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. Holocene vegetation changes through Lac Ledro sediments (Trentino, Italy).

    NASA Astrophysics Data System (ADS)

    Joannin, Sebastien; Vannière, Boris; Galop, Didier; Magny, Michel; Gilli, Adrian; Chapron, Emmanuel; Wirth, Stéfanie; Anselmetti, Flavio; Desmet, Marc

    2010-05-01

    Lake Ledro is part of the French program ANR LAMA (coordinators: M. Magny and N. Combourieu Nebout) which aims to link Holocene paleoenvironmental changes along a north-south transect in Italy. Lake Ledro (652 m a.s.l.; Trentino, north-eastern Italy) is the northward component of the transect. It is located on the southern slope of the Alps and its catchment area covers 131 km2 with mountains culminating at 1500-2000 m. A multi-proxy approach based on biotic and abiotic indicators (lake-level, palynology, geochemistry and geophysic) was developed from deep and littoral cores, including sediment sequences in Early and Middle Bronze Age lake-shore archaeological sites. We aim reconstructing paleoenvironmental changes resulting from both climate and anthropic influences trough the entire Holocene. A deep master core was built after extracting twin cores from a non disturbed sediment zone recognised by seismic-reflexion investigations. The age-depth model is based on 13 AMS 14C ages measured on terrestrial plant macrofossils and the mean temporal resolution for analyses is ca 60 years. Palynological study shows the usual vegetation succession for the southern slope of the Alps. During the first part of the Holocene, abrupt changes are observed in pollen assemblages in relation to changes in other proxies (XRF and Magnetic Susceptibility) and correlate with cold events associated to the deglaciation in the North-Atlantic area. Cool episodes corresponding to the PreBoreal Oscillation (ca 11.3 ka cal BP) and 8.2 ka event are respectively characterized by stopping afforestation and a strong development of Abies in the local ecosystem. During the second part of the Holocene, two declines of arboreal pollen abundance are observed in relation with occurrences in both cereal and anthropic pollen indicators. These two phases are confirmed by increase in soil erosion as indicated by abiotic proxies. They give evidence of two successive steps for human settlement (Early

  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. An MSC2 Promoter-lacZ Fusion Gene Reveals Zinc-Responsive Changes in Sites of Transcription Initiation That Occur across the Yeast Genome

    PubMed Central

    Wu, Yi-Hsuan; Taggart, Janet; Song, Pamela Xiyao; MacDiarmid, Colin; Eide, David J.

    2016-01-01

    The Msc2 and Zrg17 proteins of Saccharomyces cerevisiae form a complex to transport zinc into the endoplasmic reticulum. ZRG17 is transcriptionally induced in zinc-limited cells by the Zap1 transcription factor. In this report, we show that MSC2 mRNA also increases (~1.5 fold) in zinc-limited cells. The MSC2 gene has two in-frame ATG codons at its 5’ end, ATG1 and ATG2; ATG2 is the predicted initiation codon. When the MSC2 promoter was fused at ATG2 to the lacZ gene, we found that unlike the chromosomal gene this reporter showed a 4-fold decrease in lacZ mRNA in zinc-limited cells. Surprisingly, β-galactosidase activity generated by this fusion gene increased ~7 fold during zinc deficiency suggesting the influence of post-transcriptional factors. Transcription of MSC2ATG2-lacZ was found to start upstream of ATG1 in zinc-replete cells. In zinc-limited cells, transcription initiation shifted to sites just upstream of ATG2. From the results of mutational and polysome profile analyses, we propose the following explanation for these effects. In zinc-replete cells, MSC2ATG2-lacZ mRNA with long 5’ UTRs fold into secondary structures that inhibit translation. In zinc-limited cells, transcripts with shorter unstructured 5’ UTRs are generated that are more efficiently translated. Surprisingly, chromosomal MSC2 did not show start site shifts in response to zinc status and only shorter 5’ UTRs were observed. However, the shifts that occur in the MSC2ATG2-lacZ construct led us to identify significant transcription start site changes affecting the expression of ~3% of all genes. Therefore, zinc status can profoundly alter transcription initiation across the yeast genome. PMID:27657924

  7. 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…

  8. 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

  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. SS Lac Revisited

    NASA Astrophysics Data System (ADS)

    Milone, E. F.; Schiller, S. J.; Munari, U.; Kallrath, J.

    1999-05-01

    We have evidence confirming changes in light curve amplitude of the former eclipsing and current SB2 system SS Lac in the open cluster NGC 7209. Remeasured Harvard plate data and published and compiled data sets reveal that the depth of the primary minimum increased between the 1890s and early 1900s and decreased in the 1920s and 1930s. Peak fittings of the amplitude with phase suggests a peak amplitude centered ca. 1911.5, with eclipse onset at about 1885 and effective eclipse cessation late in 1937. We thus concur with the findings of Lehmann (IBVS 3610, 1991), that the apparent inclination varies with time and that a central eclipse occurred about 1911, and of Mossakovskaya (Astron. Lett., 19, 35, 1993), that eclipses ceased prior to 1940. Estimates of SS Lac from plates taken at Tashkent between 1937 and 1940 serve to confirm these results. We have completed now an exhaustive study of the radial velocity curves of Tomasella & Munari (1998, A&A, 335, 561) and all three potentially useful archival light curves available to us, and will discuss the implications of the solutions for models of the system and the cluster to which it belongs. This work was supported in part by grants to Milone from NSERC of Canada, and the URGC of the University of Calgary.

  11. Acceptance in behavior therapy: Understanding the process of change

    PubMed Central

    Cordova, James V.

    2001-01-01

    Acceptance is integral to several cutting-edge behavior therapies. However, several questions about acceptance remain to be clearly answered. First, what does acceptance look like, and can it be observed and measured? Second, what are the behavioral principles involved in the promotion of acceptance? Third, when is acceptance indicated or contraindicated as a therapeutic goal? The current paper attempts to clarify answers to these questions. The goal is to provide a conceptualization of the what, how, and when of acceptance that is accessible to behavior analysts, both to promote our understanding of acceptance as a behavioral phenomenon and to facilitate its empirical study and therapeutic utility. PMID:22478366

  12. [Identification of different lac with infrared spectrum].

    PubMed

    Dong, Qin; Qiu, Jian; He, Run-xi; Zhang, Jian-yun

    2004-05-01

    Fourier infrared spectrum was used to differentiate raw lac, bleached las and lac mixed with resin. The results indicate that the infrared spectra of raw lac and lac mixed with resin are similar, so the authors can differentiate them by the following items: (1) the position and the shape of absorbing peak between 3500 and 2500 cm(-1), (2) the difference of the vibration peak at 1700 cm(-1) for C=O, (3) characteristic peak between 1200 and 1400 cm(-1), (4) the number of peaks and the change in the position of peak. But with bleached and graft copolymerization lacs the properties have been changed by chemical processing. Graft copolymerization of lac is made from methyl-acrylic acid-methyl fat by using potassium permanganate as stimulant. Their main differences are: the change of vibration peak of 1700 cm(-1) for C=O, a sharp small peak at 1558 cm(-1), a peak with middle strength at 681 cm(-1), and spliting to two small peaks at 1151 cm(-1). The experiment shows that the method of infrared spectrum is more scientific and effective than traditional method. PMID:15769053

  13. Treatment Fidelity: Relation to Treatment Acceptability and Change over Time

    ERIC Educational Resources Information Center

    Tanol, Gizem

    2010-01-01

    The purpose of this study was: (a) to examine the relation between acceptability and fidelity of an intervention package in natural classroom settings, and (b) to examine how fidelity of implementation varies in relation to high vs. low treatment acceptability over the course of an academic school year. Participants were 44 teachers, from 15…

  14. 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

  15. 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.

  16. 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.

  17. The Use of Acceptance to Promote Positive Change by Decreasing Shame and Guilt: A Practice Exemplar.

    PubMed

    Meltzer, Mary-Ellen

    2015-01-01

    The use of acceptance by mental health clinicians in the clinical setting is an effective method for providing a safe environment for clients to make positive changes. Acceptance means that mental health clinicians are non-judgmental and acknowledge the clients' situations as they are. When actively used by clinicians, acceptance decreases clients' anxiety and the intensity of their feelings of guilt and shame. Clients are then able to begin to accept themselves as they are. The purpose of this article is to discuss the ways in which mental health clinicians promote clients' acceptance of themselves using the tools of acceptance and commitment therapy and dialectical behavioral therapy. PMID:26514261

  18. 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

  19. 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…

  20. 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…

  1. 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.

  2. 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…

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  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. LacR Is a Repressor of lacABCD and LacT Is an Activator of lacTFEG, Constituting the lac Gene Cluster in Streptococcus pneumoniae

    PubMed Central

    Afzal, Muhammad; Shafeeq, Sulman

    2014-01-01

    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

  10. 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

  11. 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,...

  12. 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....

  13. 46 CFR 164.120-15 - Procedure for acceptance of material change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Procedure for acceptance of material change. 164.120-15 Section 164.120-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Fire Retardant Resins for Lifeboats...

  14. 46 CFR 164.120-15 - Procedure for acceptance of material change.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Procedure for acceptance of material change. 164.120-15 Section 164.120-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Fire Retardant Resins for Lifeboats...

  15. 46 CFR 164.120-15 - Procedure for acceptance of material change.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 6 2012-10-01 2012-10-01 false Procedure for acceptance of material change. 164.120-15 Section 164.120-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Fire Retardant Resins for Lifeboats...

  16. 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…

  17. 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'…

  18. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false What major life-changing event evidence will we not accept? 418.1260 Section 418.1260 Employees' Benefits SOCIAL SECURITY ADMINISTRATION MEDICARE SUBSIDIES Medicare Part B Income-Related Monthly Adjustment Amount Determinations Using A More Recent...

  19. [Effects of lac insect honeydew on the diversity of ground-dwelling ants in lac plantation].

    PubMed

    Lu, Zhi-Xing; Chen, You-Qing; Li, Qiao; Wang, Si-Ming; Liu, Chun-Ju; Zhang, Wei

    2012-04-01

    By the method of pitfall trapping, an investigation was conducted on the diversity of ground-dwelling ants in a lac plantation in Yayi Town of Mojiang County, Yunnan Province of Southwest China in December 2009-May 2010, aimed to understand the effects of lac insect honeydew on the diversity of ground-dwelling ants. The presence or absence of lac insect honeydew and its dynamics all affected the species composition, abundance, and diversity of ground-dwelling ants. In the lac plantation with lac insect hosting, a total of 4953 ant individuals were collected, belonging to 34 species, 23 genera, and 5 subfamilies of Formicidae; whereas in the lac plantation without lac insect hosting, a total of 2416 ant individuals were collected, belonging to 30 species, 20 genera, and 5 subfamilies of Formicidae. The relative abundance, species richness (S), and ACE index in the lac plantation with lac insect hosting were higher than those in the lac plantation without lac insect hosting, and the common species and indicator species of ground-dwelling ants in the lac plantation with lac insect hosting differed from those in the lac plantation without lac insect hosting, suggesting that lac insect hosting altered the community structure of ground-dwelling ants. The adult lac insects excreted larger quantity of honeydew than the larval lac insects, and the relative abundance, S, and ACE index of ground-dwelling ants were higher at the adult stage than at the larval stage of lac insects. The common species and indicator species of ground-dwelling ants also had great differences between the two stages of lac insects.

  20. 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... Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change an... issue a notice of proceeding to change an accepted analytical principle. In addition, any...

  1. 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... Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change an... issue a notice of proceeding to change an accepted analytical principle. In addition, any...

  2. 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... Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC REPORTING § 3050.11 Proposals to change an... issue a notice of proceeding to change an accepted analytical principle. In addition, any...

  3. 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

  4. Transient repression of the lac operon.

    PubMed

    Tyler, B; Loomis, W F; Magasanik, B

    1967-12-01

    Severe transient repression of constitutive or induced beta-galactosidase synthesis occurs upon the addition of glucose to cells of Escherichia coli growing on glycerol, succinic acid, or lactic acid. Only mutants particularily well adapted to growth on glucose exhibit this phenomenon when transferred to a glucose-containing medium. No change in ribonucleic acid (RNA) metabolism was observed during transient repression. We could show that transient repression is pleiotropic, affecting all products of the lac operon. It occurs in a mutant insensitive to catabolite repression. It is established much more rapidly than catabolite repression, and is elicited by glucose analogues that are phosphorylated but not further catabolized by the cell. Thus, transient repression is not a consequence of the exclusion of inducer from the cell, does not require catabolism of the added compound, and does not involve a gross change in RNA metabolism. We conclude that transient repression is distinct from catabolite repression. PMID:4864411

  5. 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

  6. 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…

  7. 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.

  8. 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

  9. 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.

  10. Psychological flexibility and catastrophizing as associated change mechanisms during online Acceptance & Commitment Therapy for chronic pain.

    PubMed

    Trompetter, Hester R; Bohlmeijer, Ernst T; Fox, Jean-Paul; Schreurs, Karlein M G

    2015-11-01

    The underlying mechanisms of the effectiveness of cognitive behavioural interventions for chronic pain need further clarification. The role of, and associations between, pain-related psychological flexibility (PF) and pain catastrophizing (PC) were examined during a randomized controlled trial on internet-based Acceptance & Commitment Therapy (ACT) for chronic pain. We assessed (1) the unique and combined indirect effects of PF and PC on outcomes, and (2) the causality of relations between PF, PC and the primary outcome pain interference in daily life (MPI) during ACT. A total of 238 pain sufferers were allocated to either ACT, a control condition on Expressive Writing, or a waiting list condition. Non-parametric cross-product of coefficients mediational analyses and cross-lagged panel designs were applied. Compared to control conditions, both baseline to post-intervention changes in PF and PC seemed to uniquely mediate baseline to three-month follow-up changes in pain interference and psychological distress. Only PF mediated changes in pain intensity. Indirect effects were twice as large for PF (κ2 = .09-.19) than for PC (κ² PCS = .05-.10). Further assessment of changes during ACT showed, however, that only PF, and not PC, predicted subsequent changes in MPI, while early and late changes in both PF and PC predicted later changes in each other. In conclusion, only PF functioned as a direct, causal working mechanism during ACT, with larger indirect effects that occurred earlier than changes in PC. Additionally, PC may function as an indirect mechanism of change during ACT for chronic pain via its direct influence on PF.

  11. Setting limits for acceptable change in sediment particle size composition following marine aggregate dredging.

    PubMed

    Cooper, Keith M

    2012-08-01

    In the UK, Government policy requires marine aggregate extraction companies to leave the seabed in a similar physical condition after the cessation of dredging. This measure is intended to promote recovery, and the return of a similar faunal community to that which existed before dredging. Whilst the policy is sensible, and in line with the principles of sustainable development, the use of the word 'similar' is open to interpretation. There is, therefore, a need to set quantifiable limits for acceptable change in sediment composition. Using a case study site, it is shown how such limits could be defined by the range of sediment particle size composition naturally found in association with the faunal assemblages in the wider region. Whilst the approach offers a number of advantages over the present system, further testing would be required before it could be recommended for use in the regulatory context. PMID:22721693

  12. 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.

  13. First photometric study of W UMa binary star LU Lac

    NASA Astrophysics Data System (ADS)

    Liao, W.-P.; Qian, S.-B.; Zhao, E.-G.; Jiang, L.-Q.

    2014-08-01

    LU Lac is a neglected W UMa binary star in photometric investigations. In this paper, we present BVRI CCD photometric light curves obtained on one night in 2012. The first photometric solutions of this system are computed by using the Wilson-Devinney code. It is shown that LU Lac is a marginal contact W-type system with a degree of contact factor of f=8.9%, a mass ratio of q=2.085 and a high inclination of i=82°.20. From the first analyses of orbital period changes, we found the period variation of the system includes an oscillation (A3=0.0125 days and T3=51.92 years). The cyclic change may be attributed to the light-travel time effect through the presence of a third body.

  14. 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.

  15. 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

  16. The role of cis-acting sequences governing catabolite repression control of lacS expression in the archaeon Sulfolobus solfataricus.

    PubMed Central

    Hoang, Viet; Bini, Elisabetta; Dixit, Vidula; Drozda, Melissa; Blum, Paul

    2004-01-01

    The archaeon Sulfolobus solfataricus uses a catabolite repression-like system to control production of several glycoside hydrolases. To better understand this regulatory system, studies of the regulation of expression of the beta-glycosidase gene (lacS) were conducted. Expression of lacS varies in response to medium composition and to mutations at an unlinked gene called car. Despite gene overlap, expression of the lacS promoter proximal gene, SSO3017, exhibited coregulation but not cotranscription with lacS. Measurements of mRNA half-life excluded differential stability as a factor in lacS regulation. Chromosomal repositioning by homologous recombination of a lacS deletion series clarified critical cis-acting sequences required for lacS regulation. lacS repositioned at amyA exhibited increased lacS expression and compromised the response to medium composition independently of lacS 5' flanking sequence composition. In contrast, regulation of lacS by the car mutation was dependent on sequences upstream of the archaeal TATA box. Expression of a promoter fusion between lacS and the car-independent malA promoter integrated either at amyA or at the natural lacS locus was insensitive to the allelic state of car. In contrast, the promoter fusion retained a response to medium composition only at the lacS locus. These results indicate that car acts at the lacS promoter and that the response to medium composition involves locus-specific sequences exclusive of those present 5' to lacS or within the lacS transcription unit. PMID:15342498

  17. 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

  18. Integrating mindfulness meditation with cognitive and behavioural therapies: the challenge of combining acceptance- and change-based strategies.

    PubMed

    Lau, Mark A; McMain, Shelley F

    2005-11-01

    Recent innovations in psychological treatments have integrated mindfulness meditation techniques with traditional cognitive and behavioural therapies, challenging traditional cognitive and behavioural therapists to integrate acceptance- and change-based strategies. This article details how 2 treatments, mindfulness-based cognitive therapy and dialectical behaviour therapy, have met this challenge. We review the integration rationale underlying the 2 treatments, how the treatments combine strategies from each modality to accomplish treatment goals, implications for therapist training, and treatment effectiveness. In addition, we discuss the challenges of assessing the benefits of incorporating acceptance-based strategies. Both therapies have integrated acceptance-based mindfulness approaches with change-based cognitive and behavioural therapies to create efficacious treatments.

  19. Mindfulness and acceptance-based group therapy and traditional cognitive behavioral group therapy for social anxiety disorder: Mechanisms of change.

    PubMed

    Kocovski, Nancy L; Fleming, Jan E; Hawley, Lance L; Ho, Moon-Ho Ringo; Antony, Martin M

    2015-07-01

    The present study investigated mechanisms of change for two group treatments for social anxiety disorder (SAD): cognitive behavioral group therapy (CBGT) and mindfulness and acceptance-based group therapy (MAGT). Participants were treatment completers (n = 37 for MAGT, n = 32 for CBGT) from a randomized clinical trial. Cognitive reappraisal was the hypothesized mechanism of change for CBGT. Mindfulness and acceptance were hypothesized mechanisms of change for MAGT. Latent difference score (LDS) analysis results demonstrate that cognitive reappraisal coupling (in which cognitive reappraisal is negatively associated with the subsequent rate of change in social anxiety) had a greater impact on social anxiety for CBGT than MAGT. The LDS bidirectional mindfulness model (mindfulness predicts subsequent change in social anxiety; social anxiety predicts subsequent change in mindfulness) was supported for both treatments. Results for acceptance were less clear. Cognitive reappraisal may be a more important mechanism of change for CBGT than MAGT, whereas mindfulness may be an important mechanism of change for both treatments.

  20. 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.

  1. 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

  2. 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

  3. 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...

  4. 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...

  5. 77 FR 5089 - Surety Companies Acceptable on Federal Bonds-Name Change: American Hardware Mutual Insurance Company

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ..., 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 American Hardware Mutual Insurance Company... Fiscal Service Surety Companies Acceptable on Federal Bonds--Name Change: American Hardware...

  6. 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…

  7. 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.

  8. 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

  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. 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

  11. Waste acceptance and the DWPF Startup Test Program: Impacts of process changes

    SciTech Connect

    Plodinec, M.J.

    1992-08-24

    The DWPF is currently carrying out a Startup Test Program which will lead to radioactive operations in the facility. The objective of a significant portion of this program is to demonstrate that the DWPF can reliably make glass which satisfies DOE`s product specifications. This objective will be achieved through a series of integrated process campaigns using feeds of various compositions (the Qualification Runs).2 During these campaigns, the DWPF Glass Product Control Programs (GPCP) will be used to ensure that glass is made which meets specifications. The GPCP uses a correlation between glass composition and leach test results to determine whether a particular batch of feed will make acceptable glass (i.e., glass which will meet the specifications).

  12. Waste acceptance and the DWPF Startup Test Program: Impacts of process changes

    SciTech Connect

    Plodinec, M.J.

    1992-08-24

    The DWPF is currently carrying out a Startup Test Program which will lead to radioactive operations in the facility. The objective of a significant portion of this program is to demonstrate that the DWPF can reliably make glass which satisfies DOE's product specifications. This objective will be achieved through a series of integrated process campaigns using feeds of various compositions (the Qualification Runs).2 During these campaigns, the DWPF Glass Product Control Programs (GPCP) will be used to ensure that glass is made which meets specifications. The GPCP uses a correlation between glass composition and leach test results to determine whether a particular batch of feed will make acceptable glass (i.e., glass which will meet the specifications).

  13. 20 CFR 418.1260 - What major life-changing event evidence will we not accept?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false What major life-changing event evidence will... Year's Modified Adjusted Gross Income § 418.1260 What major life-changing event evidence will we not... defined benefit pension plan unless the documents are original documents or copies from the...

  14. 75 FR 36153 - Surety Companies Acceptable On Federal Bonds-Change in Business Address and Redomestication...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ..., 2009, at 74 FR 31536. FOR FURTHER INFORMATION CONTACT: Surety Bond Branch at (202) 874-6850... changed their ``BUSINESS ADDRESS'' to ``2815 Forbs Avenue, Suite 200, Hoffman Estates, IL 60192... CODE 4810-35-M...

  15. 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...

  16. 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....

  17. 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

  18. 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

  19. 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

  20. 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…

  1. 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

  2. AlloRep: A Repository of Sequence, Structural and Mutagenesis Data for the LacI/GalR Transcription Regulators.

    PubMed

    Sousa, Filipa L; Parente, Daniel J; Shis, David L; Hessman, Jacob A; Chazelle, Allen; Bennett, Matthew R; Teichmann, Sarah A; Swint-Kruse, Liskin

    2016-02-22

    Protein families evolve functional variation by accumulating point mutations at functionally important amino acid positions. Homologs in the LacI/GalR family of transcription regulators have evolved to bind diverse DNA sequences and allosteric regulatory molecules. In addition to playing key roles in bacterial metabolism, these proteins have been widely used as a model family for benchmarking structural and functional prediction algorithms. We have collected manually curated sequence alignments for >3000 sequences, in vivo phenotypic and biochemical data for >5750 LacI/GalR mutational variants, and noncovalent residue contact networks for 65 LacI/GalR homolog structures. Using this rich data resource, we compared the noncovalent residue contact networks of the LacI/GalR subfamilies to design and experimentally validate an allosteric mutant of a synthetic LacI/GalR repressor for use in biotechnology. The AlloRep database (freely available at www.AlloRep.org) is a key resource for future evolutionary studies of LacI/GalR homologs and for benchmarking computational predictions of functional change. PMID:26410588

  3. 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

  4. 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.

  5. 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.

  6. BATSE observations of BL Lac objects

    SciTech Connect

    Connaughton, V.; Laurent-Muehleisen, S.; McCollough, M.A; Robinson, C.F.

    1998-06-01

    The Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory has been shown to be sensitive to non-transient hard X-ray sources in our galaxy, down to flux levels of 100 mCrab for daily measurements, 3 mCrab for integrations over several years. We use the continuous BATSE database and the Earth Occultation technique to extract average flux values between 20 and 2OO keV from complete and radio- and X-ray- selected BL Lac samples over a 2 year period.

  7. 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

  8. Lateral Attitude Change.

    PubMed

    Glaser, Tina; Dickel, Nina; Liersch, Benjamin; Rees, Jonas; Süssenbach, Philipp; Bohner, Gerd

    2015-08-01

    The authors propose a framework distinguishing two types of lateral attitude change (LAC): (a) generalization effects, where attitude change toward a focal object transfers to related objects, and (b) displacement effects, where only related attitudes change but the focal attitude does not change. They bring together examples of LAC from various domains of research, outline the conditions and underlying processes of each type of LAC, and develop a theoretical framework that enables researchers to study LAC more systematically in the future. Compared with established theories of attitude change, the LAC framework focuses on lateral instead of focal attitude change and encompasses both generalization and displacement. Novel predictions and designs for studying LAC are presented.

  9. Subdividing repressor function: DNA binding affinity, selectivity, and allostery can be altered by amino acid substitution of nonconserved residues in a LacI/GalR homologue.

    PubMed

    Zhan, Hongli; Taraban, Marc; Trewhella, Jill; Swint-Kruse, Liskin

    2008-08-01

    Many mutations that impact protein function occur at residues that do not directly contact ligand. To understand the functional contributions from the sequence that links the DNA-binding and regulatory domains of the LacI/GalR homologues, we have created a chimeric protein (LLhP), which comprises the LacI DNA-binding domain, the LacI linker, and the PurR regulatory domain. Although DNA binding site residues are identical in LLhP and LacI, thermodynamic measurements of DNA binding affinity show that LLhP does not discriminate between alternative DNA ligands as well as LacI. In addition, small-angle scattering experiments show that LLhP is more compact than LacI. When DNA is released, LacI shows a 20 A increase in length that was previously attributed to unfolding of the linker. This change is not seen in apo-LLhP, even though the linker sequences of the two proteins are identical. Together, results indicate that long-range functional and structural changes are propagated across the interface that forms between the linker and regulatory domain. These changes could be mediated via the side chains of several linker residues that contact the regulatory domains of the naturally occurring proteins, LacI and PurR. Substitution of these residues in LLhP leads to a range of functional effects. Four variants exhibit altered affinity for DNA, with no changes in selectivity or allosteric response. Another two result in proteins that bind operator DNA with very low affinity and no allosteric response, similar to LacI binding nonspecific DNA sequences. Two more substitutions simultaneously diminish affinity, enhance allostery, and profoundly alter DNA ligand selectivity. Thus, positions within the linker can be varied to modulate different aspects of repressor function.

