Abstract: Much of the literature on research design has focused
on research conducted in developed, uni-cultural or primarily English
speaking countries. Studies of qualitative case study research, the
challenges, and prospects have been embedded in Western/Eurocentric
society and social theories. Although there have been some
theoretical studies, few empirical studies have been conducted to
explore the nature of the challenges of qualitative case study in
developing countries. These challenges include accessibility to
organizations, conducting interviews in developing countries,
accessing documents and observing official meetings, language and
cultural challenges, the use of consent forms, issues affecting access
to companies, respondent issues, and data analysis. The author, while
conducting qualitative case study research in Libya, faced all these
issues. The discussion in this paper examines these issues in order to
make a contribution toward the literature in this area.
Abstract: We have studied the temporal characteristics of
bistable perception of the stimuli of two types: one involves
alterations in a perceived depth and another one has an ambiguous
content. We used the Necker lattice and lines of shadowed circles
ambiguously perceived either as spheres or holes as stimuli of the
first type. The Winson figure (the Eskimo/Indian picture) was a
stimulus of the second type. We have analyzed how often the
reversals occurred (reversal rate) and for how long each of the two
interpretations, or percepts, was observed during one presentation
(stability durations). For all three ambiguous images the reversal rate
and the stability durations had similar values, which provide another
evidence for a significant role of top-down processes in multistable
perception.
Abstract: Selenium is an-antioxidant which is important for
human health enters food chain through crops. In Kenya Zea mays is
consumed by 96% of population hence is a cheap and convenient
method to provide selenium to large number of population. Several
soil factors are known to have antagonistic effects on selenium
speciation hence the uptake by Zea mays. There are no studies in
Kenya that has been done to determine the effects of soil
characteristics (pH, Tcarbon, CEC, Eh) affect accumulation of
selenium in Zea mays grains in Maize Belt in Kenya. About 100 Zea mays grain samples together with 100 soil samples
were collected from the study site put in separate labeled Ziplocs and
were transported to laboratories at room temperature for analysis.
Maize grains were analyzed for selenium while soil samples were
analyzed for pH, Cat Ion Exchange Capacity, total carbon, and
electrical conductivity. The mean selenium in Zea mays grains varied from 1.82 ± 0.76
mg/Kg to 11±0.86 mg/Kg. There was no significant difference
between selenium levels between different grain batches {χ (Df =76)
= 26.04 P= 1.00} The pH levels varied from 5.43± 0.58 to 5.85±
0.32. No significant correlations between selenium in grains and soil
pH (Pearson’s correlations = - 0.143), and between selenium levels in
grains and the four (pH, Tcarbon, CEC, Eh) soil chemical
characteristics {F (4,91) = 0.721 p = 0.579} was observed. It can be concluded that the soil chemical characteristics in the
study site did not significantly affect the accumulation of native
selenium in Zea mays grains.
Abstract: This research work presents the surface
thermodynamics approach to M-TB/HIV-Human sputum
interactions. This involved the use of the Hamaker coefficient
concept as a surface energetics tool in determining the interaction
processes, with the surface interfacial energies explained using van
der Waals concept of particle interactions. The Lifshitz derivation for
van der Waals forces was applied as an alternative to the contact
angle approach which has been widely used in other biological
systems. The methodology involved taking sputum samples from
twenty infected persons and from twenty uninfected persons for
absorbance measurement using a digital Ultraviolet visible
Spectrophotometer. The variables required for the computations with
the Lifshitz formula were derived from the absorbance data. The
Matlab software tools were used in the mathematical analysis of the
data produced from the experiments (absorbance values). The
Hamaker constants and the combined Hamaker coefficients were
obtained using the values of the dielectric constant together with the
Lifshitz Equation. The absolute combined Hamaker coefficients
A132abs and A131abs on both infected and uninfected sputum samples
gave the values of A132abs = 0.21631x10-21Joule for M-TB infected
sputum and Ã132abs = 0.18825x10-21Joule for M-TB/HIV infected
sputum. The significance of this result is the positive value of the
absolute combined Hamaker coefficient which suggests the existence
of net positive van der waals forces demonstrating an attraction
between the bacteria and the macrophage. This however, implies that
infection can occur. It was also shown that in the presence of HIV,
the interaction energy is reduced by 13% conforming adverse effects
observed in HIV patients suffering from tuberculosis.
