.

    PubMed Central

    Kleinman, N. R.; Lewandowska, K.; Culp, L. A.

    1994-01-01

    Human Platt neuroblastoma cells were transfected with the marker gene, bacterial lacZ, to track cells at the earliest stages after ectopic injection at two different sites in athymic nude mice. Three clones (LZPt-1,-2 and -3) of differing morphologies were analysed. All clones yielded large primary tumours subcutaneously or intradermally with similar latency. While LZPt-2 and -3 clones generated well-staining primary tumours, LZPt-1 cells yielded many non-staining tumours, indicating greater instability of lacZ expression for this clone in situ (stability of lacZ expression in culture was similar for all three clones). After s.c. or intradermal injections, tumour cells were tracked for 1 h to > 3 weeks (palpable) to evaluate the topology and population expansion characteristics at the earliest times. From 1 h to 2 days, tumour cells were concentrated in central masses with 'crinkly hair' distributions emanating from the periphery. Between 3 and 7 days, these 'crinkly hair' patterns were cleared from the tissue, leaving dense ovoid patterns of tumour cells. These concentrations of cells expanded collectively, not by division of one or a few cells, but by division of many cells. For clone LZPt-1, cells stained well with X-gal for 2-3 days; by 7 days, most cells were non-staining. Evidence suggests that lacZ expression is turned off in these tumour cells, rather than a lacZ- cell type clonally dominating the population. For all three clones, tumour cells remained rounded and did not spread in any tissue environment at all time points, indicating very different matrix adhesion mechanisms operating in situ compared with their distinctive spreading patterns in culture. Angioneogenesis near primary tumours became evident by 2-3 days, leading to extensive vascularisation by 1-2 weeks. Overall, these studies indicate common tumour progression characteristics for three different clones of human neuroblastoma, insight into lacZ instability mechanisms operating in one of these

  19. Nitrogen trailer acceptance test report

    SciTech Connect

    Kostelnik, A.J.

    1996-02-12

    This Acceptance Test Report documents compliance with the requirements of specification WHC-S-0249. The equipment was tested according to WHC-SD-WM-ATP-108 Rev.0. The equipment being tested is a portable contained nitrogen supply. The test was conducted at Norco`s facility.

  20. Helping Our Children Accept Themselves.

    ERIC Educational Resources Information Center

    Gamble, Mae

    1984-01-01

    Parents of a child with muscular dystrophy recount their reactions to learning of the diagnosis, their gradual acceptance, and their son's resistance, which was gradually lessened when he was provided with more information and treated more normally as a member of the family. (CL)

  1. Acceptability of Treatments for Plagiarism

    ERIC Educational Resources Information Center

    Carter, Stacy L.; Punyanunt-Carter, Narissra Maria

    2007-01-01

    This study focused on various treatments for addressing incidents of plagiarism by college students. College students rated the acceptability of different responses by college faculty to a case description of a college student who engaged in plagiarism. The findings revealed that students found some methods of addressing this problem behavior by…

  2. Euthanasia Acceptance: An Attitudinal Inquiry.

    ERIC Educational Resources Information Center

    Klopfer, Fredrick J.; Price, William F.

    The study presented was conducted to examine potential relationships between attitudes regarding the dying process, including acceptance of euthanasia, and other attitudinal or demographic attributes. The data of the survey was comprised of responses given by 331 respondents to a door-to-door interview. Results are discussed in terms of preferred…

  3. Radial derivatives of the mouse ventral pallium traced with Dbx1-LacZ reporters.

    PubMed

    Puelles, Luis; Medina, Loreta; Borello, Ugo; Legaz, Isabel; Teissier, Anne; Pierani, Alessandra; Rubenstein, John L R

    2016-09-01

    The progeny of Dbx1-expressing progenitors was studied in the developing mouse pallium, using two transgenic mouse lines: (1) Dbx1(nlslacZ) mice, in which the gene of the β-galactosidase reporter (LacZ) is inserted directly under the control of the Dbx1 promoter, allowing short-term lineage tracing of Dbx1-derived cells; and (2) Dbx1(CRE) mice crossed with a Cre-dependent reporter strain (ROSA26(loxP-stop-loxP-LacZ)), in which the Dbx1-derived cells result permanently labeled (Bielle et al., 2005). We thus examined in detail the derivatives of the postulated longitudinal ventral pallium (VPall) sector, which has been defined among other features by its selective ventricular zone expression of Dbx1 (the recent ascription by Puelles, 2014 of the whole olfactory cortex primordium to the VPall was tested). Earlier notions about a gradiental caudorostral reduction of Dbx1 signal were corroborated, so that virtually no signal was found at the olfactory bulb and the anterior olfactory area. The piriform cortex was increasingly labeled caudalwards. The only endopiriform grisea labeled were the ventral endopiriform nucleus and the bed nucleus of the external capsule. Anterior and basolateral parts of the whole pallial amygdala also were densely marked, in contrast to the negative posterior parts of these pallial amygdalar nuclei (leaving apart medial amygdalar parts ascribed to subpallial or extratelencephalic sources of Dbx1-derived GABAergic and non-GABAergic neurons). Alternative tentative interpretations are discussed to explain the partial labeling obtained of both olfactory and amygdaloid structures. This includes the hypothesis of an as yet undefined part of the pallium, potentially responsible for the posterior amygdala, or the hypothesis that the VPall may not be wholly characterized by Dbx1 expression (this gene not being necessary for VPall molecular distinctness and histogenetic potency), which would leave a dorsal Dbx1-negative VPall subdomain of variable size

  4. Factors Potentially Influencing Student Acceptance of Biological Evolution

    NASA Astrophysics Data System (ADS)

    Wiles, Jason R.

    This investigation explored scientific, religious, and otherwise nonscientific factors that may influence student acceptance of biological evolution and related concepts, how students perceived these factors to have influenced their levels of acceptance of evolution and changes therein, and what patterns arose among students' articulations of how their levels of acceptance of evolution may have changed. This exploration also measured the extent to which students' levels of acceptance changed following a treatment designed to address factors identified as potentially affecting student acceptance of evolution. Acceptance of evolution was measured using the MATE instrument (Rutledge and Warden, 1999; Rutledge and Sadler, 2007) among participants enrolled in a secondary-level academic program during the summer prior to their final year of high school and as they transitioned to the post-secondary level. Student acceptance of evolution was measured to be significantly higher than pre-treatment levels both immediately following and slightly over one year after treatment. Qualitative data from informal questionnaires, from formal course evaluations, and from semi-structured interviews of students engaged in secondary level education and former students at various stages of post-secondary education confirmed that the suspected factors were perceived by participants to have influenced their levels of acceptance of evolution. Furthermore, participant reports provided insight regarding the relative effects they perceived these factors to have had on their evolution acceptance levels. Additionally, many participants reported that their science teachers in public schools had avoided, omitted, or denigrated evolution during instruction, and several of these students expressed frustration regarding what they perceived to have been a lack of education of an important scientific principle. Finally, no students expressed feelings of being offended by having been taught about

  5. Establishment of lacZ marked strain of phosphate solubilizing bacterium in the rhizosphere and its effect on plant growth in mungbean.

    PubMed

    Sunita, S; Kapoor, K K; Goyal, S; Sharma, P K

    2010-10-01

    The establishment of lacZ marked strain of P-solubilizing bacterium Pseudomonas in the rhizosphere of mungbean (Vigna radiata) under pothouse conditions was studied. The lacZ marker was transferred to Pseudomonas P-36 on LB medium using donor strain of E. coli. The lacZ marked strain formed blue colonies on selective media and could be identified from soil on the basis of this character. The lacZ marked strain was able to survive in rhizosphere of mungbean under pothouse conditions and maintained a population of about 10(4) g(-1) of rhizosphere soils up to 60 days study period. Positive effect of inoculation with P-solubilizing bacterium on dry matter yield, P and N-uptake was observed using rock phosphate and single super phosphate as P sources with and without farmyard amendment. PMID:22815583

  6. Resisting body dissatisfaction: fat women who endorse fat acceptance.

    PubMed

    McKinley, Nita Mary

    2004-05-01

    Fat women who endorsed fat acceptance (N=128) were recruited from Radiance Magazine. Relationships between objectified body consciousness (OBC), body esteem, and psychological well-being for the mostly European American sample were similar to those found in other samples. OBC was independently related to body esteem when weight dissatisfaction was controlled. Those who endorsed the need for social change in attitudes towards fat people had higher body esteem and self-acceptance, and lower body shame, than those who endorsed personal acceptance of body size only. PMID:18089154

  7. Use of the promoter fusion transposon Tn5 lac to identify mutations in Bordetella pertussis vir-regulated genes.

    PubMed Central

    Weiss, A A; Melton, A R; Walker, K E; Andraos-Selim, C; Meidl, J J

    1989-01-01

    Mutants of Bordetella pertussis deficient in virulence-associated factors were identified by using the transposon Tn5 lac. Tn5 lac is a derivative of Tn5 which generates promoter fusions for beta-galactosidase. Tn5 lac insertions in the vir-regulated genes of B. pertussis were identified by selecting for kanamycin-resistant mutants that expressed beta-galactosidase when the vir-regulated genes were expressed but not when the vir-regulated genes were turned off. Fourteen different mutations in vir-regulated genes were identified. Two mutants were deficient in the production of the filamentous hemagglutinin, two mutants were deficient in the production of adenylate cyclase toxin and hemolysin, and one mutant was deficient in the production of dermonecrotic toxin. One insertion mapped adjacent to the pertussis toxin gene, but the mutant produced pertussis toxin. The phenotypes of the remaining eight mutants were not determined, but the mutants did not appear to be deficient in the production of the 69,000-dalton outer membrane protein (agglutinogen 3) or the capsule. Screening for mutations in either of the fimbrial genes proved to be problematic since the parental strain was found to switch from a fimbriated to a nonfimbriated state at a high frequency, which was suggestive of the metastable expression of pili in other bacteria. We used Southern blot analysis with a 30-mer specific for the fimbrial sequences. No bands with the predicted increase in size due to the 12 kilobases from Tn5 lac were observed, which suggests that none of these genes were mutated. Southern blot analysis also revealed that seven of the eight unidentified mutations mapped to different restriction fragments, which suggests that they could be deficient in as many as seven different genes. Images PMID:2569447

  8. Use of the promoter fusion transposon Tn5 lac to identify mutations in Bordetella pertussis vir-regulated genes.

    PubMed

    Weiss, A A; Melton, A R; Walker, K E; Andraos-Selim, C; Meidl, J J

    1989-09-01

    Mutants of Bordetella pertussis deficient in virulence-associated factors were identified by using the transposon Tn5 lac. Tn5 lac is a derivative of Tn5 which generates promoter fusions for beta-galactosidase. Tn5 lac insertions in the vir-regulated genes of B. pertussis were identified by selecting for kanamycin-resistant mutants that expressed beta-galactosidase when the vir-regulated genes were expressed but not when the vir-regulated genes were turned off. Fourteen different mutations in vir-regulated genes were identified. Two mutants were deficient in the production of the filamentous hemagglutinin, two mutants were deficient in the production of adenylate cyclase toxin and hemolysin, and one mutant was deficient in the production of dermonecrotic toxin. One insertion mapped adjacent to the pertussis toxin gene, but the mutant produced pertussis toxin. The phenotypes of the remaining eight mutants were not determined, but the mutants did not appear to be deficient in the production of the 69,000-dalton outer membrane protein (agglutinogen 3) or the capsule. Screening for mutations in either of the fimbrial genes proved to be problematic since the parental strain was found to switch from a fimbriated to a nonfimbriated state at a high frequency, which was suggestive of the metastable expression of pili in other bacteria. We used Southern blot analysis with a 30-mer specific for the fimbrial sequences. No bands with the predicted increase in size due to the 12 kilobases from Tn5 lac were observed, which suggests that none of these genes were mutated. Southern blot analysis also revealed that seven of the eight unidentified mutations mapped to different restriction fragments, which suggests that they could be deficient in as many as seven different genes. PMID:2569447

  9. Resolution of the fluorescence decay of the two tryptophan residues of lac repressor using single tryptophan mutants.

    PubMed Central

    Royer, C A; Gardner, J A; Beechem, J M; Brochon, J C; Matthews, K S

    1990-01-01

    We have studied the time-resolved intrinsic tryptophan fluorescence of the lac repressor (a symmetric tetramer containing two tryptophan residues per monomer) and two single-tryptophan mutant repressors obtained by site-directed mutagenesis, lac W201Y and lac W220Y. These mutant repressor proteins have tyrosine substituted for tryptophan at positions 201 and 220, respectively, leaving a single tryptophan residue per monomeric subunit at position 220 for the W201Y mutant and at position 201 in the W220Y mutant. It was found that the two decay rates recovered from the analysis of the wild type data do not correspond to the rates recovered from the analysis of the decays of the mutant proteins. Each of these residues in the mutant repressors displays at least two decay rates. Global analysis of the multiwavelength data from all three proteins, however, yielded results consistent with the fluorescence decay of the wild type lac repressor corresponding simply to the weighted linear combination of the decays from the mutant proteins. The effect of ligation by the antagonistic ligands, inducer and operator DNA, was similar for all three proteins. The binding of the inducer sugar resulted in a quenching of the long-lived species, while binding by the operator decreased the lifetime of the short components. Investigation of the time-resolved anisotropy of the intrinsic tryptophan fluorescence in these three proteins revealed that the depolarization of fluorescence resulted from a fast motion and the global tumbling of the macromolecule. Results from the simultaneous global analysis of the frequency domain data sets from the three proteins revealed anisotropic rotations for the macromolecule, consistent with the known elongated shape of the repressor tetramer. In addition, it appears that the excited-state dipole of tryptophan 220 is alighed with the long axis of the repressor. PMID:2207244

  10. Transgenic LacZ under control of Hec-6st regulatory sequences recapitulates endogenous gene expression on high endothelial venules

    PubMed Central

    Liao, Shan; Bentley, Kevin; Lebrun, Marielle; Lesslauer, Werner; Ruddle, Frank H.; Ruddle, Nancy H.