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Lessons from the gonadotropin-regulated long chain acyl-CoA synthetase (GR-LACS) null mouse model: a role in steroidogenesis, but not result in X-ALD phenotype.

    PubMed

    Sheng, Yi; Tsai-Morris, Chon-Hwa; Li, Jie; Dufau, Maria L

    2009-03-01

    Gonadotropin-regulated long chain fatty acid Acyl-CoA synthetase (GR-LACS), is a member of the LACS family that is regulated by gonadotropin in the rat Leydig cell (LC). Its mouse/human homologs, lipidosin/bubblegum, have been suggested to participate in X-linked adrenoleukodystrophy (X-ALD), an adreno/neurodegenerative disorder with accumulation of very long chain fatty acids (VLCFA) in tissues and plasma. To further gain insights into its regulatory function, a GR-LACS/lipidosin null mouse was generated. No apparent phenotypic abnormalities were observed in the X-ALD target tissues (brain, testis, adrenal). Nuclear inclusions seen in mice >15 month-old, were present in LC of 9 month-old GR-LACS(-/-) mice. LC of the null mice showed refractoriness to the gonadotropin-induced desensitization of testosterone production that is observed in adult animals. LCFAs were moderately increased in the testis, ovary and brain, but not in the adrenal gland of GR-LACS(-/-) mice, with no major changes in VLCFA. No change in LACS activity was observed in these tissues, suggesting a compensatory mechanism exhibited by other LACS members. The GR-LACS(-/-) model did not support its association with X-ALD. These studies revealed a role of GR-LACS in reducing the aging process of the LC, and its participation in gonadotropin-induced testicular desensitization of testosterone production.

  15. 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

  16. 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

  17. Multifrequency spectra of BL Lac objects

    NASA Technical Reports Server (NTRS)

    Urry, C. M.; Kondo, Y.; Mufson, S. L.; Wandel, A.

    1988-01-01

    A program to obtain simultaneous multifrequency spectra of BL Lacertae objects that are known X-ray sources is discussed. The IUE spectra are generally featureless and well-fitted by power law models. For the faintest exposures, Gaussian extraction of the spectrum can greatly impove the signal-to-noise. Most program objects vary in the ultraviolet, although the time scales are not known because of limited observing time. The broadband spectra of BL Lacs exhibit a range of characteristics but the curvature is always downward and the shape is generally smooth. This can be interpreted as synchrotron emission from a relativistic jet; different jet models are possible, and each allows a range of values for the bulk velocity, magnetic field strength, and electron density. Synchrotron models are not required, however an accretion disk model also gives a good fit to the ultraviolet-through-X-ray continuum.

  18. 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

  19. 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

  20. 76 FR 68124 - Television Broadcasting Services; Fond du Lac, WI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Fond du Lac, WI AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: In this document, the Commission denies a petition...

  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. Functional consequences of exchanging domains between LacI and PurR are mediated by the intervening linker sequence.

    PubMed

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

    2007-07-01

    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 approximately 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

  3. 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

  4. Fine-tuning function: correlation of hinge domain interactions with functional distinctions between LacI and PurR.

    PubMed

    Swint-Kruse, Liskin; Larson, Christopher; Pettitt, B Montgomery; Matthews, Kathleen Shive

    2002-04-01

    LacI and PurR are highly homologous proteins. Their functional units are homodimers, with an N-terminal DNA binding domain that comprises the helix-turn-helix (HTH), N-linker, and hinge regions from both monomers. Hinge structural changes are known to occur upon DNA dissociation but are difficult to monitor experimentally. The initial steps of hinge unfolding were therefore examined using molecular dynamics simulations, utilizing a truncated, chimeric protein comprising the LacI HTH/N-linker and PurR hinge. A terminal Gly-Cys-Gly was added to allow "dimerization" through disulfide bond formation. Simulations indicate that differences in LacI and PurR hinge primary sequence affect the quaternary structure of the hinge x hinge' interface. However, these alternate hinge orientations would be sterically restricted by the core domain. These results prompted detailed comparison of recently available DNA-bound structures for LacI and truncated LacI(1-62) with the PurR structure. Examination revealed that different N-linker and hinge contacts to the core domain of the partner monomer (which binds effector molecule) affect the juxtapositions of the HTH, N-linker, and hinge regions in the DNA binding domain. In addition, the two full-length repressors exhibit significant differences in the interactions between the core and the C-linker connection to the DNA binding domain. Both linkers and the hinge have been implicated in the allosteric response of these repressors. Intriguingly, one functional difference between these two proteins is that they exhibit opposite allosteric response to effector. Simulations and observed structural distinctions are correlated with mutational analysis and sequence information from the LacI/GalR family to formulate a mechanism for fine-tuning individual repressor function.

  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. 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…

  7. The protein burden of lac operon products.

    PubMed

    Koch, A L

    1983-01-01

    A new approach to measuring the slowing of growth due to the manufacture of proteins not needed by a bacterium is presented. An entire single colony of Escherichia coli was used to start a chemostat culture that was then given a selective pressure by the addition of phenylgalactoside (phi-gal). This enriched the population for constitutive mutants that produced beta-galactosidase without induction and could split phi-gal, consume the galactose, and grow faster. When the phi-gal was removed, the constitutives grew slower than the parental strain and were gradually lost. This procedure allows competition experiments to be carried out with minimum effects due to genetic drift. Experiments with both strains having wild-type and mutant permease genes were conducted. With the former the selective disadvantage was initially much greater than expected from the simplest hypothesis that extra unused proteins would slow growth in proportion to their fraction of the total protein synthesis. This phase was followed by a second phase where the selective disadvantage was smaller than predicted by this simple hypothesis. With a very slowly reverting permease negative strain the selective disadvantage, and therefore the protein burden, was found to be much smaller and not statistically different from zero. Thus, while one would expect under carbon and energy limitation in the chemostat the protein burden to be larger than under unlimited conditions, it is so small that even the refined technique used here could not measure it accurately. It is certainly less than the fraction of 'waste' protein synthesis; but it could be between zero and the fraction of the cells' energy and carbon budget spent on manufacture of the proteins of the lac operon. PMID:6361271

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Vancomycin resistance: modeling backbone variants with D-Ala-D-Ala and D-Ala-D-Lac peptides.

    PubMed

    Leung, Siegfried S F; Tirado-Rives, Julian; Jorgensen, William L

    2009-02-15

    To seek vancomycin analogs with broader antibacterial activity, effects of backbone modifications for the agylcon 2 on binding with D-Ala-D-Ala- and D-Ala-D-Lac-containing peptides were investigated by Monte Carlo/free energy perturbation (MC/FEP) calculations. The experimental trend in binding affinities for 2 with three tripeptides was well reproduced. Possible modifications of the peptide bond between residues 4 and 5 were then considered, specifically for conversion of the OCNH linkage to CH(2)NH(2)(+) (6), FCCH (7), HCCH (8), and HNCO (9). The MC/FEP results did not yield binding improvements for 7, 8, and 9, though the fluorovinyl replacement is relatively benign. The previously reported analog 6 remains as the only variant that exhibits improved affinity for the D-Ala-D-Lac sequence and acceptable affinity for the D-Ala-D-Ala sequence. PMID:19128968

  16. Cysteine residues in the zinc finger and amino acids adjacent to the finger are necessary for DNA binding by the LAC9 regulatory protein of Kluyveromyces lactis.

    PubMed Central

    Witte, M M; Dickson, R C

    1988-01-01

    LAC9 is a positive regulatory protein that controls transcription of the lactose-galactose regulon in Kluyveromyces lactis. LAC9 is homologous to the GAL4 protein of Saccharomyces cerevisiae. Both proteins have a single "zinc finger" which plays a role in DNA binding. We previously hypothesized (L. V. Wray, M. M. Witte, R. C. Dickson, and M. I. Riley, Mol. Cell. Biol. 7:1111-1121, 1987) that the DNA-binding domain of the LAC9 protein consisted of the zinc finger as well as a region of amino acids on the carboxyl-terminal side of the zinc finger. In this study we used oligonucleotide-directed mutagenesis to introduce 13 single-amino-acid changes into the proposed DNA-binding domain of the LAC9 protein. Variant LAC9 proteins carrying an amino acid substitution in any one of the four highly conserved Cys residues of the zinc finger had reduced DNA-binding activity, suggesting that each Cys is necessary for DNA binding. Three of four variant LAC9 proteins with amino acid substitutions located on the carboxyl-terminal side of the zinc finger had reduced DNA-binding activity. These results support our hypothesis that the DNA-binding domain of the LAC9 protein is composed of the zinc finger and the adjacent region on the carboxyl side of the zinc finger, a region that has the potential to form an alpha-helix. Finally, LAC9 proteins containing His residues substituted for the conserved Cys residues also had reduced DNA-binding activity, indicating that His residues are not equivalent to Cys residues, as had been previously thought. Images PMID:3146691

  17. 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

  18. Short lesson plan associated with increased acceptance of evolutionary theory and potential change in three alternate conceptions of macroevolution in undergraduate students.

    PubMed

    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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. Diffuse γ-ray emission from unresolved BL Lac objects

    SciTech Connect

    Di Mauro, M.; Donato, F.; Lamanna, G.; Sanchez, D. A.

    2014-05-10

    Blazars, active galactic nuclei with a jet pointing toward the Earth, represent the most abundant class of high-energy extragalactic γ-ray sources. The subset of blazars known as BL Lac objects is on average closer to Earth (i.e., younger) and characterized by harder spectra at high energy than the whole sample. The fraction of BL Lacs that is too dim to be detected and resolved by current γ-ray telescopes is therefore expected to contribute to the high-energy isotropic diffuse γ-ray background (IGRB). The IGRB has been recently measured over a wide energy range by the Large Area Telescope (LAT) on board the Gamma-ray Space Telescope (Fermi). We present a new prediction of the diffuse γ-ray flux due to the unresolved BL Lac blazar population. The model is built upon the spectral energy distribution and the luminosity function derived from the fraction of BL Lacs detected (and spectrally characterized) in the γ-ray energy range. We focus our attention on the O(100) GeV energy range, predicting the emission up to the TeV scale and taking into account the absorption on the extragalactic background light. In order to better shape the BL Lac spectral energy distribution, we combine the Fermi-LAT data with Imaging Atmospheric Cerenkov Telescope measurements of the most energetic sources. Our analysis is carried on separately for low- and intermediate-synchrotron-peaked BL Lacs on the one hand and high-synchrotron-peaked BL Lacs on the other hand: we find in fact statistically different features for the two. The diffuse emission from the sum of both BL Lac classes increases from about 10% of the measured IGRB at 100 MeV to ∼100% of the data level at 100 GeV. At energies greater than 100 GeV, our predictions naturally explain the IGRB data, accommodating their softening with increasing energy. Uncertainties are estimated to be within of a factor of two of the best-fit flux up to 500 GeV.

  5. In vivo expression of the lacY gene in two segments leads to functional lac permease

    SciTech Connect

    Bibi, E.; Kaback, H.R. )

    1990-06-01

    The lacY gene of Escherichia coli was cut into two approximately equal-size fragments with Afl II and subcloned individually or together under separate lac operator/promoters in plasmid pT7-5. Under these conditions, lac permease is expressed in two portions: (i) the N-terminal portion (the N terminus, the first six putative transmembrane helices, and most of putative loop 7) and (ii) the C-terminal portion (the last six putative transmembrane helices and the C terminus). Cells harboring pT7-5 encoding both fragments transport lactose at about 30% the rate of cells expressing intact permease to a comparable steady-state level of accumulation. In contrast, cells expressing either half of the permease independently do not transport lactose. As judged by ({sup 35}S)methionine labeling and immunoblotting, intact permease in completely absent from the membrane of cells expressing lacY fragments either individually or together. Thus, transport activity must result from an association between independently synthesized pieces of lac permease. When the gene fragments are expressed individually, the N-terminal portion of the permease is observed inconsistently, and the C-terminal portion is not observed. When the gene fragments are expressed together, polypeptides identified as the N- and C-terminal moieties of the permease are found in the membrane. It is concluded that the N- or C-terminal halves of lac permease are proteolyzed when synthesized independently and that association between the two complementing polypeptides leads to a more stable, catalytically active complex.

  6. 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

  7. 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.

  8. Structural Explanation for Allolactose (lac Operon Inducer) Synthesis by lacZ β-Galactosidase and the Evolutionary Relationship between Allolactose Synthesis and the lac Repressor

    PubMed Central

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

    2013-01-01

    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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. Fertility in couples heterozygous for the tyrosinemia gene in Saguenay Lac-St-Jean.

    PubMed

    De Braekeleer, M; Lamarre, V; Scriver, C R; Larochelle, J; Bouchard, G

    1990-01-01

    A case-control study of 84 couples from Saguenay-Lac-St-Jean, jointly heterozygous for the tyrosinemia gene, was done to determine whether the birth of an homozygous child affected their fertility rates. The mean number of children born to tyrosinemia and control couples between 1940 and 1986 was not different (p greater than 0.05). The knowledge that tyrosinemia was an autosomal recessive disorder, with risk of recurrence in these families, did not appear to modify reproductive behaviour. Fertility fell significantly in both the tyrosinemia and control families in the period of observation. This change reflects the decline in fertility of French Canadians in general during this period.

  17. 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

  18. 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.

  19. 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

  20. 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).

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Strongly coupled electronic, magnetic, and lattice degrees of freedom in LaC o5 under pressure

    NASA Astrophysics Data System (ADS)

    Stillwell, Ryan L.; Jeffries, Jason R.; McCall, Scott K.; Lee, Jonathan R. I.; Weir, Samuel T.; Vohra, Yogesh K.

    2015-11-01

    We have performed high-pressure magnetotransport and x-ray diffraction measurements on ferromagnetic LaC o5 , confirming the theoretically predicted electronic topological transition driving the magnetoelastic collapse seen in the related compound YC o5 . Our x-ray diffraction results show an anisotropic lattice collapse of the c axis near 10 GPa that is also commensurate with a change in the majority charge carriers evident from high-pressure Hall effect measurements. The coupling of the electronic, magnetic, and lattice degrees of freedom is further substantiated by the evolution of the anomalous Hall effect, which couples to the magnetization of the ordered state of LaC o5 .

  10. The mechanistic-holistic divide revisited: The case of the lac operon.

    PubMed

    Racine, Valérie

    2016-10-01

    In this paper, I revisit the development of the repression model of genetic regulation in the lac operon to challenge a common application of a conceptual framework in the history of biology. I take Allen's (1978) account of the changes in the life sciences during the early and mid-twentieth century as an example of a common application of a framework based on the dichotomy between a mechanistic, or reductionist, approach to science and a holistic one. From this conceptual framework, Allen infers two general claims about the process of science and its goals: (1) that "mechanistic materialism" has often presented a more practical way to begin the study of complex phenomena in the life sciences, and (2) that the approach described as "holistic materialism" provides a more complete or accurate description of the natural world. The development of the lac operon model does not fit Allen's generalizations about scientific developments, and it can be used to cast some doubt on the scope of application of that conceptual framework. I argue that a better framework to interpret particular episodes in the history of molecular biology is to consider the ways in which biologists prioritize and track different aspects of the phenomena under study, rather than to focus on whether certain scientific practices are best described as developing from mechanistic to more holistic approaches. I end with some implications for the historiography of science by considering the appropriateness of different conceptual frameworks for different grains of resolution in the history of biology.

  11. Intelligent Local Avoided Collision (iLAC) MAC Protocol for Very High Speed Wireless Network

    NASA Astrophysics Data System (ADS)

    Hieu, Dinh Chi; Masuda, Akeo; Rabarijaona, Verotiana Hanitriniala; Shimamoto, Shigeru

    Future wireless communication systems aim at very high data rates. As the medium access control (MAC) protocol plays the central role in determining the overall performance of the wireless system, designing a suitable MAC protocol is critical to fully exploit the benefit of high speed transmission that the physical layer (PHY) offers. In the latest 802.11n standard [2], the problem of long overhead has been addressed adequately but the issue of excessive colliding transmissions, especially in congested situation, remains untouched. The procedure of setting the backoff value is the heart of the 802.11 distributed coordination function (DCF) to avoid collision in which each station makes its own decision on how to avoid collision in the next transmission. However, collision avoidance is a problem that can not be solved by a single station. In this paper, we introduce a new MAC protocol called Intelligent Local Avoided Collision (iLAC) that redefines individual rationality in choosing the backoff counter value to avoid a colliding transmission. The distinguishing feature of iLAC is that it fundamentally changes this decision making process from collision avoidance to collaborative collision prevention. As a result, stations can avoid colliding transmissions with much greater precision. Analytical solution confirms the validity of this proposal and simulation results show that the proposed algorithm outperforms the conventional algorithms by a large margin.

  12. 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.

  13. 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

  14. 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.

  15. Studies on gene control regions X. The effect of specific adenine-thymine transversions on the lac repressor-lac operator interaction.

    PubMed Central

    Sista, H S; Loder, R T; Caruthers, M H

    1979-01-01

    Chemical and enzymatic methods were used to synthesize a transition (AT to GC) and a transversion (AT to TA) at a lac operator site known to interact with lac repressor through the thymine 5 methyl group. These operators also contained a poly(dA) . poly(dT) tail 8 to 12 base pairs in length at one end. Results suggest that the steric constraints of lac repressor relative to the position of the 5 methyl group are quite critical. For example a seven fold reduction in stability was observed for the transversion. Results also suggest that the operator spans at least 21 base pairs. Images PMID:379824

  16. The physical properties of Fermi TeV BL Lac objects jets

    NASA Astrophysics Data System (ADS)

    Ding, N.; Zhang, X.; Xiong, D. R.; Zhang, H. J.

    2016-09-01

    We investigate the physical properties of Fermi TeV BL Lac objects jets by modeling the quasi-simultaneous spectral energy distribution of 29 Fermi TeV BL Lacs in the frame of a one-zone leptonic synchrotron self-Compton model. Our main results are the following: (i) There is a negative correlation between B and δ in our sample, which suggests that B and δ are dependent on each other mainly in Thomson regime. (ii) There are negative correlations between νsy and r, the νIC and r, which is a signature of the energy-dependence statistical acceleration or the stochastic acceleration. There is a significant correlation between r and s, which suggests that the curvature of the electron energy distribution is attributed to the energy-dependence statistical acceleration mechanism. (iii) By assuming one proton per relativistic electron, we estimate the jet power and radiative power. A size relation Pe ˜ Pp > Pr ≳ PB is found in our sample. The Pe > PB suggests that the jets are particle dominated, and the Pe ˜ Pp means that the mean energy of relativistic electrons approaches mp/me. There are not significant correlations between Pjet and black hole mass in high or low state with a sub-sample of 18 sources, which suggests that the jet power weakly depends on the black hole mass. (iv) There is a correlation between the changes in the flux density at 1 TeV and the changes in the γpeak, which suggests the change/evolution of electron energy distribution may be mainly responsible for the flux variation.

  17. 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

  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. Expression and phylogenetic relationships of a novel lacZ homologue from Actinobacillus pleuropneumoniae.

    PubMed

    Anderson, T J; MacInnes, J I

    1997-07-01

    To learn more about the genetics and physiology of the important swine pathogen, Actinobacillus pleuropneumoniae, we cloned the lacZ gene by complementation of an Escherichia coli delta lac mutant. The A. pleuropneumoniae lacZ gene has an open reading frame of 3015 bp which could encode a protein with a predicted molecular mass of 117022. The deduced protein shares 26.8-34.8% identity with beta-galactosidases from both Gram-positive and Gram-negative bacteria. Sequences with homology to seven regions commonly found in beta-galactosidases are present and amino acids corresponding to active site residues Tyr-503 and Glu-537 in E. coli LacZ are also conserved; however, there is a leucine in the place of Gly-794, a residue which has been implicated in substrate recognition. The sequences flanking the A. pleuropneumoniae lacZ gene do not share homology with known transport or regulatory genes nor do they share homology with cAMP receptor protein (CRP) or LacI binding sites. Low levels of beta-galactosidase activity could be detected when the protein was expressed from a multicopy plasmid in E. coli delta lac and when it was measured in A. pleuropneumoniae. The level of activity was not markedly reduced in the presence of glucose. Although the A. pleuropneumoniae LacZ shares some features with other beta-galactosidases, its constitutive expression and an unusual active site residue suggest that it may have a unique function. PMID:9228778

  20. Structural and Enzymatic characterization of the lactonase SisLac from Sulfolobus islandicus

    PubMed Central

    Chabriere, Eric; Elias, Mikael

    2012-01-01

    Background A new member of the Phosphotriesterase-Like Lactonases (PLL) family from the hyperthermophilic archeon Sulfolobus islandicus (SisLac) has been characterized. SisLac is a native lactonase that exhibits a high promiscuous phosphotriesterase activity. SisLac thus represents a promising target for engineering studies, exhibiting both detoxification and bacterial quorum quenching abilities, including human pathogens such as Pseudomonas aeruginosa. Methodology/Principal Findings Here, we describe the substrate specificity of SisLac, providing extensive kinetic studies performed with various phosphotriesters, esters, N-acyl-homoserine lactones (AHLs) and other lactones as substrates. Moreover, we solved the X-ray structure of SisLac and structural comparisons with the closely related SsoPox structure highlighted differences in the surface salt bridge network and the dimerization interface. SisLac and SsoPox being close homologues (91% sequence identity), we undertook a mutational study to decipher these structural differences and their putative consequences on the stability and the catalytic properties of these proteins. Conclusions/Significance We show that SisLac is a very proficient lactonase against aroma lactones and AHLs as substrates. Hence, data herein emphasize the potential role of SisLac as quorum quenching agent in Sulfolobus. Moreover, despite the very high sequence homology with SsoPox, we highlight key epistatic substitutions that influence the enzyme stability and activity. PMID:23071703

  1. 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…

  2. A historically-controlled Phase III study in adults to characterize the acceptability of a process change for manufacturing inactivated quadrivalent influenza vaccine

    PubMed Central

    2014-01-01

    was immunogenic, conforming to regulatory acceptance criteria, with a reactogenicity and safety profile in line with the TIV manufactured using a licensed process. These results support acceptability of a manufacturing process change in which the thimerosal preservative is added at the point at which batches are filled into multidose vials. Trial registration These trials were registered at ClinicalTrials.gov: NCT01440387; NCT01153685. PMID:24606983

  3. 78 FR 45556 - Notice of Intent to Prepare an Environmental Impact Statement for the Proposed Lac du Flambeau...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-29

    ... Lac du Flambeau Band Fee-to-Trust Acquisition and Casino Project in Shullsburg, Wisconsin AGENCY... fee-to-trust transfer and casino project in the City of Shullsburg, Wisconsin, proposed by the Lac du... address and the caption specifying ``Scoping Comments for Proposed Lac du Flambeau Band Casino'' on...

  4. Reproductive attitudes of couples having a child with cystic fibrosis in Saguenay-Lac-Saint-Jean (Quebec, Canada).

    PubMed

    De Braekeleer, M; Bellis, G; Rault, G; Allard, C; Milot, M; Simard, F

    2000-01-01

    Cystic fibrosis (CF) has a high incidence (1/936 live births) and carrier rate (1/15 inhabitants) in Saguenay-Lac-Saint-Jean. One objective of a major enquiry among several subsets of individuals from this high-risk population for CF was to evaluate the reproductive behaviour of couples with a CF child attending the comprehensive CF clinic in Chicoutimi. The knowledge of the recurrence risk resulted in deciding against further progeny or in reducing the number of children. More reliable contraception methods after the birth of the CF child, but not prenatal diagnosis, were used. Although a minority of parents with a CF child would abort a CF foetus, they apparently started viewing pregnancy interruption for CF after prenatal diagnosis as an acceptable reproductive option.

  5. Upstream operators enhance repression of the lac promoter.

    PubMed

    Mossing, M C; Record, M T

    1986-08-22

    To study regulation of transcription by distant elements, a wild-type lac operator was inserted upstream of a promoter-constitutive operator control region. The upstream operator is shown to aid in repression of transcription from the mutant control region. The effectiveness of the upstream operator as a function of its distance from the mutant control region parallels the length dependence observed for DNA cyclization. A quantitative model is proposed for action-at-a-distance of DNA control sites in which protein-protein and protein-DNA interactions are mediated by DNA looping. In this model, the effective concentrations of interacting proteins that are tethered by DNA are determined by the length of the intervening DNA and by its inherent bending and torsional stiffness. This model makes a number of predictions for both eukaryotic and prokaryotic control sequences located far from their sites of action. PMID:3090685

  6. Test Observation of EN Lac with Iodine Cell at Okayama

    NASA Astrophysics Data System (ADS)

    Kambe, E.; Sato, B.; Izumiura, H.; Takeda, Y.

    2007-03-01

    It is crucial to detect as many nonradial pulsation (NRP) modes as possible for asteroseismology. The precise radial velocity measurement with an iodine cell, which gives us a fiducial wavelength reference to the precision of at least several m s^{-1} under various observing configurations, may be a handy way to detect small amplitude oscillations even in early-type stars. With the completion of the iodine cell at Okayama, we collected about 200 spectra of the β Cep star, EN Lac, over two months in 2001, and determined its radial velocities from about 30 absorption lines between 5000 and 6000 Å. From their period analysis, we clearly detected the three well-known periods in the star. In this paper, we report our preliminary result along with discussion of the applicability of the iodine cell technique to such stars. Full description of our results will be presented in a separate paper.

