5,463 research outputs found
A study of frequency and pulses for stepper motor controller system by using programmable logic controller
The stepper motor movement process produced different frequency and pulses. This research explained about the frequency and pulses for the stepper motor movement by using Programmable Logic Controller (PLC) as research method. The study was done to find the suitable frequency and pulses for stepper motor movement by developing a prototype stepper motor controller system. The pulse frequency used did not affected the distance of moving load in the stepper motor operations. The increasing number of pulse frequency only will affect the time taken for the stepper motor to complete its operations. The result showed that number of pulse frequency at high operation was 5000 Hz. Pulse number reacted as a manipulated variable that affected both factor which is time taken of stepper motor operation and the distance of moving load
Curvaton and the inhomogeneous end of inflation
We study the primordial density perturbations and non-Gaussianities generated
from the combined effects of an inhomogeneous end of inflation and curvaton
decay in hybrid inflation. This dual role is played by a single isocurvature
field which is massless during inflation but acquire a mass at the end of
inflation via the waterfall phase transition. We calculate the resulting
primordial non-Gaussianity characterized by the non-linearity parameter,
, recovering the usual end-of-inflation result when the field decays
promptly and the usual curvaton result if the field decays sufficiently late.Comment: 13 pages, 5 figure
Issues on Generating Primordial Anisotropies at the End of Inflation
We revisit the idea of generating primordial anisotropies at the end of
inflation in models of inflation with gauge fields. To be specific we consider
the charged hybrid inflation model where the waterfall field is charged under a
U(1) gauge field so the surface of end of inflation is controlled both by
inflaton and the gauge fields. Using delta N formalism properly we find that
the anisotropies generated at the end of inflation from the gauge field
fluctuations are exponentially suppressed on cosmological scales. This is
because the gauge field evolves exponentially during inflation while in order
to generate appreciable anisotropies at the end of inflation the spectator
gauge field has to be frozen and scale invariant. We argue that this is a
generic feature, that is, one can not generate observable anisotropies at the
end of inflation within an FRW background.Comment: V3: new references added, JCAP published versio
Aggression is a dominant behavior among adolescents in Al-Sadr city, Baghdad-Iraq
Background: Aggression is any behavior intending to harm another living being that desires to avoid such harm. Aggression is considered as a public health problem worldwide. Exposure to violence is a determinant of aggression. Al-Sadr city, which is an overcrowded residential area in Baghdad, was exposed to violence through wars, civil war, and widespread inter-personal violence). This situation was an impetus to study aggression in this city.
Objectives: To estimate the prevalence of aggression among secondary school students in Al-Sadr city, Baghdad.
Methodology: A cross-sectional study was carried out in Al-Sadr city in Baghdad. A total of 720 adolescent secondary schools students from both genders were included in the study. They were selected by multistage random sampling. Their age was ranged from 13-21 years. Data was collected from 1st of February 2019 to 30 of April 2019 through a self-reported questionnaire (Aggression-Problem Behavior Frequency Scale).
Results: The mean age of participants was 16.2±2.04 years. Of all participants, 84.3% were assessed to be aggressive; including 329 (91.4%) males and 278 (77.2%) females. Males showed significantly higher aggression than females (p=0.001). Absence from school and low academic achievement were dominating among aggressive students (88.2% and 86.9%, respectively). Non-physical Aggression was the most common type of aggression (76.4%).
