2,936 research outputs found
Assessment on Hybrid E-Learning Instrument
This study aims to improve Hybrid e-Learning 9.3. A total of 233 students of International Islamic University Malaysia, Gombak who have the experience in hybrid teaching and learning were involved as respondents. Rasch Measurement Model was used for this study. Validity analyses conducted were on (i) the compatibility of the items, (ii) mapping of items and respondents, (iii) scaling of instruments, and (iv) unidimentional items. The findings of the study show that (i) the items developed correspond with the construct they represent, (ii) items are evenly distributed on the mean of the respondents, (iii) the scale of instruments to be improved, and (iv) the instrument is multidimensional. Therefore, it shows that Hybrid e-Learning instrument has the items that measure the construct it represents as well as the compatibility with the capability of the respondents of the study
Implementation of adaptive coding and modulation for satellite communication links in heavy rain region: an operators perspective
This contribution presents an implementation of adaptive modulation and coding (ACM) for the real operating satellite- based internet protocol (IP) communication system from the Nigeria communication satellite (NigComSat-1R) very small aperture terminal (VSAT) network. Specifically, different modulation schemes are chosen according to the weather conditions in order to achieve the highest available data rate and preserve the link availability. The experimental results indicate that at least a 24% bandwidth reduction can be achieved with the same data rate by implementing the ACM technique. Further work should focus on the ACM selection strategy based on the peculiarities of the meteorological characteristics in a specific area so that ACM implementation will lead to maximum efficiency in terms of radio resource management and exploitation
Interference and electromagnetic compatibility challenges in 5G wireless network deployments
5G wireless network technology is going operate within the environment of other electrical, electronic and electromagnetic devices, components and systems, with capability of high speed data connectivity acting as network transceiver stations with Massive MIMO for Internet of Things (IoT). Considering the level of interoperability, electromagnetic Interference and electromagnetic compatibility to avoid electromagnetic pulse effects (EMP) which is capable of not only causing network malfunctions but total devices and equipments failure in mission critical operations, like hospital MRI scan machines, security profiling and data handling or even personal healthcare devices like heart pacemaker. Electromagnetic energy coupling in PCB due to: radiation, reflection and Crosstalk generates reliability challenges affecting Signal Integrity between traces of multilayer boards stalks, power bus and packaging creating Electromagnetic interference (EMI) in PCB leading false clock response to system failure. Above were considered very essential when deploying 5G wireless network facility as presented in this paper
Ultrafast all-optical switching via coherent modulation of metamaterial absorption
We report on the demonstration of a femtosecond all-optical modulator
providing, without nonlinearity and therefore at arbitrarily low intensity,
ultrafast light-by-light control. The device engages the coherent interaction
of optical waves on a metamaterial nanostructure only 30 nm thick to
efficiently control absorption of near-infrared (750-1040 nm) femtosecond
pulses, providing switching contrast ratios approaching 3:1 with a modulation
bandwidth in excess of 2 THz. The functional paradigm illustrated here opens
the path to a family of novel meta-devices for ultra-fast optical data
processing in coherent networks.Comment: 5 pages, 4 figure
Space Climate Manifestation in Earth Prices - from Medieval England Up to Modern Usa
In this study we continue to search for possible manifestations of space
weather influence on prices of agricultural products and consumables. We note
that the connection between solar activity and prices is based on the causal
chain that includes several nonlinear transition elements. These non-linear
elements are characterized by threshold sensitivity to external parameters and
lead to very inhomogeneous local sensitivity of the price to space weather
conditions. It is noted that "soft type" models are the most adequate for
description of this class of connections. Two main observational effects
suitable for testing causal connections of this type of sensitivity are
considered: burst-like price reactions on changes in solar activity and price
asymmetry for selected phases of the sunspot cycle. The connection, discovered
earlier for wheat prices of Medieval England, is examined in this work on the
basis of another 700-year data set of consumable prices in England. Using the
same technique as in the previous part of our work (Pistilnik and Yom Din 2004)
we show that statistical parameters of the interval distributions for price
bursts of consumables basket and for sunspot minimum states are similar one to
another, like it was reported earlier for wheat price bursts. Possible sources
of these consistencies between three different multiyear samples are discussed.