  7. X-ray observations of BL Lac objects

    NASA Technical Reports Server (NTRS)

    Mushotzky, R. F.; Boldt, E. A.; Holt, S. A.; Pravdo, S. H.; Serlemitsos, P. J.; Swank, J. H.; Rothschild, R. H.

    1978-01-01

    The BL Lac objects MK501 and MK421 were observed with OSO-8 and HEAO-1 X-ray detectors in the 2-60 keV band. Their spectra are similar with best fitting power laws having energy index -.4 alpha 4. A soft X-ray excess is indicated in their spectra. There was no detectable X-ray absorption with implied column densities N sub H 1.5 x 10 to the 22d power at sq cm. MK421 was a factor 6 weaker in November 1977 than in May 1977. An identification of PKS0548-322 with a new source H0548,-32 is suggested.

  8. 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.

  9. 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

  10. 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

  11. Regulation of lac Operon Expression: Reappraisal of the Theory of Catabolite Repression

    PubMed Central

    Wanner, Barry L.; Kodaira, Ryoji; Neidhardt, Frederick C.

    1978-01-01

    The physiological state of Escherichia coli with respect to (permanent) catabolite repression was assessed by measuring the steady-state level of β-galactosidase in induced or in constitutive cells under a variety of growth conditions. Four results were obtained. (i) Catabolite repression had a major effect on fully induced or constitutive expression of the lac gene, and the magnitude of this effect was found to be dependent on the promoter structure; cells with a wild-type lac promoter showed an 18-fold variation in lac expression, and cells with the lacP37 (formerly lac-L37) promoter exhibited several hundred-fold variation. (ii) Exogenous adenosine cyclic 3′,5′-monophosphoric acid (cAMP) could not abolish catabolite repression, even though several controls demonstrated that cAMP was entering the cells in significant amounts. (Rapid intracellular degradation of cAMP could not be ruled out.) (iii) Neither the growth rate nor the presence of biosynthetic products altered the degree of catabolite repression; all variation could be related to the catabolites present in the growth medium. (iv) Slowing by imposing an amino acid restriction decreased the differential rate of β-galactosidase synthesis from the wild-type lac promoter when bacteria were cultured in either the absence or presence of cAMP; this decreased lac expression also occurred when the bacteria harbored the catabolite-insensitive lacP5 (formerly lacUV5) promoter mutation. These findings support the idea that (permanent) catabolite repression is set by the catabolites in the growth medium and may not be related to an imbalance between catabolism and anabolism. PMID:214424

  12. The nature of X-ray emission in BL Lac objects

    NASA Astrophysics Data System (ADS)

    Massaro, Francesco

    2011-10-01

    The 77% of TeV extragalactic sources are BL Lacs. They belong to the High frequency peaked BL Lacs (HBLs) subclass characterized by a low-energy component with power peaking between the UV and the X-rays. We propose xmm~observations of a selected sample of HBLs, to study the spectral behavior of their optical to X-ray component. In addition, on the basis of our previous X-ray analyses of TeV e non TeV HBLs, these proposed xmm~observations will allow us to identify BL Lac candidates for future TeV observations.

  13. Ion concentration and temperature dependence of DNA binding: comparison of PurR and LacI repressor proteins.

    PubMed

    Moraitis, M I; Xu, H; Matthews, K S

    2001-07-10

    Purine repressor (PurR) binding to specific DNA is enhanced by complexing with purines, whereas lactose repressor (LacI) binding is diminished by interaction with inducer sugars despite 30% identity in their protein sequences and highly homologous tertiary structures. Nonetheless, in switching from low- to high-affinity DNA binding, these proteins undergo a similar structural change in which the hinge region connecting the DNA and effector binding domains folds into an alpha-helix and contacts the DNA minor groove. The differences in response to effector for these proteins should be manifest in the polyelectrolyte effect which arises from cations displaced from DNA by interaction with positively charged side chains on a protein and is quantitated by measurement of DNA binding affinity as a function of ion concentration. Consistent with structural data for these proteins, high-affinity operator DNA binding by the PurR-purine complex involved approximately 15 ion pairs, a value significantly greater than that for the corresponding state of LacI (approximately 6 ion pairs). For both proteins, however, conversion to the low-affinity state results in a decrease of approximately 2-fold in the number of cations released per dimeric DNA binding site. Heat capacity changes (DeltaC(p)) that accompany DNA binding, derived from buried apolar surface area, coupled folding, and restriction of motional freedom of polar groups in the interface, also reflect the differences between these homologous repressor proteins. DNA binding of the PurR-guanine complex is accompanied by a DeltaC(p) (-2.8 kcal mol(-1) K(-1)) more negative than that observed previously for LacI (-0.9 to -1.5 kcal mol(-1) K(-1)), suggesting that more extensive protein folding and/or enhanced structural rigidity may occur upon DNA binding for PurR compared to DNA binding for LacI. The differences between these proteins illustrate plasticity of function despite high-level sequence and structural homology and

  14. 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

  15. 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…

  16. Phase-dependent dynamics of the lac promoter under nutrient stress.

    PubMed

    Viswanathan, Anisha; Anufrieva, Olga; Sala, Adrien; Yli-Harja, Olli; Kandhavelu, Meenakshisundaram

    2016-01-01

    To survive, a bacterial population must sense nutrient availability and adjust its growth phase accordingly. Few studies have quantitatively analyzed the single-cell behavior of stress and growth phase-related transcriptional changes in Escherichia coli. To investigate the dynamic changes in transcription during different growth phases and starvation, we analyzed the single-cell transcriptional dynamics of the E. coli lac promoter. Cells were grown under different starvation conditions, including glucose, magnesium, phosphate and thiamine limitations, and transcription dynamics was quantified using a single RNA detection method at different phases. Differences in gene expression over conditions and phases indicate that stochasticity in transcription dynamics is directly connected to cell phase and availability of nutrients. Except for glucose, the pattern of transcription dynamics under all starvation conditions appears to be similar. Transcriptional bursts were more prominent in lag and stationary phase cells starved for energy sources. Identical behavior was observed in exponential phase cells starved for phosphate and thiamine. Noise measurements under all nutrient exhaustion conditions indicate that intrinsic noise is higher than extrinsic noise. Our results, obtained in a relA1 mutational background, which led to suboptimal production of ppGpp, suggest that the single-cell transcriptional changes we observed were largely ppGpp-independent. Taken together, we propose that, under different starvation conditions, cells are able to decrease the trend in cell-to-cell variability in transcription as a common means of adaptation.

  17. Molecular cloning of Mu d(bla lacZ) transcriptional and translational fusions.

    PubMed Central

    Wanner, B L

    1987-01-01

    The vector pBW2 was made to selectively clone chimeric plasmids with chromosomal Mu d(bla lacZ) transcriptional or translational fusions. It was tetracycline resistant and had the carboxyl-terminal end of bla distal to its PstI site. Because ligation of PstI-digested chromosomal DNA of a Mu d(bla lacZ) insertion with pBW2 restored bla, ampicillin-resistant chimeric plasmids were selectable. These plasmids had the Mu d bla amino terminus and simultaneously acquired other Mu d sequences including lacZ, the chromosomal fusion joint, and the DNA adjacent to the nearest chromosomal PstI site. The plasmid pBW2 was useful in the molecular cloning of several psi and pho::lacZ(Mu d) fusions, as well as chromosomal genes located near Mu d insertions. PMID:3032905

  18. 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.

  19. 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.

  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. [Diversity of grasshopper community in lac plantation-farmland ecosystem].

    PubMed

    Li, Qiao; Chen, You-qing; Chen, Yan-lin; Chen, Zhen

    2009-03-01

    The grasshopper communities in the paddy field, dry land, natural forest, and plantation forest of lac plantation-farmland ecosystem in Lvchun County, Yunnan were investigated by sweep netting. A total of 1426 grasshoppers belonging to 33 species, 22 genena, and 5 families were captured. In the paddy field, dry land, natural forest, and plantation forest of the ecosystem, the species richness S were 16.333, 13.000, 11.000, and 12.000, Margalef index was 2.873, 2.266, 2.335, and 2. 137, Shannon-Wiener index was 2.034, 1.976, 1.982, and 1.488, Simpson index was 0.196, 0.189, 0.174, and 0.323, and Pielou index was 0.728, 0.787, 0.829, 0.599, respectively. This ecosystem had a lower diversity of grasshopper communities, and different land use habitats in the ecosystem had different species component and diversity. In paddy field, grasshopper had a higher diversity than in dry land, but its evenness and stability were moderate; in natural forest, the diversity was high and the stability was strong; while in plantation forest, the diversity was low and the stability was weak. There existed species exchange in different land use habitats in the ecosystem.

  2. 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).

  3. 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

  4. 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

  5. Evolutionary behaviour of AGN: Investigations on BL Lac objects and Seyfert II galaxies

    NASA Astrophysics Data System (ADS)

    Beckmann, V.

    2000-12-01

    The evolution and nature of AGN is still one of the enigmatic questions in astrophysics. While large and complete Quasar samples are available, special classes of AGN, like BL Lac objects and Seyfert II galaxies, are still rare objects. In this work I present two new AGN samples. The first one is the HRX-BL Lac survey, resulting in a sample of X-ray selected BL Lac objects. This sample results from 223 BL Lac candidates based on a correlation of X-ray sources with radio sources. The identification of this sample is 98% complete. 77 objects have been identified as BL Lac objects and form the HRX-BL Lac complete sample, the largest homogeneous sample of BL Lac objects existing today. For this sample, redshifts are now known for 62 objects (81 %). In total I present 101 BL Lac objects in the enlarged HRX-BL Lac survey, for which redshift information is available for 84 objects. During the HRX-BL Lac survey I found several objects of special interest. 1ES 1517+656 turned out to be the brightest known BL Lac object in the universe. 1ES 0927+500 could be the first BL Lac object with a line detected in the X-ray region. RX J1211+2242 is probably the the counterpart of the up to now unidentified gamma-ray source 3EG J1212+2304. Additionally I present seven candidates for ultra high frequency peaked BL Lac objects. RX J1054+3855 and RX J1153+3517 are rare high redshift X-ray bright QSO or accreting binary systems with huge magnetic fields. For the BL Lac objects I suggest an unified scenario in which giant elliptical galaxies, formed by merging events of spiral galaxies at z > 2, start as powerful, radio dominated BL Lacs. As the jet gets less powerful, the BL Lacs start to get more X-ray dominated, showing less total luminosities (for z < 1). This effect is seen in the different evolutionary behavior detected in high and low frequency cut off BL Lac objects (HBL and LBL, respectively). The model of negative evolution is supported by assumptions about the energetic effects

  6. Offer/Acceptance Ratio.

    ERIC Educational Resources Information Center

    Collins, Mimi

    1997-01-01

    Explores how human resource professionals, with above average offer/acceptance ratios, streamline their recruitment efforts. Profiles company strategies with internships, internal promotion, cooperative education programs, and how to get candidates to accept offers. Also discusses how to use the offer/acceptance ratio as a measure of program…

  7. Segment-specific mutagenesis: extensive mutagenesis of a lac promoter/operator element.

    PubMed

    Weiher, H; Schaller, H

    1982-03-01

    A method for highly efficient segment-specific mutagenesis is described. The method uses as target for sodium bisulfite mutagenesis the DNA single strands of a DNA restriction fragment that had been separated by cloning into base-complementary regions of a pair of phage fd vectors. After repair synthesis in vitro, the mutagenized DNA fragment is recovered by cloning into a nonmutated plasmid vector and analyzed for sequence and by functional tests. By using this method, the nucleotide sequence of a 109-base pair restriction fragment containing the lac promoter/operator from Escherichia coli was extensively modified. More than 90% of the 235 isolates obtained showed a change in phenotype; all of 22 analyzed for their nucleotide sequence were found to carry multiple C leads to T point mutations in up to 60% of the possible target positions. Nevertheless, few isolates showed major changes in promoter activity relative to the nonmutated promoter element, which indicates a high degree of flexibility in the promoter sequence. PMID:7041119

  8. 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

  9. Beware of your Cre-Ation: lacZ expression impairs neuronal integrity and hippocampus-dependent memory.

    PubMed

    Reichel, J M; Bedenk, B T; Gassen, N C; Hafner, K; Bura, S A; Almeida-Correa, S; Genewsky, A; Dedic, N; Giesert, F; Agarwal, A; Nave, K-A; Rein, T; Czisch, M; Deussing, J M; Wotjak, C T

    2016-10-01

    Expression of the lacZ-sequence is a widely used reporter-tool to assess the transgenic and/or transfection efficacy of a target gene in mice. Once activated, lacZ is permanently expressed. However, protein accumulation is one of the hallmarks of neurodegenerative diseases. Furthermore, the protein product of the bacterial lacZ gene is ß-galactosidase, an analog to the mammalian senescence-associated ß-galactosidase, a molecular marker for aging. Therefore we studied the behavioral, structural and molecular consequences of lacZ expression in distinct neuronal sub-populations. lacZ expression in cortical glutamatergic neurons resulted in severe impairments in hippocampus-dependent memory accompanied by marked structural alterations throughout the CNS. In contrast, GFP expression or the expression of the ChR2/YFP fusion product in the same cell populations did not result in either cognitive or structural deficits. GABAergic lacZ expression caused significantly decreased hyper-arousal and mild cognitive deficits. Attenuated structural and behavioral consequences of lacZ expression could also be induced in adulthood, and lacZ transfection in neuronal cell cultures significantly decreased their viability. Our findings provide a strong caveat against the use of lacZ reporter mice for phenotyping studies and point to a particular sensitivity of the hippocampus formation to detrimental consequences of lacZ expression. © 2016 Wiley Periodicals, Inc.

  10. 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.

  11. 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…

  12. 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

  13. 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

  14. Ion effects on the lac repressor--operator equilibrium.

    PubMed

    Barkley, M D; Lewis, P A; Sullivan, G E

    1981-06-23

    The effects of ions on the interaction of lac repressor protein and operator DNA have been studied by the membrane filter technique. The equilibrium association constant was determined as a function of monovalent and divalent cation concentrations, anions, and pH. The binding of repressor and operator is extremely sensitive to the ionic environment. The dependence of the observed equilibrium constant on salt concentration is analyzed according to the binding theory of Record et al. [Record, M. T., Jr., Lohman, T. M., & deHaseth, P. L. (1976) J. Mol. Biol. 107, 145]. The number of ionic interactions in repressor--operator complex is deduced from the slopes of the linear log-log plots. About 11 ionic interactions are formed between repressor and DNA phosphates at pH 7.4 and about 9 ionic interactions at pH 8.0, in reasonable agreement with previous estimates. A favorable nonelectrostatic binding free energy of about 9-12 kcal/mol is estimated from the extrapolated equilibrium constants at the 1 M standard state. The values are in good accord with recent results for the salt-independent binding of repressor core and operator DNA. The effects of pH on the repressor--operator interaction are small, and probably result from titration of functional groups in the DNA-binding site of the protein. For monovalent salts, the equilibrium constant is slightly dependent on cation type and highly dependent on anion type. At constant salt concentration, the equilibrium constant decreases about 10000-fold in the order CH3CO2- greater than or equal to F- greater than Cl- greater than Br- greater than NO3- greater than SCN- greater than I-. The wide range of accessible equilibrium constants provides a useful tool for in vitro studies of the repressor--operator interaction.

  15. 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

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

    PubMed Central

    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

  17. 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

  18. 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.

  19. Variable X-ray spectra of BL Lac objects: HEAO-1 observations of PKS 0548-322 and 2A 1219+305

    NASA Technical Reports Server (NTRS)

    Worrall, D. M.; Boldt, E. A.; Holt, S. S.; Mushotzky, R. F.; Serlemitsos, P. J.

    1980-01-01

    X-ray spectra for the BL Lac objects PKS 0548-322 and 2A 1219+305 measured with the HEAO-1 A2 detectors during pointing maneuvers on September 30, 1978 and May 31, 1978 respectively are presented. Both fit single power law components with low energy absorption. For 2A 1219+305, a thermal bremsstrahlung form gives an unacceptable fit. From a comparison with other statistically poorer observations taken at 6 month intervals while the satellite was in its normal scanning mode, it is found that the sources exhibit spectral variability. A summary of measurements of the 5 BL Lac objects detected with the A2 experiment is presented and it is concluded that X-ray spectral changes in this class of source are common. Their general X-ray spectral characteristics distinguish BL Lac objects from other classes of X-ray emitting active galactic nuclei. Analysis of their total spectra indicates that most of the energy is emitted in the 5 to 100 eV band.

  20. 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.

  1. Distinction of Indian commercial lac insect lines of Kerria spp. (Homoptera: Coccoidea) based on their morphometrics.

    PubMed

    Ahmad, Ayashaa; Ramani, Ranganathan; Sharma, Kewal K; Vidyarthi, Ambrish S; Ramamurthy, Vilayanoor V

    2014-01-01

    The lac insects belong to the genus Kerria (Hemiptera: Coccoidea: Kerriidae) and are commercially exploited worldwide for the production of lac, which comes from their waxy test and has diverse industrial applications. The insects are maintained by the Indian Institute of Natural Resins and Gums as distinctive lines that are cultivated and commercialized in the lac producing areas of India. The lines are all considered to belong to the genus Kerria but without validation of their taxonomic characters, and their identity to species has not been ascertained. This study used single-factor analysis of variance and several multivariate analyses, such as principal component analysis, discriminant function analysis, and canonical discriminant analysis to explore the morphometrics of some of the adult female lac insect lines. The results have enabled the identification of some taxonomically significant characters in adult females, which has grouped the 32 lac insect lines studied into 15 species along with validation of the most significant characters. Distinctive grouping patterns for the species of Kerria have been brought out using morphometrics.

  2. 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.

  3. Activation of the lac genes of Tn951 by insertion sequences from Pseudomonas cepacia.

    PubMed

    Wood, M S; Lory, C; Lessie, T G

    1990-04-01

    We have identified three transposable gene-activating elements from Pseudomonas cepacia on the basis of their abilities to increase expression of the lac genes of the broad-host-range plasmid pGC91.14 (pRP1::Tn951). When introduced into auxotrophic derivatives of P. cepacia 249 (ATCC 17616), this plasmid failed to confer the ability to utilize lactose. The lac genes of Tn951 were poorly expressed in P. cepacia and were not induced by isopropyl-beta-D-thiogalactopyranoside. Lac+ variants of the pGC91.14-containing strains which formed beta-galactosidase at high constitutive levels as a consequence of transposition of insertion sequences from the P. cepacia genome to sites upstream of the lacZ gene of Tn951 were isolated. Certain of the elements also increased gene expression in other bacteria. For example, IS407 strongly activated the lacZ gene of Tn951 in Pseudomonas aeruginosa and Escherichia coli, and IS406 (but not IS407) did so in Zymomonas mobilis. The results indicate that IS elements from P. cepacia have potential for turning on the expression of foreign genes in a variety of gram-negative bacteria. PMID:2156800

  4. 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.

  5. 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

  6. Acceptability of BCG vaccination.

    PubMed

    Mande, R

    1977-01-01

    The acceptability of BCG vaccination varies a great deal according to the country and to the period when the vaccine is given. The incidence of complications has not always a direct influence on this acceptability, which depends, for a very large part, on the risk of tuberculosis in a given country at a given time.

  7. ATLAS ACCEPTANCE TEST

    SciTech Connect

    Cochrane, J. C. , Jr.; Parker, J. V.; Hinckley, W. B.; Hosack, K. W.; Mills, D.; Parsons, W. M.; Scudder, D. W.; Stokes, J. L.; Tabaka, L. J.; Thompson, M. C.; Wysocki, Frederick Joseph; Campbell, T. N.; Lancaster, D. L.; Tom, C. Y.

    2001-01-01

    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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Different effects of two newly-isolated probiotic Lactobacillus plantarum 15HN and Lactococcus lactis subsp. Lactis 44Lac strains from traditional dairy products on cancer cell lines.

    PubMed

    Haghshenas, Babak; Abdullah, Norhafizah; Nami, Yousef; Radiah, Dayang; Rosli, Rozita; Khosroushahi, Ahmad Yari

    2014-12-01

    Lactobacillus and Lactococcus strains isolated from food products can be introduced as probiotics because of their health-promoting characteristics and non-pathogenic nature. This study aims to perform the isolation, molecular identification, and probiotic characterization of Lactobacillus and Lactococcus strains from traditional Iranian dairy products. Primary probiotic assessments indicated high tolerance to low pH and high bile salt conditions, high anti-pathogenic activities, and susceptibility to high consumption antibiotics, thus proving that both strains possess probiotic potential. Cytotoxicity assessments were used to analyze the effects of the secreted metabolite on different cancer cell lines, including HT29, AGS, MCF-7, and HeLa, as well as a normal human cell line (HUVEC). Results showed acceptable cytotoxic properties for secreted metabolites (40 μg/ml dry weight) of Lactococcus lactis subsp. Lactis 44Lac. Such performance was similar to that of Taxol against all of the treated cancer cell lines; however, the strain exhibited no toxicity on the normal cell line. Cytotoxic assessments through flow cytometry and fluorescent microscopy demonstrated that apoptosis is the main cytotoxic mechanism for secreted metabolites of L. lactis subsp. Lactis 44Lac. By contrast, the effects of protease-treated metabolites on the AGS cell line verified the protein nature of anti-cancer metabolites. However, precise characterizations and in vitro/in vivo investigations on purified proteins should be conducted before these metabolites are introduced as potential anti-cancer therapeutics. PMID:25168457

  13. Ultraviolet and X-ray observations of the BL Lac object PKS 05 8-322

    NASA Technical Reports Server (NTRS)

    Urry, C. M.; Mushotzky, R. F.; Hackney, K. R. H.; Hackney, R. L.

    1982-01-01

    Spectrophotometric observations of the BL Lac object PKS 0548-322 were made with ultraviolet and X-ray instruments on the IUE and HEAO-2 satellites. Two observations in each spectral region, one set of which was obtained simultaneously are presented. A power law of energy index approximately 1.0 gives a good description of the data from ultraviolet through X-ray frequencies. This source is reported to be variable on short timescales (Gilmore 1980); the implications of the spectral properties and apparent variability are discussed in light of a relativistic jet model. Findings support the jet picture of BL Lac objects.

  14. SSC Model Fits to Simultaneous Fermi and CAO observations of Bl Lac's

    NASA Astrophysics Data System (ADS)

    Gordon, Tyler; Macomb, Daryl J.; Hand, Jared; Norris, Jay P.; Long, Min

    2016-01-01

    The Challis Astronomical Observatory (CAO) has been surveying a sample of blazar-type AGN since 2010. The CAO blazar sample includes4 3 sources - comprising 30 FSRQs, 15 BL Lacs, one radio galaxy and four unclassified sources - covering a redshift range 0.02 < z < 2. Observations are carried out in BVRI filters. Here we describe photometric results on a small sample emphasizing BL Lacs. We combine the CAO data with Fermi/LAT data and explore the suitability of fits to the data using the uniform conical jet model of Potter and Cotter (MNRAS, 2012, 423, 756-765).

  15. 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).

  16. 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.

  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.

  18. Chinese Nurses' Acceptance of PDA: A Cross-Sectional Survey Using a Technology Acceptance Model.

    PubMed

    Wang, Yanling; Xiao, Qian; Sun, Liu; Wu, Ying

    2016-01-01

    This study explores Chinese nurses' acceptance of PDA, using a questionnaire based on the framework of Technology Acceptance Model (TAM). 357 nurses were involved in the study. The results reveal the scores of the nurses' acceptance of PDA were means 3.18~3.36 in four dimensions. The younger of nurses, the higher nurses' title, the longer previous usage time, the more experienced using PDA, and the more acceptance of PDA. Therefore, the hospital administrators may change strategies to enhance nurses' acceptance of PDA, and promote the wide application of PDA.

  19. 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…

  20. 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

  1. Acceptance procedures: Microfilm printer

    NASA Technical Reports Server (NTRS)

    Lockwood, H. E.

    1973-01-01

    Acceptance tests were made for a special order automatic additive color microfilm printer. Tests include film capacity, film transport, resolution, illumination uniformity, exposure range checks, and color cuing considerations.

  2. 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.

  3. Polarimetría óptica multibanda del objeto BL Lac PKS 2155-304

    NASA Astrophysics Data System (ADS)

    Tommasi, L.; Díaz, R. J.; Pian, E.; Mast, D.; Palazzi, E.; Poretti, E.; Scaltriti, F.; Treves, A.

    The polarized and total flux of the BL Lac object PKS 2155-304 were monitored intensively and simultaneously in the optical UBVRI bands during 4 campaigns in June, August, November 1998 and August 1999. The observations were carried out with the Turin Photopolarimeter at the Casleo 2.15 m telescope and the Multifunctional Spectrograph at the Bosque Alegre 1.54 m telescope. The effective observation time amounted ~50 hours. PKS 2155-304 showed linear polarization percentage usually ranging between 3% and 7% and a polarization position angle mainly between 70o and 120o. The highest temporal resolution of our observations, 15 minutes, is unprecedent for simultaneous monitoring of this kind of source, and has allowed us to detect amplitude variations of the linear polarization percentage from 6 to 7.5% in time scales of hours. In some nights the polarization percentage increases toward shorter wavelengths, however the polarized spectrum does not vary significant with time. The most remarkable variability event occurred on 1998 June 18, when the degree of linear polarization decreased by more than a factor 2 in one day in all bands, while the PA rotated by 90o. This is consistent with the presence of two emission components, of different polarization degree and position angle. Intranight variability of P and PA can be interpreted as small amplitude physical or geometrical changes within the relativistic jet. Measurements of the circular polarization over time intervals of days set upper limits of 0.2%. The total flux did not show variations correlated with those of the linearly polarized flux.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. Dct::lacZ ES cells: a novel cellular model to study melanocyte determination and differentiation.