    2007-01-01

    Hec-6st is a highly specific high endothelial venule (HEV) gene that is crucial for regulating lymphocyte homing to lymph nodes (LN). The enzyme is also expressed in HEV-like vessels in tertiary lymphoid organs that form in chronic inflammation in autoimmunity, graft rejection, and microbial infection. Understanding the molecular nature of Hec-6st regulation is crucial for elucidating its function in development and disease. However, studies of HEV are limited because of the difficulties in isolating and maintaining the unique characteristics of these vessels in vitro. The novel pClasper yeast homologous recombination technique was used to isolate from a BAC clone a 60-kb DNA fragment that included the Hec-6st (Chst4) gene with flanking sequences. Transgenic mice were generated with the β-galactosidase (LacZ) reporter gene inserted in-frame in the exon II of Hec-6st within the isolated BAC DNA fragment. LacZ was expressed specifically on HEV in LN, as indicated by its colocalization with peripheral node vascular addressin. LacZ was increased in nasal-associated lymphoid tissue during development and was reduced in LN and nasal-associated lymphoid tissue by LTβR-Ig (lymphotoxin-β receptor human Ig fusion protein) treatment in a manner identical to the endogenous gene. The transgene was expressed at high levels in lymphoid accumulations with characteristics of tertiary lymphoid organs in the salivary glands of aged mice. Thus, the Hec-6s-LacZ construct faithfully reproduces Hec-6st tissue-specific expression and can be used in further studies to drive expression of reporter or effector genes, which could visualize or inhibit HEV in autoimmunity. PMID:17360566

  11. The olivine macrocryst problem: New insights from minor and trace element compositions of olivine from Lac de Gras kimberlites, Canada

    NASA Astrophysics Data System (ADS)

    Bussweiler, Yannick; Foley, Stephen F.; Prelević, Dejan; Jacob, Dorrit E.

    2015-04-01

    This study presents detailed petrographical and geochemical investigations on remarkably fresh olivines in kimberlites from the EKATI Diamond Mine™ located in the Tertiary/Cretaceous Lac de Gras kimberlite field within the Slave craton of Canada. Olivine, constituting about 42 vol.% of the analyzed samples, can be divided into two textural groups: (i) macrocrystic olivines, > 100 μm sub-rounded crystals and (ii) groundmass olivines, < 100 μm subhedral crystals. Olivines from both populations define two distinct chemical trends; a "mantle trend" with angular cores, showing low Ca (< 0.1 wt.% CaO) and high Ni (0.3-0.4 wt.% NiO) at varying Mg# (0.86-0.93), contrasts with a "melt trend" typified by thin (< 100 μm) rims with increasing Ca (up to 1.0 wt.% CaO) and decreasing Ni (down to 0.1 wt.% NiO) contents at constant Mg# (~ 0.915). These findings are in agreement with recent studies suggesting that virtually all olivine is composed of xenocrystic (i.e. mantle-related) cores with phenocrystic (i.e. melt-related) overgrowths, thereby challenging the traditional view that the origin of kimberlitic olivine can be distinguished based on size and morphology. The two main trends can be further resolved into sub-groups refining the crystallization history of olivine; the mantle trend indicates a multi-source origin that samples the layered lithosphere below the Slave craton, whereas the melt trend represents multi-stage crystallization comprising a differentiation trend starting at mantle conditions and a second trend controlled by the crystallization of additional phases (e.g. chromite) and changing magma conditions (e.g. oxidation). These trends are also seen in the concentrations of trace elements not routinely measured in olivine (e.g. Na, P, Ti, Co, Sc, Zr). Trace element mapping with LA-ICP-MS reveals the distribution of these elements within olivine grains. The trace element distribution between the two trends appears to be consistent with phenocrystic olivine

  12. Changes.

    ERIC Educational Resources Information Center

    Weikel, William J.

    1999-01-01

    The author, founding editor of the American Mental Health Counselors Association (AMHC) Journal, now the Journal of Mental Health Counseling, examines some of the changes that have taken place in the profession over the past 20 years. Special emphasis is given to the visionary excellence that set the "AMHCA Agenda" over 20 years ago. (Author)

  13. An emerging population of BL Lacs with extreme properties: towards a class of EBL and cosmic magnetic field probes?

    NASA Astrophysics Data System (ADS)

    Bonnoli, G.; Tavecchio, F.; Ghisellini, G.; Sbarrato, T.

    2015-07-01

    High-energy observations of extreme BL Lac objects, such as 1ES 0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic field estimate. However, the number of these extreme highly peaked BL Lac objects (EHBL) is still rather small. Aiming at increase their number, we selected a group of EHBL candidates starting from the BL Lac sample of Plotkin et al. (2011), considering those undetected (or only barely detected) by the Large Area Telescope onboard Fermi and characterized by a high X-ray versus radio flux ratio. We assembled the multiwavelength spectral energy distribution of the resulting nine sources, profiting of publicly available archival observations performed by Swift, GALEX, and Fermi satellites, confirming their nature. Through a simple one-zone synchrotron self-Compton model we estimate the expected very high energy flux, finding that in the majority of cases it is within the reach of present generation of Cherenkov arrays or of the forthcoming Cherenkov Telescope Array.

  14. Unusual optical quiescence of the classical BL Lac object PKS 0735+178 on intranight time-scale

    NASA Astrophysics Data System (ADS)

    Goyal, Arti; Gopal-Krishna; Anupama, G. C.; Sahu, D. K.; Sagar, R.; Britzen, S.; Karouzos, M.; Aller, M. F.; Aller, H. D.

    2009-11-01

    We present the result of our extensive intranight optical monitoring of the well-known low-energy peaked BL Lac (LBL) object PKS 0735+178. This long-term follow-up consists of R-band monitoring for a minimum duration of ~4 hours, on 17 nights spanning 11 years (1998-2008). Using the CCD as an N-star photometer, a detection limit of around 1 per cent was attained for the intranight optical variability (INOV). Remarkably, an INOV amplitude of >=3 per cent on hour-like time-scale was not observed on any of the 17 nights, even though the likelihood of a typical LBL showing such INOV levels in a single session of >~4 hours duration is known to be high (~50 per cent). Our observations have thus established a peculiar long-term INOV quiescence of this radio-selected BL Lac object. Moreover, the access to unpublished optical monitoring data of similarly high sensitivity, acquired in another programme, has allowed us to confirm the same anomalous INOV quiescence of this LBL all the way back to 1989, the epoch of its historically largest radio outburst. Here, we present observational evidence revealing the very unusual INOV behaviour of this classical BL Lac object and discuss this briefly in the context of its other known exceptional properties.

  15. A comparative ab initio study of superconductivity in the body centered tetragonal YC2 and LaC2

    NASA Astrophysics Data System (ADS)

    Tütüncü, H. M.; Srivastava, G. P.

    2015-04-01

    Ab initio studies of the electronic band structure and phonon dispersion relations, using the planewave pseudopotential method and the density functional theory, have been made for the superconducting materials YC2 and LaC2. Differences in the phonon spectrum and density of states both in the acoustical and optical ranges between these materials are investigated and discussed. By integrating the Eliashberg spectral function α2F(ω), the average electron-phonon coupling parameter is found to be λ = 0.55 for YC2 and 0.54 for LaC2, indicating these to be weak-coupling BCS superconductors. It is established that about 60% of λ is contributed by acoustic phonons in both materials. Using a reasonable value of μ* = 0.13 for the effective Coulomb repulsion parameter, the superconducting critical temperature Tc is found to be 3.81 K for YC2 and 2.44 K for LaC2, in good agreement with values reported from experimental measurements.

  16. Genetic analysis of the low calcium response in Yersinia pestis mu d1(Ap lac) insertion mutants.

    PubMed Central

    Goguen, J D; Yother, J; Straley, S C

    1984-01-01

    Yersinia pestis strain KIM requires plasmid pCD1 for expression of the low calcium response, plague virulence antigen V, and virulence. We constructed Mu d1(Ap lac) insertion mutants of this plasmid which were unable to express the low calcium response. The insertions mapped to a 17-kilobase region of the plasmid. By determining the orientation of the insertions and examining beta-galactosidase production from the Mu d1 lac genes, we determined that this region contains three units of transcription, one of which is transcribed in a direction opposite the direction of transcription of the other two. Transcription of at least two of these units was induced significantly at 37 degrees C compared with 26 degrees C. Ca2+ (2.5 mM) and ATP (18 mM) had no significant effect on the level of expression of the Mu d1 lac genes of these mutants. All insertions in the region strongly reduced production of the V antigen. Insertions from each unit of transcription also reduced virulence in mice. PMID:6094509

  17. Comparison between S+L- assay and LacZ marker rescue assay for detecting replication-competent gammaretroviruses.

    PubMed

    Hashimoto-Gotoh, A; Yoshikawa, R; Miyazawa, T

    2015-09-01

    To avoid contamination of adventitious gammaretroviruses in biological products such as vaccines, it is necessary to check the master seed cells for manufacturing. There are several assays to detect infectious gammaretroviruses. Among these, sarcoma-positive, leukemia-negative (S+L-) assay is a classical infectivity assay, which is often recommended in governmental guidelines. The S+L- cells used in S+L- assay generate unique focus upon the infection of replication-competent gammaretroviruses. Although S+L- assay is well recognized for the detection, their applicability is questionable in some cases. On the other hand, LacZ marker rescue (LMR) assay detects infectious gammaretroviruses by transducing LacZ marker gene to the target cells, which shows lacZ-positive foci if the infectious virus is present. In this study, we compared LMR and S+L- assays for detection of a variety of endogenous and exogenous gammaretroviruses. As results, LMR assay could detect all gammaretroviruses examined. On the other hand, S+L- assay using feline S+L- cells, termed QN10S, could not detect porcine endogenous retrovirus (PERV) subgroups A/B. Further, S+L- mink cells could not detect feline leukemia virus subgroups B in addition to PERV-A/B. These data indicate that LMR assay is better suited to detect wider range of gammaretroviruses. PMID:26164289

  18. ANTI-CORRELATED OPTICAL FLUX AND POLARIZATION VARIABILITY IN BL LAC

    SciTech Connect

    Gaur, Haritma; Gupta, Alok C.; Wiita, Paul J.; Uemura, Makoto; Itoh, Ryosuke; Sasada, Mahito

    2014-01-20

    We present the results of photometric (V band) and polarimetric observations of the blazar BL Lac during 2008-2010 using TRISPEC attached to the KANATA 1.5 m telescope in Japan. The data reveal a great deal of variability ranging from days to months with detection of strong variations in fractional polarization. The V band flux strongly anticorrelates with the degree of polarization during the first of two observing seasons but not during the second. The direction of the electric vector, however, remained roughly constant during all of our observations. These results are consistent with a model with at least two emission regions being present, with the more variable component having a polarization direction nearly perpendicular to that of the relatively quiescent region so that a rising flux can produce a decline in degree of polarization. We also computed models involving helical jet structures and single transverse shocks in jets and show that they might also be able to agree with the anticorrelations between flux and fractional polarization.

  19. The Lac Des Iles Palladium Deposit, Ontario, Canada. Part II. Halogen variations in apatite

    NASA Astrophysics Data System (ADS)

    Schisa, Paul; Boudreau, Alan; Djon, Lionnel; Tchalikian, Arnaud; Corkery, John

    2015-03-01

    Analysis of apatite from the Mine Block Intrusion (MBI) of the Lac des Iles Igneous Complex shows two pronounced trends in the halogens. Apatite from relatively fresh norite and melanorites from the Pd-sulfide zone contain up to 57 mol% chlorapatite endmember with significant hydroxyapatite component. In contrast, in altered rock (amphibolite and greenschist assemblages) the chlorapatite component is typically less than 10 mol% with wide variation in the F- and OH-endmember components. The latter trend is attributed to Cl loss to degassing and alteration, whereas the former is attributed to Cl enrichment in the ore-bearing rocks. It is suggested that the relatively H2O-rich and intermediate Cl content of the early igneous fluids degassed from the deeper levels of the MBI can explain the high Pd/Pt and Pd/Ir ratios of the deposit. A model is presented in which disseminated Pd-rich sulfides are initially introduced by a high-temperature magmatic fluid that also influenced crystallization to produce the gross modal variations of the igneous host rock. This high-temperature mineralization event was subsequently modified by the influx of late igneous and country fluids at amphibolite to greenschist conditions.

  20. Halogen Variations in Apatite of the Lac Des Iles Palladium Deposit, Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Boudreau, A. E.

    2014-12-01

    Analysis of apatite from the Mine Block Intrusion (MBI) of the Lac des Iles Igneous Complex show two pronounced trends in the halogens. Apatite from relatively fresh norite and melanorites from the Pd-sulfide zone contain up to 57 mole % chlorapatite endmember with significant hydroxyapatite component. In contrast, in altered rock (amphibolite and greenschist assemblages) and in the more evolved barren rocks the chlorapatite component is typically less than 10 mole % with wide variation in the F- and OH-endmember components. The latter trend is attributed to Cl loss to degassing and alteration whereas the former is attributed to Cl-enrichment in the ore-bearing rocks. It is suggested that the relatively H2O-rich and intermediate Cl content of the early igneous fluids degassed from the deeper levels of the MBI can explain the high Pd/Pt and Pd/Ir ratios of the deposit. A model is presented in which disseminated Pd-rich sulfide are initially introduced by a high temperature magmatic fluid that also influenced crystallization to produce the gross modal variations of the igneous host rock. This high temperature mineralization event was subsequently modified by the influx of late igneous and country fluids at amphibolite to greenschist conditions.

