7,640 research outputs found

    The alternating least-squares algorithm for CDPCA

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    Clustering and Disjoint Principal Component Analysis (CDP CA) is a constrained principal component analysis recently proposed for clustering of objects and partitioning of variables, simultaneously, which we have implemented in R language. In this paper, we deal in detail with the alternating least-squares algorithm for CDPCA and highlight its algebraic features for constructing both interpretable principal components and clusters of objects. Two applications are given to illustrate the capabilities of this new methodology

    Probing Short Range Nucleon Correlations in High Energy Hard Quasielastic pd Reactions

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    We show that the strong dependence of the amplitude for NNNN hard scattering on the collision energy can be used to magnify the effects of short range nucleon correlations in quasielastic pdpd scattering. Under specific kinematical conditions the effect of initial and final state interactions can be accounted for by rescaling the cross section calculated within the plane wave impulse approximation. The feasibility to investigate the role of relativistic effects in the deuteron wave function is demonstrated by comparing the predictions of different formalisms. Binding effects due to short range correlations in deuteron are discussed as well.Comment: 18 pages (LaTex) + 10 postscript figs (available on request

    A model-based multithreshold method for subgroup identification

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    Thresholding variable plays a crucial role in subgroup identification for personalizedmedicine. Most existing partitioning methods split the sample basedon one predictor variable. In this paper, we consider setting the splitting rulefrom a combination of multivariate predictors, such as the latent factors, principlecomponents, and weighted sum of predictors. Such a subgrouping methodmay lead to more meaningful partitioning of the population than using a singlevariable. In addition, our method is based on a change point regression modeland thus yields straight forward model-based prediction results. After choosinga particular thresholding variable form, we apply a two-stage multiple changepoint detection method to determine the subgroups and estimate the regressionparameters. We show that our approach can produce two or more subgroupsfrom the multiple change points and identify the true grouping with high probability.In addition, our estimation results enjoy oracle properties. We design asimulation study to compare performances of our proposed and existing methodsand apply them to analyze data sets from a Scleroderma trial and a breastcancer study

    Seleksi Bakteri Penambat Nitrogen Dan Penghasil Hormon Iaa (Indole Acetic Acid) Dari Rizosfer Tanah Perkebunan Kedelai (Glycine Max L.)

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    Rizosphere bacteria can be used to fix nitrogen and produce IAA (Indol Acetic Acid) as biofertilizer to support plant growth. The ability of rhizosphere bacteria can be improved using biotechnology. The aim of this study is to select the most potential nitrogen fixing and IAA producing bacteria. Nitrogen fixing and IAA producing bacteria were isolated using JNFB and Luria Bertani + L-tryptofan medium respectively. The ability of nitrogen fixing bacteria were tested by ARA method, while the ability of IAA producing bacteria were investigated by spectrophotometer technique of 535 nm. The highest IAA concentration was produced by isolate I3 which was 33.3 ppm and the highest concentration of nitrogen was yielded by isolate N3 which was 29.93 ppm. Both N3 isolate and I3 isolate potentially as biofertilizer known as PGPR (Plant Growth Promoting Rhizobacteria)

    Optimal packages: binding regular polyhedra

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    Strings on the surface of gift boxes can be modelled as a special kind of cable-and-joint structure. This paper deals with systems composed of idealised (frictionless) closed loops of strings that provide stable binding to the underlying convex polyhedron (‘package’). Optima are searched in both the sense of topology and geometry in finding minimal number of closed loops as well as the minimal (total) length of cables to ensure such a stable binding for simple cases of polyhedra

    Parents and children during the COVID-19 quarantine process: Experiences from Turkey and China

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    This paper reports Turkish and Chinese parents’ experiences with their 3-6-year-old children during the COVID-19 quarantine process. Thirteen Turkish and 11 Chinese parents participated in a study that employed semi-structured interviews to examine participant self-perceived experiences. Findings show that the study revealed many commonalities in the experiences of Turkish and Chinese parents with their children during the COVID-19 quarantine process. Cultural differences between parents did not appear to significantly reflect the responses of parents during this extraordinary period. Parents mostly described difficulties with home quarantine. Most parents stated that their daily schedule and routines had changed as a result of home quarantine. Parents also said that they were unaware of their children’s developmental progress and the extent to which their children had grown up before the quarantine. Parents shared both positive and negative experiences during the process. Since the quarantine process is an extraordinary experience for all family members, parents should be encouraged to put those positive experiences and acquisitions into their future life