    PubMed

    Pla, Patrick; Solov'eva, Olga; Moore, Robert; Alberti, Christophe; Kunisada, Takahiro; Larue, Lionel

    2004-04-01

    Embryonic stem (ES) cells differentiate into various cell lineages in vitro. A procedure was previously designed to promote the differentiation of ES cells towards the melanocyte lineage and to obtain large and reproducible amounts of melanocytes. To elucidate the main events that lead to the development of melanocytes in vitro, we used transgenic Dct::lacZ mouse blastocysts to establish ES cell lines expressing the lacZ reporter gene under the control of the Dct promoter. Dct, a melanoblast marker, is expressed just after melanoblast determination in vivo. We evaluated the importance of recruitment, proliferation and differentiation during melanocyte ontogeny after the in vitro differentiation of Dct::lacZ ES cells into melanocytes. We showed that bFGF and cholera toxin induce precocious melanoblast determination, associated with early melanocyte differentiation. Edn3 induced melanoblast proliferation and long-term melanoblast recruitment, but not precocious determination. The lack of basic Fibroblast Growth Factor (bFGF) and cholera toxin can be partially compensated by Edn3. Thus, Dct::lacZ ES cells can be used as a model to study determination, proliferation and differentiation in the melanocyte lineage in vitro.

  10. 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.

  11. Influence of salt content and processing time on sensory characteristics of cooked "lacón".

    PubMed

    Purriños, Laura; Bermúdez, Roberto; Temperán, Sara; Franco, Daniel; Carballo, Javier; Lorenzo, José M

    2011-04-01

    The influence of salt content and processing time on the sensory properties of cooked "lacón" were determined. "Lacón" is a traditional dry-cured and ripened meat product made in the north-west of Spain from the fore leg of the pig, following a similar process to that of dry-cured ham. Six batches of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)) and ripened during two times (56 and 84 days of dry-ripening). Cured odour in all batches studied, red colour and rancid odour in MS and HS batches, flavour intensity in MS batch and fat yellowness, rancid flavour and hardness in the HS batch were significantly different with respect to the time of processing. Appearance, odour, flavour and texture were not significantly affected by the salt content (P>0.05). However, the saltiness score showed significant differences with respect to the salt levels in all studied batches (56 and 84 days of process). The principal component analysis showed that physicochemical traits were the most important ones concerning the quality of dry-cured "lacón" and offered a good separation of the mean samples according to the dry ripening days and salt level. PMID:21168978

  12. 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

    ... Statement: Fond du Lac & Sheboygan Counties, WI AGENCY: Federal Highway Administration (FHWA), DOT. ACTION... Road, Suite 8000, Madison, WI 53717-2157; Telephone: (608) 662-2119. You may also contact Rebecca...., Madison, WI 53704-2549; Telephone (608) 246-5399. SUPPLEMENTARY INFORMATION: The FHWA, in cooperation...

  13. A simple system for converting lacZ to gfp reporter fusions in diverse bacteria.

    PubMed

    Goulian, Mark; van der Woude, Marjan

    2006-05-10

    We describe new plasmids that facilitate the rapid conversion of lacZ fusions to gfp transcriptional fusions in bacteria. The exchange is based on a double recombination between lacZ sequences in a suicide vector and the recipient chromosome. The suicide vector is a mobilizable, conditionally replicative plasmid that contains the gene for gfp with flanking lacZ homology and is derived from a broad host range plasmid that has been successfully used in a wide range of bacterial species. The technique was used to convert lacZ reporter fusions to gfp fusions in Escherichia coli, Bordetella bronchiseptica and Agrobacterium tumefaciens. Green fluorescent protein expression in the new recombinants reflected the beta galactosidase expression in the parent strains. GFP is particularly useful for rapid quantification of gene expression in real time and in single cells. As a demonstration of an application of this system, we studied the induction of virE transcription by the VirA/VirG two-component system in A. tumefaciens in response to various levels of phenolic inducer. Analysis of GFP fluorescence in single cells revealed that at intermediate levels of inducer the population of cells was remarkably heterogeneous. The tools described here will be useful for general studies of transcriptional regulation as well as for applications that require spatial and temporal identification of gene expression, such as in the study of biofilms, and interactions between bacteria and their environment. PMID:16500039

  14. Single molecule study of non-specific binding kinetics of LacI in mammalian cells.

    PubMed

    Caccianini, Laura; Normanno, Davide; Izeddin, Ignacio; Dahan, Maxime

    2015-01-01

    Many key cellular processes are controlled by the association of DNA-binding proteins (DBPs) to specific sites. The kinetics of the search process leading to the binding of DBPs to their target locus are largely determined by transient interactions with non-cognate DNA. Using single-molecule microscopy, we studied the dynamics and non-specific binding to DNA of the Lac repressor (LacI) in the environment of mammalian nuclei. We measured the distribution of the LacI-DNA binding times at non-cognate sites and determined the mean residence time to be τ(1D) = 182 ms. This non-specific interaction time, measured in the context of an exogenous system such as that of human U2OS cells, is remarkably different compared to that reported for the LacI in its native environment in E. coli (<5 ms). Such a striking difference (more than 30 fold) suggests that the genome, its organization, and the nuclear environment of mammalian cells play important roles on the dynamics of DBPs and their non-specific DNA interactions. Furthermore, we found that the distribution of off-target binding times follows a power law, similar to what was reported for TetR in U2OS cells. We argue that a possible molecular origin of such a power law distribution of residence times is the large variability of non-cognate sequences found in the mammalian nucleus by the diffusing DBPs. PMID:26387491

  15. Establishment of a LacZ marker rescue assay to detect infectious RD114 virus.

    PubMed

    Sakaguchi, Shoichi; Okada, Masaya; Shojima, Takayuki; Baba, Kenji; Miyazawa, Takayuki

    2008-08-01

    Cats have an infectious endogenous retrovirus, named RD114 virus, and there is a possibility that RD114 virus has contaminated live attenuated vaccines, for which feline cells are used as a substrate. To monitor infectious RD114 virus in vaccines for cats, we developed a LacZ marker rescue assay to detect infectious RD114 virus. Among four human cell lines examined, TE671 cells (human rhabdomyosarcoma) were most susceptible to RD114 virus and supported RD114 replication efficiently. Infection was enhanced approximately 5 times by the addition of polybrene at concentrations of 2 to 8 microg/ml in the medium during viral adsorption. A 4-hr viral adsorption period was sufficient to obtain the maximum titer. By inoculating samples into TE671 cells transduced with the lacZ marker gene, the limiting diluted sample (i.e., less than 10 infectious units) was detected at 12 days post-inoculation by the LacZ marker rescue assay. Based on the results obtained in this study, we propose a standard protocol of the LacZ marker rescue assay to detect infectious RD114 virus.

  16. 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

  17. 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.

  18. Measurement of Ligand-Induced Activation in Single Viable T Cells Using the lacZ Reporter Gene

    NASA Astrophysics Data System (ADS)

    Karttunen, Jaana; Shastri, Nilabh

    1991-05-01

    We have used the bacterial β-galactosidase gene (lacZ) as a reporter gene for the rapid measurement of T-cell antigen receptor (TCR)-mediated activation of individual T cells. The reporter construct contained the lacZ gene under the control of the nuclear factor of activated T cells (NF-AT) element of the human interleukin 2 enhancer [Fiering, S., Northrop, J. P., Nolan, G. P., Matilla, P., Crabtree, G. R. & Herzenberg, L. A. (1990) Genes Dev. 4, 1823-1834]. The activity of the intracellular lacZ enzyme was analyzed by flow cytometric measurement of fluorescein accumulation in cells loaded with the fluorogenic β-galactosidase substrate fluorescein di-β-D-galactopyranoside. As a model system, the T-cell hybridoma BO4H9.1, which is specific for the lysozyme peptide (amino acids 74-88)/A^b complex, was transfected with the NF-AT-lacZ construct. lacZ activity was induced in 50-100% of the transfectant cells following exposure to pharmacological agents, to the physiological peptide/major histocompatibility complex ligand, or to other TCR-specific stimuli. Interestingly, increasing concentrations of the stimulus increased the fraction of lacZ^+ cells, but not the level of lacZ activity per cell. Even under widely varying levels of stimulus, the level of lacZ activity in individual lacZ^+ cells remained within a remarkably narrow range. These results demonstrate that TCR-mediated activation can be readily measured in single T cells and strongly suggest that, once committed to activation, the level of NF-AT transcriptional activity in individual T cells is independent of the form or concentration of stimulus. This assay is likely to prove useful for the study of early activation events in individual T cells and of TCR ligands.

  19. Smaller hospitals accept advertising.

    PubMed

    Mackesy, R

    1988-07-01

    Administrators at small- and medium-sized hospitals gradually have accepted the role of marketing in their organizations, albeit at a much slower rate than larger institutions. This update of a 1983 survey tracks the increasing competitiveness, complexity and specialization of providing health care and of advertising a small hospital's services. PMID:10288550

  20. Students Accepted on Probation.

    ERIC Educational Resources Information Center

    Lorberbaum, Caroline S.

    This report is a justification of the Dalton Junior College admissions policy designed to help students who had had academic and/or social difficulties at other schools. These students were accepted on probation, their problems carefully analyzed, and much effort devoted to those with low academic potential. They received extensive academic and…

  1. 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.

  2. 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.

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

    PubMed

    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

  4. Analysis of natural coloring matters in food. III. Application of methylation with diazomethane for the detection of lac color.

    PubMed

    Yamada, S; Noda, N; Mikami, E; Hayakawa, J; Yamada, M

    1989-01-01

    A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thin-layer chromatography and reverse-phase liquid chromatography.

  5. Nutrient, trace-element, and ecological history of Musky Bay, Lac Courte Oreilles, Wisconsin, as inferred from sediment cores

    USGS Publications Warehouse

    Fitzpatrick, Faith A.; Garrison, Paul J.; Fitzgerald, Sharon A.; Elder, John F.

    2003-01-01

    Sediment cores were collected from Musky Bay, Lac Courte Oreilles, and from surrounding areas in 1999 and 2001 to determine whether the water quality of Musky Bay has declined during the last 100 years or more as a result of human activity, specifically cottage development and cranberry farming. Selected cores were analyzed for sedimentation rates, nutrients, minor and trace elements, biogenic silica, diatom assemblages, and pollen over the past several decades. Two cranberry bogs constructed along Musky Bay in 1939 and the early 1950s were substantially expanded between 1950?62 and between 1980?98. Cottage development on Musky Bay has occurred at a steady rate since about 1930, although currently housing density on Musky Bay is one-third to one-half the housing density surrounding three other Lac Courte Oreilles bays. Sedimentation rates were reconstructed for a core from Musky Bay by use of three lead radioisotope models and the cesium-137 profile. The historical average mass and linear sedimentation rates for Musky Bay are 0.023 grams per square centimeter per year and 0.84 centimeters per year, respectively, for the period of about 1936?90. There is also limited evidence that sedimentation rates may have increased after the mid-1990s. Historical changes in input of organic carbon, nitrogen, phosphorus, and sulfur to Musky Bay could not be directly identified from concentration profiles of these elements because of the potential for postdepositional migration and recycling. Minor- and trace-element profiles from the Musky Bay core possibly reflect historical changes in the input of clastic material over time, as well as potential changes in atmospheric deposition inputs. The input of clastic material to the bay increased slightly after European settlement and possibly in the 1930s through 1950s. Concentrations of copper in the Musky Bay core increased steadily through the early to mid-1900s until about 1980 and appear to reflect inputs from atmospheric

  6. 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

  7. 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)

  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. Tight-binding repressors of the lac operon: selection system and in vitro analysis.

    PubMed

    Pfahl, M

    1979-01-01

    The isolation and characterization of altered repressors of the lac operon which have an increased affinity for an operator should give useful clues about the molecular basis for the very tight and specific interaction between repressor and operator. A selection system has been devised which allows the isolation of such repressor mutants. This system selects for mutant repressors which can overcome lac operator-constitutive (Oc) mutations. By using in vivo assays, 24 candidates were obtained which, compared with wild type, have an increased trans effect of their repressor on one or several Oc operators. Three of these candidates have been investigated in vitro; the affinity of their repressor for inducer was unchanged, whereas the affinity for wild-type operator was increased 15-, 86-, and 262-fold, respectively. PMID:104955

  10. Flexibility and Disorder in Gene Regulation: LacI/GalR and Hox Proteins*

    PubMed Central

    Bondos, Sarah E.; Swint-Kruse, Liskin; Matthews, Kathleen S.

    2015-01-01

    To modulate transcription, a variety of input signals must be sensed by genetic regulatory proteins. In these proteins, flexibility and disorder are emerging as common themes. Prokaryotic regulators generally have short, flexible segments, whereas eukaryotic regulators have extended regions that lack predicted secondary structure (intrinsic disorder). Two examples illustrate the impact of flexibility and disorder on gene regulation: the prokaryotic LacI/GalR family, with detailed information from studies on LacI, and the eukaryotic family of Hox proteins, with specific insights from investigations of Ultrabithorax (Ubx). The widespread importance of structural disorder in gene regulatory proteins may derive from the need for flexibility in signal response and, particularly in eukaryotes, in protein partner selection. PMID:26342073

  11. 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

  12. VERITAS observations and spectral energy distribution of H 1426+428 BL Lac

    NASA Astrophysics Data System (ADS)

    Khassen, Y.

    2014-07-01

    The VERITAS array of 12-m atmospheric-Cherenkov telescopes in southern Arizona is one of the world's most sensitive detectors of astrophysical very high energy (VHE) γ-rays above 100 GeV. We present results from VERITAS observations of the BL Lac object H 1426+428. The VERITAS array has been monitoring this source since 2007 and has accumulated over 35 hours of data. The source was first detected in the VHE range by the Whipple 10-m γ-ray telescope in 2002 during a flaring state. It is classified as an extreme high-frequency peaked BL Lac (HBL), with the peak of the synchrotron emission lying above 100 keV, even during low states. The spectral energy distribution of H 1426+428, including contemporaneous VERITAS, Fermi-LAT, Swift XRT/UVOT and optical data, will be presented.

  13. 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.

  14. 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.

  15. 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

  16. Purification, crystallization and preliminary crystallographic analysis of recombinant Lac15 from a marine microbial metagenome.

    PubMed

    Ge, Honghua; Xu, Peisong; Xu, Ying; Fang, Zemin; Xiao, Yazhong

    2011-08-01

    Laccases are members of the blue multi-copper oxidase family that can oxidize a wide range of aromatic compounds. A new bacterial laccase (Lac15) has recently been obtained from a marine microbial metagenome from the South China Sea and characterized. In this work, recombinant Lac15 was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. An X-ray diffraction data set was collected to 2.2 Å resolution. The crystal belonged to space group C121, with unit-cell parameters a = 123.41, b = 91.36, c = 86.157 Å, β = 112.10°.

  17. 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

  18. 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.

  19. VERITAS observations of low- and intermediate-frequency peaked BL Lac objects

    NASA Astrophysics Data System (ADS)

    Nelson, T.; VERITAS Collaboration

    2012-12-01

    We present highlights of long-term monitoring of low- and intermediate-frequency peaked BL Lac objects with the VERITAS gamma-ray observatory carried out in 2010, 2011 and 2012. These include the key results obtained from observations of a bright VHE flare in BL Lacertae in June 2011, as well as preliminary results of monitoring observations of five northern blazars. Two IBLs-3C 66A and W Comae-are detected in low flux states for the first time.

  20. 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.

  1. 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.

  2. The use of lacZ marker in enumeration of Azotobacter chroococcum in carrier based inoculants.

    PubMed

    Solanki, Manu; Garg, Faquir C

    2014-01-01

    A transconjugant of Azotobacter chroococcum Mac 27 tagged with lac Z(A. chroococcum Mac27 L) was found to possess high levels of β-galactosidase activity constitutively. Further, the lac Z marker was found to be stably integrated into the chromosome of the A. chroococcum Mac 27 and did not have any adverse effect on growth, nitrogen fixation and excretion of ammonia. A quick method to determine the viable cell number in broth culture and carrier based inoculants has been developed on the basis of β-galactosidase assay. It was found that there was a direct relationship between the number of cell as determined by standard plate count and intensity of colour that developed upon degradation of ONPG due to β-galactosidase activity. The method was found to be sensitive enough to determine 1.7 × 10(6) CFU mL(-1) in broth culture as well as carrier based Azotobacter inoculants. Further, it was observed that when A. chroococcum Mac27 L was inoculated on Brassica campestris, it could be detected in the presence of other bacteria capable of growing on Burks agar medium containing X-gal on the basis of lac Z genetic marker.

  3. Paradoxical Effect of Weak Inducers on the lac Operon of Escherichia coli

    PubMed Central

    Williams, Beverly; Paigen, Kenneth

    1968-01-01

    Previously, we reported the existence of a group of compounds whose function in the regulation of the lac operon was “paradoxical” in that they acted as either inducers or repressors depending on the circumstances. We now show that this group of compounds does not repress the lac operon by catabolite repression, transient repression, or by preventing the uptake of inducers. A model is presented which shows that “paradoxical” behavior is to be expected if a weak inducer is present at a concentration that is high relative to its binding affinity for the regulatory macromolecule. This model depends on the assumptions that the regulatory macromolecule is an allosteric protein which undergoes a transition between two conformational states and that the rate of enzyme synthesis depends on the fraction of protein molecules in each state. The previous observations on the responses of lac regulatory mutants to weak inducers have been extended to a series of such mutants. Weak inducers repress β-galactosidase synthesis in several i− mutants. When this happens, enzyme synthesis can be reinduced by using a strong inducer such as isopropyl-β-d-thiogalactoside. These compounds induce operator constitutives and the it mutant more easily than they induce a wild-type strain. PMID:4882023

  4. 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.

  5. 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.

  6. The first synthesis of chem-prep varistor LAC (lightning arrestor connector) granules

    SciTech Connect

    Tuttle, B.A.; Voigt, J.A.; Andrews, L.A.

    1988-03-01

    ZnO variestor granules are the active medis for many lightning arrestor connectors (LACs). The 150 to 200 micron diameter granules provide a controlled electrical breakdown in the 400 micron gap between the electrically conductive pin and web of the connector. Tradiationally, the varistor granules are made from commercially available, reagent grade, mixed oxide powders that range in particle size from 1 to 20 microns. For the first time, we have synthesized varistor granules from chemically prepared powders developed at Sandia. These chem-prep varistor powders are more homogeneous and much finer than the mixed oxide powders; the mean particle size of the chem-prep powders is approximately 0.06 microns. LAC granules were formed from chemically prepared powders by traditional ceramic processing techniques. Although the chem-prep granules were not as spherical as the mixed oxide granules, the chem-prep granules did meet present LAC component requirements for fast-rise breakdown voltage and insulation resistance. The insulation resistance of chem-prep granules for a 200 volt pin-to-web voltage was 100 times less than for mixed oxide granules; however, both types of granules had similar insulation resistance for a 250 volt pin-to-web voltage.

  7. 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.

  8. 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

  9. The use of lacZ marker in enumeration of Azotobacter chroococcum in carrier based inoculants

    PubMed Central

    Solanki, Manu; Garg, Faquir C.

    2014-01-01

    A transconjugant of Azotobacter chroococcum Mac 27 tagged with lac Z(A. chroococcum Mac27 L) was found to possess high levels of β-galactosidase activity constitutively. Further, the lac Z marker was found to be stably integrated into the chromosome of the A. chroococcum Mac 27 and did not have any adverse effect on growth, nitrogen fixation and excretion of ammonia. A quick method to determine the viable cell number in broth culture and carrier based inoculants has been developed on the basis of β-galactosidase assay. It was found that there was a direct relationship between the number of cell as determined by standard plate count and intensity of colour that developed upon degradation of ONPG due to β-galactosidase activity. The method was found to be sensitive enough to determine 1.7 × 106 CFU mL−1 in broth culture as well as carrier based Azotobacter inoculants. Further, it was observed that when A. chroococcum Mac27 L was inoculated on Brassica campestris, it could be detected in the presence of other bacteria capable of growing on Burks agar medium containing X-gal on the basis of lac Z genetic marker. PMID:25242946

  10. Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

    USGS Publications Warehouse

    Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

    2014-01-01

    resulting simulated lake stage and water budgets to stages and water budgets from the calibrated model. Simulated lake water budgets and water level changes illustrate the importance of understanding the position of a lake within the hydrologic system (headwater or downstream), the type of lake (surface-water drainage or seepage lake), and the role of groundwater in dampening the effects of large-scale changes in weather patterns on lake levels. Areas contributing recharge to drinking-water supply wells on the Reservation were delineated using forward particle tracking from the water table to the well. Monte Carlo uncertainty analyses were used to produce maps showing the probability of groundwater capture for areas around each well nest. At the Main Pumphouse site near the Village of Lac du Flambeau, most of the area contributing recharge to the wells occurs downgradient from a large wetland between the wells and the wastewater infiltration lagoons. Nonetheless, a small potential for the wells to capture infiltrated wastewater is apparent when considering uncertainty in the model parameter values. At the West Pumphouse wells south of Flambeau Lake, most of the area contributing recharge is between the wells and Tippecanoe Lake. The extent of infiltrated wastewater from two infiltration lagoons was tracked using the groundwater flow model and Monte Carlo uncertainty analyses. Wastewater infiltrated from the lagoons flows predominantly south toward Moss Lake as it integrates with the regional groundwater flow system. The wastewater-plume-extent simulations support the area-contributing-recharge simulations, indicating that there is a possibility, albeit at low probability, that some wastewater could be captured by water-supply wells. Comparison of simulated water-table contours indicate that the lagoons may mound the water table approximately 4 ft, with diminishing levels of mounding outward from the lagoons. Four scenarios, representing potential alternatives for wastewater

  11. MULTI-WAVELENGTH STUDY OF FLARING ACTIVITY IN BL Lac OBJECT S5 0716+714 DURING THE 2015 OUTBURST

    SciTech Connect

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

    2015-08-20

    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.

  12. 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.

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

    DOE PAGES

    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

  14. 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.

  15. 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.

  16. 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

  17. Modulation of neuropeptide Y and Y1 receptor expression in the amygdala by fluctuations in the brain content of neuroactive steroids during ethanol drinking discontinuation in Y1R/LacZ transgenic mice.

    PubMed

    Eva, Carola; Mele, Paolo; Collura, Devis; Nai, Antonella; Pisu, Maria Giuseppina; Serra, Mariangela; Biggio, Giovanni

    2008-02-01

    Previous studies have shown that GABAergic neuroactive steroids increase Y1 receptor (Y1R) gene expression in the amygdala of Y1R/LacZ transgenic mice, harbouring the murine Y1R gene promoter linked to a LacZ reporter gene. As ethanol is known to increase GABAergic neuroactive steroids, we investigated the relationship between fluctuations in the brain content of neuroactive steroids induced by chronic voluntary ethanol consumption or ethanol discontinuation and both the level of neuropeptide Y (NPY) immunoreactivity and Y1R gene expression in the amygdala of Y1R/LacZ transgenic mice. Ethanol discontinuation (48 h) after voluntary consumption of consecutive solutions of 3%, 6%, 10% and 20% (v/v) ethanol over 4 weeks produced an anxiety-like behaviour as measured by elevated plus maze. Voluntary ethanol intake increased the cerebrocortical concentration of the progesterone metabolite 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha,5alpha-TH PROG) that returned to control level 48 h after discontinuation of ethanol intake. Ethanol discontinuation significantly decreased NPY immunoreactivity and concomitantly increased Y1R/LacZ transgene expression in the amygdala, whereas chronic ethanol intake failed to affect these parameters. The 5alpha-reductase inhibitor finasteride prevented both the increase in the cerebrocortical concentration of 3alpha,5alpha-TH PROG apparent after 4 weeks of ethanol intake and the changes in NPY immunoreactivity and transgene expression induced by ethanol discontinuation. Data suggest that 3alpha,5alpha-TH PROG plays an important role in the changes in NPY-Y1R signalling in the amygdala during ethanol discontinuation.

  18. 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

  19. LacR mutations are frequently observed in Streptococcus intermedius and are responsible for increased intermedilysin production and virulence.

    PubMed

    Tomoyasu, Toshifumi; Imaki, Hidenori; Masuda, Sachiko; Okamoto, Ayumi; Kim, Hyejin; Waite, Richard D; Whiley, Robert A; Kikuchi, Ken; Hiramatsu, Keiichi; Tabata, Atsushi; Nagamune, Hideaki

    2013-09-01

    Streptococcus intermedius secretes a human-specific cytolysin, intermedilysin (ILY), which is considered to be the major virulence factor of this pathogen. We screened for a repressor of ily expression by using random gene disruption in a low-ILY-producing strain (PC574). Three independent high-ILY-producing colonies that had plasmid insertions within a gene that has high homology to lacR were isolated. Validation of these observations was achieved through disruption of lacR in strain PC574 with an erythromycin cassette, which also led to higher hemolytic activity, increased transcription of ily, and higher cytotoxicity against HepG2 cells, compared to the parental strain. The direct binding of LacR within the ily promoter region was shown by a biotinylated DNA probe pulldown assay, and the amount of ILY secreted into the culture supernatant by PC574 cells was increased by adding lactose or galactose to the medium as a carbon source. Furthermore, we examined lacR nucleotide sequences and the hemolytic activity of 50 strains isolated from clinical infections and 7 strains isolated from dental plaque. Of the 50 strains isolated from infections, 13 showed high ILY production, 11 of these 13 strains had one or more point mutations and/or an insertion mutation in LacR, and almost all mutations were associated with a marked decline in LacR function. These results strongly suggest that mutation in lacR is required for the overproduction of ILY, which is associated with an increase in pathogenicity of S. intermedius.