  1. A LacI-Family Regulator Activates Maltodextrin Metabolism of Enterococcus faecium

    PubMed Central

    Zhang, Xinglin; Rogers, Malbert; Bierschenk, Damien; Bonten, Marc J. M.; Willems, Rob J. L.; van Schaik, Willem

    2013-01-01

    Enterococcus faecium is a gut commensal of humans and animals. In the intestinal tract, E. faecium will have access to a wide variety of carbohydrates, including maltodextrins and maltose, which are the sugars that result from the enzymatic digestion of starch by host-derived and microbial amylases. In this study, we identified the genetic determinants for maltodextrin utilization of E. faecium E1162. We generated a deletion mutant of the mdxABCD-pulA gene cluster that is homologous to maltodextrin uptake genes in other Gram-positive bacteria, and a deletion mutant of the mdxR gene, which is predicted to encode a LacI family regulator of mdxABCD-pulA. Both mutations impaired growth on maltodextrins but had no effect on the growth on maltose and glucose. Comparative transcriptome analysis showed that eight genes (including mdxABCD-pulA) were expressed at significantly lower levels in the isogenic ΔmdxR mutant strain compared to the parental strain when grown on maltose. Quantitative real-time RT-PCR confirmed the results of transcriptome analysis and showed that the transcription of a putative maltose utilization gene cluster is induced in a semi-defined medium supplemented with maltose but is not regulated by MdxR. Understanding the maltodextrin metabolism of E. faecium could yield novel insights into the underlying mechanisms that contribute to the gut commensal lifestyle of E. faecium. PMID:23951303

  2. THE 2001-2003 LOW STATE OF NOVA LACERTAE 1950 (DK LAC)

    SciTech Connect

    Honeycutt, R. K.; Jacobson, H.; Hoffman, D.; Maxwell, T.; Croxall, K.; Kafka, S.; Henden, A. A.; Robertson, J. W. E-mail: jacob189@msu.edu E-mail: tmaxwell@astro.indiana.edu E-mail: skafka@dtm.ciw.edu E-mail: Jeff.Robertson@atu.edu

    2011-04-15

    We report on extensive photometry of DK Lac obtained during the interval 1990-2009, which includes a 2 mag low state during 2001-2003. Much of the photometry consists of exposures obtained with a typical spacing of several days, but also includes 26 sequences of continuous photometry each lasting 2-7 hr. We find no evidence for periodicities in our data. We do find that the random variations in the low state are approximately twice those in the high state, when expressed in magnitudes. The lack of orbital-timescale variations is attributed to the nearly face-on presentation of the disk. There is a 0.2 mag decline in the high-state brightness of the system over 19 years, which is consistent with the behavior of other old novae in the decades following outburst. High-state spectra are also presented and discussed. We find that the equivalent width of H{alpha} falls by about double from 1991 to 2008. The photometric properties are discussed in the context of the hibernation scenario for the behavior of novae between outbursts, in which we conclude that low states in old novae are probably unrelated to their possible entrance into hibernation.

  3. The Gamma-Ray Bright BL Lac Object RX J1211+2242

    NASA Technical Reports Server (NTRS)

    Beckmann, V.; Favre, P.; Tavecchio, F.; Bussien, T.; Fliri, J.; Wolter, A.

    2004-01-01

    RX J1211+2242 is an optically faint (B approximately equal to 19.2mag) but X-ray bright (f2-10kev = 5 x l0(exp -12)erg per square centimeter per second) AGN, which has been shown to be a BL Lac object at redshift z = 0.455. The ROSAT X-ray, Calar Alto optical, and NVSS radio data suggest that the peak of the synchrotron emission of this object is at energies as high as several keV. BeppoSAX observations have been carried out simultaneously with optical observations in order to extend the coverage to higher energies. The new data indeed indicate a turn-over in the 2 - 10keV energy region. We propose that RX J1211+2242 is the counterpart of the unidentified EGRET source 3EG J1212+2304, making it a gamma-ray emitter with properties similar to, for example, Markarian 501 in its bright state, though being at a much larger distance.

  4. BL LAC OBJECT PKS B1144-379: AN EXTREME SCINTILLATOR

    SciTech Connect

    Turner, R. J.; Ellingsen, S. P.; Shabala, S. S.; Blanchard, J.; Lovell, J. E. J.; McCallum, J. N.; Cimo, G.

    2012-08-01

    Rapid variability in the radio flux density of the BL Lac object PKS B1144-379 has been observed at four frequencies, ranging from 1.5 to 15 GHz, with the Very Large Array and the University of Tasmania's Ceduna antenna. Intrinsic and line-of-sight effects were examined as possible causes of this variability, with interstellar scintillation best explaining the frequency dependence of the variability timescales and modulation indices. This scintillation is consistent with a compact source 20-40 {mu}as or 0.15-0.3 pc in size. The inferred brightness temperature for PKS B1144-379 (assuming that the observed variations are due to scintillation) is 6.2 Multiplication-Sign 10{sup 12} K at 4.9 GHz, with approximately 10% of the total flux in the scintillating component. We show that scintillation surveys aimed at identifying variability timescales of days to weeks are an effective way to identify the active galactic nuclei with the highest brightness temperatures.

  5. Complete genome sequence of hypervirulent and outbreak-associated Acinetobacter baumannii strain LAC-4: epidemiology, resistance genetic determinants and potential virulence factors

    PubMed Central

    Ou, Hong-Yu; Kuang, Shan N.; He, Xinyi; Molgora, Brenda M.; Ewing, Peter J.; Deng, Zixin; Osby, Melanie; Chen, Wangxue; Xu, H. Howard

    2015-01-01

    Acinetobacter baumannii is an important human pathogen due to its multi-drug resistance. In this study, the genome of an ST10 outbreak A. baumannii isolate LAC-4 was completely sequenced to better understand its epidemiology, antibiotic resistance genetic determinants and potential virulence factors. Compared with 20 other complete genomes of A. baumannii, LAC-4 genome harbors at least 12 copies of five distinct insertion sequences. It contains 12 and 14 copies of two novel IS elements, ISAba25 and ISAba26, respectively. Additionally, three novel composite transposons were identified: Tn6250, Tn6251 and Tn6252, two of which contain resistance genes. The antibiotic resistance genetic determinants on the LAC-4 genome correlate well with observed antimicrobial susceptibility patterns. Moreover, twelve genomic islands (GI) were identified in LAC-4 genome. Among them, the 33.4-kb GI12 contains a large number of genes which constitute the K (capsule) locus. LAC-4 harbors several unique putative virulence factor loci. Furthermore, LAC-4 and all 19 other outbreak isolates were found to harbor a heme oxygenase gene (hemO)-containing gene cluster. The sequencing of the first complete genome of an ST10 A. baumannii clinical strain should accelerate our understanding of the epidemiology, mechanisms of resistance and virulence of A. baumannii. PMID:25728466

  6. Acceptability of reactors in space

    SciTech Connect

    Buden, D.

    1981-04-01

    Reactors are the key to our future expansion into space. However, there has been some confusion in the public as to whether they are a safe and acceptable technology for use in space. The answer to these questions is explored. The US position is that when reactors are the preferred technical choice, that they can be used safely. In fact, it dies not appear that reactors add measurably to the risk associated with the Space Transportation System.

  7. Acceptability of reactors in space

    SciTech Connect

    Buden, D.

    1981-01-01

    Reactors are the key to our future expansion into space. However, there has been some confusion in the public as to whether they are a safe and acceptable technology for use in space. The answer to these questions is explored. The US position is that when reactors are the preferred technical choice, that they can be used safely. In fact, it does not appear that reactors add measurably to the risk associated with the Space Transportation System.

  8. Reactor tank UT acceptance criteria

    SciTech Connect

    Daugherty, W.L.

    1990-01-30

    The SRS reactor tanks are constructed of type 304 stainless steel, with 0.5 inch thick walls. An ultrasonic (UT) in-service inspection program has been developed for examination of these tanks, in accordance with the ISI Plan for the Savannah River Production Reactors Process Water System (DPSTM-88-100-1). Prior to initiation of these inspections, criteria for the disposition of any indications that might be found are required. A working group has been formed to review available information on the SRS reactor tanks and develop acceptance criteria. This working group includes nationally recognized experts in the nuclear industry. The working group has met three times and produced three documents describing the proposed acceptance criteria, the technical basis for the criteria and a proposed initial sampling plan. This report transmits these three documents, which were prepared in accordance with the technical task plan and quality assurance plan for this task, task 88-001-A- 1. In addition, this report summarizes the acceptance criteria and proposed sampling plan, and provides further interpretation of the intent of these three documents where necessary.

  9. 12 CFR 7.1007 - Acceptances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Acceptances. 7.1007 Section 7.1007 Banks and... § 7.1007 Acceptances. A national bank is not limited in the character of acceptances it may make in financing credit transactions. Bankers' acceptances may be used for such purpose, since the making...

  10. 12 CFR 7.1007 - Acceptances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Acceptances. 7.1007 Section 7.1007 Banks and... § 7.1007 Acceptances. A national bank is not limited in the character of acceptances it may make in financing credit transactions. Bankers' acceptances may be used for such purpose, since the making...

  11. 21 CFR 820.86 - Acceptance status.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Acceptance status. 820.86 Section 820.86 Food and... QUALITY SYSTEM REGULATION Acceptance Activities § 820.86 Acceptance status. Each manufacturer shall identify by suitable means the acceptance status of product, to indicate the conformance or...

  12. 12 CFR 615.5550 - Bankers' acceptances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Bankers' acceptances. 615.5550 Section 615.5550... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Bankers' Acceptances § 615.5550 Bankers' acceptances. Banks for cooperatives may rediscount with other purchasers the acceptances they have created. The bank...

  13. 48 CFR 245.606-3 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Acceptance. 245.606-3... Contractor Inventory 245.606-3 Acceptance. (a) If the schedules are acceptable, the plant clearance officer shall, within 15 days, complete and send the contractor a DD Form 1637, Notice of Acceptance...

  14. 48 CFR 12.402 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Acceptance. 12.402 Section... Acceptance. (a) The acceptance paragraph in 52.212-4 is based upon the assumption that the Government will rely on the contractor's assurances that the commercial item tendered for acceptance conforms to...

  15. 21 CFR 820.86 - Acceptance status.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Acceptance status. 820.86 Section 820.86 Food and... QUALITY SYSTEM REGULATION Acceptance Activities § 820.86 Acceptance status. Each manufacturer shall identify by suitable means the acceptance status of product, to indicate the conformance or...

  16. 12 CFR 615.5550 - Bankers' acceptances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Bankers' acceptances. 615.5550 Section 615.5550... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Bankers' Acceptances § 615.5550 Bankers' acceptances. Banks for cooperatives may rediscount with other purchasers the acceptances they have created. The bank...

  17. 48 CFR 12.402 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acceptance. 12.402 Section... Acceptance. (a) The acceptance paragraph in 52.212-4 is based upon the assumption that the Government will rely on the contractor's assurances that the commercial item tendered for acceptance conforms to...

  18. Improving the Terrain-Based Parameter for the Assessment of Snow Redistribution in the Col du Lac Blanc Area and Comparisons with TLS Snow Depth Data

    NASA Astrophysics Data System (ADS)

    Schön, Peter; Prokop, Alexander; Naaim-Bouvet, Florence; Nishimura, Kouichi; Vionnet, Vincent; Guyomarc'h, Gilbert

    2014-05-01

    Wind and the associated snow drift are dominating factors determining the snow distribution and accumulation in alpine areas, resulting in a high spatial variability of snow depth that is difficult to evaluate and quantify. The terrain-based parameter Sx characterizes the degree of shelter or exposure of a grid point provided by the upwind terrain, without the computational complexity of numerical wind field models. The parameter has shown to qualitatively predict snow redistribution with good reproduction of spatial patterns, but has failed to quantitatively describe the snow redistribution, and correlations with measured snow heights were poor. The objective of our research was to a) identify the sources of poor correlations between predicted and measured snow re-distribution and b) improve the parameters ability to qualitatively and quantitatively describe snow redistribution in our research area, the Col du Lac Blanc in the French Alps. The area is at an elevation of 2700 m and particularly suited for our study due to its constant wind direction and the availability of data from a meteorological station. Our work focused on areas with terrain edges of approximately 10 m height, and we worked with 1-2 m resolution digital terrain and snow surface data. We first compared the results of the terrain-based parameter calculations to measured snow-depths, obtained by high-accuracy terrestrial laser scan measurements. The results were similar to previous studies: The parameter was able to reproduce observed patterns in snow distribution, but regression analyses showed poor correlations between terrain-based parameter and measured snow-depths. We demonstrate how the correlations between measured and calculated snow heights improve if the parameter is calculated based on a snow surface model instead of a digital terrain model. We show how changing the parameter's search distance and how raster re-sampling and raster smoothing improve the results. To improve the parameter

  19. Public Acceptance of Nuclear Energy in Mexico

    SciTech Connect

    Ramirez-Sanchez, Jose R.; Alonso, Gustavo; Palacios, H. Javier

    2006-07-01

    The nuclear energy is attracting renewed interest of public and policy makers due to his potential role in long term strategies aiming to reduce the risk of global warming and in a more general, to carry out sustainable policies, however, any project of nuclear nature arise concerns about the risks associated with the release of radioactivity during accident conditions, radioactive waste disposal and nuclear weapons proliferation. Then in light of the likeliness for a new nuclear project in Mexico, is necessary to design a strategy to improve the social acceptance of nuclear power. This concern is been boarding since the environmental and economic point of view. The information that can change the perception of nuclear energy towards increase public acceptance, should be an honest debate about the benefits of nuclear energy, of course there are questions and they have to be answered, but in a realistic and scientific way: So thinking in Mexico as a first step it is important to communicate to the government entities and political parties that nuclear energy is a proven asset that it is emission free and safe. Of course besides the guarantee of a proven technology, clean and safe relies the economic fact, and in Mexico this could be the most important aspect to communicate to key people in government. Based in the Laguna Verde survey it is clear that we have to find the adequate means to distribute the real information concerning nuclear technology to the public, because the results shows that Mexican people does not have complete information about nuclear energy, but public can support it when they have enough information. From the IAEA study we can say that in Mexico public acceptance of nuclear energy it s not so bad, is the highest percentage of acceptance of nuclear technology for health, considering benefits to the environment Mexican opposition to build new plants is the second less percentage, and generally speaking 60% of the people accept somehow nuclear

  20. Stability of the lac repressor headpiece against thermal denaturation and tryptic hydrolysis.

    PubMed

    Schnarr, M; Maurizot, J C

    1982-04-01

    The stability of the conformation of the lac repressor headpiece against thermal denaturation and tryptic hydrolysis has been studied by circular dichroism measurements. In both cases the stability depends strongly on the concentration of NaCl. This effect is larger than generally observed for proteins. The midpoint of the thermal denaturation curve (Tm) is shifted from about 37 degrees C in the absence of NaCl to about 68 degrees C in 1 M NaCl. After a first non-linear increase of the Tm with the NaCl concentration (up to about 0.2 M NaCl) the Tm varies linearly with the salt concentration. Assuming a two-state mechanism for the thermal denaturation, enthalpies of 30-36 kcal/mol have been determined. The decrease of the circular dichroism signal due to the tryptic cleavage follows pseudo first-order kinetics for all salt concentrations studied. The half-life time of hydrolysis increased by about 40-times from 2 mM to the highest NaCl concentration we have used (655 mM). Assuming that only the unfolded state of the headpiece is a good substrate for trypsin, the observed stabilization against proteolytic degradation may be explained by a shift of the unfolding equilibrium of the headpiece due to the salt, and a subsequent decrease of the concentration of the unfolded state. The unusual stabilization of the headpiece is discussed with respect to its positive charge and to its function to bind to DNA. PMID:7044423

  1. Baryon Loading Efficiency and Particle Acceleration Efficiency of Relativistic Jets: Cases for Low Luminosity BL Lacs

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Tanaka, Yasuyuki T.