    Characteristics of aluminosilicates prepared from rice husk silica and aluminum metal

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    This study investigated use of the electrochemical method to prepare aluminosilicates from rice husk silica and aluminum metal. The aluminosilicate precursors were characterized using Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), Fourier Transform Infrared (FTIR) spectroscopy, and X-ray Diffraction spectroscopy (XRD). The precursors were subsequently sintered at 700–1400 °C and their microstructures and phase compositions were characterized. Results showed that the proposed method could be used to prepare aluminosilicates with high uniformity in terms of surface morphology and the particle size with mullite and quartz as the major phases formed

    Unified covariant treatment of hyperfine splitting for heavy and light mesons

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    This paper aims at proving the fundamental role of a relativistic formulation for quarkonia models. We present a completely covariant description of a two-quark system interacting by the Cornell potential with a Breit term describing the hyperfine splitting. Using an appropriate procedure to calculate the Breit correction, we find heavy meson masses in excellent agreement with experimental data. Moreover, also when applied to light quarks and even taking average values of the running coupling constant, we prove that covariance properties and hyperfine splitting are sufficient to explain the light mesons spectrum and to give a very good agreement with the data.Comment: 4 page

    Ticarcillin hypersusceptibility in pseudomonas aeruginosa in cystic fibrosis

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    Background: A subpopulation of Pseudomonas aeruginosa (PsA) exists in cysticfibrosis (CF) patients that&nbsp; is&nbsp; hypersusceptible&nbsp; to&nbsp; ticarcillin,&nbsp; a&nbsp; carboxypenicillin,&nbsp; in&nbsp; vitro (Tichs strain)&nbsp; defined&nbsp; as&nbsp; a minimum inhibitory concentration (MIC) ≤4μg/ml. Methods: In a retrospective cohort study, isolates of PsA from CF (23),&nbsp; non-cystic fibrosis bronchiectasis (NCFB) (17) and control (18) patients were analysed. MICs for each isolate were determined using agar dilution against six antibiotics and interpreted using EUCAST breakpoints. Prevalence of Tichs in&nbsp; each&nbsp; cohort&nbsp; was&nbsp; calculated.&nbsp; A&nbsp; point&nbsp; prevalence&nbsp; survey&nbsp; was&nbsp; conducted&nbsp; in&nbsp; CF&nbsp; to&nbsp; review&nbsp; the&nbsp; patients’ clinical progress following PsA isolation. Results: Prevalence of the Tichs strain in PsA was 48%, 76% and 0% in the CF, NCFB and control cohorts respectively. A statistically significant difference in geometric mean MIC was seen between the Tichs and non-Tichs&nbsp; cohorts in CF for ticarcillin (as expected) and temocillin (p=0.041and p=0.036 respectively). A similar trend was observed in NCFB for ticarcillin (p=0.038) and temocillin (p=0.067), although statistical significance was not reached for the latter.In&nbsp; CF,&nbsp; the&nbsp; Tichs&nbsp; strain&nbsp; demonstrated&nbsp; lower&nbsp; MICs&nbsp; to&nbsp; all antibiotics&nbsp; tested&nbsp; apart&nbsp; from&nbsp; gentamicin compared&nbsp; to&nbsp; their&nbsp; non-Tichs counterparts. Those&nbsp; who&nbsp; had the Tichs strain&nbsp; in&nbsp; CF&nbsp; had&nbsp; fewer&nbsp; antibiotics (13.9&nbsp; days&nbsp; versus&nbsp; 23.5&nbsp; days,&nbsp; Tichs&nbsp; and&nbsp; non-Tichs respectively)&nbsp; although&nbsp; this&nbsp; result&nbsp; was&nbsp; not&nbsp; statistically significant p=0.202. Conclusion: Our&nbsp; data&nbsp; supports&nbsp; the&nbsp; existence&nbsp; of&nbsp; a&nbsp; Tichs strain&nbsp; of&nbsp; PsA&nbsp; in&nbsp; our&nbsp; CF&nbsp; and&nbsp; NCFB&nbsp; patient populations. This strain correlated with reduced MICs to temocillin in CF, to which PsA would normally be resistant, which may be of clinical relevance.</p
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