  20. Determination of mutational spectrum of the pesticide, captan, with an improved set of Escherichia coli LacZ mutants.

    PubMed

    Lu, C; Pfeil, R M; Rice, C P

    1995-07-01

    The mutational spectrum of the fungicide, captan, was determined using a set of improved Escherichia coli lacZ mutants. Captan created mutations mostly at dA-dT sites (83%) with only 17% occurring at dG-dC sites. The hydrolysis products of captan do not appear to be mutagenic because samples of captan at different hydrolysis stages showed basically the same mutational spectra: 31% at AT --> CG transversions, 8% of GC --> AT transitions, 2% of GC --> CG transversions, 8% of GC --> TA transversions, 19% of AT --> TA transversions, and 32% of AT --> GC transitions. Prepared solutions of captan lost their mutational activity gradually over time, indicating that the rate of decrease in mutagenicity agreed with the kinetics of captan hydrolysis reported in other studies. Using the change in mutagenicity to predict degradation, the hydrolysis of captan in pH 7.0 buffer was about three times faster than the hydrolysis carried out in pH 4.5 buffer. To our knowledge, this is the first presentation of mutational spectrum of captan.

  1. 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

  2. Geology and ground-water resources of Fond du Lac County, Wisconsin

    USGS Publications Warehouse

    Newport, Thomas G.

    1962-01-01

    The principal water-bearing rocks underlying Fond du Lac County, Wis., are sandstones of Cambrian and Ordovician age and dolomite of Silurian age. Other aquifers include dolomite of Ordovician age and sand. and gravel of Quaternary age. Crystalline rocks of Precambrian age, which underlie all the water-bearing formations, form a practically impermeable basement complex and yield little or no water to wells. Ground water is the source of all public and most private and industrial water supplies in the county. The municipalities and industries obtain water chiefly from wells that penetrate the sandstones of Cambrian and Ordorician age. The Platteville formation and Galena dolomite of Ordovician age and the Niagara dolomite of Silurian age supply water to most domestic and stock wells and to a few industrial wells. Several buried valleys in the bedrock surface contain water-bearing deposits of sand and gravel. The source of the ground water in Fond du Lac County is local precipitation. Recharge to the water-bearing beds occurs in most of the county but is greatest where the bedrock formations are near the surface. Ground water is discharged by seeps and springs, by evaporation and transpiration, and by wells. Ground-water levels in wells fluctuate in response to recharge and to natural discharge and pumping. In areas not affected by pumping, water levels generally decline through the summer months because of natural discharge and lack of recharge, recover slightly in the fall after the first killing frost, decline during the winter, and recover in the spring when recharge is greatest. In areas of heavy pumping, the water levels are lowest in late summer and highest in late winter. Water levels in wells in the Fond du Lac area were about 5 to 50 feet above the land surface in 1885, but they had declined to as low as 185 feet below the land surface by 1957. Coefficients of transmissibility and storage of the sandstones of Cambrian and Ordovician age were determined by

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. The long-term color variability of the BL Lac object OQ 530

    NASA Astrophysics Data System (ADS)

    Zhang, Bing-Kai; Zhang, Kai-Yin; Yu, Li-Zhi; Dai, Ben-Zhong; Zhang, Li; Zha, Min; Cao, Zhen

    2011-12-01

    The optical light curve of the BL Lac object OQ 530 is constructed based on published data. Diagrams showing the correlations of fluxes in different wavelength ranges are constructed and used to analyze the color variations. The relative spectral energy distribution of the variable source in the optical can be represented by a power law that is stable on long time scales. The average spectral index is -1.15±0.02, indicating that the radiation of the variable source probably has a synchrotron nature.

  16. 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).

  17. 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.

  18. 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.

  19. 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.

  20. A change in the X-ray spectrum of MK 421

    NASA Technical Reports Server (NTRS)

    Mushotzky, R. F.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

    1979-01-01

    HEAO-1 experiment A-2 observations of the BL Lac object MK421 in May 1978 show a marked spectral change from the OSO-8 observations of May 1977. The source was not detected above 10 keV in May 1978. The 2-10 keV spectrum could be well fit by a power law of energy slope 2.2 is less than or minus 4.2; thermal bremsstrahlung models with T less than 2 X 10 to the 7th power deg K are also acceptable. There was no indication of any low energy turnover, so that the inferred column density N sub H is less than 7 X 10 to the 21st power at/sq cm. The total flux is consistent with an extrapolation of the UV data from IUE, but the slope is not consistent with the UV slope. Possible models for the origin of the spectral transition are discussed.

  1. 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

  2. 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

  3. Expression pattern of STOP lacZ reporter gene in adult and developing mouse brain.

    PubMed

    Couégnas, Alice; Schweitzer, Annie; Andrieux, Annie; Ghandour, M Said; Boehm, Nelly

    2007-05-15

    Stable tubulin-only polypeptide (STOP) proteins are microtubule-associated proteins responsible for microtubule stabilization in neurons. STOP null mice show apparently normal cerebral anatomy but display synaptic defects associated with neuroleptic-sensitive behavioral disorders. STOP null mice have therefore been proposed as an animal model for the study of schizophrenia. In the present study, the expression pattern of STOP gene in developing and adult brain has been examined by using lacZ gene inserted in the STOP locus, as a reporter gene. beta-Galactosidase (beta-gal) immunostaining was confined to neuronal cells and projections. Strong labeling was observed in the whole olfactory system, cortical layer VII, hippocampus, hypothalamus, cerebellum, habenula, fasciculus retroflexus, and interpeduncular nucleus in adults. Additionally, ventral thalamic nucleus, clusters of positive cells in striatum, and Cajal-Retzius cells of cortical layer I were labeled in young mice. The strong expression of STOP lacZ reporter gene observed in brain is confined to areas that may be involved in the schizophrenia-related symptoms observed in STOP-deficient mice.

  4. 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

  5. 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

  6. Corepressor system for catabolite repression of the lac operon in Escherichia coli.

    PubMed

    Dobrogosz, W J

    1969-03-01

    Acetylated amino sugars, normally used in the biosynthesis of cell walls and cell membranes, were found to play a role as corepressors for catabolite repression of the lac operon in Escherichia coli. This conclusion was derived from studies conducted on mutants of E. coli that were able to assimilate an exogenous source of N-acetylglucosamine (AcGN) but were unable to dissimilate or grow on this compound. At concentrations less than 10(-4)m, AcGN caused severe catabolite repression of beta-galactosidase synthesis in cultures grown under either nonrepressed or partially repressed conditions. This repression occurred in the absence of any effect of AcGN on either the carbon and energy metabolism or the growth of the organism. In addition, this repression by AcGN occurred in a mutant strain that is constitutive for beta-galactosidase production, demonstrating that the AcGN effect does not involve the uptake of inducer. This model for the corepressor system of catabolite repression is discussed in relation to the existing theories on repression of the lac operon. PMID:4887497

  7. In vitro transcription accurately predicts lac repressor phenotype in vivo in Escherichia coli

    PubMed Central

    2014-01-01

    A multitude of studies have looked at the in vivo and in vitro behavior of the lac repressor binding to DNA and effector molecules in order to study transcriptional repression, however these studies are not always reconcilable. Here we use in vitro transcription to directly mimic the in vivo system in order to build a self consistent set of experiments to directly compare in vivo and in vitro genetic repression. A thermodynamic model of the lac repressor binding to operator DNA and effector is used to link DNA occupancy to either normalized in vitro mRNA product or normalized in vivo fluorescence of a regulated gene, YFP. An accurate measurement of repressor, DNA and effector concentrations were made both in vivo and in vitro allowing for direct modeling of the entire thermodynamic equilibrium. In vivo repression profiles are accurately predicted from the given in vitro parameters when molecular crowding is considered. Interestingly, our measured repressor–operator DNA affinity differs significantly from previous in vitro measurements. The literature values are unable to replicate in vivo binding data. We therefore conclude that the repressor-DNA affinity is much weaker than previously thought. This finding would suggest that in vitro techniques that are specifically designed to mimic the in vivo process may be necessary to replicate the native system. PMID:25097824

  8. 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}.

  9. 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.

  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. 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.

  12. 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.

  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.

    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. 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

  15. 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.

  16. Parsec-scale magnetic field structures in HEAO-1 BL Lacs

    NASA Astrophysics Data System (ADS)

    Kharb, P.; Gabuzda, D.; Shastri, P.

    2008-02-01

    We present very long baseline interferometry polarization images of an X-ray-selected sample of BL Lacertae objects belonging to the first HEAO-1 and the ROSAT-Green Bank (RGB) surveys. These are primarily high-energy-peaked BL Lacs (HBLs) and exhibit core-jet radio morphologies on pc scales. They show moderately polarized jet components, similar to those of low-energy-peaked BL Lacs (LBLs). The fractional polarization in the unresolved cores of the HBLs is, on average, lower than in the LBLs, while the fractional polarizations in the pc-scale jets of HBLs and LBLs are comparable. However, a difference is observed in the orientation of the inferred jet magnetic fields - while LBL jets are well known to preferentially exhibit transverse magnetic fields, the HBL jets tend to display longitudinal magnetic fields. Although a `spine-sheath' jet velocity structure, along with larger viewing angles for HBLs could produce the observed magnetic field configuration, differences in other properties of LBLs and HBLs, such as their total radio power, cannot be fully reconciled with the different-angle scenario alone. Instead it appears that LBLs and HBLs differ intrinsically, perhaps in the spin rates of their central black holes.

  17. 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.

  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. GB6 J1058+5628: A New Quasi-periodic BL Lac Object from the Asiago Plate Archive

    NASA Astrophysics Data System (ADS)

    Nesci, R.

    2010-06-01

    We present the historic photographic light curves of three little known blazars (two BL Lac objects and one FSRQ), GB6 J1058+5628, GB6 J1148+5254, and GB6 J1209+4119, spanning a time interval of about 50 years, mostly built using the Asiago plate archive. All objects show evident long-term variability, over which short-term variations are superposed. One source, GB6 J1058+5628, showed a marked quasi-periodic variability of 1 mag on timescale of about 6.3 years, making it one of the few BL Lac objects with a quasi-periodic behavior.

  20. GB6 J1058+5628: A NEW QUASI-PERIODIC BL LAC OBJECT FROM THE ASIAGO PLATE ARCHIVE

    SciTech Connect

    Nesci, R.

    2010-06-15

    We present the historic photographic light curves of three little known blazars (two BL Lac objects and one FSRQ), GB6 J1058+5628, GB6 J1148+5254, and GB6 J1209+4119, spanning a time interval of about 50 years, mostly built using the Asiago plate archive. All objects show evident long-term variability, over which short-term variations are superposed. One source, GB6 J1058+5628, showed a marked quasi-periodic variability of 1 mag on timescale of about 6.3 years, making it one of the few BL Lac objects with a quasi-periodic behavior.

  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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. Dissolution test acceptance sampling plans.

    PubMed

    Tsong, Y; Hammerstrom, T; Lin, K; Ong, T E

    1995-07-01

    The U.S. Pharmacopeia (USP) general monograph provides a standard for dissolution compliance with the requirements as stated in the individual USP monograph for a tablet or capsule dosage form. The acceptance rules recommended by USP have important roles in the quality control process. The USP rules and their modifications are often used as an industrial lot release sampling plan, where a lot is accepted when the tablets or capsules sampled are accepted as proof of compliance with the requirement. In this paper, the operating characteristics of the USP acceptance rules are reviewed and compared to a selected modification. The operating characteristics curves show that the USP acceptance rules are sensitive to the true mean dissolution and do not reject a lot or batch that has a large percentage of tablets that dissolve with less than the dissolution specification.

  9. Decadal to millennial scale geomagnetic field variations in the Levantine archaeointensity curve (LAC): methodology and applications

    NASA Astrophysics Data System (ADS)

    Shaar, Ron; Tauxe, Lisa; Ron, Hagai; Agnon, Amotz; Ben-Yosef, Erez; Finkelstein, Israel; Zuckerman, Sharon; Levy, Thomas E.

    2014-05-01

    ) according to the dating method employed (archaeological, historical, radiocarbon). In addition, we cross check results from multiple archaeological sites using different source materials dated using different methodologies. The results of this effort are summarized in a regional compilation namely Levantine Archaeomagnetic Curve - LAC. The initial version of the LAC includes recently published data from ancient copper production sites, and new data from two important biblical archaeological mounds in Israel - Tel Megiddo ("Armageddon") and Tel Hazor. In this talk we review our working methodologies, report the current status of the LAC, and discuss its implications on our understanding of geomagnetic secular variations.

  10. 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.

  11. 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%.

  12. 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

  13. Sliding and target location of DNA-binding proteins: an NMR view of the lac repressor system.

    PubMed

    Loth, Karine; Gnida, Manuel; Romanuka, Julija; Kaptein, Robert; Boelens, Rolf

    2013-05-01

    In non-specific lac headpiece-DNA complexes selective NMR line broadening is observed that strongly depends on length and composition of the DNA fragments. This broadening involves amide protons found in the non-specific lac-DNA structure to be interacting with the DNA phosphate backbone, and can be ascribed to DNA sliding of the protein along the DNA. This NMR exchange broadening has been used to estimate the 1D diffusion constant for sliding along non-specific DNA. The observed 1D diffusion constant of 4×10(-12) cm(2)/s is two orders of magnitude smaller than derived from previous kinetic experiments, but falls in the range of values determined more recently using single molecule methods. This strongly supports the notion that sliding could play at most a minor role in the association kinetics of binding of lac repressor to lac operator and that other processes such as hopping and intersegment transfer contribute to facilitate the DNA recognition process.

  14. Structure-Based Rational Design to Enhance the Solubility and Thermostability of a Bacterial Laccase Lac15

    PubMed Central

    Fang, Zemin; Zhou, Peng; Chang, Fei; Yin, Qiang; Fang, Wei; Yuan, Jing; Zhang, Xuecheng; Xiao, Yazhong

    2014-01-01

    Bacterial laccases are ideal alternatives of fungal laccases for specific industrial applications due to specific characteristics such as alkalescence dependence and high chloride tolerance. However, some bacterial laccases presented as inclusion bodies when expressing in Escherichia coli and showed thermal instability. In this study, rational design was employed to enhance the solubility and the thermostablity of the bacterial laccase Lac15-His6 based on the crystal structure obtained previously. After deletion of His-tag and residues323–332, the obtained Lac15D was completely expressed in soluble form even at a higher temperature of 28°C, compared to only 50% of Lac15-His6 expressed solubly at 16°C. It showed a two-time higher activity at temperatures lower than 35°C and a half-life increasing from 72 min to 150 min at 45°C. When used in chromogenic reactions, Lac15D showed constant activity toward dye precursors and their combinations under alkaline conditions, demonstrating its application potential in hair coloring biotechnology. PMID:25036001

  15. A set of lacZ mutations in Escherichia coli that allow rapid detection of specific frameshift mutations.

    PubMed

    Cupples, C G; Cabrera, M; Cruz, C; Miller, J H

    1990-06-01

    We have used site-directed mutagenesis to alter bases in lacZ near the region encoding essential residues in the active site of beta-galactosidase. The altered sequences generate runs of six or seven identical base pairs which create a frameshift, resulting in a Lac- phenotype. Reversion to Lac+ in each strain can occur only by a specific frameshift at these sequences. Monotonous runs of A's (or of T's on the opposite strand) and G's (or C's) have been constructed, as has an alternating -C-G- sequence. These specific frameshift indicator strains complement a set of six previously described strains which detect each of the base substitutions. We have examined a variety of mutagens and mutators for their ability to cause reversion to Lac+. Surprisingly, frameshifts are well stimulated at many of these runs by ethyl methanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine and 2-amino-purine, mutagens not widely known to induce frameshifts. A comparison of ethyl methanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine and 2-aminopurine frameshift specificity with that found with a mutH strain suggests that these mutagens partially or fully saturate or inactivate the methylation-directed mismatch repair system and allow replication errors leading to frameshifts to escape repair. This results in a form of indirect mutagenesis, which can be detected at certain sites. PMID:2199309

  16. Evidence for the pulsational origin of the Long Secondary Periods: The red supergiant star V424 Lac (HD 216946)

    NASA Astrophysics Data System (ADS)

    Messina, Sergio

    2007-10-01

    The results of a long-term UBV photometric monitoring of the red supergiant (RSG) star V424 Lac are presented. V424 Lac shows multiperiodic brightness variations which can be attributed to pulsational oscillations. A much longer period ( P = 1601 d), that allows us to classify this star as a long secondary period variable star (LSPV) has been also detected. The B - V and U - B color variations related to the long secondary period (LSP) are similar to those related to the shorter periods, supporting the pulsational nature of LSP. The long period brightness variation of V424 Lac is accompanied by a near-UV (NUV) excess, which was spectroscopically detected in a previous study [Massey, P., Plez, B., Levesque, E.M., et al., 2005. ApJ 634, 1286] and which is now found to be variable from photometry. On the basis of the results found for V424 Lac, the NUV excess recently found in a number of RSGs may be due not solely to circumstellar dust but may also have a contribution from a still undetected LSP variability.

  17. Electron spin coherence in metallofullerenes: Y, Sc, and La@C82

    NASA Astrophysics Data System (ADS)

    Brown, Richard M.; Ito, Yasuhiro; Warner, Jamie H.; Ardavan, Arzhang; Shinohara, Hisanori; Briggs, G. Andrew D.; Morton, John J. L.

    2010-07-01

    Endohedral fullerenes encapsulating a spin-active atom or ion within a carbon cage offer a route to self-assembled arrays such as spin chains. In the case of metallofullerenes the charge transfer between the atom and the fullerene cage has been thought to limit the electron spin phase coherence time (T2) to the order of a few microseconds. We study electron spin relaxation in several species of metallofullerene as a function of temperature and solvent environment, yielding a maximum T2 in deuterated o-terphenyl greater than 200μs for Y, Sc, and La@C82 . The mechanisms governing relaxation ( T1 , T2 ) arise from metal-cage vibrational modes, spin-orbit coupling and the nuclear spin environment. The T2 times are over 2 orders of magnitude longer than previously reported and consequently make metallofullerenes of interest in areas such as spin labeling, spintronics, and quantum computing.

  18. 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.

  19. 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.

  20. p21-LacZ reporter mice reflect p53-dependent toxic insult

    SciTech Connect

    Vasey, Douglas B. Wolf, C. Roland; MacArtney, Thomas; Brown, Ken; Whitelaw, C. Bruce A.

    2008-03-15

    There is an urgent need to discover less toxic and more selective drugs to treat disease. The use of transgenic mice that report on toxic insult-induced transcription can provide a valuable tool in this regard. To exemplify this strategy, we have generated transgenic mice carrying a p21-LacZ transgene. Transgene activity reflected endogenous p21 gene activation in various tissues, displayed compound-specific spatial expression signatures in the brain and immune tissues and enabled p53-dependent and p53-independent responses to be identified. We discuss the application of these mice in delineating the molecular events in normal cellular growth and disease and for the evaluation of drug toxicity.

  1. 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

  2. Site-specific DNA-affinity chromatography of the lac repressor.

    PubMed Central

    Herrick, G

    1980-01-01

    To test the feasibility of site-specific DNA-affinity chromatography, E. coli lac repressor was bound to an operator-containing DNA column, and in parallel to a non-operator DNA column. Salt gradient elution shows: 1) elution from non-operator DNA was near 250mM KCl or NaCl; interpretation of this result suggests the usefulness of the procedure for studying salt-dependence of DNA-protein affinities; 2) elution from operator-containing DNA was delayed (average elution = 1000mM salt), demonstrating a feasibility of site-specific DNA-affinity chromatography, if one provides a sufficiently favorable ratio of specific to non-specific DNA binding sites; 3) repressor eluted from operator-containing DNA over a very broad salt range, which may represent chromatography-generated repressor heterogeneity. PMID:7001362

  3. 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.

  4. 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

  5. X-RAY FLARES OF EV Lac: STATISTICS, SPECTRA, AND DIAGNOSTICS

    SciTech Connect

    Huenemoerder, David P.; Schulz, Norbert S.; Testa, Paola; Drake, Jeremy J.; Osten, Rachel A.; Reale, Fabio

    2010-11-10

    We study the spectral and temporal behavior of X-ray flares from the active M dwarf EV Lac in 200 ks of exposure with the Chandra/HETGS. We derive flare parameters by fitting an empirical function which characterizes the amplitude, shape, and scale. The flares range from very short (<1 ks) to long ({approx}10{sup 4} s) duration events with a range of shapes and amplitudes for all durations. We extract spectra for composite flares to study their mean evolution and to compare flares of different lengths. Evolution of spectral features in the density-temperature plane shows probable sustained heating. The short flares are significantly hotter than the longer flares. We determined an upper limit to the Fe K fluorescent flux, the best-fit value being close to what is expected for compact loops.

  6. 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.

  7. Extending the Technology Acceptance Model: Policy Acceptance Model (PAM)

    NASA Astrophysics Data System (ADS)

    Pierce, Tamra

    There has been extensive research on how new ideas and technologies are accepted in society. This has resulted in the creation of many models that are used to discover and assess the contributing factors. The Technology Acceptance Model (TAM) is one that is a widely accepted model. This model examines people's acceptance of new technologies based on variables that directly correlate to how the end user views the product. This paper introduces the Policy Acceptance Model (PAM), an expansion of TAM, which is designed for the analysis and evaluation of acceptance of new policy implementation. PAM includes the traditional constructs of TAM and adds the variables of age, ethnicity, and family. The model is demonstrated using a survey of people's attitude toward the upcoming healthcare reform in the United States (US) from 72 survey respondents. The aim is that the theory behind this model can be used as a framework that will be applicable to studies looking at the introduction of any new or modified policies.

  8. 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

  9. 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.

  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. TOO_awehrle_4: Extended Observations of Flaring BL Lac in Nov 2012- Feb 2013

    NASA Astrophysics Data System (ADS)

    Wehrle, A.

    2012-11-01

    We propose to continue our Herschel TOO observations of the flaring eponymous blazar, BL Lac, which is now 2-6 times brighter than it was when we proposed our current TOO observations two months ago, depending on band. BL Lac has now reached 10-to-30-year historical maxima at centimeter, millimeter, submillimeter, and X-ray bands, and is brighter than any previous far infrared observations (ATEL #4557, Wehrle et al.). Our goal is to use 10 weekly Herschel observations with PACS and SPIRE of 15.9 minutes each, (total 2.7 hrs excluding 1.7 hrs time constraint penalty) in combination with VLBI imaging and ground-based millimeter and submillimeter photometry to determine if the far infrared emission is coming from stationary shock regions identified with bright knots in the parsec scale jet. We do this by seeing if the far-infrared emission brightens at the same time as the stationary knots ``light up" in VLBI images from the passage of an energetic disturbance down the jet. In addition, we will continue our evaluation of the physical cause of the flares as either magnetic field line reconnection or turbulence within shocks, and we will derive the physical conditions in the jet by modelling the SEDs as the flare evolves. We will compare the physics of the jet in this TeV blazar to the non-TeV blazar 3C454.3 which we observed with Herschel in November 2010-January 2011 (Wehrle et al. 2012).

  12. 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.

  13. 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…

  14. Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

    USGS Publications Warehouse

    Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

    2014-01-01

    resulting simulated lake stage and water budgets to stages and water budgets from the calibrated model. Simulated lake water budgets and water level changes illustrate the importance of understanding the position of a lake within the hydrologic system (headwater or downstream), the type of lake (surface-water drainage or seepage lake), and the role of groundwater in dampening the effects of large-scale changes in weather patterns on lake levels. Areas contributing recharge to drinking-water supply wells on the Reservation were delineated using forward particle tracking from the water table to the well. Monte Carlo uncertainty analyses were used to produce maps showing the probability of groundwater capture for areas around each well nest. At the Main Pumphouse site near the Village of Lac du Flambeau, most of the area contributing recharge to the wells occurs downgradient from a large wetland between the wells and the wastewater infiltration lagoons. Nonetheless, a small potential for the wells to capture infiltrated wastewater is apparent when considering uncertainty in the model parameter values. At the West Pumphouse wells south of Flambeau Lake, most of the area contributing recharge is between the wells and Tippecanoe Lake. The extent of infiltrated wastewater from two infiltration lagoons was tracked using the groundwater flow model and Monte Carlo uncertainty analyses. Wastewater infiltrated from the lagoons flows predominantly south toward Moss Lake as it integrates with the regional groundwater flow system. The wastewater-plume-extent simulations support the area-contributing-recharge simulations, indicating that there is a possibility, albeit at low probability, that some wastewater could be captured by water-supply wells. Comparison of simulated water-table contours indicate that the lagoons may mound the water table approximately 4 ft, with diminishing levels of mounding outward from the lagoons. Four scenarios, representing potential alternatives for wastewater

  15. 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

  16. 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

  17. Identification of base and backbone contacts used for DNA sequence recognition and high-affinity binding by LAC9, a transcription activator containing a C6 zinc finger

    SciTech Connect

    Halvorsen, Yuan-Di C.; Nandabalan, K.; Dickson, R.C. )

    1991-04-01

    The LAC9 protein of Kluyveromyces lactis is a transcriptional regulator of genes in the lactose-galactose regulon. To regulate transcription, LAC9 must bind to 17-bp upstream activator sequences (UASs) located in front of each target gene. LAC9 is homologous to the GAL4 protein of Saccharomyces cerevisiae, and the two proteins must bind DNA in a very similar manner. In this paper the authors show that high-affinity, sequence-specific binding by LAC9 dimers is mediated primarily by 3 bp at each end of the UAS. In addition, at least one half of the UAS must have a GC or CG base pair at position 1 for high-affinity binding; LAC9k binds preferentially to the half containing the GC base pair. Hydroxyl radical footprinting shows that a LAC9 dimer binds an unusually broad region on one face of the DNA helix. Because of the data, they suggest that LAC9 contacts positions 6, 7, and 8, both plus and minus, of the UAS, which are separated by more than one turn of the DNA helix, and twists part way around the DNA, thus protecting the broad region of the minor groove between the major-groove contacts.