    2016-09-01

    Relativistic jets launched by supermassive black holes, so-called active galactic nuclei (AGNs), are known as the most energetic particle accelerators in the universe. However, the baryon loading efficiency onto the jets from the accretion flows and their particle acceleration efficiencies have been veiled in mystery. With the latest data sets, we perform multi-wavelength spectral analysis of quiescent spectra of 13 TeV gamma-ray detected high-frequency-peaked BL Lacs (HBLs) following one-zone static synchrotron self-Compton (SSC) model. We determine the minimum, cooling break, and maximum electron Lorentz factors following the diffusive shock acceleration (DSA) theory. We find that HBLs have {P}B/{P}e∼ 6.3× {10}-3 and the radiative efficiency {ε }{{rad,jet}}∼ 6.7× {10}-4, where P B and P e is the Poynting and electron power, respectively. By assuming 10 leptons per one proton, the jet power relates to the black hole mass as {P}{{jet}}/{L}{{Edd}}∼ 0.18, where {P}{{jet}} and {L}{{Edd}} is the jet power and the Eddington luminosity, respectively. Under our model assumptions, we further find that HBLs have a jet production efficiency of {η }{{jet}}∼ 1.5 and a mass loading efficiency of {ξ }{{jet}}≳ 5× {10}-2. We also investigate the particle acceleration efficiency in the blazar zone by including the most recent Swift/BAT data. Our samples ubiquitously have particle acceleration efficiencies of {η }g∼ {10}4.5, which is inefficient to accelerate particles up to the ultra-high-energy-cosmic-ray (UHECR) regime. This implies that the UHECR acceleration sites should not be the blazar zones of quiescent low power AGN jets, if one assumes the one-zone SSC model based on the DSA theory.

  2. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France.

    PubMed

    Certad, Gabriela; Dupouy-Camet, Jean; Gantois, Nausicaa; Hammouma-Ghelboun, Ourida; Pottier, Muriel; Guyot, Karine; Benamrouz, Sadia; Osman, Marwan; Delaire, Baptiste; Creusy, Colette; Viscogliosi, Eric; Dei-Cas, Eduardo; Aliouat-Denis, Cecile Marie; Follet, Jérôme

    2015-01-01

    Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the

  3. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France

    PubMed Central

    Certad, Gabriela; Dupouy-Camet, Jean; Gantois, Nausicaa; Hammouma-Ghelboun, Ourida; Pottier, Muriel; Guyot, Karine; Benamrouz, Sadia; Osman, Marwan; Delaire, Baptiste; Creusy, Colette; Viscogliosi, Eric; Aliouat-Denis, Cecile Marie; Follet, Jérôme

    2015-01-01

    Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the

  4. A gene expression resource generated by genome-wide lacZ profiling in the mouse

    PubMed Central

    Tuck, Elizabeth; Estabel, Jeanne; Oellrich, Anika; Maguire, Anna Karin; Adissu, Hibret A.; Souter, Luke; Siragher, Emma; Lillistone, Charlotte; Green, Angela L.; Wardle-Jones, Hannah; Carragher, Damian M.; Karp, Natasha A.; Smedley, Damian; Adams, Niels C.; Bussell, James N.; Adams, David J.; Ramírez-Solis, Ramiro; Steel, Karen P.; Galli, Antonella; White, Jacqueline K.

    2015-01-01

    ABSTRACT Knowledge of the expression profile of a gene is a critical piece of information required to build an understanding of the normal and essential functions of that gene and any role it may play in the development or progression of disease. High-throughput, large-scale efforts are on-going internationally to characterise reporter-tagged knockout mouse lines. As part of that effort, we report an open access adult mouse expression resource, in which the expression profile of 424 genes has been assessed in up to 47 different organs, tissues and sub-structures using a lacZ reporter gene. Many specific and informative expression patterns were noted. Expression was most commonly observed in the testis and brain and was most restricted in white adipose tissue and mammary gland. Over half of the assessed genes presented with an absent or localised expression pattern (categorised as 0-10 positive structures). A link between complexity of expression profile and viability of homozygous null animals was observed; inactivation of genes expressed in ≥21 structures was more likely to result in reduced viability by postnatal day 14 compared with more restricted expression profiles. For validation purposes, this mouse expression resource was compared with Bgee, a federated composite of RNA-based expression data sets. Strong agreement was observed, indicating a high degree of specificity in our data. Furthermore, there were 1207 observations of expression of a particular gene in an anatomical structure where Bgee had no data, indicating a large amount of novelty in our data set. Examples of expression data corroborating and extending genotype-phenotype associations and supporting disease gene candidacy are presented to demonstrate the potential of this powerful resource. PMID:26398943

  5. Accumulation and therapeutic modulation of 6-sulfo LacNAc+ dendritic cells in multiple sclerosis

    PubMed Central

    Thomas, Katja; Dietze, Kristin; Wehner, Rebekka; Metz, Imke; Tumani, Hayrettin; Schultheiß, Thorsten; Günther, Claudia; Schäkel, Knut; Reichmann, Heinz; Brück, Wolfgang; Schmitz, Marc

    2014-01-01

    Objective: To examine the potential role of 6-sulfo LacNAc+ (slan) dendritic cells (DCs) displaying pronounced proinflammatory properties in the pathogenesis of multiple sclerosis (MS). Methods: We determined the presence of slanDCs in demyelinated brain lesions and CSF samples of patients with MS. In addition, we explored the impact of methylprednisolone, interferon-β, glatiramer acetate, or natalizumab on the frequency of blood-circulating slanDCs in patients with MS. We also evaluated whether interferon-β modulates important proinflammatory capabilities of slanDCs. Results: SlanDCs accumulate in highly inflammatory brain lesions and are present in the majority of CSF samples of patients with MS. Short-term methylprednisolone administration reduces the percentage of slanDCs in blood of patients with MS and the proportion of tumor necrosis factor-α– or CD150-expressing slanDCs. Long-term interferon-β treatment decreases the percentage of blood-circulating slanDCs in contrast to glatiramer acetate or natalizumab. Furthermore, interferon-β inhibits the secretion of proinflammatory cytokines by slanDCs and their capacity to promote proliferation and differentiation of T cells. Conclusion: Accumulation of slanDCs in highly inflammatory brain lesions and their presence in CSF indicate that slanDCs may play an important role in the immunopathogenesis of MS. The reduction of blood-circulating slanDCs and the inhibition of their proinflammatory properties by methylprednisolone and interferon-β may contribute to the therapeutic efficiency of these drugs in patients with MS. PMID:25340085

  6. Baryon Loading Efficiency and Particle Acceleration Efficiency of Relativistic Jets: Cases for Low Luminosity BL Lacs

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Tanaka, Yasuyuki T.

    2016-09-01

    Relativistic jets launched by supermassive black holes, so-called active galactic nuclei (AGNs), are known as the most energetic particle accelerators in the universe. However, the baryon loading efficiency onto the jets from the accretion flows and their particle acceleration efficiencies have been veiled in mystery. With the latest data sets, we perform multi-wavelength spectral analysis of quiescent spectra of 13 TeV gamma-ray detected high-frequency-peaked BL Lacs (HBLs) following one-zone static synchrotron self-Compton (SSC) model. We determine the minimum, cooling break, and maximum electron Lorentz factors following the diffusive shock acceleration (DSA) theory. We find that HBLs have {P}B/{P}e˜ 6.3× {10}-3 and the radiative efficiency {ɛ }{{rad,jet}}˜ 6.7× {10}-4, where P B and P e is the Poynting and electron power, respectively. By assuming 10 leptons per one proton, the jet power relates to the black hole mass as {P}{{jet}}/{L}{{Edd}}˜ 0.18, where {P}{{jet}} and {L}{{Edd}} is the jet power and the Eddington luminosity, respectively. Under our model assumptions, we further find that HBLs have a jet production efficiency of {η }{{jet}}˜ 1.5 and a mass loading efficiency of {ξ }{{jet}}≳ 5× {10}-2. We also investigate the particle acceleration efficiency in the blazar zone by including the most recent Swift/BAT data. Our samples ubiquitously have particle acceleration efficiencies of {η }g˜ {10}4.5, which is inefficient to accelerate particles up to the ultra-high-energy-cosmic-ray (UHECR) regime. This implies that the UHECR acceleration sites should not be the blazar zones of quiescent low power AGN jets, if one assumes the one-zone SSC model based on the DSA theory.

  7. Activities implemented jointly: First report to the Secretariat of the United Nations Framework Convention on Climate Change. Accomplishments and descriptions of projects accepted under the U.S. Initiative on Joint Implementation

    SciTech Connect

    1996-07-01

    More than 150 countries are now Party to the United Nations Framework Convention on Climate Change (FCCC), which seeks, as its ultimate objective, to stabilize atmospheric concentrations of greenhouse gases at a level that would prevent dangerous human interference with the climate system. As a step toward this goal, all Parties are to take measures to mitigate climate change and to promote and cooperate in the development and diffusion of technologies and practices that control or reduce emissions and enhance sinks of greenhouse gases. In the US view, efforts between countries or entities within them to reduce net greenhouse gas emissions undertaken cooperatively--called joint implementation (JI)--holds significant potential both for combating the threat of global warming and for promoting sustainable development. To develop and operationalize the JI concept, the US launched its Initiative on Joint Implementation (USIJI) in October 1993, and designed the program to attract private sector resources and to encourage the diffusion of innovative technologies to mitigate climate change. The USIJI provides a mechanism for investments by US entities in projects to reduce greenhouse gas emissions worldwide and has developed a set of criteria for evaluating proposed projects for their potential to reduce net GHG emissions.

  8. Karyotypic diversity and evolutionary trends in the Neotropical catfish genus Hypostomus Lacépède, 1803 (Teleostei, Siluriformes, Loricariidae)

    PubMed Central

    Alves, Anderson Luis; de Borba, Rafael Splendore; Oliveira, Claudio; Mauro Nirchio; Granado, Angel; Foresti, Fausto

    2012-01-01

    Abstract The family Loricariidae with 813 nominal species is one of the largest fish families of the world. Hypostominae, its more complex subfamily, was recently divided into five tribes. The tribe Hypostomini is composed of a single genus, Hypostomus Lacépède, 1803, which exhibits the largest karyotypic diversity in the family Loricariidae. With the main objective of contributing to a better understanding of the relationship and the patterns of evolution among the karyotypes of Hypostomus species, cytogenetic studies were conducted in six species of the genus from Brazil and Venezuela. The results show a great chromosome variety with diploid numbers ranging from 2n=68 to 2n=76, with a clear predominance of acrocentric chromosomes. The Ag-NORs are located in terminal position in all species analyzed. Three species have single Ag-NORs (Hypostomus albopunctatus (Regan, 1908), Hypostomus prope plecostomus (Linnaeus, 1758), and Hypostomus prope paulinus (Ihering, 1905)) and three have multiple Ag-NORs (Hypostomus ancistroides (Ihering, 1911), Hypostomus prope iheringi (Regan, 1908), and Hypostomus strigaticeps (Regan, 1908)). In the process of karyotype evolution of the group, the main type of chromosome rearrangements was possibly centric fissions, which may have been facilitated by the putative tetraploid origin of Hypostomus species. The relationship between the karyotype changes and the evolution in the genus is discussed. PMID:24260683

  9. X-ray intensity and spectral variations in the BL Lac sources H2155-304 and PKS0548-322

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.; Singh, K. P.; Riegler, G. R.

    1987-01-01

    The results from the X-ray observations of two BL Lacertae objects, H2155-304 and PKS0548-322, are presented. The observations were carried out with the HEAO-1 A2 Low Energy Detectors, the High Resolution Imager, and the Monitor Proportional Counter aboard the Einstein Observatory. Correlated X-ray intensity variations of about 20 percent in the 0.15-3.5 keV energy band and about 40 percent in the 1.5-10 keV energy band are observed in H2155-304 over a period of about 8 hr. A factor of two change in the intensity of PKS0548-322 in the 3.5-10 keV energy interval is also detected over a time interval of 1 hr. Variations in the X-ray intensity over a timescale of months and the hardening of the spectrum with increasing intensity are seen in the HEAO-1 A2 data on H2155-304. The shortest observed timescale for the variability is used to derive an upper limit on the mass of the central accreting source in the two BL Lac objects studied here.

