475 research outputs found

    Short Proofs for Cut-and-Paste Sorting of Permutations

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    We consider the problem of determining the maximum number of moves required to sort a permutation of [n][n] using cut-and-paste operations, in which a segment is cut out and then pasted into the remaining string, possibly reversed. We give short proofs that every permutation of [n][n] can be transformed to the identity in at most \flr{2n/3} such moves and that some permutations require at least \flr{n/2} moves.Comment: 7 pages, 2 figure

    An improved lower bound for (1,<=2)-identifying codes in the king grid

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    We call a subset CC of vertices of a graph GG a (1,)(1,\leq \ell)-identifying code if for all subsets XX of vertices with size at most \ell, the sets {cCuX,d(u,c)1}\{c\in C |\exists u \in X, d(u,c)\leq 1\} are distinct. The concept of identifying codes was introduced in 1998 by Karpovsky, Chakrabarty and Levitin. Identifying codes have been studied in various grids. In particular, it has been shown that there exists a (1,2)(1,\leq 2)-identifying code in the king grid with density 3/7 and that there are no such identifying codes with density smaller than 5/12. Using a suitable frame and a discharging procedure, we improve the lower bound by showing that any (1,2)(1,\leq 2)-identifying code of the king grid has density at least 47/111

    Agricultural Performance of Diverse Pastures of Complementary Species and Monoculture Pastures Defoliated According to the Leaf Regrowth Stage Window of Opportunity Criterion

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    In a diverse pasture of complementary species (DPCS), individual species fulfil agro-ecological functions that confer growth asynchrony and complementarity of ecosystem functions. These attributes provide yield consistency with a more even forage supply pattern across the year compared to monocultures. A common leaf regrowth stage window opportunity (LSWO) for the diverse species enables pasture defoliation that stimulates growth and persistence. The study assessed seasonal and annual growth traits of Lolium perenne (Lp), Bromus valdivianus (Bv) and Dactylis glomerata (Dg) as single grass species (Mono) sown with Trifolium repens (Tr) and as DPCS with the four species (Lp+Bv+Dg+Tr=Mix). The defoliation criteria applied (LSWO of a target species: Lp, Bv or Dg) resulted in eleven grazing events for MonoLp and MixLp, ten grazing events for MonoBv and MixBv, and nine grazing events for MonoDg and MixDg in a year. MixBv and MixDg displayed synchronized overlaps of the three species LSWOs during the seasons and across the year. MixLp had Bv and Dg being grazed slightly earlier than their LSWOs. There were no significant differences in annual herbage accumulation for all treatments. Significant differences were found within seasons, and the seasonality of the pasture growth was reduced in the DPCS when compared to their respective Mono establishment. This resulted in a more evenly distributed pasture feed resource throughout the year and can mitigate the negative impacts of extreme climatic events (longer periods of soil water restriction or saturation). The LSWO criterion enabled the successful management of monocultures and DPCS

    A multi-compartment single and multiple dose pharmacokinetic comparison of rectally applied tenofovir 1% gel and oral tenofovir disoproxil fumarate

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    This Phase 1, randomized, two-site (United States), double-blind, placebo-controlled study enrolled 18 sexually abstinent men and women. All received a single 300-mg dose of oral tenofovir disoproxil fumarate (TDF) and were then randomized 2:1 to receive single and then seven daily rectal exposures of vaginally-formulated tenofovir (TFV) 1% gel or a hydroxyethyl cellulose (HEC) placebo gel. Blood, colonic biopsies and rectal and vaginal mucosal fluids were collected after the single oral TDF, the single topical TFV gel dose, and after 7 days of topical TFV gel dosing for extracellular analysis of TFV and intracellular analysis of the active metabolite tenofovir diphosphate (TFVdp) in peripheral blood mononuclear cells (PBMCs) and isolated mucosal mononuclear cells (MMC), including CD4+ and CD4- cell subsets. With a single rectal dose, TFV plasma concentrations were 24-33 fold lower and half-life was 5 h shorter compared to a single oral dose (p = 0.02). TFVdp concentrations were also undetectable in PBMCs with rectal dosing. Rectal tissue exposure to both TFV and TFVdp was 2 to 4-log10 higher after a single rectal dose compared to a single oral dose, and after 7 daily doses, TFVdp accumulated 4.5 fold in tissue. TFVdp in rectal tissue homogenate was predictive (residual standard error, RSE = 0.47) of tissue MMC intracellular TFVdp concentration, with the CD4+ cells having a 2-fold higher TFVdp concentration than CD4- cells. TFV concentrations from rectal sponges was a modest surrogate indicator for both rectal tissue TFV and TFVdp (RSE = 0.67, 0.66, respectively) and plasma TFV (RSE = 0.38). TFV penetrates into the vaginal cavity after oral and rectal dosing, with rectal dosing leading to higher vaginal TFV concentrations (p<0.01)