  18. Lactosylated gramicidin-based lipid nanoparticles (Lac-GLN) for targeted delivery of anti-miR-155 to hepatocellular carcinoma.

    PubMed

    Zhang, Mengzi; Zhou, Xiaoju; Wang, Bo; Yung, Bryant C; Lee, Ly J; Ghoshal, Kalpana; Lee, Robert J

    2013-06-28

    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 +3.5mV, 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.

  19. 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

  20. 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

  1. 7 CFR 1728.30 - Inclusion of an item for listing or technical acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... acceptance. Items accepted subject to certain conditions, such as limited use to gain service experience, or... submitting a letter to the Administrator requesting such a review. (h) Change in Design. RUS acceptance of an item will be conditioned on the understanding that no design changes (material or dimensions)...

  2. 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

  3. Mount St. Helens: A case study of managing for change in wildland recreation

    NASA Astrophysics Data System (ADS)

    Ewert, Alan

    1990-03-01

    Mount St. Helens provides an interesting case study of a forest and wildland area that has been radically altered in recent history. As a result of volcanic activity, the recreation environment has changed with respect to the setting, climbing opportunities, and motivations for mountaineering. An evaluation process using both qualitative and quantitative methods was developed to determine what the motivations, demographic characteristics, and preferred management techniques were for the posteruption Mount St. Helens mountain-climbing visitor. Results suggest that changes have occurred in the “new” or posteruption climbing visitor. These changes have not all been congruent with those anticipated by management. For example, the climbing visitor is now less interested in climbing opportunities and more concerned with seeing the crater and other volcanic-related features. This article discusses the findings of this research in light of how resource managers might consider the issue of visitor changes in both demands and types of uses. For example, determining quota numbers based on sociological determinants (e.g., desire for solitude) need to be firmly grounded in who the visitors actually are rather than who they were. Consequently, management tools such as the Recreational Opportunity Spectrum (ROS) and Limits of Acceptable Change (LAC) may need to be altered to accommodate a changing resource or visitor base. These and other findings have implications for the future management practices of the Mount St. Helens area and other environments where the recreation resources have undergone rapid and profound change.

  4. 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

  5. Repression and activation of transcription by Gal and Lac repressors: involvement of alpha subunit of RNA polymerase.

    PubMed Central

    Choy, H E; Park, S W; Aki, T; Parrack, P; Fujita, N; Ishihama, A; Adhya, S

    1995-01-01

    Gal or Lac repressor binding to an upstream DNA segment, in the absence of DNA looping, represses the P1 promoter located on the same face and activates the P2 promoter situated on the opposite face of the DNA helix in the gal operon. Both inhibition and stimulation of transcription requires the physical presence of the C-terminal domain of the alpha subunit of RNA polymerase although the latter is not required for transcription itself. We propose that Gal and Lac repressors inhibit or stimulate transcription initiation by disabling or stimulating RNA polymerase activity at a post-binding step by directly or indirectly altering the C-terminal alpha domain to an unfavorable state at P1 or a more favorable state at P2, respectively. Images PMID:7556095

  6. Observations of low and intermediate-frequency-peaked BL Lacs above 100 GeV with VERITAS

    NASA Astrophysics Data System (ADS)

    Errando, M.

    2013-12-01

    Most of the ~ 50 blazars detected to date at TeV energies (E > 0.1 TeV) are high-frequency-peaked BL Lacs (HBLs). Only a handful episodic detections of low- and intermediate-frequency-peaked BL Lacs (LBL/IBLs, with synchrotron peak frequencies in the infrared and optical regime) have been reported by ground-based gamma-ray telescopes, typically during high-flux states. The VERITAS array located in southern Arizona has observed five known TeV LBL/IBLs since 2009: 3C 66A, WComae, PKS 1424+240, S5 0716+714 and BL Lacertae, with exposures of 5-10 hours/year, which so far resulted in the detection of a bright, sub-hour timescale gamma-ray flare of BL Lacertae in June 2011. We also report the detection and characterization of two new IBLs: VER J0521+211 and B2 1215+30.

  7. 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

  8. Fermi LAT detection of a GeV gamma-ray flare from the BL Lac object AP Librae

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano

    2016-08-01

    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 AP Lib (also known as PKS 1514-24 and 3FGL J1517.6-2422), with radio counterpart position R.A.: 229.424221 deg, Dec.: -24.372076 deg, (J2000.0, Johnston et al. 1995, AJ, 110, 880).

  9. 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

  10. Characterisation of Muta™Mouse λgt10-lacZ transgene: evidence for in vivo rearrangements

    PubMed Central

    Shwed, Philip S.; Crosthwait, Jennifer; Douglas, George R.; Seligy, Vern L.

    2010-01-01

    The multicopy λgt10-lacZ transgene shuttle vector of Muta™Mouse serves as an important tool for genotoxicity studies. Here, we describe a model for λgt10-lacZ transgene molecular structure, based on characterisation of transgenes recovered from animals of our intramural breeding colony. Unique nucleotide sequences of the 47 513 bp monomer are reported with GenBank® assigned accession numbers. Besides defining ancestral mutations of the λgt10 used to construct the transgene and the Muta™Mouse precursor (strain 40.6), we validated the sequence integrity of key λ genes needed for the Escherichia coli host-based mutation reporting assay. Using three polymerase chain reaction (PCR)-based chromosome scanning and cloning strategies, we found five distinct in vivo transgene rearrangements, which were common to both sexes, and involved copy fusions generating ∼10 defective copies per haplotype. The transgene haplotype was estimated by Southern hybridisation and real-time–polymerase chain reaction, which yielded 29.0 ± 4.0 copies based on spleen DNA of Muta™Mouse, and a reconstructed CD2F1 genome with variable λgt10-lacZ copies. Similar analysis of commercially prepared spleen DNA from Big Blue® mouse yielded a haplotype of 23.5 ± 3.1 copies. The latter DNA is used in calibrating a commercial in vitro packaging kit for E.coli host-based mutation assays of both transgenic systems. The model for λgt10-lacZ transgene organisation, and the PCR-based methods for assessing copy number, integrity and rearrangements, potentially extends the use of Muta™Mouse construct for direct, genomic-type assays that detect the effects of clastogens and aneugens, without depending on an E.coli host, for reporting effects. PMID:20724577

  11. Imaginary Companions and Peer Acceptance

    ERIC Educational Resources Information Center

    Gleason, Tracy R.

    2004-01-01

    Early research on imaginary companions suggests that children who create them do so to compensate for poor social relationships. Consequently, the peer acceptance of children with imaginary companions was compared to that of their peers. Sociometrics were conducted on 88 preschool-aged children; 11 had invisible companions, 16 had personified…

  12. Acceptance of Others (Number Form).

    ERIC Educational Resources Information Center

    Masters, James R.; Laverty, Grace E.

    As part of the instrumentation to assess the effectiveness of the Schools Without Failure (SWF) program in 10 elementary schools in the New Castle, Pa. School District, the Acceptance of Others (Number Form) was prepared to determine pupil's attitudes toward classmates. Given a list of all class members, pupils are asked to circle a number from 1…

  13. W-025, acceptance test report

    SciTech Connect

    Roscha, V.

    1994-10-04

    This acceptance test report (ATR) has been prepared to establish the results of the field testing conducted on W-025 to demonstrate that the electrical/instrumentation systems functioned as intended by design. This is part of the RMW Land Disposal Facility.

  14. 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…

  15. 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)

  16. Acceptance and Commitment Therapy: Introduction

    ERIC Educational Resources Information Center

    Twohig, Michael P.

    2012-01-01

    This is the introductory article to a special series in Cognitive and Behavioral Practice on Acceptance and Commitment Therapy (ACT). Instead of each article herein reviewing the basics of ACT, this article contains that review. This article provides a description of where ACT fits within the larger category of cognitive behavior therapy (CBT):…

  17. Who accepts first aid training?

    PubMed

    Pearn, J; Dawson, B; Leditschke, F; Petrie, G; Nixon, J

    1980-09-01

    The percentage of individuals trained in first aid skills in the general community is inadequate. We report here a study to investigate factors which influence motivation to accept voluntary training in first aid. A group of 700 randomly selected owners of inground swimming pools (a parental high-risk group) was offered a course of formal first aid instruction. Nine per cent attended the offered training course. The time commitment involved in traditional courses (eight training nights spread over four weeks) is not a deterrent, the same percentage accepting such courses as that who accept a course of one night's instruction. Cost is an important deterrent factor, consumer resistance rising over 15 cost units (one cost unit = the price of a loaf of bread). The level of competent first aid training within the community can be raised by (a) keeping to traditional course content, but (b) by ensuring a higher acceptance rate of first aid courses by a new approach to publicity campaigns, to convince prospective students of the real worth of first aid training. Questions concerning who should be taught first aid, and factors influencing motivation, are discussed.

  18. Immobilized glycosylated Fmoc-amino acid for SPR: comparative studies of lectin-binding to linear or biantennary diLacNAc structures.

    PubMed

    Nakamura, Kosuke; Sakagami, Hiromi; Asanuma-Date, Kimie; Nagasawa, Nao; Nakahara, Yoshiaki; Akiyama, Hiroshi; Ogawa, Haruko

    2013-12-15

    A method to immobilize glycan-linked amino acids with protected α-amino groups, which are key intermediates to produce the desired neoglycoprotein, to a Biacore sensor chip was developed and its utility for interaction analyses was demonstrated. Two types of diN-acetyllactosamine (diLacNAc)-containing glycans, a core 2 hexasaccharide involving linear diLacNAc that is O-linked to N-(9-fluorenyl)methoxycarbonyl (Fmoc)-Thr and a biantennary diLacNAc that is N-linked to Fmoc-Asn, were used as ligands. For immobilization, the free carboxyl groups of the amino acid residues were activated with EDC/NHS, then reacted with the ethylenediamine-derivatized carboxymethyldextran sensor chip to obtain the desired ligand concentrations. Interactions of the ligands with five plant lectins were analyzed by surface plasmon resonance, and the bindings were compared. The resonance unit of each lectin was corrected by subtracting that of the reference cell on which the Fmoc-Thr-core 1 or Fmoc-Asn was immobilized as a ligand. The carbohydrate specificities of interactions were verified by preincubating lectins with their respective inhibitory sugar before injection. By steady state analysis, the Lycopersicon esculentum lectin showed a 27-fold higher affinity to linear diLacNAc than to biantennary diLacNAc, while Datura stramonium and Solanum tuberosum lectins both showed low Ka,apps of 10(6)M(-1) for these two ligands. In contrast, Ricinus communis agglutinin-120 showed a 3.2-fold higher Ka,app to biantennary LacNAc than to linear diLacNAc. A lectin purified from Pleurocybella porrigens mushroom interacted at the high affinity of 10(8)M(-1) with both linear and biantennary diLacNAcs, which identified it as a unique probe. This method provides a useful and sensitive system to analyze interactions by simulating the glycans on the cell surface. PMID:24211369

  19. Modular, Multi-Input Transcriptional Logic Gating with Orthogonal LacI/GalR Family Chimeras

    PubMed Central

    2015-01-01

    In prokaryotes, the construction of synthetic, multi-input promoters is constrained by the number of transcription factors that can simultaneously regulate a single promoter. This fundamental engineering constraint is an obstacle to synthetic biologists because it limits the computational capacity of engineered gene circuits. Here, we demonstrate that complex multi-input transcriptional logic gating can be achieved through the use of ligand-inducible chimeric transcription factors assembled from the LacI/GalR family. These modular chimeras each contain a ligand-binding domain and a DNA-binding domain, both of which are chosen from a library of possibilities. When two or more chimeras have the same DNA-binding domain, they independently and simultaneously regulate any promoter containing the appropriate operator site. In this manner, simple transcriptional AND gating is possible through the combination of two chimeras, and multiple-input AND gating is possible with the simultaneous use of three or even four chimeras. Furthermore, we demonstrate that orthogonal DNA-binding domains and their cognate operators allow the coexpression of multiple, orthogonal AND gates. Altogether, this work provides synthetic biologists with novel, ligand-inducible logic gates and greatly expands the possibilities for engineering complex synthetic gene circuits. PMID:25035932

  20. 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.

  1. Evidence of late glacial paleoseismicity from submarine landslide deposits within Lac Dasserat, northwestern Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Brooks, Gregory R.

    2016-09-01

    An integrated seismo- and chronostratigraphic investigation at Lac Dasserat, northwestern Quebec, identified 74 separate failures within eight event horizons. Horizons E and B, and H and G have strong or moderately-strong multi-landslide signatures, respectively, composed of 11-23 failures, while horizons F, D, C, and A have minor landslide signatures consisting of a single or pair of deposit(s). Cores collected at six sites recovered glacial Lake Ojibway varve deposits that are interbedded with the event horizons. The correlation of the varves to the regional Timiskaming varve series allowed varve ages or ranges of varve ages to be determined for the event horizons. Horizons H, G, E, and B are interpreted to be evidence of paleoearthquakes with differing levels of interpretative confidence, based on the relative strength of the multi-landslide signatures, the correlation to other disturbed deposits of similar age in the region, and the lack or possibility of alternative aseismic mechanisms. The four interpreted paleoearthquakes occurred between 9770 ± 200 and 8470 ± 200 cal yr BP, when glacial Lake Ojibway was impounded behind the Laurentide Ice Sheet during deglaciation. They probably represent an elevated period of seismicity at deglaciation that was driven by crustal unloading.

  2. Induction kinetics and cell surface distribution of Escherichia coli lipoprotein under lac promoter control.

    PubMed Central

    Hiemstra, H; de Hoop, M J; Inouye, M; Witholt, B

    1986-01-01

    The induction kinetics and surface accessibility of the outer membrane lipoprotein were studied in an Escherichia coli strain with the lpp gene under control of the lac promoter. Free lipoprotein appeared rapidly after induction with isopropyl-beta-D-thiogalactopyranoside and reached a steady-state level after 30 min. The newly induced lipoprotein was slowly bound to the peptidoglycan layer. Immunological methods were developed to detect lipoprotein accessible at the cell surface after various pretreatments as well as peptidoglycan-bound lipoprotein at the surface of isolated peptidoglycan sacculi with specific antibodies in combination with 125I-protein A. With these methods an increase in lipoprotein molecules at the cell surface and bound to the peptidoglycan sacculus could be detected following induction. The topology of newly synthesized lipoprotein was examined in thin sections as well as at the cell surface and the surface of the peptidoglycan sacculus with immunoelectron microscopy. Ultrathin cell sections, whole cells, and isolated peptidoglycan sacculi showed lipoprotein distributed homogeneously over the entire surface. Images PMID:3531164

  3. 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

  4. Peculiar Optical Variability in BL Lac object S5 0716+714

    NASA Astrophysics Data System (ADS)

    Chandra, Sunil; Ganesh, Shashikiran; Baliyan, Kiran

    Blazars are very well known for flux variations over complete energy spectrum ranging from radio to very high energy gamma-rays (TeV). The different timescales of variations represents different emission mechanism responsible. The violent activities in the jets are directly manifested in the form of flux variations. Here, we report a very peculiar nature of optical intranight variability (INV) in BL Lac object S5 0716+714. The preliminary results from the seven year optical observations of this source, monitored using MIRO, revealed completely unexpected scenario of intranight variations during different brightness state of this object. The duty cycle of INV corresponding to the continuous monitoring of 2 hours or more turned to well in agreement with the literature (84 %). However, the amplitudes of INV are seen to highly dependent of the brightness state. The highest amplitude is seen when source was in relatively fainter state which again questions the traditional internal shock model which emphasize the maximum activity when source in most turbulent state. This clearly indicate the significant contribution of emission due to disk instabilities, reflecting such a rapid and strong flux variations.

  5. Crystallization and emplacement of the Lac St-Jean anorthosite massif (Quebec, Canada)

    NASA Astrophysics Data System (ADS)

    Woussen, G.; Dimroth, E.; Corriveau, L.; Archer, P.

    1981-05-01

    The Lac St-Jean anorthosite massif underlies an area of over 20,000 km2 and has been emplaced into migmatitic gneisses of the central granulite terrain of the Grenville Province of the Canadian shield. Field data and petrography in an area straddling the anorthosite-gneiss contact, close to Chicoutimi (Quebec) permits an outline of its tecto-magmatic evolution. Depositional magmatic textures in the massif reveals that it crystallized from a magma in a relatively calm tectonic environment. The absence of fusion in pelitic gneisses at the contact proves that the crystallization did not take place at the level presently exposed. The parallelism of subvertical foliation in the enveloping gneisses and the anorthosite indicates that both were deformed together. It is suggested that the deformation results from a diapiric ascent of the anorthosite massif after its consolidation at depth. The depth of consolidation of the anorthosite is estimated at ˜ 25 30 km from subsolidus reaction between plagioclase and olivine. The diapiric ascent is further substantiated by the fact that three sets of mafic dykes of different ages, intrusive into the anorthosite, have a mineralogy which indicates successively decreasing P, T conditions of emplacement from granulite fades to amphibolite facies. An evolution of the basement gneisses and the anorthosite is proposed as a working hypothesis; it relies on the fact that metabasite dyke swarms in the basement gneisses represent a period of major crustal extension and could be used as a stratigraphic subdivision of the Grenville Province.

  6. A LacI-family regulator activates maltodextrin metabolism of Enterococcus faecium.

    PubMed

    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.

  7. 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.

  8. 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.

  9. 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.

  10. Frameshift mutagenicity of aromatic amines related to aminofluorene in a lacZ reversion assay in E. coli

    SciTech Connect

    Hoffmann, G.R.; Janel-Bintz, R.; Fuchs, R.P.P.

    1997-10-01

    We studied in the mutagenicity of three aromatic amines in a lacZ reversion assay in E. coli: 2-nitrofluorene (NF), N-2-acetylaminofluorene (AAF), and N-hydroxy-N-2-acetylaminofluorene (NHA). Mutations that confer the Lac{sup +} phenotype were measured using an F{prime} factor from strain CC109 of Cupples et al. The F{prime} contains a lacZ mutation that reverts by a -2 frameshift at a site of repetitive dinucleotides (CG{sub 5} to CG{sub 4}). The F{prime} was transferred into strains carrying an LPS{sup d} mutation that increases permeability to aromatic amines and a plasmid (pYG219) that contains the Salmonella nat gene, which confers N- and O-acetyltransferase (NAT/OAT) activity. Mutagenesis was measured by papillation assays and quantitative reversion assays. The results show that the LPS{sup d} mutation, conferring enhanced permeability, facilitates measuring the mutagenicity of aromatic amines but is not absolutely required, in that a lower level of mutagenicity is detected in LPS{sup +} strains. The NAT/OAT activity conferred by pYG219 strongly potentiates the mutagenicity of NF and NHA. The mutagenicity of NF is undoubtedly ascribable to aminofluorene (AF) adducts: The mutagenicity of NHA may be due either to AAF adducts or to AF adducts produced by deacetylation. Surprisingly, AAF was weakly mutagenic in a NAT/OAT LPS{sup d} strain even without metabolic activation by a mammalian cytochrome P450.

  11. 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.

  12. 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

  13. High-Resolution Identification of Specificity Determining Positions in the LacI Protein Family Using Ensembles of Sub-Sampled Alignments

    PubMed Central

    Sloutsky, Roman

    2016-01-01

    Since the advent of large-scale genomic sequencing, and the consequent availability of large numbers of homologous protein sequences, there has been burgeoning development of methods for extracting functional information from multiple sequence alignments (MSAs). One type of analysis seeks to identify specificity determining positions (SDPs) based on the assumption that such positions are highly conserved within groups of sequences sharing functional specificity, but conserved to different amino acids in different specificity groups. This unsupervised approach to utilizing evolutionary information may elucidate mechanisms of specificity in protein-protein interactions, catalytic activity of enzymes, sensitivity to allosteric regulation, and other types of protein functionality. We present an analysis of SDPs in the LacI family of transcriptional regulators in which we 1) relax the constraint that all specificity groups must contribute to SDP signal, and 2) use a novel approach to robust treatment of sequence alignment uncertainty based on sub-sampling. We find that the vast majority of SDP signal occurs at positions with a conservation pattern that significantly complicates detection by previously described methods. This pattern, which we term “partial SDP”, consists of the commonly accepted SDP conservation pattern among a subset of specificity groups and strong degeneracy among the rest. An upshot of this fact is that the SDP complement of every specificity group appears to be unique. Additionally, sub-sampling gives us the ability to assign a confidence interval to the SDP score, as well as increase fidelity, as compared to analysis of a single, comprehensive alignment—the current standard in multiple sequence alignment methodologies. PMID:27681038

  14. Lac-regulated system for generating adenovirus 5 vaccine vectors expressing cytolytic human immunodeficiency virus 1 genes

    PubMed Central

    Zhao, Chunxia; Crews, Charles Jefferson; Derdeyn, Cynthia A.; Blackwell, Jerry L.

    2009-01-01

    Adenovirus (Ad) vectors have been developed as human immunodeficiency-1 (HIV-1) vaccine vectors because they consistently induce immune responses in preclinical animal models and human trials. Strong promoters and codon-optimization are often used to enhance vaccine-induced HIV-1 gene expression and immunogenicity. However, if the transgene is inherently cytotoxic in the cell line used to produce the vector, and is expressed at high levels, it is difficult to rescue a stable Ad HIV-1 vaccine vector. Therefore we hypothesized that generation of Ad vaccine vectors expressing cytotoxic genes, such as HIV-1 env, would be more efficient if expression of the transgene was down regulated during Ad rescue. To test this hypothesis, a Lac repressor-operator system was applied to regulate expression of reporter luciferase and HIV-1 env transgenes during Ad rescue. The results demonstrate that during Ad rescue, constitutive expression of the Lac repressor in 293 cells reduced transgene expression levels to approximately 5% of that observed in the absence of regulation. Furthermore, Lag-regulation translated into more efficient Ad rescue compared to traditional 293 cells. Importantly, Ad vectors rescued with this system showed high levels of transgene expression when transduced into cells that lack the Lac repressor protein. The Lac-regulated system also facilitated the rescue of modified Ad vectors that have non-native receptor tropism. These tropism-modified Ad vectors infect a broader range of cell types than the unmodified Ad, which could increase their effectiveness as a vaccine vector. Overall, the Lac-regulated system described here (i) is backwards compatible with Ad vector methods that employ bacterial-mediated homologous recombination (ii) is adaptable for the engineering of tropism-modified Ad vectors and (iii) does not require co-expression of regulatory genes from the vector or the addition of exogenous chemicals to induce or repress transgene expression. This

  15. Accepting the T3D

    SciTech Connect

    Rich, D.O.; Pope, S.C.; DeLapp, J.G.

    1994-10-01

    In April, a 128 PE Cray T3D was installed at Los Alamos National Laboratory`s Advanced Computing Laboratory as part of the DOE`s High-Performance Parallel Processor Program (H4P). In conjunction with CRI, the authors implemented a 30 day acceptance test. The test was constructed in part to help them understand the strengths and weaknesses of the T3D. In this paper, they briefly describe the H4P and its goals. They discuss the design and implementation of the T3D acceptance test and detail issues that arose during the test. They conclude with a set of system requirements that must be addressed as the T3D system evolves.

  16. Sweeteners: consumer acceptance in tea.

    PubMed

    Sprowl, D J; Ehrcke, L A

    1984-09-01

    Sucrose, fructose, aspartame, and saccharin were compared for consumer preference, aftertaste, and cost to determine acceptability of the sweeteners. A 23-member taste panel evaluated tea samples for preference and aftertaste. Mean retail cost of the sweeteners were calculated and adjusted to take sweetening power into consideration. Sucrose was the least expensive and most preferred sweetener. No significant difference in preference for fructose and aspartame was found, but both sweeteners were rated significantly lower than sucrose. Saccharin was the most disliked sweetener. Fructose was the most expensive sweetener and aspartame the next most expensive. Scores for aftertaste followed the same pattern as those for preference. Thus, a strong, unpleasant aftertaste seems to be associated with a dislike for a sweetener. From the results of this study, it seems that there is no completely acceptable low-calorie substitute for sucrose available to consumers.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. The use of an escape contingency and a token economy to increase food acceptance.

    PubMed

    Kahng, SungWoo; Boscoe, James H; Byrne, Shannon

    2003-01-01

    Escape (termination of a meal) and token-based differential reinforcement of alternative behavior were used as reinforcement to increase acceptance of food. Using a changing criterion design, the number of bites accepted and consumed was gradually increased to 15 bites per meal. These data suggest that, in some cases, escape may be a potent reinforcer for food acceptance. PMID:14596575

  2. The use of an escape contingency and a token economy to increase food acceptance.

    PubMed

    Kahng, SungWoo; Boscoe, James H; Byrne, Shannon

    2003-01-01

    Escape (termination of a meal) and token-based differential reinforcement of alternative behavior were used as reinforcement to increase acceptance of food. Using a changing criterion design, the number of bites accepted and consumed was gradually increased to 15 bites per meal. These data suggest that, in some cases, escape may be a potent reinforcer for food acceptance.

  3. Acceptance and Commitment Therapy for Anxiety Disorders: Three Case Studies Exemplifying a Unified Treatment Protocol

    ERIC Educational Resources Information Center

    Eifert, Georg H.; Forsyth, John P.; Arch, Joanna; Espejo, Emmanuel; Keller, Melody; Langer, David

    2009-01-01

    Acceptance and Commitment Therapy (ACT) is an innovative acceptance-based behavior therapy that has been applied broadly and successfully to treat a variety of clinical problems, including the anxiety disorders. Throughout treatment ACT balances acceptance and mindfulness processes with commitment and behavior change processes. As applied to…

  4. 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

  5. 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

  6. 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

  7. 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.