  10. The Essential yhcSR Two-Component Signal Transduction System Directly Regulates the lac and opuCABCD Operons of Staphylococcus aureus

    PubMed Central

    Yan, Meiying; Hall, Jeffrey W.; Yang, Junshu; Ji, Yinduo

    2012-01-01

    Our previous studies suggested that the essential two-component signal transduction system, YhcSR, regulates the opuCABCD operon at the transcriptional level, and the Pspac-driven opuCABCD partially complements the lethal effects of yhcS antisense RNA expression in Staphylococcus aureus. However, the reason why yhcSR regulon is required for growth is still unclear. In this report, we present that the lac and opuC operons are directly transcriptionally regulated by YhcSR. Using real-time RT-PCR we showed that the down-regulation of yhcSR expression affected the transcription of lacA encoding galactose-6-phosphotase isomerase subunit LacA, and opuCA encoding a subunit of a glycine betaine/carnitine/choline ABC transporter. Promoter-lux reporter fusion studies further confirmed the transcriptional regulation of lac by YhcSR. Gel shift assays revealed that YhcR binds to the promoter regions of the lac and opuC operons. Moreover, the Pspac-driven lacABC expression in trans was able to partially complement the lethal effect of induced yhcS antisense RNA. Likewise, the Pspac-driven opuCABCD expression in trans complemented the growth defect of S. aureus in a high osmotic strength medium during the depletion of YhcSR. Taken together, the above data indicate that the yhcSR system directly regulates the expression of lac and opuC operons, which, in turn, may be partially associated with the essentiality of yhcSR in S. aureus. These results provide a new insight into the biological functions of the yhcSR, a global regulator. PMID:23226327

  11. THE ENVIRONMENTAL TECHNOLOGIES ACCEPTANCE (ETA) PROGRAM

    SciTech Connect

    Christina B. Behr-Andres

    2001-10-01

    The objective of the Environmental Technologies Acceptance (ETA) Program at the Energy & Environmental Research Center (EERC) is to advance the development, commercial acceptance, and timely deployment of selected private sector technologies for the cleanup of sites in the nuclear defense complex as well as the greater market. As a result of contract changes approved by National Energy Technology Laboratory (NETL) representatives to incorporate activities previously conducted under another NETL agreement, there are now an additional task and an expansion of activities within the stated scope of work of the ETA program. As shown in Table 1, this cooperative agreement, funded by NETL (No. DE-FC26-00NT40840), consists of four tasks: Technology Selection, Technology Development, Technology Verification, and System Engineering. As currently conceived, ETA will address the needs of as many technologies as appropriate under its current 3-year term. There are currently four technical subtasks: Long-Term Stewardship Initiative at the Mound Plant Site; Photocatalysis of Mercury-Contaminated Water; Subcritical Water Treatment of PCB and Metal-Contaminated Paint Waste; and Vegetative Covers for Low-Level Waste Repositories. This report covers activities during the second six months of the three-year ETA program.

  12. Lac Télé structure, Republic of Congo: Geological setting of a cryptozoological and biodiversity hotspot, and evidence against an impact origin

    NASA Astrophysics Data System (ADS)

    Master, Sharad

    2010-11-01

    Lac Télé is a large lake, ˜5.6 km in diameter, with an ovoid shape, situated at 17°10'E, 1°20'N, in the great tropical rain forest region of the Republic of Congo. This lake has attracted widespread attention, mainly because of the legends among the local people that it harbours a strange animal known as the Mokele-Mbembe, but also because it is situated in a region that is a hotbed of biodiversity and conservation efforts with respect to various endangered mammalian species, including gorillas and chimpanzees. Because of its appearance, Lac Télé has been regarded as a possible meteorite impact structure. Various expeditions, studying cryptozoology, conservation ecology, biodiversity, and the impact hypothesis, have visited Lac Télé in the past several decades. The Lac Télé structure is located in the NW part of the intracratonic Congo Basin, in a region dominated by Holocene alluvium, dense tropical rain forest, and swamps which form part of the basin of the Likouala aux Herbes, a multi-branched meandering river flowing over very low gradients into the Sangha river, a major tributary of the Congo river. Previous bathymetric studies have shown that the average depth of Lac Télé is only 4 m, including organic-rich silty sediments. The structure is that of a flat-bottomed dish. Modelling of the Lac Télé as an impact structure indicates a number of features which ought to be present. The absence of any of these features, coupled with the irregular ovoid shape, the palynological record, and the location of the structure at the intersection of major regional lineaments, is regarded as evidence against the impact hypothesis. Lac Télé as an isolated lake ecosystem is not unique in the Congo Basin, and there are several other similar small shallow isolated lakes surrounded by rain forest and marshes, some of which formed by damming of drainage systems by neotectonic faults. It is suggested that the formation of Lac Télé may be related to its location

  13. 48 CFR 811.103 - Market acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Market acceptance. 811.103 Section 811.103 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS COMPETITION AND... acceptance....

  14. 48 CFR 811.103 - Market acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Market acceptance. 811.103 Section 811.103 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS COMPETITION AND... acceptance....

  15. Computer acceptance of older adults.

    PubMed

    Nägle, Sibylle; Schmidt, Ludger

    2012-01-01

    Even though computers play a massive role in everyday life of modern societies, older adults, and especially older women, are less likely to use a computer, and they perform fewer activities on it than younger adults. To get a better understanding of the factors affecting older adults' intention towards and usage of computers, the Unified Theory of Acceptance and Usage of Technology (UTAUT) was applied as part of a more extensive study with 52 users and non-users of computers, ranging in age from 50 to 90 years. The model covers various aspects of computer usage in old age via four key constructs, namely performance expectancy, effort expectancy, social influences, and facilitating conditions, as well as the variables gender, age, experience, and voluntariness it. Interestingly, next to performance expectancy, facilitating conditions showed the strongest correlation with use as well as with intention. Effort expectancy showed no significant correlation with the intention of older adults to use a computer. PMID:22317258

  16. Pre-induced Lac Operon Effect on Non Specific Sugars: Pre-culture Effect is Dependent on Strength of Induction, Exponential Phase and Substrate Concentration.

    PubMed

    Malakar, Pushkar

    2015-01-01

    The source and history of the cell plays an important role in influencing the phenotypic properties of the organism in a particular environmental condition. Pre-induced lac operon provides benefit on lactose environment. During metabolism lactose is broken down into glucose and galactose. The fate of cells with pre-induced lac operon on glucose and galactose milieu is not known. The influence of nutritional status of the medium, level of pre-induction and growth phase on pre-culture effect is not investigated. Effect of pre-induced lac operon on non specific sugars along with the factors that influence this effect was enumerated in the present study. Results of this present study indicate that pre-induced lac operon provide benefit in terms of growth on galactose milieu. This study also suggests that Pre induced lac operon effect depends on the (i) strength of induction in the pre-culture, (ii) nutritional content of the environment and (iii) exponential growth phase of the organism. The above study will help in the better characterization of the pre culture effect. It will also help in the better understanding of the relation between gene expression and growth physiology. PMID:26161153

  17. Effect of plasmid copy number and lac operator sequence on antibiotic-free plasmid selection by operator-repressor titration in Escherichia coli.

    PubMed

    Cranenburgh, Rocky M; Lewis, Kathryn S; Hanak, Julian A J

    2004-01-01

    The Escherichia coli strain DH1lacdapD enables plasmid selection and maintenance that is free from antibiotics and selectable marker genes. This is achieved by using only the lac operator sequence as a selectable element. This strain is currently used to generate high copy number plasmids with no antibiotic resistance genes for use as DNA vaccines and for expression of recombinant proteins. Until now these have been limited to pUC-based plasmids containing a high copy number pMB1-derived origin of replication, and the principle lacO(1) and auxiliary lacO(3) operators. In this study we have shown that this system can also be used to select and maintain pBR322-based plasmids with the lower copy number pMB1 origin of replication, and that lacO(1) alone or a palindromic version of lacO(1) can provide a sufficient level of repressor titration for plasmid selection. This is advantageous for recombinant protein production, where low copy number plasmids are often used and plasmid maintenance is important. The degree of repressor titration due to these plasmids was measured using the natural lactose operon in E. coli DH1 as a model. PMID:15383717

  18. Pre-induced Lac Operon Effect on Non Specific Sugars: Pre-culture Effect is Dependent on Strength of Induction, Exponential Phase and Substrate Concentration

    PubMed Central

    Malakar, Pushkar

    2015-01-01

    The source and history of the cell plays an important role in influencing the phenotypic properties of the organism in a particular environmental condition. Pre-induced lac operon provides benefit on lactose environment. During metabolism lactose is broken down into glucose and galactose. The fate of cells with pre-induced lac operon on glucose and galactose milieu is not known. The influence of nutritional status of the medium, level of pre-induction and growth phase on pre-culture effect is not investigated. Effect of pre-induced lac operon on non specific sugars along with the factors that influence this effect was enumerated in the present study. Results of this present study indicate that pre-induced lac operon provide benefit in terms of growth on galactose milieu. This study also suggests that Pre induced lac operon effect depends on the (i) strength of induction in the pre-culture, (ii) nutritional content of the environment and (iii) exponential growth phase of the organism. The above study will help in the better characterization of the pre culture effect. It will also help in the better understanding of the relation between gene expression and growth physiology. PMID:26161153

  19. Study of BL Lac VLBA Data at 8 and 15 GHz in a Super-resolution Mode

    NASA Astrophysics Data System (ADS)

    Tateyama, Claudio E.

    2009-11-01

    In this work, we show Very Long Baseline Array data at 8 GHz (RRFID) and 15 GHz (MOJAVE) of BL Lac from 1995 to 2007 by examining the structure in the maps given by the CLEAN-point components (represented by a restoring beam of 0.1 mas). The CLEAN-point maps show a well-ordered train of individual points in the inner core jet. The result shows a narrow elongated stationary component at about 1.5 mas from the core which was interpreted as superposition of trailing components. The inner core-jet structure shows ballistic motion and a precessing ejection nozzle period of 26 years.

  20. A singly bonded derivative of endohedral metallofullerene: La@C82CBr(COOC2H5).

    PubMed

    Feng, Lai; Nakahodo, Tsukasa; Wakahara, Takatsugu; Tsuchiya, Takahiro; Maeda, Yutaka; Akasaka, Takeshi; Kato, Tatsuhisa; Horn, Ernst; Yoza, Kenji; Mizorogi, Naomi; Nagase, Shigeru

    2005-12-14

    A novel Bingel monoadduct of La@C82 (mono-A) has been synthesized by the reaction with diethyl bromomalonate in the presence of DBU (Bingel-Hirsch reaction). Its structure has been fully determined by NMR spectroscopic and X-ray crystallographic analyses. The most distinct feature of mono-A is the single bond moiety between the functional group and fullerene cage, which is very different from the cyclopropane moiety in a conventional Bingel adduct of empty fullerenes. Further spectroscopic characterizations and calculations revealed the closed-shell structure of mono-A. Its formation mechanism was discussed according to calculation results. PMID:16332032

  1. Fermi and Swift observations of correlated outburst activity from the BL Lac object OT 081 (PKS 1749+096)

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano; Gonzalez, Josefa Becerra; Pivato, Giovanna; Thompson, David J.

    2016-07-01

    We report a strong multi-wavelength outburst in the BL Lac object OT 081 (also known as PKS 1749+096, 4C +09.57) with the radio counterpart position R.A.: 267.88674 deg, Dec.: 9.65020 deg (J2000.0, Lanyi et al. 2010, AJ, 139, 1695) and with redshift z=0.322 (Stickel, Fried, Kuehr 1988, A & A, 191, 16). Gamma ray and X-ray flares reached peaks during the interval 2016 July 16 and 20 simultaneous with an optical outburst (Balonek et al, 2016, ATel #9259).

  2. Fermi-LAT detection of a GeV gamma-ray flare from the BL Lac object OT 081

    NASA Astrophysics Data System (ADS)

    Becerra Gonzalez, J.; Thompson, D.; Fermi-LAT Collaboration

    2016-07-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with the BL Lac object OT 081 (also known as PKS 1749+096, 4C 09.57, 0FGL J1751.5+0935, 1FGL J1751.5+0937, 2FGL J1751.5+0938, 1FHL J1751.5+0938, 3FGL J1751.5+0939), with the radio counterpart position R.A.: 267.88674 deg, Dec.: 9.65020 deg (J2000.0, Lanyi et al. 2010, AJ, 139, 1695).

  3. 7 CFR 966.29 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 966.29 Section 966.29 Agriculture... Regulating Handling Committee § 966.29 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance with the Secretary within ten days after being notified...

  4. 7 CFR 924.25 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 924.25 Section 924.25 Agriculture....25 Acceptance. Any person selected by the Secretary as a member or as an alternate member of the committee shall qualify by filing a written acceptance with the Secretary promptly after being notified...

  5. 7 CFR 924.25 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 924.25 Section 924.25 Agriculture....25 Acceptance. Any person selected by the Secretary as a member or as an alternate member of the committee shall qualify by filing a written acceptance with the Secretary promptly after being notified...

  6. 7 CFR 923.25 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 923.25 Section 923.25 Agriculture... COUNTIES IN WASHINGTON Order Regulating Handling Administrative Body § 923.25 Acceptance. Any person prior... written acceptance of willingness to serve on the committee....

  7. 7 CFR 993.31 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 993.31 Section 993.31 Agriculture... Order Regulating Handling Prune Marketing Committee § 993.31 Acceptance. Each person selected as a... with the Secretary a written acceptance within 15 days after receiving notice of his selection....

  8. 7 CFR 1215.23 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Acceptance. 1215.23 Section 1215.23 Agriculture... Acceptance. Each individual nominated for membership of the Board shall qualify by filing a written acceptance with the Secretary at the time of nomination....

  9. 7 CFR 906.25 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 906.25 Section 906.25 Agriculture... RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Committee § 906.25 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance with the...

  10. 7 CFR 946.26 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 946.26 Section 946.26 Agriculture... Order Regulating Handling Administrative Committee § 946.26 Acceptance. Any person selected by the Secretary as a committee member or as an alternate shall qualify by filing a written acceptance with...

  11. 7 CFR 959.29 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 959.29 Section 959.29 Agriculture... Regulating Handling Committee § 959.29 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance within ten days after being notified of such selection....

  12. 12 CFR 250.164 - Bankers' acceptances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Bankers' acceptances. 250.164 Section 250.164... MISCELLANEOUS INTERPRETATIONS Interpretations § 250.164 Bankers' acceptances. (a) Section 207 of the Bank Export... bankers' acceptances (“BAs”) that may be created by an individual member bank from 50 per cent (or 100...

  13. 24 CFR 3282.355 - Submission acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Submission acceptance. 3282.355... § 3282.355 Submission acceptance. (a) A party whose submission is determined by the Department to be adequate shall be granted provisional acceptance until December 15, 1976, or for a six month period...