Conclusion: A high prevalence of aggression (mainly non-physical) was found, which was significantly associated with gender, being higher among males. Aggression was negatively affecting school achievement
Characterization and modelling of electromagnetic interactions in aircraft
This article describes the development of modelling techniques and simulation tools for the electromagnetic (EM) analysis of aircraft. It is shown that hybrid solvers and multi-scale techniques can be used effectively to analyse the EM response of aircraft. The importance of supplementing models with appropriate measurement and characterization techniques for parameter extraction and for validation is also demonstrated
Fine needle aspiration cytological diagnosis of thyroid nodule with its clinical correlation
Background: Nodular goiter is common in Bangladesh. Thyroid nodules are important for their malignant potential especially the solitary and cold ones and when functionally euthyroid. Objectives: This study was designed to investigate the frequency of malignancy and cellular aberration detected by fine needle aspiration cytology (FNAC) in euthyroid nodules and its correlation with clinical findings. Methods: Subjects with nodular goiter attending Endocrine out patient department [n=150, nonpregnant, age (mean± SD): 37±12 years; sex (male: female): 21:129] were recruited for this study. All subjects underwent clinical risk stratification, estimation ofFT4 and TSH as well as ultrnsonogram (USG) and isotope scan of thyroid. Thyroid nodules were categorized into malignant, suspicious, benign and indeterminant on the basis of cellular character by FNAC. Statistical analysis was done by Chi-square and multiple regression analysis. Results: Patients were mostly females (86%) and 4.7% had family history of thyroid problems. Some had recent changes of size (14.7%), pain in the nodule (4%) and dysphagia (6%). Nodules were solitary in 45.3% and the rest (54.7%) had multinodular goiter. Enlarged regional lymph node was found in 12.7% patients. About 41 % were partially-cold followed by cold nodules (26.7%), patchy (16.7%), isoform (12%) and hot (4%) by isotope scan. Frequency of malignant (10%) character was highest in cold nodules followed by uniform (5.6%), patchy (4.0%) and partially cold (1.6%) while none in hot nodules; which were 22.5%, 11.1 %, 4.0%, 9.8% and 16.7% respectively for suspicious nodules. About 17% showed cellular aberration and 4.7% were clearly malignant, whereas 124 (82.7%) were benign. Of the malignant, 4 were solitary and 3 were multinodular; which were 10 and 9 among the suspicious ones. A significant number (77%, 20 out of 26) among the malignant/suspicious nodules fell into moderate to high risk category (x2=22.861, p<0.001), while 23.1 % of the FNAC proven malignant/suspicious nodules were of low risk category. Enlarged lymph nodes (p<0.001), increased diameter of nodules of >4 cm (p=0.039) and recent changes in nodular size (p=0.042) were independently and significantly related to cellular aberration. Conclusions: FNAC is a useful tool for cellular diagnosis of thyroid nodules. Clinical suspicion for malignancy strongly correlates with the FNAC findings. But a good number of clinically Low risk categories would escape malignant cellular character unless FNAC is done
Projection of meteorological droughts in Nigeria during growing seasons under climate change scenarios
Like many other African countries, incidence of drought is increasing in Nigeria. In this work, spatiotemporal changes in droughts under different representative concentration pathway (RCP) scenarios were assessed; considering their greatest impacts on life and livelihoods in Nigeria, especially when droughts coincide with the growing seasons. Three entropy-based methods, namely symmetrical uncertainty, gain ratio, and entropy gain were used in a multi-criteria decision-making framework to select the best performing General Circulation Models (GCMs) for the projection of rainfall and temperature. Performance of four widely used bias correction methods was compared to identify a suitable method for correcting bias in GCM projections for the period 2010–2099. A machine learning technique was then used to generate a multi-model ensemble (MME) of the bias-corrected GCM projection for different RCP scenarios. The standardized precipitation evapotranspiration index (SPEI) was subsequently computed to estimate droughts from the MME mean of GCM projected rainfall and temperature to predict possible spatiotemporal changes in meteorological droughts. Finally, trends in the SPEI, temperature and rainfall, and return period of droughts for different growing seasons were estimated using a 50-year moving window, with a 10-year interval, to understand driving factors