  8. Hypomaturation Enamel Defects in Klk4 Knockout/LacZ Knockin Mice*

    PubMed Central

    Simmer, James P.; Hu, Yuanyuan; Lertlam, Rangsiyakorn; Yamakoshi, Yasuo; Hu, Jan C.-C.

    2009-01-01

    Kallikrein 4 (Klk4) is believed to play an essential role in enamel biomineralization, because defects in KLK4 cause hypomaturation amelogenesis imperfecta. We used gene targeting to generate a knockin mouse that replaces the Klk4 gene sequence, starting at the translation initiation site, with a lacZ reporter gene. Correct targeting of the transgene was confirmed by Southern blot and PCR analyses. Histochemical X-gal (5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside) staining demonstrated expression of β-galactosidase in maturation stage ameloblasts. No X-gal staining was observed in secretory stage ameloblasts or in odontoblasts. Retained enamel proteins were observed in the maturation stage enamel of the Klk4 null mouse, but not in the Klk4 heterozygous or wild-type mice. The enamel layer in the Klk4 null mouse was normal in thickness and contained decussating enamel rods but was rapidly abraded following weaning, despite the mice being maintained on soft chow. In function the enamel readily fractured within the initial rod and interrod enamel above the parallel enamel covering the dentino-enamel junction. Despite the lack of Klk4 and the retention of enamel proteins, significant levels of crystal maturation occurred (although delayed), and the enamel achieved a mineral density in some places greater than that detected in bone and dentin. An important finding was that individual enamel crystallites of erupted teeth failed to grow together, interlock, and function as a unit. Instead, individual crystallites seemed to spill out of the enamel when fractured. These results demonstrate that Klk4 is essential for the removal of enamel proteins and the proper maturation of enamel crystals. PMID:19578120

  9. Acceptance as a mediator in internet-delivered acceptance and commitment therapy and cognitive behavior therapy for tinnitus.

    PubMed

    Hesser, Hugo; Westin, Vendela Zetterqvist; Andersson, Gerhard

    2014-08-01

    Despite demonstrated efficacy of behavioral and cognitive techniques in treating the impact of tinnitus (constant ringing in the ears), little is known about the mechanisms by which these techniques achieve their effect. The present study examined acceptance of tinnitus as a potential mediator of treatment changes on global tinnitus severity in internet-delivered acceptance and commitment therapy (iACT) and internet-delivered cognitive behavior therapy (iCBT). Data from 67 participants who were distressed by tinnitus and who were randomly assigned to 1 of the 2 treatments were analyzed using a multilevel moderated mediation model. We predicted that acceptance as measured with the two subscales of the tinnitus acceptance questionnaire (i.e., activity engagement and tinnitus suppression) would mediate the outcome in iACT, but not in iCBT. Results provided partial support to the notion that mediation was moderated by treatment: tinnitus suppression mediated changes in tinnitus severity in iACT, but not in iCBT. However, inconsistent with the view that the treatments worked through different processes of change, activity engagement mediated treatment changes across both iACT and iCBT. Acceptance is identified as a key source of therapeutic change in behavioral-based treatments for tinnitus.

  10. 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)

  11. The necessity of magnesium cation for acid assistance aglycone departure in catalysis by Escherichia coli (lacZ) beta-galactosidase.

    PubMed

    Sinnott, M L; Withers, S G

    1978-11-01

    1. Removal of Mg2+ from Escherichia coli (lacZ) beta-galactosidase slightly increases the rate of hydrolysis of galactosyl pyridinium salts, but decreases the rate of hydrolysis of arylgalactosides. 2. Fair correlation of logkcat. and log (Km) with the pKa of aglycone is now observed for arglygalactosides, as well as for glycosyl pyridinium salts. 3. Degalactosylation of Mg2+-free enzyme is the rate-limiting step in the hydrolysis of 2,4-dinitrophenyl galactoside. 4. alpha-Deuterium kinetic isotope effects for both sets of substrates are consistent with the rate-determining generation of a glycosyl cation. 5. The pH-independent, SNl hydrolysis of 3,4-dinitrophenyl galactoside has been measured: it is as fast as that of the galactosyl 3-chloropyridinium ion. 6. Hydrolysis of these two substrates by Mg2+-free enzyme proceeds at very similar rates. 7. It is concluded that loss of both types of aglycone takes place, without acid catalysis, from the first ES complex of substrate and apoenzyme. 8. Data for galactosyl azide and thiopicrate confirm that neither charge nor change of atom is the cause of the differences in behavior between aryl galactosides and galactosylpyridinium salts.

  12. 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

  13. 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

  14. Acceptance of nicotine dependence treatment among currently depressed smokers.

    PubMed

    Haug, Nancy A; Hall, Sharon M; Prochaska, Judith J; Rosen, Amy B; Tsoh, Janice Y; Humfleet, Gary; Delucchi, Kevin; Rossi, Joseph S; Redding, Colleen A; Eisendrath, Stuart

    2005-04-01

    This study reports on baseline characteristics associated with acceptance and refusal of available smoking treatment among currently depressed smokers in a psychiatric outpatient clinic who were enrolled in a larger clinical trial. The sample (N=154) was 68% female and 72% White, with a mean age of 41.4 years and average smoking rate of 17 cigarettes/day. All participants were assigned to a repeated contact experimental condition; received a stage-based expert system program to facilitate treatment acceptance; and were then offered smoking treatment, consisting of behavioral counseling, nicotine patch, and bupropion. Acceptors (n=53) were defined as those accepting behavioral counseling and pharmacological treatment at some point during the 18-month study, whereas refusers (n=101) received only the expert system. The number of days to treatment acceptance was significantly predicted by stage of change, with those in preparation entering treatment more quickly than contemplators or precontemplators. In a logistic regression, the variables most strongly associated with accepting treatment were current use of psychiatric medication and perceived success for quitting. Severity of depressive symptoms, duration of depression history, and history of recurrent depression were not related to treatment acceptance. Findings have implications for the psychiatric assessment and treatment of smokers in clinical settings. Psychiatric medication may play a significant role in smoking cessation treatment acceptance by currently depressed smokers. PMID:16036278

  15. Public perceptions and acceptance of intensive forestry in Sweden.

    PubMed

    Hemström, Kerstin; Mahapatra, Krushna; Gustavsson, Leif

    2014-03-01

    The use of intensive forestry on part of the forested area in Sweden increases the production of forest biomass and enables an increased use of such biomass to mitigate climate change. However, with increasing conflicting interests in forests and forestry, the success of such a strategy depends on the public acceptance. In this paper, the results of a mail survey show that although a majority of the general public in Sweden supports measures to increase forest growth, they oppose the use of intensive forestry practices such as the cultivation of exotic tree species, clones, and forest fertilization. The acceptance of such practices is mainly influenced by the perceptions of their environmental consequences. Public acceptance was highest for forest fertilization, whereas clone cultivation was the least accepted practice.

  16. Topological analysis of a haloacid permease of a Burkholderia sp. bacterium with a PhoA-LacZ reporter

    PubMed Central

    2009-01-01

    Background 2-Haloacids can be found in the natural environment as degradative products of natural and synthetic halogenated compounds. They can also be generated by disinfection of water and have been shown to be mutagenic and to inhibit glyceraldehyde-3-phosphate dehydrogenase activity. We have recently identified a novel haloacid permease Deh4p from a bromoacetate-degrading bacterium Burkholderia sp. MBA4. Comparative analyses suggested that Deh4p is a member of the Major Facilitator Superfamily (MFS), which includes thousands of membrane transporter proteins. Members of the MFS usually possess twelve putative transmembrane segments (TMS). Deh4p was predicted to have twelve TMS. In this study we characterized the topology of Deh4p with a PhoA-LacZ dual reporters system. Results Thirty-six Deh4p-reporter recombinants were constructed and expressed in E. coli. Both PhoA and LacZ activities were determined in these cells. Strength indices were calculated to determine the locations of the reporters. The results mainly agree with the predicted model. However, two of the TMS were not verified. This lack of confirmation of the TMS, using a reporter, has been reported previously. Further comparative analysis of Deh4p has assigned it to the Metabolite:H+ Symporter (MHS) 2.A.1.6 family with twelve TMS. Deh4p exhibits many common features of the MHS family proteins. Deh4p is apparently a member of the MFS but with some atypical features. Conclusion The PhoA-LacZ reporter system is convenient for analysis of the topology of membrane proteins. However, due to the limitation of the biological system, verification of some of the TMS of the protein was not successful. The present study also makes use of bioinformatic analysis to verify that the haloacid permease Deh4p of Burkholderia sp. MBA4 is a MFS protein but with atypical features. PMID:19878597

  17. Acceptance on the move: public reaction to shifting vaccination realities.

    PubMed

    Velan, Baruch

    2011-12-01

    This review examines four events related to vaccination that have occurred in recent years: (a) the ongoing recovery from the MMR/Autism scare in the UK, (b) the upgrading of the Varicella vaccine to a universal childhood vaccine, (c) the major effort of authorities to provide a vaccine for A/H1N1 influenza and its rejection by the public, and, d) the current attempts to change the HPV vaccine target from girls only to boys and girls. All of these changes have been met with shifts in the public acceptance of the relevant vaccine. These shifts are characterized not only by the number of people willing to be vaccinated, but also by the attitudes and the motives related to acceptance. Examination of the interrelationship between changes in vaccination realities, and changes in acceptance patterns suggests that today, the public has a better understanding of vaccination, is acting in a more reflexive way, and is capable of changing attitudes and behavior. All together, changes in vaccination enhance debates and dialogues about vaccines, and lead to higher awareness and more conscious acceptance. PMID:22108039

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. STUDY OF BL Lac VLBA DATA AT 8 AND 15 GHz IN A SUPER-RESOLUTION MODE

    SciTech Connect

    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.

  4. 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.

  5. 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).

  6. 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).

  7. 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.

  8. VERITAS Observations of the BL Lac Object PG 1553+113

    NASA Astrophysics Data System (ADS)

    Aliu, E.; Archer, A.; Aune, T.; Barnacka, A.; Behera, B.; Beilicke, M.; Benbow, W.; Berger, K.; Bird, R.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Errando, M.; Falcone, A.; Federici, S.; Feng, Q.; Finley, J. P.; Fortin, P.; Fortson, L.; Furniss, A.; Galante, N.; Gillanders, G. H.; Griffin, S.; Griffiths, S. T.; Grube, J.; Gyuk, G.; Håkansson, N.; Hanna, D.; Holder, J.; Hughes, G.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krawczynski, H.; Krennrich, F.; Kumar, S.; Lang, M. J.; Madhavan, A.; McArthur, S.; McCann, A.; Meagher, K.; Millis, J.; Moriarty, P.; Nieto, D.; O'Faoláin de Bhróithe, A.; Ong, R. A.; Orr, M.; Otte, A. N.; Park, N.; Perkins, J. S.; Pohl, M.; Popkow, A.; Prokoph, H.; Pueschel, E.; Quinn, J.; Ragan, K.; Rajotte, J.; Reyes, L. C.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Sembroski, G. H.; Shahinyan, K.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Varlotta, A.; Vassiliev, V. V.; Wakely, S. P.; Weinstein, A.; Welsing, R.; Wilhelm, A.; Williams, D. A.; Zitzer, B.

    2015-01-01

    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) × 10-11 photons cm-2 s-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) × 10-11 photons cm-2 s-1 (10.3% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44 +/- 0.71) × 10-11 {photons} {cm}-2 {s}-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 χ2 probability for a steady flux of 0.03%.

  9. 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%.

  10. Databases and software for the analysis of mutations in the human p53 gene, human hprt gene and both the lacI and lacZ gene in transgenic rodents.

    PubMed

    Cariello, N F; Douglas, G R; Gorelick, N J; Hart, D W; Wilson, J D; Soussi, T

    1998-01-01

    We have created databases and software applications for the analysis of DNA mutations at the human p53 gene, the human hprt gene and both the rodent transgenic lacI and lacZ loci. The databases themselves are stand-alone dBASE files and the software for analysis of the databases runs on IBM-compatible computers with Microsoft Windows. Each database has a separate software analysis program. The software created for these databases permit the filtering, ordering, report generation and display of information in the database. In addition, a significant number of routines have been developed for the analysis of single base substitutions. One method of obtaining the databases and software is via the World Wide Web. Open the following home page with a Web Browser: http://sunsite.unc.edu/dnam/mainpage. html . Alternatively, the databases and programs are available via public FTP from: anonymous@sunsite.unc.edu. There is no password required to enter the system. The databases and software are found beneath the subdirectory: pub/academic/biology/dna-mutations. Two other programs are available at the site, a program for comparison of mutational spectra and a program for entry of mutational data into a relational database.

  11. 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.

  12. 48 CFR 2911.103 - Market acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... offered have either achieved commercial market acceptance or been satisfactorily supplied to an agency... 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....

  13. 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...

  14. 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...

  15. 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…

  16. Apollo experience report environmental acceptance testing

    NASA Technical Reports Server (NTRS)

    Laubach, C. H. M.

    1976-01-01

    Environmental acceptance testing was used extensively to screen selected spacecraft hardware for workmanship defects and manufacturing flaws. The minimum acceptance levels and durations and methods for their establishment are described. Component selection and test monitoring, as well as test implementation requirements, are included. Apollo spacecraft environmental acceptance test results are summarized, and recommendations for future programs are presented.

  17. 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..., DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT GOVERNMENT PROPERTY Reporting, Redistribution, and Disposal of Contractor Inventory 245.606-3 Acceptance. (a) If the schedules are acceptable, the plant clearance...

  18. 46 CFR 28.73 - Accepted organizations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 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...

  19. 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...

  20. 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...

  1. 46 CFR 28.73 - Accepted organizations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 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...

  2. 46 CFR 28.73 - Accepted organizations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 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...

  3. Thermodynamic and alkylation interference analysis of the lac repressor-operator substituted with the analogue 7-deazaguanine.

    PubMed

    Zhang, X; Gottlieb, P A

    1993-10-26

    Guanine residues in the lac operator were substituted with the isosteric analogue of 7-deazaguanine. The observed equilibrium dissociation constants for lac repressor binding to substituted operators were measured in 10 mM Tris, 150 mM KCl, 0.1 mM EDTA, and 0.1 mM DTE, pH 7.6, at 25 degrees C, using either a standard equilibrium assay or a competition assay. Of the seven individual sites tested, only three significantly altered the complex affinity. Two of these sites are symmetrically related and are positioned in the major grooves that are known to interact directly with repressor, and the third site is located in the central core region of the operator. The alkylation interference assay, which identifies essential phosphate sites, was used to define the extent of perturbation on the protein-DNA complex by the modified nucleotide. Chemical footprinting data for the singly substituted operator done at a single concentration of protein reflected the alignment of sterically incompatible groups or disruption in the local conformation, but did not appear to alter general phosphate backbone interactions. Similar experiments with a doubly substituted operator revealed that the free energy of binding was an additive combination of each of the individual sites, and the alkylation interference data were similar to the singly substituted and wild-type operators. A constitutive mutant which also had a higher binding constant had a similar alkylation interference pattern. PMID:8218202

  4. Threshold Ionization of La(C_5H_8) Formed by La-MEDIATED Dehydrogenation of 1-PENTENE

    NASA Astrophysics Data System (ADS)

    Cao, Wenjin; Zhang, Yuchen; Yang, Dong-Sheng

    2016-06-01

    La(C_5H_8) was formed by La reaction with 1-pentene (CH2=CH-CH2-CH3) in a laser-vaporization supersonic molecular beam source and characterized with mass-analyzed threshold ionization (MATI) spectroscopy. The MATI spectrum displays an origin band at 38988 (5) wn and three vibrational intervals of 130, 294, and 415 wn. The La(C_5H_8) complex is identified as a five-membered metallacycle in C1 point group, with the doublet and singlet being the lowest energy states of the neutral and cation, respectively. The energy at 38998 wn corresponds to the adiabatic ionization energy of the complex, and the three vibration intervals in the order of the frequency increase are assigned to the terminal CH_3 torsion, asymmetric La-ligand stretch, and symmetric La-ligand stretch excitation of the ion. The La + 1-penetene reaction will also be compared with La reactions with other five-carbon hydrocarbon molecules, such as isoprene, 1-pentyne, and 1,4-pentadiene.

  5. Comments on Methods to Suppress Endogenous β-Galactosidase Activity in Mouse Tissues Expressing the LacZ Reporter Gene.

    PubMed

    Merkwitz, Claudia; Blaschuk, Orest; Schulz, Angela; Ricken, Albert Markus

    2016-10-01

    The Escherichia coli LacZ gene (encoding β-galactosidase) is a widely used reporter for gene regulation analysis in transgenic mice. Determination of β-galactosidase activity is classically performed using 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside/ferri-/ferrocyanide (X-Gal/FeCN) histochemistry. Uncertainty about the origin of the β-galactosidase signal is encountered in tissues containing high levels of endogenous β-galactosidase. Here, we show that reliable results can nevertheless be obtained in these tissues by performing the histochemical reaction under slightly basic pH conditions (pH 8-9). We further demonstrate that in this context, analysis of tissue sections may be advantageous over that of conventional whole-mount tissues because poor dye penetration and remaining tissue acidity are avoided in tissue sections. We also recommend that bacterial debris should always be carefully removed from the luminal surface of gastrointestinal tract specimens unless staining of resident microflora is deliberately used as an internal positive control in the assay. Finally, we show that 6-chloro-3-indolyl-β-d-galactopyranoside with nitrotetrazolium blue chloride works well as an alternative chromogenic substrate for visualizing LacZ reporter gene expression in cryostat sections. Its use in high endogenous β-galactosidase-expressing organs is superior over the use of X-Gal/FeCN at slightly basic pH conditions. PMID:27555495

  6. 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.

  7. Comments on Methods to Suppress Endogenous β-Galactosidase Activity in Mouse Tissues Expressing the LacZ Reporter Gene.

    PubMed

    Merkwitz, Claudia; Blaschuk, Orest; Schulz, Angela; Ricken, Albert Markus

    2016-10-01

    The Escherichia coli LacZ gene (encoding β-galactosidase) is a widely used reporter for gene regulation analysis in transgenic mice. Determination of β-galactosidase activity is classically performed using 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside/ferri-/ferrocyanide (X-Gal/FeCN) histochemistry. Uncertainty about the origin of the β-galactosidase signal is encountered in tissues containing high levels of endogenous β-galactosidase. Here, we show that reliable results can nevertheless be obtained in these tissues by performing the histochemical reaction under slightly basic pH conditions (pH 8-9). We further demonstrate that in this context, analysis of tissue sections may be advantageous over that of conventional whole-mount tissues because poor dye penetration and remaining tissue acidity are avoided in tissue sections. We also recommend that bacterial debris should always be carefully removed from the luminal surface of gastrointestinal tract specimens unless staining of resident microflora is deliberately used as an internal positive control in the assay. Finally, we show that 6-chloro-3-indolyl-β-d-galactopyranoside with nitrotetrazolium blue chloride works well as an alternative chromogenic substrate for visualizing LacZ reporter gene expression in cryostat sections. Its use in high endogenous β-galactosidase-expressing organs is superior over the use of X-Gal/FeCN at slightly basic pH conditions.

  8. 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

  9. 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.

  10. 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.

  11. Simultaneous measurement of benzo[a]pyrene-induced Pig-a and lacZ mutations, micronuclei and DNA adducts in Muta™ Mouse.

    PubMed

    Lemieux, Christine L; Douglas, George R; Gingerich, John; Phonethepswath, Souk; Torous, Dorothea K; Dertinger, Stephen D; Phillips, David H; Arlt, Volker M; White, Paul A

    2011-12-01

    In this study we compared the response of the Pig-a gene mutation assay to that of the lacZ transgenic rodent mutation assay, and demonstrated that multiple endpoints can be measured in a 28-day repeat dose study. Muta™Mouse were dosed daily for 28 days with benzo[a]pyrene (BaP; 0, 25, 50 and 75 mg/kg body weight/day) by oral gavage. Micronucleus (MN) frequency was determined in reticulocytes (RETs) 48 hr following the last dose. 72 h following the last dose, mice were euthanized, and tissues (glandular stomach, small intestine, bone marrow and liver) were collected for lacZ mutation and DNA adduct analysis, and blood was evaluated for Pig-a mutants. BaP-derived DNA adducts were detected in all tissues examined and significant dose-dependent increases in mutant Pig-a phenotypes (i.e., RET(CD24-) and RBC (CD24-)) and lacZ mutants were observed. We estimate that mutagenic efficiency (i.e., rate of conversion of adducts into mutations) was much lower for Pig-a compared to lacZ, and speculate that this difference is likely explained by differences in repair capacity between the gene targets, and differences in the cell populations sampled for Pig-a versus lacZ. The BaP doubling doses for both gene targets, however, were comparable, suggesting that similar mechanisms are involved in the accumulation of gene mutations. Significant dose-related increases in % MN were also observed; however, the doubling dose was considerably higher for this endpoint. The similarity in dose response kinetics of Pig-a and lacZ provides further evidence for the mutational origin of glycosylphosphatidylinositol (GPI)-anchor deficiencies detected in the Pig-a assay.

  12. Ion transport mediated by the valinomycin analogue cyclo(L-Lac-L-Val-D- Pro-D-Val)3 in lipid bilayer membranes

    PubMed Central

    1981-01-01

    Cyclo(L-Lac-L-Val-D-Pro-D-Val)3 (PV-Lac) a structural analogue of the ion-carrier valinomycin, increases the cation permeability of lipid bilayer membranes by forming a 1:1 ion-carrier complex. The selectively sequence for PV-Lac is identical to that of valinomycin; i.e., Rb+ greater than K+ greater than Cs+ greater than or equal to NH+4 greater than Na+ greater than Li+. The steady-state zero-voltage conductance, G(0), is a saturating function of KCl concentration. A similar behavior was found for Rb+, Cs+, and NH+4. However, the ion concentration at which G(0) reaches a plateau strongly depends on membrane composition. The current-voltage curves present saturating characteristics, except at low ion concentrations of Rb+, K+, or Cs+. The ion concentration at which the saturating characteristics appear depends on membrane composition. These and other results presented in this paper agree with a model that assumes complexation between carrier and ion at the membrane-water interface. Current relaxation after voltage-jump studies were also performed for PV-Lac. Both the time constant and the amplitude of the current after a voltage jump strongly depend on ion concentration and membrane composition. These results, together with the stationary conductance data, were used to evaluate the rate constants of the PV-Lac-mediated K+ transport. In glycerolmonooleate they are: association rate constant, 2 x 10(6) M-1 s-1; dissociation rate constant, 4 x 10(5) s-1; translocation rate constant for complex, 5 x 10(4) s-1; and the rate of translocation of the free carrier (ks), 55 s-1. ks is much smaller for PV-Lac than for valinomycin and thus limits the efficiency with which the carrier is able to translocate cations across the membrane. PMID:7241088

  13. 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.

  14. 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

  15. Calculating time since death in a mock crime case comparing a new computational method (ExLAC) with the ADH method.

    PubMed

    Reibe-Pal, Saskia; Madea, Burkhard

    2015-03-01

    We compared the results of calculating a minimum post-mortem interval (PMImin) in a mock crime case using two different methods: accumulated degree hours (ADH method) and a newly developed computational model called ExLAC. For the ADH method we further applied five reference datasets for the development time of Calliphora vicina (Diptera: Calliphoridae) from 5 different countries and our results confirmed the following: (1) Reference data for blowfly development that has not been sampled using a local blowfly colony should not, in most circumstances, be used in estimating a PMI in real cases; and (2) The new method ExLAC might be a potential alternative to the ADH method.

  16. 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…

  17. 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…

  18. 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.

  19. 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

  20. 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…

  1. [ACCEPTANCE AND COMMITMENT THERAPY (ACT): BEHAVIORISM, MINDFULNESS AND VALUES].