Abstract: Rotary entrainment is a phenomenon in which the
interface of two immiscible fluids are subjected to external flux by
means of rotation. Present work reports the experimental study on
rotary motion of a horizontal cylinder between the interface of air and
water to observe the penetration of gas inside the liquid. Experiments
have been performed to establish entrainment of air mass in water
alongside the cylindrical surface. The movement of tracer and seeded
particles has been tracked to calculate the speed and path of the
entrained air inside water. Simplified particle image velocimetry
technique has been used to trace the movement of particles/tracers at
the moment they are injected inside the entrainment zone and
suspended beads have been used to replicate the particle movement
with respect to time in order to determine the flow dynamics of the
fluid along the cylinder. Present paper establishes a thorough experimental analysis of the
rotary entrainment phenomenon between air and water keeping in
interest the extent to which we can intermix the two and also to study
its entrainment trajectories.
Abstract: Gastric Cancer (GC) has high morbidity and fatality
rate in various countries. It is still one of the most frequent and
deadly diseases. Gastrokine1 (GKN1) and gastrokine2 (GKN2) genes
are highly expressed in the normal stomach epithelium and play
important roles in maintaining the integrity and homeostasis of
stomach mucosal epithelial cells. In this study, 47 paired samples that
were grouped according to the types of gastric cancer and the clinical
characteristics of the patients, including gender and average of age.
They were investigated with gene expression analysis and mutation
screening by monitoring RT-PCR, SSCP and nucleotide sequencing
techniques. Both GKN1 and GKN2 genes were observed significantly
reduced found by (Wilcoxon signed rank test; p
Abstract: Monitoring the conditions of rotating machinery, such
as bearings, is important in order to improve the stability of work.
Acoustic Emission (AE) and vibration analysis are some of the most
accomplished techniques used for this purpose. Acoustic emission
has the ability to detect the initial phase of component degradation.
Moreover, it has been observed that vibration analysis is not as
successful at low rotational speeds (below 100 rpm). This because the
energy generated within this speed region is not detectable using
conventional vibration. From this perspective, this paper has
presented a brief review of using acoustic emission techniques for
monitoring bearing conditions.
Abstract: In this paper, we propose the variational EM inference
algorithm for the multi-class Gaussian process classification model
that can be used in the field of human behavior recognition. This
algorithm can drive simultaneously both a posterior distribution of a
latent function and estimators of hyper-parameters in a Gaussian
process classification model with multiclass. Our algorithm is based
on the Laplace approximation (LA) technique and variational EM
framework. This is performed in two steps: called expectation and
maximization steps. First, in the expectation step, using the Bayesian
formula and LA technique, we derive approximately the posterior
distribution of the latent function indicating the possibility that each
observation belongs to a certain class in the Gaussian process
classification model. Second, in the maximization step, using a derived
posterior distribution of latent function, we compute the maximum
likelihood estimator for hyper-parameters of a covariance matrix
necessary to define prior distribution for latent function. These two
steps iteratively repeat until a convergence condition satisfies.
Moreover, we apply the proposed algorithm with human action
classification problem using a public database, namely, the KTH
human action data set. Experimental results reveal that the proposed
algorithm shows good performance on this data set.
Abstract: For the last decade, researchers have started to focus
their interest on Multicast Group Key Management Framework. The
central research challenge is secure and efficient group key
distribution. The present paper is based on the Bit model based
Secure Multicast Group key distribution scheme using the most
popular absolute encoder output type code named Gray Code. The
focus is of two folds. The first fold deals with the reduction of
computation complexity which is achieved in our scheme by
performing fewer multiplication operations during the key updating
process. To optimize the number of multiplication operations, an
O(1) time algorithm to multiply two N-bit binary numbers which
could be used in an N x N bit-model of reconfigurable mesh is used
in this proposed work. The second fold aims at reducing the amount
of information stored in the Group Center and group members while
performing the update operation in the key content. Comparative
analysis to illustrate the performance of various key distribution
schemes is shown in this paper and it has been observed that this
proposed algorithm reduces the computation and storage complexity
significantly. Our proposed algorithm is suitable for high
performance computing environment.
Abstract: The aim of the study is to describe and analyze design
of mobile teaching for students collaborative learning in distance
higher education with a focus on mobile technologies as online
webinars (web-based seminars or conferencing) by using laptops,
smart phones, or tablets. These multimedia tools can provide face-toface
interactions, recorded flipped classroom videos and parallel chat
communications. The data collection consists of interviews with 22
students and observations of online face-to-face webinars, as well
two surveys. Theoretically, the study joins the research tradition of
Computer Supported Collaborative learning, CSCL, as well as
Computer Self-Efficacy, CSE concerned with individuals’ media and
information literacy. Important conclusions from the study
demonstrated mobile interactions increased student centered
learning. As the students were appreciating the working methods,
they became more engaged and motivated. The mobile technology
using among student also contributes to increased flexibility between
space and place, as well as media and information literacy.
