7,168 research outputs found

    Colour Confinement and Deformed Baryons in Quantum Chromodynamics

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    The confinement of coloured entities in Quantum Chromodynamics (QCD) is traced to colour singletness of the observed entities. This is believed to arise from colour singlet state of quark-antiquark for mesons and a fully colour antisymmetric state for baryons. This demands a spherically symmetric baryon in the ground state. However it is pointed out that a deformed baryon in the ground state has been found to be extremely successful phenomenology. There are convincing experimental supports for a deformed nucleon as well. This means that something has been missed in the fundamental theory. In this paper this problem is traced to a new colour singlet state for baryons which has been missed hitherto and incorporation of which provides a consistent justification of a deformed baryon in the ground state. Interestingly this new colour singlet state is global in nature.Comment: 5 pages, 1 figur

    The Use of Questioning the Author (Qta) Strategy in Improving Students' Ability in Reading Descriptive Text at the Seventh Grade Students of SMP Islam Plus Jannatul Firdaus Pekanbaru

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    Students at SMP Islam Plus Jannatul Firdaus Pekanbaru had problems in understanding the text when reading process, those were because: the students ought to construct of generic structure of descriptive text namely identification and description. The students ought to comprehend the contents of identification. The students ought to comprehend the contents of description. Then, the researcher tested based-score of reading descriptive text, the researcher found that the students' mean score was just 68. This research aimed to improve the students' ability in reading descriptive text by using Questioning the Author (QtA) Strategy. Thus, this research conducted Classroom Action Research (CAR) consisting of one cycles. There were 15 students at Grade VII of SMP Islam Plus Jannatul Firdaus Pekanbaru as the participants of the research. To gain the data, the researcher used four instruments namely: test, observation, field note, and interview. The result of the reading test in cycle 1 (78.33) was better than the based-score. The factors influeced the changing of students' ability in reading descriptive text were the vocabulary mastery, the condition of the class, and absolutely the strategy used by the teacher in teaching reading. In conclusion, Questioning the Author (QtA) strategy can improve the students' ability in reading descriptive text

    Analytical Investigation of Mobile NFC Adaption with SWOT-AHP Approach: A Case of Italian Telecom

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    The purpose of this study is to appraise the critical factors in near field communication (NFC) adoption process and to utilize findings in order to support launching NFC implementations in Italy, by means of applying a combination of SWOT and AHP approaches. Hence, a set of twenty SWOT factors is identified qualitatively through extended interviews with telecommunication experts as well as exploratory studies on case which are supported by quantitative investigation through pair-wise comparisons matrices as an application of AHP approach. However, this combined methodology enables us to describe NFC adoption process, providing guidance to clarify the critical factors during adoption process. As the first application of joint SWOT and AHP approaches in telecommunication networks, managerial perceptions are promising either for policy makers concerning NFC or further academic researches on NFC application and full scale deployment in market

    Severe respiratory distress in term infants born electively at high altitude

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    BACKGROUND: We studied the contribution of elective delivery to severe respiratory distress syndrome (RDS) in term babies born at high altitude. METHODS: We prospectively studied the charts of term babies born in Taif Maternity Hospital (1640 m above sea level) between 1/1/2004 and 31/10/2004 who developed RDS and required mechanical ventilation. RESULTS: 8634 deliveries occurred from 37–<41 weeks; 13 (0.15%) had RDS requiring mechanical ventilation. Seven infants delivered at 37–<38 weeks, (OR for RDS = 26 95%CI -4.6 to 5.8), five delivered at 38–<39 weeks, (OR for RDS = 10 95%CI -4.9 to 5.4) and one delivered at >39 weeks. Six of 13 infants were electively delivered without documented lung maturity. CONCLUSION: Infants born at 37 and 38 weeks' gestation remain at significantly increased risk for severe RDS. Elective delivery is responsible for 50% of the potentially avoidable cases. Our data suggest that the altitude does not seem to influence the incidence of severe RDS in term infants born electively

    Spectral characteristics of normal and nutrient-deficient maize leaves

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    Reflectance, transmittance and absorbance spectra of normal and six types of mineral-deficient (N,P,K,S,Mg and Ca) maize (Zea mays L.) leaves were analyzed at 30 selected wavelengths along the electromagnetic spectrum from 500 to 2600 nm. Chlorophyll content and percent leaf moisture were also determined. Leaf thermograms were obtained for normal, N- and S- deficient leaves. The results of the analysis of variance showed significant differences in reflectance, transmittance and absorbance in the visible wavelengths among leaf numbers 3, 4, and 5, among the seven nutrient treatments, and among the interactions of leaves and treatments. In the reflective infrared wavelengths only treatments produced significant differences. The chlorophyll content of leaves was reduced in all deficiencies in comparison to controls. Percent moisture was increased in S-, Mg- and N- deficiencies. Positive correlation (r = 0.707) between moisture content and percent absorption at both 1450 and 1930 nm were obtained. Polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related (r = 0.894)

    Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint

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    We present the detection of 6,371 RR Lyrae (RRL) stars distributed across ~14,000 deg^2 of the sky from the combined data of the Sloan Digital Sky Survey (SDSS), the Panoramic Survey Telescope and Rapid Response System 1 (PS1), and the second photometric catalogue from the Catalina Survey (CSDR2), out of these, ~2,021 RRL stars (~572 RRab and 1,449 RRc) are new discoveries. The RRL stars have heliocentric distances in the 4--28 kpc distance range. RRL-like color cuts from the SDSS and variability cuts from the PS1 are used to cull our candidate list. We then use the CSDR2 multi-epoch data to refine our sample. Periods were measured using the Analysis of Variance technique while the classification process is performed with the Template Fitting Method in addition to the visual inspection of the light curves. A cross-match of our RRL star discoveries with previous published catalogs of RRL stars yield completeness levels of ~50% for both RRab and RRc stars, and an efficiency of ~99% and ~87% for RRab and RRc stars, respectively. We show that our method for selecting RRL stars allows us to recover halo structures. The full lists of all the RRL stars are made publicly available.Comment: 14 pages, 11 figures. Accepted 2014 March 30. Received 2014 March 12; in original form 2013 November 2

    Complex Role of Secondary Electron Emissions in Dust Grain Charging in Space Environments: Measurements on Apollo 11 and 17 Dust Grains

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    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions. Knowledge of the dust grain charges and equilibrium potentials is important for understanding of a variety of physical and dynamical processes in the interstellar medium (ISM), and heliospheric, interplanetary, planetary, and lunar environments. The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. It has been well recognized that the charging properties of individual micron/submicron size dust grains are expected to be substantially different from the corresponding values for bulk materials and theoretical models. In this paper we present experimental results on charging of individual dust grains selected from Apollo 11 and Apollo 17 dust samples by exposing them to mono-energetic electron beams in the 10- 400 eV energy range. The charging rates of positively and negatively charged particles of approximately 0.2 to 13 microns diameters are discussed in terms of the secondary electron emission (SEE) process, which is found to be a complex charging process at electron energies as low as 10-25 eV, with strong particle size dependence. The measurements indicate substantial differences between dust charging properties of individual small size dust grains and of bulk materials

    Placenta accreta and emergency cesarean delivery correlates to cervical length and transcervical placental thickness measurement

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    Background: The study aims to evaluate the effect of cervical length and the transcervical placental thickness measurement at 28-30 weeks gestation in predicting the risk of antepartum haemorrhage (APH) and emergency preterm caesarean delivery (CD) in women with placenta previa accreta.Methods: A prospective cohort study conducted at Aswan university hospital from June 2015 to April 2017 included one hundred and five cases diagnosed as placenta previa accreta by transvaginal ultrasound (TVS) between 28-30 weeks gestation were divided into three groups according to their cervical length which measured by TVS: group I (cervical length >30 mm), group II (cervical length 20-30 mm) and group III (cervical length <20 mm). Also, placental thickness measurement was done. Cervical length and placental thickness and correlated with the clinical outcome regarding to gestational age at delivery, APH, emergency CD due to massive haemorrhage, the need for blood transfusion and caesarean hysterectomy.Results: APH and emergency CD due to massive bleeding were significantly higher in cases with short cervical length and thick placenta. APH occurred in 6 cases (15%) in group I, 14 cases (40%) in group II and 24 cases (80%) in group III, (p=0.0001). Emergency CD in group I was performed in 5 cases (12.5 %), 12 cases (34.3 %) in group II and 24 cases (80%) in group III, (p =0.0001). The incidence of APH was higher in thick placenta [6 cases (42.9 %) compared to none with thin placenta in group I (p=0.001), 13 cases (68.4%) compared to one case (6.2%) in group II (p=0.0001) and 21 cases (100%) compared to 3 cases (33.3%) in group III (p=0.0001)].Conclusions: Short cervical length and increased placental thickness may predict the risk of APH and emergency preterm CD in patients with placenta accreta
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