    PubMed

    Coletti, Juan Pablo; Teti, Germán Leandro

    2015-01-01

    Over the last decades a series of psychological treatments labeled have been developed. Acceptance and Commitment Therapy (ACT) is a third generation therapy that essentially seeks to promote the acceptance of private events in opposition to their modification or change, with the aim of promoting cognitive flexibility. Thus, it is intended that the subject be permitted to choose their behavior consistent with personal values. The current work aims to provide overview specific to the contextual conditions that promoted the emergence of ACT, the underlying philosophy and theory, and the particularities of the intervention model. PMID:26323112

  2. Status of Two Species of Lac Insects in the Genus Kerria from China Based on Morphological, Cellular, and Molecular Evidence

    PubMed Central

    Chen, Xiaoming; Chen, Hang; Feng, Ying; He, Rui; Yang, Zixiang

    2011-01-01

    The taxonomic status of the Chinese lac insects Kerria yunnanensis (Ou and Hong) (Hemiptera: Kerridae) and K. ruralis (Wang, Yao, Teiu and Liang) were analyzed in this paper by comparing morphological, cellular, and molecular data. Cladistic analysis showed K. yunnanensis and K. ruralis to be distinct from other Kerria species such as K. lacca and K. chinensis. The karyotype of K. yunnanensis was 3A and the chromosome structure was K = 6m + 2sm + 10T, while in K. ruralis the karyotype was 3B and the chromosome structure was K = 8m + 10T. Kerria ruralis and K. yunnanensis had the closest relationship among species in the genus as they had the most similar karyotype homology. Based on the karyotype analysis, K. sindica and K. lacca formed a sister group with K. ruralis and K. yunnanensis. Kerria pusana and K. nepalensis were clustered as a sister branch, indicating the close relationship of these taxa. The karyotype of K. chinensis was however, different from the other six species and formed a separate branch. RAPD analysis also showed that K. yunnanensis and K. ruralis had distinct differences from other species of Kerria, although they did not form sister taxa. Molecular analysis based on the EF1α gene using ML, MP, and Mr. Bayes' methods indicated that seven species of lac insects cluster in two major groups. In group 1, K. sindica and K. lacca formed a sister clade and were primitive members of the genus. In group 2, K. chinensis formed the earliest diverging branch followed by K. ruralis. Kerria yunnanensis was the next to diverge followed by the cluster containing K. pusana and K. nepalensis. Hybridization testing showed that crosses neither between K. yunnanensis and K. sindica, nor between K. yunnanensis and K. lacca could produce first generation larvae. This was indicative that K. yunnanensis had a distant genetic relationship from the other species. Morphological, cellular, molecular, and hybridization results confirmed the independent status of the

  3. A search of CO emission lines in blazars: the low molecular gas content of BL Lac objects compared to quasars

    NASA Astrophysics Data System (ADS)

    Fumagalli, Michele; Dessauges-Zavadsky, Miroslava; Furniss, Amy; Prochaska, J. Xavier; Williams, David A.; Kaplan, Kyle; Hogan, Matthew

    2012-08-01

    BL Lacertae (Lac) objects that are detected at very high energies (VHE) are of fundamental importance to study multiple astrophysical processes, including the physics of jets, the properties of the extragalactic background light and the strength of the intergalactic magnetic field. Unfortunately, since most blazars have featureless optical spectra that preclude a redshift determination, a substantial fraction of these VHE extragalactic sources cannot be used for cosmological studies. To assess whether molecular lines are a viable way to establish distances, we have undertaken a pilot programme at the Institut of Millimétrique (IRAM) 30 m telescope to search for CO lines in three BL Lac objects with known redshifts. We report a positive detection of 12 MH_2 ˜ 3 × 10>8 M⊙ towards 1ES 1959+650, but due to the poor quality of the baseline, this value is affected by a large systematic uncertainty. For the remaining two sources, W Comae and RGB J0710+591, we derive 3σ upper limits at, respectively, H2 < 8.0 × 108 and 1.6 × 109 M⊙, assuming a line width of 150 km s-1 and a standard conversion factor α = 4 M⊙ (K km s-1 pc2)-1. If these low molecular gas masses are typical for blazars, blind redshift searches in molecular lines are currently unfeasible. However, deep observations are still a promising way to obtain precise redshifts for sources whose approximate distances are known via indirect methods. Our observations further reveal a deficiency of molecular gas in BL Lac objects compared to quasars, suggesting that the host galaxies of these two types of active galactic nuclei (AGN) are not drawn from the same parent population. Future observations are needed to assess whether this discrepancy is statistically significant, but our pilot programme shows how studies of the interstellar medium in AGN can provide key information to explore the connection between the active nuclei and the host galaxies. Based on observations carried out with the IRAM 30 m

  4. 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

  5. Treatment acceptability among mexican american parents.

    PubMed

    Borrego, Joaquin; Ibanez, Elizabeth S; Spendlove, Stuart J; Pemberton, Joy R

    2007-09-01

    There is a void in the literature with regard to Hispanic parents' views about common interventions for children with behavior problems. The purpose of this study was to examine the treatment acceptability of child management techniques in a Mexican American sample. Parents' acculturation was also examined to determine if it would account for differences in treatment acceptability. Mexican American parents found response cost, a punishment-based technique, more acceptable than positive reinforcement-based techniques (e.g., differential attention). Results suggest that Mexican American parents' acculturation has little impact on acceptability of child management interventions. No association was found between mothers' acculturation and treatment acceptability. However, more acculturated Mexican American fathers viewed token economy as more acceptable than less acculturated fathers. Results are discussed in the context of clinical work and research with Mexican Americans.

  6. 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

  7. Food-grade host/vector expression system for Lactobacillus casei based on complementation of plasmid-associated phospho-beta-galactosidase gene lacG.

    PubMed

    Takala, T M; Saris, P E J; Tynkkynen, S S H

    2003-01-01

    A new food-grade host/vector system for Lactobacillus casei based on lactose selection was constructed. The wild-type non-starter host Lb. casei strain E utilizes lactose via a plasmid-encoded phosphotransferase system. For food-grade cloning, a stable lactose-deficient mutant was constructed by deleting a 141-bp fragment from the phospho-beta-galactosidase gene lacG via gene replacement. The deletion resulted in an inactive phospho-beta-galactosidase enzyme with an internal in-frame deletion of 47 amino acids. A complementation plasmid was constructed containing a replicon from Lactococcus lactis, the lacG gene from Lb. casei, and the constitutive promoter of pepR for lacG expression from Lb. rhamnosus. The expression of the lacG gene from the resulting food-grade plasmid pLEB600 restored the ability of the lactose-negative mutant strain to grow on lactose to the wild-type level. The vector pLEB600 was used for expression of the proline iminopeptidase gene pepI from Lb. helveticus in Lb. casei. The results show that the food-grade expression system reported in this paper can be used for expression of foreign genes in Lb. casei. PMID:12536257

  8. Mesoscale modeling of multi-protein-DNA assemblies: the role of the catabolic activator protein in Lac-repressor-mediated looping

    PubMed Central

    Swigon, David; Olson, Wilma K.

    2009-01-01

    DNA looping plays a key role in the regulation of the lac operon in Escherichia coli. The presence of a tightly bent loop (between sequentially distant sites of Lac repressor protein binding) purportedly hinders the binding of RNA polymerase and subsequent transcription of the genetic message. The unexpectedly favorable binding interaction of this protein-DNA assembly with the catabolic activator protein (CAP), a protein that also bends DNA and paradoxically facilitates the binding of RNA polymerase, stimulated extension of our base-pair level theory of DNA elasticity to the treatment of DNA loops formed in the presence of several proteins. Here we describe in detail a procedure to determine the structures and free energies of multi-protein-DNA assemblies and illustrate the predicted effects of CAP binding on the configurations of the wild-type 92-bp Lac repressor-mediated O3-O1 DNA loop. We show that the DNA loop adopts an antiparallel orientation in the most likely structure and that this loop accounts for the published experimental observation that, when CAP is bound to the loop, one of the arms of LacR binds to an alternative site that is displaced from the original site by 5 bp. PMID:23874000

  9. Acceptability of blood and blood substitutes.

    PubMed

    Ferguson, E; Prowse, C; Townsend, E; Spence, A; Hilten, J A van; Lowe, K

    2008-03-01

    Alternatives to donor blood have been developed in part to meet increasing demand. However, new biotechnologies are often associated with increased perceptions of risk and low acceptance. This paper reviews developments of alternatives and presents data, from a field-based experiment in the UK and Holland, on the risks and acceptance of donor blood and alternatives (chemical, genetically modified and bovine). UK groups perceived all substitutes as riskier than the Dutch. There is a negative association between perceived risk and acceptability. Solutions to increasing acceptance are discussed in terms of implicit attitudes, product naming and emotional responses.

  10. 7 CFR 932.32 - Acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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 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...

  12. 7 CFR 932.32 - Acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 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...

  13. 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...

  14. 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...

  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. 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...

  17. 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...

  18. 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...

  19. 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...

  20. The cost of expression of Escherichia coli lac operon proteins is in the process, not in the products.

    PubMed

    Stoebel, Daniel M; Dean, Antony M; Dykhuizen, Daniel E

    2008-03-01

    Transcriptional regulatory networks allow bacteria to express proteins only when they are needed. Adaptive hypotheses explaining the evolution of regulatory networks assume that unneeded expression is costly and therefore decreases fitness, but the proximate cause of this cost is not clear. We show that the cost in fitness to Escherichia coli strains constitutively expressing the lactose operon when lactose is absent is associated with the process of making the lac gene products, i.e., associated with the acts of transcription and/or translation. These results reject the hypotheses that regulation exists to prevent the waste of amino acids in useless protein or the detrimental activity of unnecessary proteins. While the cost of the process of protein expression occurs in all of the environments that we tested, the expression of the lactose permease could be costly or beneficial, depending on the environment. Our results identify the basis of a single selective pressure likely acting across the entire E. coli transcriptome. PMID:18245823

  1. Physical characteristics of stream subbasins in the Lac qui Parle River basin, southwestern Minnesota and eastern South Dakota

    USGS Publications Warehouse

    Lorenz, D.L.; Sanocki, C.A.; Winterstein, Thomas A.

    1994-01-01

    Data describing the physical characteristics of stream subbasins upstream from selected points on streams in the Lac qui Parle River basin, located in southwestern Minnesota and eastern South Dakota, are presented in this report. The physical charac- teristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length. and the main-channel slope. The points on the stream include outlets of subbasins of at least 5 square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  2. WHAT IS THE REDSHIFT OF THE GAMMA-RAY BL LAC SOURCE S4 0954+65?

    SciTech Connect

    Landoni, M.; Falomo, R.; Treves, A.; Scarpa, R.; Payá, D. Reverte

    2015-12-15

    High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by the MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in 2015 February, making the determination of its distance particularly relevant for our understanding of the properties of the extragalactic background light. Contrary to previous reports on the redshift, we found that the optical spectrum is featureless at an equivalent width limit of ∼0.1 Å. A critical analysis of the existing observations indicates that the redshift is still unknown. Based on the new data we estimate a lower limit to the redshift at z ≥ 0.45.

  3. Complete Genomes of Bacillus coagulans S-lac and Bacillus subtilis TO-A JPC, Two Phylogenetically Distinct Probiotics

    PubMed Central

    Ramya, T. N. C.; Subramanian, Srikrishna

    2016-01-01

    Several spore-forming strains of Bacillus are marketed as probiotics due to their ability to survive harsh gastrointestinal conditions and confer health benefits to the host. We report the complete genomes of two commercially available probiotics, Bacillus coagulans S-lac and Bacillus subtilis TO-A JPC, and compare them with the genomes of other Bacillus and Lactobacillus. The taxonomic position of both organisms was established with a maximum-likelihood tree based on twenty six housekeeping proteins. Analysis of all probiotic strains of Bacillus and Lactobacillus reveal that the essential sporulation proteins are conserved in all Bacillus probiotic strains while they are absent in Lactobacillus spp. We identified various antibiotic resistance, stress-related, and adhesion-related domains in these organisms, which likely provide support in exerting probiotic action by enabling adhesion to host epithelial cells and survival during antibiotic treatment and harsh conditions. PMID:27258038

  4. 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

  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. 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

  7. LacZ β-galactosidase: structure and function of an enzyme of historical and molecular biological importance.

    PubMed

    Juers, Douglas H; Matthews, Brian W; Huber, Reuben E

    2012-12-01

    This review provides an overview of the structure, function, and catalytic mechanism of lacZ β-galactosidase. The protein played a central role in Jacob and Monod's development of the operon model for the regulation of gene expression. Determination of the crystal structure made it possible to understand why deletion of certain residues toward the amino-terminus not only caused the full enzyme tetramer to dissociate into dimers but also abolished activity. It was also possible to rationalize α-complementation, in which addition to the inactive dimers of peptides containing the "missing" N-terminal residues restored catalytic activity. The enzyme is well known to signal its presence by hydrolyzing X-gal to produce a blue product. That this reaction takes place in crystals of the protein confirms that the X-ray structure represents an active conformation. Individual tetramers of β-galactosidase have been measured to catalyze 38,500 ± 900 reactions per minute. Extensive kinetic, biochemical, mutagenic, and crystallographic analyses have made it possible to develop a presumed mechanism of action. Substrate initially binds near the top of the active site but then moves deeper for reaction. The first catalytic step (called galactosylation) is a nucleophilic displacement by Glu537 to form a covalent bond with galactose. This is initiated by proton donation by Glu461. The second displacement (degalactosylation) by water or an acceptor is initiated by proton abstraction by Glu461. Both of these displacements occur via planar oxocarbenium ion-like transition states. The acceptor reaction with glucose is important for the formation of allolactose, the natural inducer of the lac operon. PMID:23011886

  8. A KPC-Scale X-Ray Jet in the BL Lac Source S5 2007+777

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita M.; Donato, Davide; Cheung, C.C.; Tavecchio, F.; Maraschi, L.

    2008-01-01

    X-ray jets in AGN are commonly observed in FRII and FRI radiogalaxies, but rarely in BL Lacs, most probably due to their orientation close to the line of sight and the ensuing foreshortening effects. Only three BL Lacs are known so far to contain a kpc-scale X-ray jet. In this paper, we present the evidence for the existence of a fourth extended X-ray jet in the classical radio-selected source S5 2007+777, which for its hybrid FRI/II radio morphology has been classified as a HYMOR (HYbrid MOrphology Radio source). Our Chandra ACISS observations of this source revealed an X-ray counterpart to the 19"-long radio jet. Interestingly, the X-ray properties of the kpc-scale jet in S5 2007+777 are very similar to those observed in FRII jets. First, the X-ray morphology closely mirrors the radio one, with the X-rays being concentrated in the discrete radio knots. Second, the X-ray continuum of the jet/brightest knot is described by a very hard power law, with photon index gamma(sub x) approximately 1. Third, the optical upper limit from archival HST data implies a concave radio-to-X-ray SED. If the X-ray emission is attributed to IC/CMB with equipartition, strong beaming (delta= 13) is required, implying a very large scale (Mpc) jet. The beaming requirement can be somewhat relaxed assuming a magnetic field lower than equipartition. Alternatively, synchrotron emission from a second population of very high-energy electrons is viable. Comparison to other HYMOR jets detected with Chandra is discussed, as well as general implications for the origin of the FRI/II division.

  9. EVN Observations of HESS J1943+213: Evidence for an Extreme TeV BL Lac Object

    NASA Astrophysics Data System (ADS)

    Akiyama, Kazunori; Stawarz, Łukasz; Tanaka, Yasuyuki T.; Nagai, Hiroshi; Giroletti, Marcello; Honma, Mareki

    2016-06-01

    We report on the 1.6 GHz (18 cm) very long baseline interferometry (VLBI) observations of the unresolved, steady TeV source HESS J1943+213 located in the Galactic plane, performed with the European VLBI Network (EVN) in 2014. Our new observations with a nearly full EVN array provide the deepest image of HESS J1943+213 at the highest resolution ever achieved, enabling us to resolve the long-standing issues of the source identification. The milliarcsecond-scale structure of HESS J1943+213 has a clear asymmetric morphology consisting of a compact core and a diffuse jet-like tail. This is broadly consistent with the previous e-EVN observations of the source performed in 2011 and re-analyzed in this work. The core component is characterized by the brightness temperature of ≳ 1.8× {10}9 K, which is typical for low-luminosity blazars in general. Overall, the radio properties of HESS J1943+213 are consistent with the source classification as an “extreme high-frequency-peaked BL Lac object.” Remarkably, we note that because HESS J1943+213 does not reveal any optical or infrared signatures of the active galactic nucleus activity, it would never be recognized and identified as a BL Lac object if not for its location close to the Galactic plane where the High Energy Stereoscopic System surveyed for and the follow-up dedicated X-ray and radio studies triggered by the source detection in the TeV range. Our results suggest, therefore, a presence of an unrecognized, possibly very numerous population of particularly extreme HBLs and simultaneously demonstrate that the low-frequency VLBI observations with high angular resolution are indispensable for a proper identification of such objects.

  10. Analysis of the LacI family regulators of Erwinia chrysanthemi 3937, involvement in the bacterial phytopathogenicity.

    PubMed

    Van Gijsegem, Frédérique; Wlodarczyk, Aleksandra; Cornu, Amandine; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole

    2008-11-01

    Analysis of the regulators of the LacI family was performed in order to identify those potentially involved in pathogenicity of Erwinia chrysanthemi (Dickeya dadantii). Among the 18 members of the LacI family, the function of 11 members is either known or predicted and only 7 members have, as yet, no proposed function. Inactivation of these seven genes, called lfaR, lfbR, lfcR, lfdR, lfeR, lffR, and lfgR, demonstrated that four of them are important for plant infection. The lfaR and lfcR mutants showed a reduced virulence on chicory, Saintpaulia sp., and Arabidopsis. The lfeR mutant showed a reduced virulence on Arabidopsis. The lfdR mutant was more efficient than the wild-type strain in initiating maceration on Saintpaulia sp. The genetic environment of each regulator was examined to detect adjacent genes potentially involved in a common function. Construction of transcriptional fusions in these neighboring genes demonstrated that five regulators, LfaR, LfcR, LfeR, LffR, and LfgR, act as repressors of adjacent genes. Analysis of these fusions also indicated that the genes controlled by LfaR, LfcR, LfgR, and LffR are expressed during plant infection. Moreover, addition of crude plant extracts to culture medium demonstrated that the expression of the LfaR- and LfgR-controlled genes is specifically induced by plant components. PMID:18842096

  11. Water in the Cratonic Mantle: Insights from FTIR Data on Lac De Gras Xenoliths (Slave Craton, Canada)

    NASA Technical Reports Server (NTRS)

    Peslier, Anne H.; Brandon, Alan D.; Schaffer, Lillian Aurora; O'Reilly, Suzanne Yvette; Griffin, William L.; Morris, Richard V.; Graff, Trevor G.; Agresti, David G.

    2014-01-01

    The mantle lithosphere beneath the cratonic part of continents is the deepest (> 200 km) and oldest (>2-3 Ga) on Earth, remaining a conundrum as to how these cratonic roots could have resisted delamination by asthenospheric convection over time. Water, or trace H incorporated in mineral defects, could be a key player in the evolution of continental lithosphere because it influences melting and rheology of the mantle. Mantle xenoliths from the Lac de Gras kimberlite in the Slave craton were analyzed by FTIR. The cratonic mantle beneath Lac de Gras is stratified with shallow (<145 km) oxidized ultradepleted peridotites and pyroxenites with evidence for carbonatitic metasomatism, underlain by reduced and less depleted peridotites metasomatized by kimberlite melts. Peridotites analyzed so far have H O contents in ppm weight of 7-100 in their olivines, 58 to 255 in their orthopyroxenes (opx), 11 to 84 in their garnet, and 139 in one clinopyroxene. A pyroxenite contains 58 ppm H2O in opx and 5 ppm H2O in its olivine and garnet. Olivine and garnet from the deep peridotites have a range of water contents extending to higher values than those from the shallow ones. The FTIR spectra of olivines from the shallow samples have more prominent Group II OH bands compared to the olivines from the deep samples, consistent with a more oxidized mantle environment. The range of olivine water content is similar to that observed in Kaapvaal craton peridotites at the same depths (129-184 km) but does not extend to as high values as those from Udachnaya (Siberian craton). The Slave, Kaapvaal and Siberian cratons will be compared in terms of water content distribution, controls and role in cratonic root longevity.

  12. Changes in the healthcare profession: from denial to acceptance.

    PubMed

    Sanford, K

    1990-01-01

    As the government and other factors seem to be increasingly gaining control over the healthcare industry, many hospital managers and staff feel as if they're increasingly losing control over their jobs and their futures. Indeed, some administrators and physicians are experiencing a kind of stress that may be seen as a grief for the way things once were. Using Elisabeth Kubler-Ross's stages of the grieving process, the author explains how such stress can be managed and some control regained. PMID:10107972

  13. Galatrox is a C-type lectin in Bothrops atrox snake venom that selectively binds LacNAc-terminated glycans and can induce acute inflammation

    PubMed Central

    Sartim, Marco A; Riul, Thalita B; Del Cistia-Andrade, Camillo; Stowell, Sean R; Arthur, Connie M; Sorgi, Carlos A; Faccioli, Lucia H; Cummings, Richard D; Dias-Baruffi, Marcelo; Sampaio, Suely V

    2014-01-01

    Previous studies indicate that snake venom contains glycan-binding proteins (GBPs), although the binding specificity and biological activities of many of these GBPs is unclear. Here we report our studies on the glycan binding specificity and activities of galatrox, a Bothrops atrox snake venom-derived GBP. Glycan microarray analysis indicates that galatrox binds most strongly to glycans expressing N-acetyllactosamine (LacNAc), with a significant preference for Galβ1-4GlcNAcβ over Galβ1-3GlcNAcβ compounds. Galatrox also bound immobilized laminin, a LacNAc-dense extracellular matrix component, suggesting that this GBP can bind LacNAc-bearing glycoproteins. As several endogenous mammalian GBPs utilize a similar binding LacNAc binding preference to regulate neutrophil and monocyte activity, we hypothesized that galatrox may mediate B. atrox toxicity through regulation of leukocyte activity. Indeed, galatrox bound neutrophils and promoted leukocyte chemotaxis in a carbohydrate-dependent manner. Similarly, galatrox administration into the mouse peritoneal cavity induced significant neutrophil migration and the release of pro-inflammatory cytokines IL-1α and IL-6. Exposure of bone marrow-derived macrophages to galatrox induced generation of pro-inflammatory mediators IL-6, TNF-α, and keratinocyte-derived chemokine. This signaling by galatrox was mediated via its carbohydrate recognition domain by activation of the TLR4-mediated MyD88-dependent signaling pathway. These results indicate that galatrox has pro-inflammatory activity through its interaction with LacNAc-bearing glycans on neutrophils, macrophages and extracellular matrix proteins and induce the release of pro-inflammatory mediators. PMID:24973254

  14. Galatrox is a C-type lectin in Bothrops atrox snake venom that selectively binds LacNAc-terminated glycans and can induce acute inflammation.

    PubMed

    Sartim, Marco A; Riul, Thalita B; Del Cistia-Andrade, Camillo; Stowell, Sean R; Arthur, Connie M; Sorgi, Carlos A; Faccioli, Lucia H; Cummings, Richard D; Dias-Baruffi, Marcelo; Sampaio, Suely V

    2014-11-01

    Previous studies indicate that snake venom contains glycan-binding proteins (GBPs), although the binding specificity and biological activities of many of these GBPs is unclear. Here we report our studies on the glycan binding specificity and activities of galatrox, a Bothrops atrox snake venom-derived GBP. Glycan microarray analysis indicates that galatrox binds most strongly to glycans expressing N-acetyllactosamine (LacNAc), with a significant preference for Galβ1-4GlcNAcβ over Galβ1-3GlcNAcβ compounds. Galatrox also bound immobilized laminin, a LacNAc-dense extracellular matrix component, suggesting that this GBP can bind LacNAc-bearing glycoproteins. As several endogenous mammalian GBPs utilize a similar binding LacNAc binding preference to regulate neutrophil and monocyte activity, we hypothesized that galatrox may mediate B. atrox toxicity through regulation of leukocyte activity. Indeed, galatrox bound neutrophils and promoted leukocyte chemotaxis in a carbohydrate-dependent manner. Similarly, galatrox administration into the mouse peritoneal cavity induced significant neutrophil migration and the release of pro-inflammatory cytokines IL-1α and IL-6. Exposure of bone marrow-derived macrophages to galatrox induced generation of pro-inflammatory mediators IL-6, TNF-α, and keratinocyte-derived chemokine. This signaling by galatrox was mediated via its carbohydrate recognition domain by activation of the TLR4-mediated MyD88-dependent signaling pathway. These results indicate that galatrox has pro-inflammatory activity through its interaction with LacNAc-bearing glycans on neutrophils, macrophages and extracellular matrix proteins and induce the release of pro-inflammatory mediators. PMID:24973254

  15. Mutational spectra of the lacI transgene isolated from Big Blue{reg_sign} mice exposed to three carcinogenic aromatic amines

    SciTech Connect

    Staedtler, F.; Locher, F.; Sreenan, G.

    1997-10-01

    In order to evaluate the in vivo genotoxic potential of three putative genotoxic mouse liver carcinogens, high doses of 4-chloro-o-phenylenediamine, 2-nitro-p-phenylenediamine and 2, 4-diaminotoluene were tested short term in the Big Blue{reg_sign} transgenic mouse mutation assay. Small statistically significant increases in the lacI mutant frequencies in the liver by factors 1.7 to 2.0 were found. A representative number of 347 lacI mutants isolated from liver tissue of male and female animals were analyses by DNA sequencing. The mutational spectra were examined with the Adams-Skopek algorithm. The spontaneous mutational spectra from untreated male and female animals were similar and consistent with spectral Big Blue{reg_sign} control data stored in the lacI database. Most of the background mutations were located in the 5{prime} portion of the coding region of the lacI gene. Single base substitutions were most prominent. G:C to A:T transitions and G:C to T:A transversions occurred predominatly and were preferentially located at CpG sites. Despite the increases observed in the mutant frequencies of the treated animals, the corresponding mutational spectra did not differ from the controls. However, it is possible that certain classes of point mutations were substantially increased but not detected due to the limited number of sequenced mutants. In two animals treated with 2, 4- diaminotoluene unusually high mutant frequencies and the multiple occurrence of certain mutations in the liver was observed. From one of these animals six lacI mutants isolated from colon tissue were all different. Since 2, 4-diaminotoluene was shown to induce liver cell proliferation these results may reflect clonal expansion of single mutated liver cells.

  16. 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 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MISCELLANEOUS INTERPRETATIONS Interpretations § 250.164 Bankers' acceptances. (a) Section 207 of the Bank...

  17. 48 CFR 3011.103 - 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. 3011.103 Section 3011.103 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY, HOMELAND... Developing Requirements Documents 3011.103 Market acceptance. (a) Contracting officers may act on behalf...

  18. 48 CFR 411.103 - Market acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Market acceptance. 411.103... ACQUISITION PLANNING DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 411.103 Market... accordance with FAR 11.103(a), the market acceptability of their items to be offered. (b) The...

  19. 48 CFR 3011.103 - 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. 3011.103 Section 3011.103 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY, HOMELAND... Developing Requirements Documents 3011.103 Market acceptance. (a) Contracting officers may act on behalf...

  20. 48 CFR 411.103 - Market acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Market acceptance. 411.103... ACQUISITION PLANNING DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 411.103 Market... accordance with FAR 11.103(a), the market acceptability of their items to be offered. (b) The...