  14. 7 CFR 906.25 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 906.25 Section 906.25 Agriculture... RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Committee § 906.25 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance with the...

  15. 24 CFR 3282.355 - Submission acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Submission acceptance. 3282.355... § 3282.355 Submission acceptance. (a) A party whose submission is determined by the Department to be adequate shall be granted provisional acceptance until December 15, 1976, or for a six month period...

  16. 48 CFR 11.103 - Market acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Market acceptance. 11.103... DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 11.103 Market acceptance. (a) Section... either— (i) Achieved commercial market acceptance; or (ii) Been satisfactorily supplied to an...

  17. 7 CFR 1250.330 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Acceptance. 1250.330 Section 1250.330 Agriculture... Research and Promotion Order Egg Board § 1250.330 Acceptance. Any person appointed by the Secretary as a member, or as an alternate member, of the Board shall qualify by filing a written acceptance with...

  18. 7 CFR 923.25 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 923.25 Section 923.25 Agriculture... COUNTIES IN WASHINGTON Order Regulating Handling Administrative Body § 923.25 Acceptance. Any person prior... written acceptance of willingness to serve on the committee....

  19. 7 CFR 1205.326 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Acceptance. 1205.326 Section 1205.326 Agriculture... Research and Promotion Order Cotton Board § 1205.326 Acceptance. Any person selected by the Secretary as a member or as an alternate member of the Board shall qualify by filing a written acceptance with...

  20. 7 CFR 953.21 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 953.21 Section 953.21 Agriculture... STATES Order Regulating Handling Administrative Committee § 953.21 Acceptance. Any person selected by the... acceptance with the Secretary within the time specified by the Secretary....

  1. 12 CFR 250.164 - Bankers' acceptances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 3 2011-01-01 2011-01-01 false Bankers' acceptances. 250.164 Section 250.164... MISCELLANEOUS INTERPRETATIONS Interpretations § 250.164 Bankers' acceptances. (a) Section 207 of the Bank Export... bankers' acceptances (“BAs”) that may be created by an individual member bank from 50 per cent (or 100...

  2. 7 CFR 966.29 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 966.29 Section 966.29 Agriculture... Regulating Handling Committee § 966.29 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance with the Secretary within ten days after being notified...

  3. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Market acceptance. 2911... DESCRIBING AGENCY NEEDS Selecting And Developing Requirements Documents 2911.103 Market acceptance. The... offered have either achieved commercial market acceptance or been satisfactorily supplied to an...

  4. 7 CFR 1215.23 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Acceptance. 1215.23 Section 1215.23 Agriculture... Acceptance. Each individual nominated for membership of the Board shall qualify by filing a written acceptance with the Secretary at the time of nomination....

  5. 7 CFR 946.26 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 946.26 Section 946.26 Agriculture... Order Regulating Handling Administrative Committee § 946.26 Acceptance. Any person selected by the Secretary as a committee member or as an alternate shall qualify by filing a written acceptance with...

  6. 7 CFR 1205.326 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Acceptance. 1205.326 Section 1205.326 Agriculture... Research and Promotion Order Cotton Board § 1205.326 Acceptance. Any person selected by the Secretary as a member or as an alternate member of the Board shall qualify by filing a written acceptance with...

  7. 7 CFR 953.21 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 953.21 Section 953.21 Agriculture... STATES Order Regulating Handling Administrative Committee § 953.21 Acceptance. Any person selected by the... acceptance with the Secretary within the time specified by the Secretary....

  8. 7 CFR 1250.330 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Acceptance. 1250.330 Section 1250.330 Agriculture... Research and Promotion Order Egg Board § 1250.330 Acceptance. Any person appointed by the Secretary as a member, or as an alternate member, of the Board shall qualify by filing a written acceptance with...

  9. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Market acceptance. 2911... DESCRIBING AGENCY NEEDS Selecting And Developing Requirements Documents 2911.103 Market acceptance. The... offered have either achieved commercial market acceptance or been satisfactorily supplied to an...

  10. 48 CFR 11.103 - Market acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Market acceptance. 11.103... DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 11.103 Market acceptance. (a) Section... either— (i) Achieved commercial market acceptance; or (ii) Been satisfactorily supplied to an...

  11. 7 CFR 1210.323 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Acceptance. 1210.323 Section 1210.323 Agriculture... PLAN Watermelon Research and Promotion Plan National Watermelon Promotion Board § 1210.323 Acceptance. Each person nominated for membership on the Board shall qualify by filing a written acceptance with...

  12. 7 CFR 959.29 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 959.29 Section 959.29 Agriculture... Regulating Handling Committee § 959.29 Acceptance. Any person selected as a committee member or alternate shall qualify by filing a written acceptance within ten days after being notified of such selection....

  13. 7 CFR 993.31 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acceptance. 993.31 Section 993.31 Agriculture... Order Regulating Handling Prune Marketing Committee § 993.31 Acceptance. Each person selected as a... with the Secretary a written acceptance within 15 days after receiving notice of his selection....

  14. 7 CFR 915.25 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acceptance. 915.25 Section 915.25 Agriculture... Regulating Handling Administrative Body § 915.25 Acceptance. Any person selected by the Secretary as a member or as an alternate member of the committee shall qualify by filing a written acceptance with...

  15. 7 CFR 1210.323 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Acceptance. 1210.323 Section 1210.323 Agriculture... PLAN Watermelon Research and Promotion Plan National Watermelon Promotion Board § 1210.323 Acceptance. Each person nominated for membership on the Board shall qualify by filing a written acceptance with...

  16. 46 CFR 28.73 - Accepted organizations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Accepted organizations. 28.73 Section 28.73 Shipping... INDUSTRY VESSELS General Provisions § 28.73 Accepted organizations. An organization desiring to be designated by the Commandant as an accepted organization must request such designation in writing. As...

  17. Older Adults' Acceptance of Information Technology

    ERIC Educational Resources Information Center

    Wang, Lin; Rau, Pei-Luen Patrick; Salvendy, Gavriel

    2011-01-01

    This study investigated variables contributing to older adults' information technology acceptance through a survey, which was used to find factors explaining and predicting older adults' information technology acceptance behaviors. Four factors, including needs satisfaction, perceived usability, support availability, and public acceptance, were…

  18. 48 CFR 11.103 - Market acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Market acceptance. 11.103... DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 11.103 Market acceptance. (a) Section... either— (i) Achieved commercial market acceptance; or (ii) Been satisfactorily supplied to an...

  19. 48 CFR 11.103 - Market acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Market acceptance. 11.103... DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 11.103 Market acceptance. (a) 41 U.S...) Achieved commercial market acceptance; or (ii) Been satisfactorily supplied to an agency under current...

  20. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Market acceptance. 2911... DESCRIBING AGENCY NEEDS Selecting And Developing Requirements Documents 2911.103 Market acceptance. The... offered have either achieved commercial market acceptance or been satisfactorily supplied to an...

  1. 48 CFR 11.103 - Market acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Market acceptance. 11.103... DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 11.103 Market acceptance. (a) Section... either— (i) Achieved commercial market acceptance; or (ii) Been satisfactorily supplied to an...

  2. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Market acceptance. 2911.103... DESCRIBING AGENCY NEEDS Selecting And Developing Requirements Documents 2911.103 Market acceptance. The... offered have either achieved commercial market acceptance or been satisfactorily supplied to an...

  3. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Market acceptance. 2911... DESCRIBING AGENCY NEEDS Selecting And Developing Requirements Documents 2911.103 Market acceptance. The... offered have either achieved commercial market acceptance or been satisfactorily supplied to an...

  4. The Relationship between Treatment Acceptability and Familism

    ERIC Educational Resources Information Center

    Pemberton, Joy R.; Borrego, Joaquin, Jr.

    2005-01-01

    Many studies have examined the acceptability of treatments for children with disruptive behaviors. However, few studies to date have tested the effects of home environment variables such as family support on treatment acceptability. In the current study, parents' level of familism was used to predict their willingness to accept several behavioral…

  5. 46 CFR 28.73 - Accepted organizations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Accepted organizations. 28.73 Section 28.73 Shipping... INDUSTRY VESSELS General Provisions § 28.73 Accepted organizations. An organization desiring to be designated by the Commandant as an accepted organization must request such designation in writing. As...

  6. Values, perceived risks and benefits, and acceptability of nuclear energy.

    PubMed

    de Groot, Judith I M; Steg, Linda; Poortinga, Wouter

    2013-02-01

    We examined how personal values and perceptions of risks and benefits are associated with the acceptability of nuclear energy (NE). A theoretical model is tested in which beliefs about the risks and benefits of NE mediate the relationship between values and acceptability. The results showed that egoistic values are positively related to the perceived benefits and acceptability of NE. In contrast, altruistic and biospheric values were positively related to the perceived risks of NE. Although it has been argued that NE may help to combat climate change through lower CO(2) emissions, these environmental benefits were not acknowledged by people with strong biospheric values. Furthermore, results confirmed that the more risks respondents perceived, the less they were inclined to accept NE. In contrast, the more a person believed that NE has beneficial consequences, the more acceptable NE was. Finally, as expected, perceived risks and benefits were found to partly mediate the relationship between personal values and acceptability. We discuss the theoretical and practical implications of these findings. PMID:22642255

  7. VERITAS OBSERVATIONS OF THE BL LAC OBJECT PG 1553+113

    SciTech Connect

    Aliu, E.; Archer, A.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Aune, T.; Barnacka, A.; Behera, B.; Chen, X.; Benbow, W.; Cerruti, M.; Berger, K.; Bird, R.; Byrum, K.; Cardenzana, J. V; Dickinson, H. J.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dumm, J.; and others

    2015-01-20

    We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a spectral index of 4.33 ± 0.09. The time-averaged integral flux above 200 GeV measured for this period was (1.69 ± 0.06) × 10{sup –11} photons cm{sup –2} s{sup –1}, corresponding to 6.9% of the Crab Nebula flux. We also present the combined γ-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100 MeV to 560 GeV. The data are well fit by a power law with an exponential cutoff at 101.9 ± 3.2 GeV. The origin of the cutoff could be intrinsic to PG 1553+113 or be due to the γ-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of z > 0.395 based on optical/UV observations of PG 1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of z ≤ 0.62. A strongly elevated mean flux of (2.50 ± 0.14) × 10{sup –11} photons cm{sup –2} s{sup –1} (10.3% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44±0.71)×10{sup −11} photons cm{sup −2} s{sup −1} (18.3% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a χ{sup 2} probability for a steady flux of 0.03%.

  8. Dust in BL Lac objects and Fanaroff-Riley radio galaxies: infrared region

    NASA Astrophysics Data System (ADS)

    Seal Braun, P.

    2015-12-01

    Here 28 BL Lac objects, 18 FR I type radio galaxies, 4 FR I/II type radio galaxies and 10 FR II type radio galaxies are studied from FIR (far infrared) to optical region (180 μm to 0.44 μm) to understand the nature of infrared emission from these objects and the physical properties of dust in the emitting region. Using the flux densities from 2MASS, IRAS, ISO, SCUBA (40 % samples), WISE All-sky Data, AKARI (10 % samples) data and optical (B) observations, the spectral energy distributions are constructed. FIR and NIR spectral indices (α_{FIR} and α_{NIR}) are estimated. The dust temperatures and dust masses of all the samples are estimated from FIR flux densities. The SEDs of most of the samples (90 %) show steep slopes from FIR to optical region and about 10 % of the samples show flat continuous spectra from FIR to NIR region. The SEDs of 80 % FR I type radio galaxies and 1 out of 4 FR I/II type radio galaxies and two RBLs show a bump in the NIR to optical region. The SEDs of these sources are compared with Radiative transfer models. From FIR to MIR region, the SEDs of 90 % of the objects studied here can be fitted to the models with luminosities L˜ 10^{9.5} L0, considering uncertainty from 10 % to 20 %. But the observable fluxes in the NIR region are higher and can be fitted to other models with higher L˜ 10^{12.5} L0. Since there is a difference in emission in NIR region, mainly for FR I radio galaxies, so the variation of apparent K magnitudes with logarithm of redshift z is also studied. The WISE colours, (W1 - W2) and (W2 - W3) are compared with isodensity contours. Comparing with radiative transfer models it can be suggested that, in the FIR and MIR region the infrared emission is from the dust containing large grains, small graphites and PAHs at temperature ˜50 K-100 K. In the NIR region hot dust is mainly due to small grains at temperature ˜1200 K and the emission is mainly from synchrotron radiation produced in the inner part of the relativistic

  9. Variables Predicting Prospective Biology Teachers' Acceptance Perceptions Regarding Gene Technology

    ERIC Educational Resources Information Center

    Yilmaz, Mirac; Demirhan, Haydar

    2014-01-01

    The different opinions on products and applications of gene technology (GT) draw attention to the training and education activities related to GT. The purpose of this study is to review some variables predicting the acceptance perception regarding GT, and to investigate their changes at levels. The prospective teachers' subjective knowledge and…

  10. Do You Have an Internet Acceptable Use Policy?

    ERIC Educational Resources Information Center

    Perks, Dennis J.; Gavitt, Donna R.; Olivo, John J.

    1997-01-01

    Developing an Internet acceptable use policy is the first step in bringing technological change to the classroom. This article defines educator's proactive responsibilities and provides a policy shell (privilege, "netiquette," security, vandalism, legal issues, warranties, and user agreements) to formulate individual school policies. Lists…

  11. Acceptance test report MICON software exhaust fan control modifications

    SciTech Connect

    SILVAN, G.R.

    1999-05-20

    This report documents the results the acceptance test HNF-4108 which verifies the MICON program changes for the new automatic transfer switch ATS-2 alarms, the Closed Loop Cooling isolator status, the CB-3 position alarm, the alarms for the new emergency fan damper backup air compressor, and the generator sequencer logic.