Abstract: This study was aimed to measure effective transverse
relaxation rates (R2*) in the liver and muscle of normal New Zealand
White (NZW) rabbits. R2* relaxation rate has been widely used in
various hepatic diseases for iron overload by quantifying iron contents
in liver. R2* relaxation rate is defined as the reciprocal of T2*
relaxation time and mainly depends on the constituents of tissue.
Different tissues would have different R2* relaxation rates. The signal
intensity decay in Magnetic resonance imaging (MRI) may be
characterized by R2* relaxation rates. In this study, a 1.5T GE Signa
HDxt whole body MR scanner equipped with an 8-channel high
resolution knee coil was used to observe R2* values in NZW rabbit’s
liver and muscle. Eight healthy NZW rabbits weighted 2 ~ 2.5 kg were
recruited. After anesthesia using Zoletil 50 and Rompun 2% mixture,
the abdomen of rabbit was landmarked at the center of knee coil to
perform 3-plane localizer scan using fast spoiled gradient echo
(FSPGR) pulse sequence. Afterwards, multi-planar fast gradient echo
(MFGR) scans were performed with 8 various echo times (TEs) to
acquire images for R2* measurements. Regions of interest (ROIs) at
liver and muscle were measured using Advantage workstation.
Finally, the R2* was obtained by a linear regression of ln(sı) on TE.
The results showed that the longer the echo time, the smaller the signal
intensity. The R2* values of liver and muscle were 44.8 ± 10.9 s-1 and
37.4 ± 9.5 s-1, respectively. It implies that the iron concentration of
liver is higher than that of muscle. In conclusion, the more the iron
contents in tissue, the higher the R2*. The correlations between R2*
and iron content in NZW rabbits might be valuable for further
exploration.
Abstract: The practical efficient approach is suggested for
estimation of the seismoacoustic sources energy in C-OTDR
monitoring systems. This approach is represents the sequential plan
for confidence estimation both the seismoacoustic sources energy, as
well the absorption coefficient of the soil. The sequential plan
delivers the non-asymptotic guaranteed accuracy of obtained
estimates in the form of non-asymptotic confidence regions with
prescribed sizes. These confidence regions are valid for a finite
sample size when the distributions of the observations are unknown.
Thus, suggested estimates are non-asymptotic and nonparametric,
and also these estimates guarantee the prescribed estimation accuracy
in form of prior prescribed size of confidence regions, and prescribed
confidence coefficient value.
Abstract: High Performance Liquid Chromatography (HPLC)
method was developed and validated for simultaneous estimation of
6-Gingerol(6G) and 6-Shogaol(6S) in joint pain relief gel containing
ginger extract. The chromatographic separation was achieved by
using C18 column, 150 x 4.6mm i.d., 5μ Luna, mobile phase
containing acetonitrile and water (gradient elution). The flow rate
was 1.0 ml/min and the absorbance was monitored at 282 nm. The
proposed method was validated in terms of the analytical parameters
such as specificity, accuracy, precision, linearity, range, limit of
detection (LOD), limit of quantification (LOQ), and determined
based on the International Conference on Harmonization (ICH)
guidelines. The linearity ranges of 6G and 6S were obtained over 20-
60 and 6-18 μg/ml respectively. Good linearity was observed over the
above-mentioned range with linear regression equation Y= 11016x-
23778 for 6G and Y = 19276x-19604 for 6S (x is concentration of
analytes in μg/ml and Y is peak area). The value of correlation
coefficient was found to be 0.9994 for both markers. The limit of
detection (LOD) and limit of quantification (LOQ) for 6G were
0.8567 and 2.8555 μg/ml and for 6S were 0.3672 and 1.2238 μg/ml
respectively. The recovery range for 6G and 6S were found to be
91.57 to 102.36 % and 84.73 to 92.85 % for all three spiked levels.
The RSD values from repeated extractions for 6G and 6S were 3.43
and 3.09% respectively. The validation of developed method on
precision, accuracy, specificity, linearity, and range were also
performed with well-accepted results.
Abstract: This paper discusses the thematic structure of Yoruba
popular music of Southwest Nigeria. It examines the use of themes
and variations in early and contemporary Juju music. The work is an
outcome of a research developed by the author in his doctoral studies
at the University of Lagos, Nigeria, with the aim of analyzing the
thematic and motivic developments in Yoruba popular genres.