accountable for future changes in droughts. The analysis revealed that MRI-CGCM3, HadGEM2-ES, CSIRO-Mk3-6-0, and CESM1-CAM5 are the most appropriate GCMs for projecting rainfall and temperature, and the linear scaling (SCL) is the best method for correcting bias. The MME mean of bias-corrected GCM projections revealed an increase in rainfall in the south-south, southwest, and parts of the northwest whilst a decrease in the southeast, northeast, and parts of central Nigeria. In contrast, rise in temperature for entire country during most of the cropping seasons was projected. The results further indicated that increase in temperature would decrease the SPEI across Nigeria, which will make droughts more frequent in most of the country under all the RCPs. However, increase in drought frequency would be less for higher RCPs due to increase in rainfall
Fluorescence Turns on-off-on Sensing of Ferric Ion and L-Ascorbic Acid by Carbon Quantum Dots
This study used a hydrothermal approach to create a sensitive and focused nanoprobe. Using an “on-off-on” sensing mechanism, the nanoprobe was employed to detect and quantify ferric ions and L-ascorbic acid. Synthesis of the carbon quantum dots was achieved with a single hydrothermal step at 180°C for 24 hours using hot pepper as the starting material. The prepared CQDs showed high fluorescence with a quantum yield of 30% when excited at 350 nm, exhibiting excitation-dependent fluorescence. The emission of the CQDs can be quenched by adding ferric ions, which can be attributed to complex formation leading to nonradiative photoinduced electron transfer (PET). Adding L-ascorbic acid, which can convert ferric ions into ferrous ions, break the complex, and restore the fluorescence of CQD. The linear range and LOD were (10–90) μM and 1 μM for ferric ions, respectively, and L-ascorbic acid’s linear range was (5–100) μM while LOD was 0.1 μM quantification of both substances was accomplished. In addition, orange fruit was used as an actual sample source for ascorbic acid analysis, yielding up to 99% recovery
The leukemogenic t(8;21) fusion protein AML1-ETO controls rRNA genes and associates with nucleolar-organizing regions at mitotic chromosomes
RUNX1/AML1 is required for definitive hematopoiesis and is frequently targeted by chromosomal translocations in acute myeloid leukemia (AML). The t(8;21)-related AML1-ETO fusion protein blocks differentiation of myeloid progenitors. Here, we show by immunofluorescence microscopy that during interphase, endogenous AML1-ETO localizes to nuclear microenvironments distinct from those containing native RUNX1/AML1 protein. At mitosis, we clearly detect binding of AML1-ETO to nucleolar-organizing regions in AML-derived Kasumi-1 cells and binding of RUNX1/AML1 to the same regions in Jurkat cells. Both RUNX1/AML1 and AML1-ETO occupy ribosomal DNA repeats during interphase, as well as interact with the endogenous RNA Pol I transcription factor UBF1. Promoter cytosine methylation analysis indicates that RUNX1/AML1 binds to rDNA repeats that are more highly CpG methylated than those bound by AML1-ETO. Downregulation by RNA interference reveals that RUNX1/AML1 negatively regulates rDNA transcription, whereas AML1-ETO is a positive regulator in Kasumi-1 cells. Taken together, our findings identify a novel role for the leukemia-related AML1-ETO protein in epigenetic control of cell growth through upregulation of ribosomal gene transcription mediated by RNA Pol I, consistent with the hyper-proliferative phenotype of myeloid cells in AML patients
Evidence for proton acceleration up to TeV energies based on VERITAS and Fermi-LAT observations of the Cas A SNR
We present a study of -ray emission from the core-collapse supernova
remnant Cas~A in the energy range from 0.1GeV to 10TeV. We used 65 hours of
VERITAS data to cover 200 GeV - 10 TeV, and 10.8 years of \textit{Fermi}-LAT
data to cover 0.1-500 GeV. The spectral analysis of \textit{Fermi}-LAT data
shows a significant spectral curvature around GeV that is
consistent with the expected spectrum from pion decay. Above this energy, the
joint spectrum from \textit{Fermi}-LAT and VERITAS deviates significantly from
a simple power-law, and is best described by a power-law with spectral index of
with a cut-off energy of TeV. These
results, along with radio, X-ray and -ray data, are interpreted in the
context of leptonic and hadronic models. Assuming a one-zone model, we exclude
a purely leptonic scenario and conclude that proton acceleration up to at least
6 TeV is required to explain the observed -ray spectrum. From modeling
of the entire multi-wavelength spectrum, a minimum magnetic field inside the
remnant of is deduced.Comment: 33 pages, 9 Figures, 6 Table
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