  12. Acceptability of GM foods among Pakistani consumers.

    PubMed

    Ali, Akhter; Rahut, Dil Bahadur; Imtiaz, Muhammad

    2016-04-01

    In Pakistan majority of the consumers do not have information about genetically modified (GM) foods. In developing countries particularly in Pakistan few studies have focused on consumers' acceptability about GM foods. Using comprehensive primary dataset collected from 320 consumers in 2013 from Pakistan, this study analyzes the determinants of consumers' acceptability of GM foods. The data was analyzed by employing the bivariate probit model and censored least absolute deviation (CLAD) models. The empirical results indicated that urban consumers are more aware of GM foods compared to rural consumers. The acceptance of GM foods was more among females' consumers as compared to male consumers. In addition, the older consumers were more willing to accept GM food compared to young consumers. The acceptability of GM foods was also higher among wealthier households. Low price is the key factor leading to the acceptability of GM foods. The acceptability of the GM foods also reduces the risks among Pakistani consumers. PMID:27494790

  13. Duration and periodicity of kimberlite volcanic activity in the Lac de Gras kimberlite field, Canada and some recommendations for kimberlite geochronology

    NASA Astrophysics Data System (ADS)

    Sarkar, Chiranjeeb; Heaman, Larry M.; Pearson, D. G.

    2015-03-01

    Establishing the emplacement ages and distribution pattern of Central Slave kimberlites has played a key role in diamond exploration within the Lac de Gras kimberlite field. Nonetheless, emplacement age information is lacking for approximately 80% of the known kimberlites in this field making the assessment of emplacement age patterns difficult. This study expands the number and geographic coverage of kimberlite emplacement ages within the Lac de Gras field to re-assess the absolute timing, duration, and possible number of pulses of kimberlite eruption. U-Pb perovskite ages for eight previously undated kimberlites and an additional thirteen kimberlites, which were previously dated by either the Rb-Sr or U-Pb methods, fall within the age range of 75-45 Ma, as previously suggested for kimberlite magmatism in this area. We report the first Carboniferous age kimberlite in the Central Lac de Gras field - the Eddie kimberlite - with a U-Pb perovskite age of 321.0 ± 3.0 Ma. A compilation of 57 kimberlite emplacement ages from the central Lac de Gras field was evaluated using probability density and mixture modeling methods. Five short-duration (4-5 Ma) periods of kimberlite magmatism are recognized at 48, 54, 61, 66 and 72 Ma; the three younger pulses have been previously recognized and remain relatively unchanged. The 54 Ma pulse represents the major kimberlite eruption event containing ~ 40% of the currently dated kimberlites in Lac de Gras field. A detailed evaluation of the temporal-spatial evolution of Lac de Gras kimberlites reveals that the oldest diamond-poor kimberlites (75-60 Ma) were emplaced in the northern and eastern parts of the field whereas the younger (55-48 Ma) economic kimberlites are concentrated in the center of the field.

  14. p53 deficiency alters the yield and spectrum of radiation-induced lacZ mutants in the brain of transgenic mice

    NASA Technical Reports Server (NTRS)

    Chang, P. Y.; Kanazawa, N.; Lutze-Mann, L.; Winegar, R. A.

    2001-01-01

    Exposure to heavy particle radiation in the galacto-cosmic environment poses a significant risk in space exploration and the evaluation of radiation-induced genetic damage in tissues, especially in the central nervous system, is an important consideration in long-term manned space missions. We used a plasmid-based transgenic mouse model system, with the pUR288 lacZ transgene integrated in the genome of every cell of C57Bl/6(lacZ) mice, to evaluate the genetic damage induced by iron particle radiation. In order to examine the importance of genetic background on the radiation sensitivity of individuals, we cross-bred p53 wild-type lacZ transgenic mice with p53 nullizygous mice, producing lacZ transgenic mice that were either hemizygous or nullizygous for the p53 tumor suppressor gene. Animals were exposed to an acute dose of 1 Gy of iron particles and the lacZ mutation frequency (MF) in the brain was measured at time intervals from 1 to 16 weeks post-irradiation. Our results suggest that iron particles induced an increase in lacZ MF (2.4-fold increase in p53+/+ mice, 1.3-fold increase in p53+/- mice and 2.1-fold increase in p53-/- mice) and that this induction is both temporally regulated and p53 genotype dependent. Characterization of mutants based on their restriction patterns showed that the majority of the mutants arising spontaneously are derived from point mutations or small deletions in all three genotypes. Radiation induced alterations in the spectrum of deletion mutants and reorganization of the genome, as evidenced by the selection of mutants containing mouse genomic DNA. These observations are unique in that mutations in brain tissue after particle radiation exposure have never before been reported owing to technical limitations in most other mutation assays.

  15. Mutagenesis induced by targeted alpha therapy using 213Bi-cDTPA-9.2.27 in lacZ transgenic mice.

    PubMed

    Allen, Barry J; So, Trina; Abbas Rizvi, Syed M; Song, Emma Y; Fernandez, Harvey R; Lutz-Mann, Louise

    2009-05-01

    Targeted alpha therapy utilizes alpha-emitting radionuclides conjugated to monoclonal antibodies to allow specific irradiation of cancer cells whilst sparing normal, healthy tissues. The mutagenic potential of (213)Bi conjugated to a human melanoma antigen-specific antibody (9.2.27) was examined using an in vivo transgenic mouse model containing multiple copies of a lacZ target gene in every cell, allowing the quantification and comparison of mutagenesis in different organs. Mice received an ip injection of 16.65 MBq of (213)Bi-cDTPA-9.2.27, and were sacrificed at 24 h, 1 w and 4 w post-injection. Pharmacokinetic studies gave the absorbed and effective doses for each organ. The mutant frequency and mutant spectra were analysed for the brain, spleen and kidneys. The brain and spleen did not show significant increases in induced mutation frequencies compared to spontaneous background levels or changes in mutant spectra, these results being independent of p53 status. However, elevated mutation frequencies and persistent size change mutations were observed in the kidneys, but are not significant at the p = 0.05 level. The effect of p53 status was also evident, as p53 heterozygotes displayed higher mutation frequencies than their wild-type counterparts, suggesting a reduction in the p53 gene may lead to an increased susceptibility to mutagenesis. These effects were time dependent and levels returned to those of the controls at 4 w post-irradiation, albeit with a predominant residue of size mutations. These effects were observed at activities very much higher than those expected for the therapy of human patients. As such, the induction of secondary cancer with the (213)Bi-cDTPA-9.2.27 alpha immunoconjugate is not expected to be a significant problem in the clinic. PMID:19337032

  16. Period studies of five neglected Algol-type binaries: RW Cet, BO Gem, DG Lac, SW Oph and WY Per

    NASA Astrophysics Data System (ADS)

    Erdem, A.; Doğru, S. S.; Soydugan, F.; Çiçek, C.; Demircan, O.

    2010-10-01

    We investigated the orbital period variations of five neglected Algol-type eclipsing binaries (RW Cet, BO Gem, DG Lac, SW Oph and WY Per) in this study. Their O- C diagrams display tilted sinusoidal variations superimposed on upward parabolic forms. The parabolic variations, which correspond to secular period increases, were interpreted in terms of the combined effect of mass transfer and loss. Then, the mass transfer rates from the less massive secondary components to more massive primaries for non-conservative cases were calculated to be ˜10-7M⊙/yr for RW Cet, DG Lac and SW Oph and ˜10-8M⊙/yr for BO Gem and WY Per. The tilted (eccentric) sinusoidal representations of the O- C variations were interpreted in terms of the light-time effect due to unseen components in the systems. The possible third bodies in four Algol binaries (excluding RW Cet) would have masses larger than one solar mass. If these hypothetical large massive third bodies were normal stars, they should be detectable. Therefore, new astrometric, photometric and spectroscopic observations of these systems and careful analyses of the resulting data are required.

  17. An Analysis of Light Periods of BL Lac Object S5 0716+714 with the MUSIC Algorithm

    NASA Astrophysics Data System (ADS)

    Tang, Jie

    2012-07-01

    The multiple signal classification (MUSIC) algorithm is introduced to the estimation of light periods of BL Lac objects. The principle of the MUSIC algorithm is given, together with a testing on its spectral resolution by using a simulative signal. From a lot of literature, we have collected a large number of effective observational data of the BL Lac object S5 0716+714 in the three optical wavebands V, R, and I from 1994 to 2008. The light periods of S5 0716+714 are obtained by means of the MUSIC algorithm and average periodogram algorithm, respectively. It is found that there exist two major periodic components, one is the period of (3.33±0.08) yr, another is the period of (1.24±0.01) yr. The comparison of the performances of periodicity analysis of two algorithms indicates that the MUSIC algorithm has a smaller requirement on the sample length, as well as a good spectral resolution and anti-noise ability, to improve the accuracy of periodicity analysis in the case of short sample length.

  18. Genetic variation among species, races, forms and inbred lines of lac insects belonging to the genus Kerria (Homoptera, Tachardiidae)

    PubMed Central

    Ranjan, Sanjeev Kumar; Mallick, Chandana Basu; Saha, Dipnarayan; Vidyarthi, Ambarish S; Ramani, Ranganathan

    2011-01-01

    The lac insects (Homoptera: Tachardiidae), belonging to the genus Kerria, are commercially exploited for the production of lac. Kerria lacca is the most commonly used species in India. RAPD markers were used for assessing genetic variation in forty-eight lines of Kerria, especially among geographic races, infrasubspecific forms, cultivated lines, inbred lines, etc., of K. lacca. In the 48 lines studied, the 26 RAPD primers generated 173 loci, showing 97.7% polymorphism. By using neighbor-joining, the dendrogram generated from the similarity matrix resolved the lines into basically two clusters and outgroups. The major cluster, comprising 32 lines, included mainly cultivated lines of the rangeeni form, geographic races and inbred lines of K. lacca. The second cluster consisted of eight lines of K. lacca, seven of the kusmi form and one of the rangeeni from the southern state of Karnataka. The remaining eight lines formed a series of outgroups, this including a group of three yellow mutant lines of K. lacca and other species of the Kerria studied, among others. Color mutants always showed distinctive banding patterns compared to their wild-type counterparts from the same population. This study also adds support to the current status of kusmi and rangeeni, as infraspecific forms of K. lacca. PMID:21931527

  19. Development of volatile compounds during the manufacture of dry-cured "lacón," a Spanish traditional meat product.

    PubMed

    Purriños, Laura; Bermúdez, Roberto; Franco, Daniel; Carballo, Javier; Lorenzo, José M

    2011-01-01

    Volatile compounds were determined throughout the manufacture of dry-cured "lacón," a traditional dry-salted, and ripened meat product made in the north-west of Spain from the foreleg of the pig following a similar process to that of dry-cured ham. Volatiles were extracted by a purge-and-trap method and analyzed by gas chromatographic/mass spectrometry. One hundred and two volatile compounds were identified. In raw material, only 34 volatile compounds were found and at very low levels. The number of volatile compounds increased during processing. The substances identified belonged to several chemical classes: aldehydes (23), alcohols (9), ketones (15), hydrocarbons (37), esters (4), acids (3), furans (4), sulphur compounds (1), chloride compounds (1), and other compounds (4). Results indicated that the most abundant chemical family in flavor at the end of the manufacturing process was aldehydes, followed by hydrocarbons and ketones. Lipids were the most important precursor of flavor compounds of dry-cured "lacón." PMID:21535660

  20. vanI: a novel D-Ala-D-Lac vancomycin resistance gene cluster found in Desulfitobacterium hafniense.

    PubMed

    Kruse, Thomas; Levisson, Mark; de Vos, Willem M; Smidt, Hauke

    2014-09-01

    The glycopeptide vancomycin was until recently considered a drug of last resort against Gram-positive bacteria. Increasing numbers of bacteria, however, are found to carry genes that confer resistance to this antibiotic. So far, 10 different vancomycin resistance clusters have been described. A chromosomal vancomycin resistance gene cluster was previously described for the anaerobic Desulfitobacterium hafniense Y51. We demonstrate that this gene cluster, characterized by its d-Ala-d-Lac ligase-encoding vanI gene, is present in all strains of D. hafniense, D. chlororespirans and some strains of Desulfosporosinus spp. This gene cluster was not found in vancomycin-sensitive Desulfitobacterium or Desulfosporosinus spp., and we show that this antibiotic resistance can be exploited as an intrinsic selection marker for Desulfitobacterium hafniense and D. chlororespirans. The gene cluster containing vanI is phylogenetically only distantly related with those described from soil and gut bacteria, but clusters instead with vancomycin resistance genes found within the phylum Actinobacteria that include several vancomycin-producing bacteria. It lacks a vanH homologue, encoding a D-lactate dehydrogenase, previously thought to always be present within vancomycin resistance gene clusters. The location of vanH outside the resistance gene cluster likely hinders horizontal gene transfer. Hence, the vancomycin resistance cluster in D. hafniense should be regarded a novel one that we here designated vanI after its unique d-Ala-d-Lac ligase. PMID:25042042

  1. Structure of LacY with an α-substituted galactoside: Connecting the binding site to the protonation site

    PubMed Central

    Kumar, Hemant; Finer-Moore, Janet S.; Kaback, H. Ronald; Stroud, Robert M.

    2015-01-01

    The X-ray crystal structure of a conformationally constrained mutant of the Escherichia coli lactose permease (the LacY double-Trp mutant Gly-46→Trp/Gly-262→Trp) with bound p-nitrophenyl-α-d-galactopyranoside (α-NPG), a high-affinity lactose analog, is described. With the exception of Glu-126 (helix IV), side chains Trp-151 (helix V), Glu-269 (helix VIII), Arg-144 (helix V), His-322 (helix X), and Asn-272 (helix VIII) interact directly with the galactopyranosyl ring of α-NPG to provide specificity, as indicated by biochemical studies and shown directly by X-ray crystallography. In contrast, Phe-20, Met-23, and Phe-27 (helix I) are within van der Waals distance of the benzyl moiety of the analog and thereby increase binding affinity nonspecifically. Thus, the specificity of LacY for sugar is determined solely by side-chain interactions with the galactopyranosyl ring, whereas affinity is increased by nonspecific hydrophobic interactions with the anomeric substituent. PMID:26157133

  2. [Relation of Lac promotor and the expression of cholera toxin subunit B gene in recombinant Escherichia coli MM2].