Observations, interviews, live recordings and CDs were used as
methods for eliciting information. Field recordings and CDs of
selected musical samples were also transcribed and notated. The
research established the prevalent use of string of themes by Juju
musicians as a compositional technique in moving from one musical
section to another, as they communicate the verbal messages in their
song. These themes consist of the popular ‘call and response’ form
found in most African music, analogous to the western ‘subject and
answer’ style of the fugue or sonata form, although without the tonic–
dominant relations. Due to the short and repetitive form of African
melodies and rhythms, a theme is restated as a variation, where its
rhythmic and melodic motifs are stylistically developed and repeated,
but still retaining its recognizable core musical structure. The
findings of this study showed that Juju musicians generally often
employ a thematic plan where new themes are used to arrange the
songs into sections, and each theme is developed into variations in
order to further expand the music, eliminate monotony, and create
musical aesthetics, serving as hallmark of its musical identity. The
study established the musical and extra-musical attributes of the
genre, while recommending further research towards analyzing the
various compositional techniques employed in African popular
genres.
Abstract: The effects of the contact ball-lens on the soda lime
glass in laser thermal cleavage with a cw Nd-YAG laser were
investigated in this study. A contact ball-lens was adopted to generate
a bending force on the crack formation of the soda-lime glass in the
laser cutting process. The Nd-YAG laser beam (wavelength of 1064
nm) was focused through the ball-lens and transmitted to the soda-lime
glass, which was coated with a carbon film on the surface with a
bending force from a ball-lens to generate a tensile stress state on the
surface cracking. The fracture was controlled by the contact ball-lens
and a straight cutting was tested to demonstrate the feasibility.
Experimental observations on the crack propagation from the leading
edge, main section and trailing edge of the glass sheet were compared
with various mechanical and thermal loadings. Further analyses on the
stress under various laser powers and contact ball loadings were made
to characterize the innovative technology. The results show that the distributions of the side crack at the
leading and trailing edges are mainly dependent on the boundary
condition, contact force, cutting speed and laser power. With the
increase of the mechanical and thermal loadings, the region of the side
cracks might be dramatically reduced with proper selection of the
geometrical constrains. Therefore the application of the contact
ball-lens is a possible way to control the fracture in laser cleavage with
improved cutting qualities.
Abstract: We consider fast and accurate solutions of scattering
problems by large perfectly conducting objects (PEC) formulated
by an optimization of the Method of Auxiliary Sources (MAS). We
present various techniques used to reduce the total computational cost
of the scattering problem. The first technique is based on replacing
the object by an array of finite number of small (PEC) object with the
same shape. The second solution reduces the problem on considering
only the half of the object.These t
Abstract: Local steel slag is produced as a by-product during the
oxidation of steel pellets in an electric arc furnace. Using local steel
slag waste as a hundred substitutes of crashed stone in construction
materials would resolve the environmental problems caused by the
large-scale depletion of the natural sources of crashed stone. This
paper reports the experimental study to investigate the influence of a
hundred replacement of crashed stone as a coarse aggregate with
local steel slag, on the fresh and hardened geopolymer concrete
properties. The investigation includes traditional testing of hardening
concrete, for selected mixes of cement and geopolymer concrete. It
was found that local steel slag as a coarse aggregate enhanced the
slump test of the fresh state of cement and geopolymer concretes.
Nevertheless, the unit weight of concretes was affected. Meanwhile,
the good performance was observed when fly ash used as geopolymer
concrete based.
Abstract: Background: Maintaining the correct body balance is
essential in the prevention of falls in the elderly, which is especially
important for women because of postmenopausal osteoporosis and
the serious consequences of falls. One of the exercise methods which
is very popular among adults, and which may affect body balance in
the positive way is the Pilates method. The aim of the study was to
evaluate the effect of regular Pilates exercises on the ability to
maintain body balance in static conditions in adult healthy women.
Material and methods: The study group consisted of 20 healthy
women attending Pilates twice a week for at least 1 year. The control
group consisted of 20 healthy women physically inactive. Women in
the age range from 35 to 50 years old without pain in musculoskeletal
system or other pain were only qualified to the groups. Body balance
was assessed using MatScan VersaTek platform with Sway Analysis
Module based on Matscan Clinical 6.7 software (Tekscan Inc.,
U.S.A). The balance was evaluated under the following conditions:
standing on both feet with eyes open, standing on both feet with eyes
closed, one-leg standing (separately on the right and left foot) with
eyes open. Each test lasted 30 seconds. The following parameters
were calculated: estimated size of the ellipse of 95% confidence, the
distance covered by the Center of Gravity (COG), the size of the
maximum shift in the sagittal and frontal planes and load distribution
between the left and right foot, as well as between rear- and forefoot.