For search of possible manifestations of the "space weather - wheat market"
connection in modern time, we analyze dynamics of wheat prices in the USA in
the twentieth century. We show that the wheat prices revealed a maximum/minimum
price asymmetry consistent with the phases of the sunspot cycle. We discuss
possible explanations of this observed asymmetry, unexpected under conditions
of globalization of the modern wheat market.Comment: First International Symposium on Space Climate: Direct and Indirect
Observations of Long-Term Solar Activity, 20-23 June 2004, Oulu, Finlan
Polymorphism of Human FcγRIIa and Its Association with P. Falciparum Density and Efficacy of Dihydroartemisinin- Piperaquine
FcγRlla dimorphism has been related to the ability of the host to eliminate malaria parasite so it is necessary to investigate the allele polymorphism FcγRlla of population in malaria-endemic areas in Indonesia in order to know the role of immunity in eliminating malaria parasite. A total of 120 samples of Dried Blood Spot (DBS) falciparum malaria acquired from DHP drug efficacy studies in 5 regions in Indonesia were analyzed by Polymerase Chain Reaction (PCR) and sequencing, to look at variants of FcγRIIa-131 allele and its Association with Parasite DensityandEfficacy ofDihydroartemisinin- Piperaquine. The FcγRIIa gene analysis indicated that genotype RH has the highest frequency (50.8%) compared to RR (17.5%) and HH (31.7%). Allele R131 showed a protective effect against High Density Parasitemia (HDP) (>5000 parasites/μL; odds ratio [OR]= 0.133, 95% confidence interval [CI]= 0.053–0.334, P< 0.001) and associated with longer gametocytes carrier clearance time (> 72 hours; Relative Risk [RR]= 1,571, 95% confidence interval [CI]= 1,005–2,456, P= 0.090).  
CP^{N-1} models and the Quantized 2D Black Holes
We have examined the coupled system of the dilaton gravity and the
theory known as a model of the confinement of massive scalar quarks. After the
quantization of the system, we could see the quantum effect of the gravitation
on the coupling constant of model and how the coupling constant of
dynamically induced gauge field changes near the black hole configuration.Comment: 12 pages, Late
Biosynthesis and Degradation of Carotenoids in Ornamental Crops with specific reference to Chrysanthemum
Carotenoids are lipophilic secondary metabolites derived from the isoprenoid pathway, accumulated in most plant organs and widely used as an antioxidant. Carotenoids synthesized in chloroplasts are essential for protecting tissues against photo-oxidative damage in the green tissues of higher plants. The importance of carotenoids for plant growth and development is evident since at least two major phytohormones, strigolactones and abscisic acid, are derived from carotenoid precursors. In flowers, carotenoids synthesized in the chromoplasts provide colour to the petals, ranging from yellow to red, in order to attract pollinators and determines the commercial value of ornamental plants. On analysis in chrysanthemum, β, ɛ-carotenoids, lutein and its derivatives, reflecting the high expression levels of lycopene ɛ-cyclase (LCYE) were found in yellow petals compared to the ratio of β, β-carotenoids to total carotenoids found in leaves reflecting the high expression levels of lycopene β-cyclase (LCYB). Petals of the yellow-flowered cultivar Yellow Paragon showed increased accumulation and drastic componential changes of carotenoids as they mature, compared to petals of the white-flowered cultivar Paragon that showed drastically decreased carotenoid content during petal development.The white petals of chrysanthemum (Chrysanthemum morifolium Ramat.) contain a factor that inhibits the accumulation of carotenoids. All the white-flowered chrysanthemum cultivars tested showed high levels of CmCCD4a transcript in their petals, whereas most of the yellow flowered cultivars showed extremely low levels indicating that in white petals of chrysanthemums, carotenoids are synthesized but subsequently degraded into colourless compounds, which results in the white colour. Studying the regulatory mechanisms underlying carotenoid accumulation in ornamental plants at the molecular level will help in producing novel coloured cultivars by plant transformation
Exact vortex solutions in a CP^N Skyrme-Faddeev type model
We consider a four dimensional field theory with target space being CP^N
which constitutes a generalization of the usual Skyrme-Faddeev model defined on
CP^1. We show that it possesses an integrable sector presenting an infinite
number of local conservation laws, which are associated to the hidden
symmetries of the zero curvature representation of the theory in loop space. We
construct an infinite class of exact solutions for that integrable submodel
where the fields are meromorphic functions of the combinations (x^1+i x^2) and
(x^3+x^0) of the Cartesian coordinates of four dimensional Minkowski
space-time. Among those solutions we have static vortices and also vortices
with waves traveling along them with the speed of light. The energy per unity
of length of the vortices show an interesting and intricate interaction among
the vortices and waves.Comment: 21 pages, plain latex, no figure
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Clinical Outcome of Breast Cancer Occurring after Treatment for Hodgkin's Lymphoma: Case-Control Analysis
Background: To evaluate diagnosis, management and outcome of breast cancer (BC) occurring after irradiation for Hodgkin's lymphoma (HL). Methods: 39 cases of BC in 28 HL survivors were retrospectively reviewed. 21 patients were included in a case-control analysis. Results: The median age at diagnosis of HL and BC was 25.3 and 45.3 years, respectively. The median interval to develop BC was 16.1 years. Eleven women (39.2%) had bilateral disease. Mode of detection of the index breast cancers was by mammographic screening in 17 patients (60.7%), palpable lump in 8 patients (28.6%), clinical examination in two patients (7.1%), and unknown in one patient (3.6%). Case-control analysis showed that histological features and prognosis of BC after HL were similar to those of primary BC, however, for BC after HL, mastectomy was the predominant surgery (P = .001) and adjuvant radiotherapy and anthracycline-based chemotherapy were less frequently used as compared to primary BC (P < .001 and .003, respectively). Conclusion: The previous history of HL does not appear to be a poor prognostic factor for BC occurring thereafter
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