    Improved Biomedical and Psychological Outcomes 1 Year After Structured Education in Flexible Insulin Therapy for People With Type 1 Diabetes: The U.K. DAFNE experience

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    OBJECTIVEdDAFNE (Dose Adjustment For Normal Eating), a structured education program in flexible insulin therapy, has been widely adopted in the U.K. after validation in a randomized trial. To determine benefits in routine practice, we collected biomedical and psychological data from all participants attending during a 12-month period. RESEARCH DESIGN AND METHODSdHbA1c, weight, self-reported hypoglycemia awareness, severe hypoglycemia frequency, PAID (Problem Areas In Diabetes), HADS (Hospital Anxiety and Depression Scale), and EuroQol Group 5-Dimension Self-Report Questionnaire scores were recorded prior to DAFNE and after 1 year. RESULTSdComplete baseline and follow-up HbA1c data were available for 639 (54.9%) of 1,163 attendees. HbA1c fell from 8.51 6 1.41 (mean 6 SD) to 8.24 6 1.29% (difference 0.27 [95% CI 0.16–0.38]; P , 0.001), with a greater mean fall of 0.44% from baseline HbA1c .8.5%. Severe hypoglycemia rate fell from 1.7 6 8.5 to 0.6 6 3.7 episodes per person per year (1.1 [0.7– 1.4]) and hypoglycemia recognition improved in 43% of those reporting unawareness. Baseline psychological distress was evident, with a PAID score of 25.2 and HADS scores of 5.3 (anxiety) and 4.8 (depression), falling to 16.7 (8.5 [6.6–10.4]), 4.6 (0.7 [0.4–1.0]), and 4.2 (0.6 [0.3–0.8]), respectively (all P , 0.001 at 1 year). Clinically relevant anxiety and depression (HADS $8) fell from 24.4 to 18.0% and 20.9 to 15.5%, respectively. CONCLUSIONSdA structured education program delivered in routine clinical practice not only improves HbA1c while reducing severe hypoglycemia rate and restoring hypoglycemia awareness but also reduces psychological distress and improves perceived well-being

    Exploring the feasibility of multi-site flow cytometric processing of gut associated lymphoid tissue with centralized data analysis for multi-site clinical trials

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    The purpose of this study was to determine whether the development of a standardized approach to the collection of intestinal tissue from healthy volunteers, isolation of gut associated lymphoid tissue mucosal mononuclear cells (MMC), and characterization of mucosal T cell phenotypes by flow cytometry was sufficient to minimize differences in the normative ranges of flow parameters generated at two trial sites. Forty healthy male study participants were enrolled in Pittsburgh and Los Angeles. MMC were isolated from rectal biopsies using the same biopsy acquisition and enzymatic digestion protocols. As an additional comparator, peripheral blood mononuclear cells (PBMC) were collected from the study participants. For quality control, cryopreserved PBMC from a single donor were supplied to both sites from a central repository (qPBMC). Using a jointly optimized standard operating procedure, cells were isolated from tissue and blood and stained with monoclonal antibodies targeted to T cell phenotypic markers. Site-specific flow data were analyzed by an independent center which analyzed all data from both sites. Ranges for frequencies for overall CD4+ and CD8+ T cells, derived from the qPBMC samples, were equivalent at both UCLA and MWRI. However, there were significant differences across sites for the majority of T cell activation and memory subsets in qPBMC as well as PBMC and MMC. Standardized protocols to collect, stain, and analyze MMC and PBMC, including centralized analysis, can reduce but not exclude variability in reporting flow data within multi-site studies. Based on these data, centralized processing, flow cytometry, and analysis of samples may provide more robust data across multi-site studies. Centralized processing requires either shipping of fresh samples or cryopreservation and the decision to perform centralized versus site processing needs to take into account the drawbacks and restrictions associated with each method
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