    PubMed

    Fang, H; Zhao, S; Yu, G; Ma, Q

    1997-08-01

    Effects of different carbon sources including glucose, lactate and acetate and IPTG induction on the expression of ctb gene, which is on the downstream of lac promotor, in recombinant Escherichia coli MM2 were studied. In medium YC were added 0.048mol/L glucose, 0.102mol/L lactate or 0.167mol/L acetate which separately produce the same energy in the condition of complete oxidization. Addition of glucose largely decreased the expression level of ctb gene because of decrease of pH during culture process. Addition of lactate increased the expression level of ctb gene by 1.15 fold and did not inhibit the growth of MM2 strain. Addition of acetate increasd the expression level of ctb gene by 0.97 fold and inhibited the growth of MM2 strain. Induction by IPTG at different time and different concentration did not increase the expression level of ctb gene, so the lac promotor had no or a little influence upon the expression of ctb gene in recombinant MM2 strain. PMID:9863203

  3. FUSE and HST FUV Spectroscopic Analysis of the Old Novae V533 Her, DI Lac and RR Pic

    NASA Astrophysics Data System (ADS)

    Sion, Edward M.; Ruby, John J.; Godon, Patrick

    2016-01-01

    The old novae V533 Her (Nova Her 1963), DI Lac (Nova Lac 1910) and RR Pic (Nova Pic 1891) are in (or near) their quiescent stage following their nova explosions and continue to accrete at a high rate in the aftermath of their explosions. All three systems appear to be accreting at high rates long after their novae. They exhibit continua that are steeply rising into the FUV as well as absorption lines and emission lines of uncertain origin. All three have FUSE spectra which offer not only higher spectral resolution but also wavelength coverage extending down to the Lyman Limit. We have matched these FUSE spectra with existing archival HST STIS and IUE spectral coverage, and adopted the newly determined interstellar reddening corrections of Selvelli and Gilmozzi (2013). The dereddened FUV spectra have been modeled with our grids of optically thick accretion disks and hot white dwarf photospheres. We present the results of our modeling analysis and discuss implications for the poorly understood quiescent states of old novae including the role of irradiation in enhancing the rate of accretion far into quiescence.This work is supported by NASA grants NNX13AF11G and NNX13AF12G to Villanova University.

  4. Acceptance in Romantic Relationships: The Frequency and Acceptability of Partner Behavior Inventory

    ERIC Educational Resources Information Center

    Doss, Brian D.; Christensen, Andrew

    2006-01-01

    Despite the recent emphasis on acceptance in romantic relationships, no validated measure of relationship acceptance presently exists. To fill this gap, the 20-item Frequency and Acceptability of Partner Behavior Inventory (FAPBI; A. Christensen & N. S. Jacobson, 1997) was created to assess separately the acceptability and frequency of both…

  5. 2013 SYR Accepted Poster Abstracts.

    PubMed

    2013-01-01

    SYR 2013 Accepted Poster abstracts: 1. Benefits of Yoga as a Wellness Practice in a Veterans Affairs (VA) Health Care Setting: If You Build It, Will They Come? 2. Yoga-based Psychotherapy Group With Urban Youth Exposed to Trauma. 3. Embodied Health: The Effects of a Mind�Body Course for Medical Students. 4. Interoceptive Awareness and Vegetable Intake After a Yoga and Stress Management Intervention. 5. Yoga Reduces Performance Anxiety in Adolescent Musicians. 6. Designing and Implementing a Therapeutic Yoga Program for Older Women With Knee Osteoarthritis. 7. Yoga and Life Skills Eating Disorder Prevention Among 5th Grade Females: A Controlled Trial. 8. A Randomized, Controlled Trial Comparing the Impact of Yoga and Physical Education on the Emotional and Behavioral Functioning of Middle School Children. 9. Feasibility of a Multisite, Community based Randomized Study of Yoga and Wellness Education for Women With Breast Cancer Undergoing Chemotherapy. 10. A Delphi Study for the Development of Protocol Guidelines for Yoga Interventions in Mental Health. 11. Impact Investigation of Breathwalk Daily Practice: Canada�India Collaborative Study. 12. Yoga Improves Distress, Fatigue, and Insomnia in Older Veteran Cancer Survivors: Results of a Pilot Study. 13. Assessment of Kundalini Mantra and Meditation as an Adjunctive Treatment With Mental Health Consumers. 14. Kundalini Yoga Therapy Versus Cognitive Behavior Therapy for Generalized Anxiety Disorder and Co-Occurring Mood Disorder. 15. Baseline Differences in Women Versus Men Initiating Yoga Programs to Aid Smoking Cessation: Quitting in Balance Versus QuitStrong. 16. Pranayam Practice: Impact on Focus and Everyday Life of Work and Relationships. 17. Participation in a Tailored Yoga Program is Associated With Improved Physical Health in Persons With Arthritis. 18. Effects of Yoga on Blood Pressure: Systematic Review and Meta-analysis. 19. A Quasi-experimental Trial of a Yoga based Intervention to Reduce Stress and

  6. Peer Acceptance and Facial Recognition.

    ERIC Educational Resources Information Center

    Kafer, Norman F.

    1981-01-01

    Developmental changes in the encoding of unfamiliar faces was studied in three experiments with Australian 7- to 12-year-old children (N=24 in experiment 1, N=48 in experiment 2, and N=32 in experiment 3). Results showed that younger children encoded unfamiliar faces in terms of striking isolated features and that avoidant children made more…

  7. Understanding and enhancing user acceptance of computer technology

    NASA Technical Reports Server (NTRS)

    Rouse, William B.; Morris, Nancy M.

    1986-01-01

    Technology-driven efforts to implement computer technology often encounter problems due to lack of acceptance or begrudging acceptance of the personnel involved. It is argued that individuals' acceptance of automation, in terms of either computerization or computer aiding, is heavily influenced by their perceptions of the impact of the automation on their discretion in performing their jobs. It is suggested that desired levels of discretion reflect needs to feel in control and achieve self-satisfaction in task performance, as well as perceptions of inadequacies of computer technology. Discussion of these factors leads to a structured set of considerations for performing front-end analysis, deciding what to automate, and implementing the resulting changes.

  8. 7 CFR 932.32 - Acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Olive Administrative Committee § 932.32 Acceptance. Any person selected by the...

  9. 7 CFR 932.32 - Acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Olive Administrative Committee § 932.32 Acceptance. Any person selected by the...

  10. 7 CFR 932.32 - Acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Olive Administrative Committee § 932.32 Acceptance. Any person selected by the...

  11. 7 CFR 1207.323 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan National Potato Promotion Board § 1207.323 Acceptance. Each...

  12. 7 CFR 1207.323 - Acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan National Potato Promotion Board § 1207.323 Acceptance. Each...

  13. 7 CFR 1207.323 - Acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan National Potato Promotion Board § 1207.323 Acceptance. Each...

  14. 7 CFR 1207.323 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan National Potato Promotion Board § 1207.323 Acceptance. Each...

  15. 7 CFR 1207.323 - Acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan National Potato Promotion Board § 1207.323 Acceptance. Each...

  16. Coarse-grained simulations of proton-dependent conformational changes in lactose permease.

    PubMed

    Jewel, Yead; Dutta, Prashanta; Liu, Jin

    2016-08-01

    During lactose/H(+) symport, the Escherichia coli lactose permease (LacY) undergoes a series of global conformational transitions between inward-facing (open to cytoplasmic side) and outward-facing (open to periplasmic side) states. However, the exact local interactions and molecular mechanisms dictating those large-scale structural changes are not well understood. All-atom molecular dynamics simulations have been performed to investigate the molecular interactions involved in conformational transitions of LacY, but the simulations can only explore early or partial global structural changes because of the computational limits (< 100 ns). In this work, we implement a hybrid force field that couples the united-atom protein models with the coarse-grained MARTINI water/lipid, to investigate the proton-dependent dynamics and conformational changes of LacY. The effects of the protonation states on two key glutamate residues (Glu325 and Glu269) have been studied. Our results on the salt-bridge dynamics agreed with all-atom simulations at early short time period, validating our simulations. From our microsecond simulations, we were able to observe the complete transition from inward-facing to outward-facing conformations of LacY. Our results showed that all helices have participated during the global conformational transitions and helical movements of LacY. The inter-helical distances measured in our simulations were consistent with the double electron-electron resonance experiments at both cytoplasmic and periplasmic sides. Our simulations indicated that the deprotonation of Glu325 induced the opening of the periplasmics side and partial closure of the cytoplasmic side of LacY, while protonation of the Glu269 caused a stable cross-domain salt-bridge (Glu130-Arg344) and completely closed the cytoplasmic side. Proteins 2016; 84:1067-1074. © 2016 Wiley Periodicals, Inc. PMID:27090495

  17. In acceptance we trust? Conceptualising acceptance as a viable approach to NGO security management.

    PubMed

    Fast, Larissa A; Freeman, C Faith; O'Neill, Michael; Rowley, Elizabeth

    2013-04-01

    This paper documents current understanding of acceptance as a security management approach and explores issues and challenges non-governmental organisations (NGOs) confront when implementing an acceptance approach to security management. It argues that the failure of organisations to systematise and clearly articulate acceptance as a distinct security management approach and a lack of organisational policies and procedures concerning acceptance hinder its efficacy as a security management approach. The paper identifies key and cross-cutting components of acceptance that are critical to its effective implementation in order to advance a comprehensive and systematic concept of acceptance. The key components of acceptance illustrate how organisational and staff functions affect positively or negatively an organisation's acceptance, and include: an organisation's principles and mission, communications, negotiation, programming, relationships and networks, stakeholder and context analysis, staffing, and image. The paper contends that acceptance is linked not only to good programming, but also to overall organisational management and structures. PMID:23278470

  18. From many deaths to some few cases of drug-resistant tuberculosis: travelling with the systems quality improvement model in Lacs Health District, Togo

    PubMed Central

    Afanvi, Kossivi Agbelenko

    2015-01-01

    The ultimate goal of every tuberculosis (TB) treatment program is a high treatment success rate. Treatment success is extremely important because, when the rate is high, it significantly contributes to declining numbers of new cases by reducing the number and period of infectious cases, TB morbidity and mortality, and prevents the emergence of resistant strains. Our aim was to decrease TB mortality by increasing pulmonary TB patients’ treatment success rate to at least 85 % in Lacs Health District by end of July 2014. A systems and dialogic analysis of the public health system related to TB patients’ treatment revealed that it was not performing well; we found weak coverage and quality of TB services, a poorly-functioning TB health information system, poor-performing health workforce, poor availability of HIV tests and antiretroviral for TB patients, and low degree of patients’ participation in their care. We redesigned the system to correct those weaknesses. The effectiveness of these changes was monitored using plan, do, study, act (PDSA) cycles. We increased TB patient success rate from 80% to 95% between February 2012 and July 2014.The mortality rate dropped from 13% to 3% and the failure to follow-up rate dropped from 3% to 2%. In conclusion, district health systems performance depends on factors such as the closeness of services to population; skilled workforce; the ability to collect and analyze data and use information for action; population empowerment, and good management and improvement capabilities of management team especially the public health director. High TB patients’ success rate depends also on the availability of antiretroviral drugs. It is highly important that every district health management team member develops improvement capabilities. PMID:26734412

  19. MyoD-lacZ transgenes are early markers in the neural retina, but MyoD function appears to be inhibited in the developing retinal cells.

    PubMed

    Kablar, Boris

    2004-06-01

    Recent findings suggest that eye and skeletal muscle development in vertebrates share the same regulatory network. In that network, Pax3 gene is apparently activated through Dach/Eya/Six feedback loop to mediate MyoD-driven myogenesis. The purpose of this study was to investigate previously reported MyoD-lacZ expression in the developing mouse neural retina and to gain insight into the potential role of MyoD in the embryonic retinal cells. The analysis of MD6.0-lacZ and 258/-2.5lacZ transgenic embryos revealed that the retinal temporal expression pattern of the two transgenes resembled their expression pattern in the MyoD-dependent precursor muscle cells. However, MyoD transcripts and protein could not be found in the sites of MyoD-lacZ retinal expression. Furthermore, our immunohistochemical analysis suggests the existence of diverse factors (e.g., Pax6 and Chx10) within the retinal cells that differentially and inappropriately activate the two transgenes. Finally, the retinal phenotype observed in Pax7-/- knock-out mice suggests a role for Pax7 in photoreceptor cell differentiation, retinal lamination and in the etiopathology of retinoblastoma. Taken together, our data suggest that the MyoD gene evolved a different mechanism to achieve its down-regulation within the retina than that of the Myf5 gene. PMID:15245757

  20. Novel insights from hybrid LacI/GalR proteins: family-wide functional attributes and biologically significant variation in transcription repression.

    PubMed

    Meinhardt, Sarah; Manley, Michael W; Becker, Nicole A; Hessman, Jacob A; Maher, L James; Swint-Kruse, Liskin

    2012-11-01

    LacI/GalR transcription regulators have extensive, non-conserved interfaces between their regulatory domains and the 18 amino acids that serve as 'linkers' to their DNA-binding domains. These non-conserved interfaces might contribute to functional differences between paralogs. Previously, two chimeras created by domain recombination displayed novel functional properties. Here, we present a synthetic protein family, which was created by joining the LacI DNA-binding domain/linker to seven additional regulatory domains. Despite 'mismatched' interfaces, chimeras maintained allosteric response to their cognate effectors. Therefore, allostery in many LacI/GalR proteins does not require interfaces with precisely matched interactions. Nevertheless, the chimeric interfaces were not silent to mutagenesis, and preliminary comparisons suggest that the chimeras provide an ideal context for systematically exploring functional contributions of non-conserved positions. DNA looping experiments revealed higher order (dimer-dimer) oligomerization in several chimeras, which might be possible for the natural paralogs. Finally, the biological significance of repression differences was determined by measuring bacterial growth rates on lactose minimal media. Unexpectedly, moderate and strong repressors showed an apparent induction phase, even though inducers were not provided; therefore, an unknown mechanism might contribute to regulation of the lac operon. Nevertheless, altered growth correlated with altered repression, which indicates that observed functional modifications are significant. PMID:22965134