2,698 research outputs found

    Index to Library Trends Volume 14

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    MCC level C formulation requirements. Shuttle TAEM targeting

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    The level C requirements for the shuttle orbiter terminal area energy management (TAEM) guidance and flight control functions to be incorporated into the Mission Control Center entry profile planning processor are described. This processor is used for preentry evaluation of the entry through landing maneuvers, and includes a simplified three degree-of-freedom model of the body rotational dynamics that is necessary to account for the effects of attitude response on the trajectory dynamics. This simulation terminates at TAEM-autoland interface

    MCC level C formulation requirements. Shuttle TAEM guidance and flight control, STS-1 baseline

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    The TAEM guidance and body rotational dynamics models required for the MCC simulation of the TAEM mission phase are defined. This simulation begins at the end of the entry phase and terminates at TAEM autoland interface. The logic presented is the required configuration for the first shuttle orbital flight (STS-1). The TAEM guidance is simulated in detail. The rotational dynamics simulation is a simplified model that assumes that the commanded rotational rates can be achieved in the integration interval. Thus, the rotational dynamics simulation is essentially a simulation of the autopilot commanded rates and integration of these rates to determine orbiter attitude. The rotational dynamics simulation also includes a simulation of the speedbrake deflection. The body flap and elevon deflections are computed in the orbiter aerodynamic simulation

    Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

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    Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

    Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

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    Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

    Certified Registered Nurse Anesthetist’s Awareness and Knowledge of Herbal Supplements and Perioperative Interactions

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    Previous studies have asserted that anesthesia providers are deficient in their knowledge of herbal supplements and their perioperative interactions. The purpose of this project was to examine the impact of an educational handout on Certified Registered Nurse Anesthetists’ (CRNAs) knowledge and attitudes of herbal supplements and their perioperative interactions utilizing a pre-posttest project design. The survey components were sent to approximately 1,600 members of the Illinois Association of Nurse Anesthetists (IANA) with a response of 140 surveys. Data was analyzed using descriptive Cohen’s d and nonparametric statistical tests. Reliability of the instruments used were assessed using Cronbach’s ɑ coefficients. The posttest Cronbach’s ɑ coefficient for attitudes subscale was 0.817, and for the knowledge subscale was 0.915, both of which indicate a high reliability of the consistency of the items in the attitude and knowledge subscale. The Cohen’s d values for attitudes and knowledge were -0.89 and -0.11 respectively. Thus, the tool had a large effect on attitudes and a small effect on knowledge. The p values for attitudes (p = 0.000) and knowledge (p = 0.043) were both statistically significant. There were no statistically significant differences found in the mean scores for attitude or knowledge based on categorical groupings by gender, level of education, years of practice, or age

    Kloning Promoter P-actin Ikan Mas, Cyprinus Carpio Lin. 1758 Dan Analisis Fungsionalnya Menggunakan Gen Target Protein Pendaran Hijau (GFP) [P-actin Promoter Cloning of Common Carp, Cyprinus Carpio Lin. 1758 and Its Functional Analysis Using Targeted Green Fluorescent Protein (GFP) Gene]

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    Promoter dalam vektor ekspresi berperan penting dalam mengatur ekspresi gen pada ikan transgenik. Dalam transgenesis ikan, peneliti yakin bahwa penggunaan vektor ekspresi semua ikan aman dan prospektif. Penelitian ini dilakukan untuk mengisolasi promoter P-aktin, promoter yang memiliki karakteristik ubiquitous, constitutive, house keeping, dari ikan mas sebagai langkah awal untuk mengkonstruksi vektor ekspresi semua ikan mas. Promoter P-aktin ikan mas (ccBA) diisolasi menggunakan metode PCR dengan primer FBP1, RBP1, dan RBP2. Sequensing dilakukan dengan menggunakan mesin ABI PRISM 3100, dan analisis sekuen dilakukan dengan menggunakan perangkat lunak GENE-TYX versi 7. Hasil analisis sekuen menunjukkan bahwa panjang fragmen DNA yang diperoleh adalah sekitar 1,5 kb. Hasil homologi dengan sekuen promoter P-aktin dari pangkalan data bank gen (No. Aksesi: M24113) adalah sebesar 97,5%. Faktor transkripsi yang tetap secara evolusioner untuk promoter P-aktin promoter termasuk CCAT, CArG, dan boks TATA ditemukan dalam sekuen. Ubiquitous dan ekspresi tertinggi protein pendaran hijau (GFP) dikendalikan oleh promoter ccBA dalam otot larva ikan mas yang dideteksi. Dengan demikian, kemungkinan besar bahwa sekuen yang terisolasi adalah promoter P-aktin ikan mas

    STUDI KROMOSOM IKAN PELANGI (Melanotaenia Lacustris) [Chromosome Study of Rainbowfish (Melanotaenia Lacustris)]

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    Penelitian sitogenetika pada ikan pelangi (Melanotaenia lacustris) difokuskan pada pengungkapan keanekaragaman kromosom dalam hal jumlah, bentuk, dan karyotipenya. Penelitian dilakukan di Laboratorium Genetika dan Reproduksi ikan Fakuitas Perikanan dan 11 mu Kelautan IPB, pada bulan on Mei — Deseber 2000. Preparat kromosom dibuat dengan metode jaringan padat yang menggunakan larva ikan umur 10-30 hari. Analisis kromosom dilakukan setelah pewarnaan dengan larutan Giemza. Kromosom diploid ikan M. lacustris adalah (2N = 46). Karyotipenya menunjukkan 46 kromosom yang terdiri atas 9 pasang berbentuk submetasentrik (SM) (no. 1, 3, 6, 7, 8, 9, 10, 13, and 14); 3 pasang subtelosentrik (ST) (no. 4, 12, 22) dan 10 pasang telosentrik (T) (no. 2, 5, 11, 15, 16, 17, IB, 19, 20, and 21) dengan 1 ST dan 1 T pada no. 23. Dari basil tersebut diduga bahwa M, lacustris memiliki kromosom sek

    Apospory appears to accelerate onset of meiosis and sexual embryo sac formation in sorghum ovules

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    <p>Abstract</p> <p>Background</p> <p>Genetically unreduced (2<it>n</it>) embryo sacs (ES) form in ovules of gametophytic apomicts, the 2<it>n </it>eggs of which develop into embryos parthenogenetically. In many apomicts, 2<it>n </it>ES form precociously during ovule development. Whether meiosis and sexual ES formation also occur precociously in facultative apomicts (capable of apomictic and sexual reproduction) has not been studied. We determined onset timing of meiosis and sexual ES formation for 569 <it>Sorghum bicolor </it>genotypes, many of which produced 2<it>n </it>ES facultatively.</p> <p>Results</p> <p>Genotype differences for onset timing of meiosis and sexual ES formation, relative to ovule development, were highly significant. A major source of variation in timing of sexual germline development was presence or absence of apomictic ES, which formed from nucellar cells (apospory) in some genotypes. Genotypes that produced these aposporous ES underwent meiosis and sexual ES formation precociously. Aposporous ES formation was most prevalent in subsp. <it>verticilliflorum </it>and in breeding lines of subsp. <it>bicolor</it>. It was uncommon in land races.</p> <p>Conclusions</p> <p>The present study adds meiosis and sexual ES formation to floral induction, apomictic ES formation, and parthenogenesis as processes observed to occur precociously in apomictic plants. The temporally diverse nature of these events suggests that an epigenetic memory of the plants' apomixis status exists throughout its life cycle, which triggers, during multiple life cycle phases, temporally distinct processes that accelerate reproduction.</p
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