Results: It was found that there is significant difference between the
groups in favor of the study group in the size of the confidence
ellipse and maximum shifts of COG in the sagittal plane during
standing on both feet, both with the eyes open and closed (p
Abstract: Introduction: Whole-Body Vibration (WBV) uses
high frequency mechanical stimuli generated by a vibration plate and
transmitted through bone, muscle and connective tissues to the whole
body. Research has shown that long-term vibration-plate training
improves neuromuscular facilitation, especially in afferent neural
pathways, responsible for the conduction of vibration and
proprioceptive stimuli, muscle function, balance and proprioception.
Some researchers suggest that the vibration stimulus briefly inhibits
the conduction of afferent signals from proprioceptors and can
interfere with the maintenance of body balance. The aim of this study
was to evaluate the influence of a single set of exercises associated
with whole-body vibration on the joint position sense and body
balance. Material and methods: The study enrolled 55 people aged
19-24 years. These individuals were randomly divided into a test
group (30 persons) and a control group (25 persons). Both groups
performed the same set of exercises on a vibration plate. The
following vibration parameters: frequency of 20Hz and amplitude of
3mm, were used in the test group. The control group performed
exercises on the vibration plate while it was off. All participants were
instructed to perform six dynamic exercises lasting 30 seconds each
with a 60-second period of rest between them. The exercises involved
large muscle groups of the trunk, pelvis and lower limbs.
Measurements were carried out before and immediately after
exercise. Joint position sense (JPS) was measured in the knee joint
for the starting position at 45° in an open kinematic chain. JPS error
was measured using a digital inclinometer. Balance was assessed in a
standing position with both feet on the ground with the eyes open and
closed (each test lasting 30 sec). Balance was assessed using Matscan
with FootMat 7.0 SAM software. The surface of the ellipse of
confidence and front-back as well as right-left swing were measured
to assess balance. Statistical analysis was performed using Statistica
10.0 PL software. Results: There were no significant differences
between the groups, both before and after the exercise (p> 0.05). JPS
did not change in both the test (10.7° vs. 8.4°) and control groups
(9.0° vs. 8.4°). No significant differences were shown in any of the
test parameters during balance tests with the eyes open or closed in
both the test and control groups (p> 0.05). Conclusions: 1.
Deterioration in proprioception or balance was not observed
immediately after the vibration stimulus. This suggests that vibrationinduced
blockage of proprioceptive stimuli conduction can have only
a short-lasting effect that occurs only as long as a vibration stimulus
is present. 2. Short-term use of vibration in treatment does not impair
proprioception and seems to be safe for patients with proprioceptive
impairment. 3. These results need to be supplemented with an
assessment of proprioception during the application of vibration
stimuli. Additionally, the impact of vibration parameters used in the
exercises should be evaluated.
Abstract: The purposes of hydraulic gate are to maintain the
functions of storing and draining water. It bears long-term hydraulic
pressure and earthquake force and is very important for reservoir and
waterpower plant. The high tensile strength of steel plate is used as
constructional material of hydraulic gate. The cracks and rusts,
induced by the defects of material, bad construction and seismic
excitation and under water respectively, thus, the mechanics
phenomena of gate with crack are probing into the cause of stress
concentration, induced high crack increase rate, affect the safety and
usage of hydroelectric power plant. Stress distribution analysis is a
very important and essential surveying technique to analyze
bi-material and singular point problems. The finite difference
infinitely small element method has been demonstrated, suitable for
analyzing the buckling phenomena of welding seam and steel plate
with crack. Especially, this method can easily analyze the singularity
of kink crack. Nevertheless, the construction form and deformation
shape of some gates are three-dimensional system. Therefore, the
three-dimensional Digital Image Correlation (DIC) has been
developed and applied to analyze the strain variation of steel plate with
crack at weld joint. The proposed Digital image correlation (DIC)
technique is an only non-contact method for measuring the variation of
test object. According to rapid development of digital camera, the cost
of this digital image correlation technique has been reduced.
Otherwise, this DIC method provides with the advantages of widely
practical application of indoor test and field test without the restriction
on the size of test object. Thus, the research purpose of this research is
to develop and apply this technique to monitor mechanics crack
variations of weld steel hydraulic gate and its conformation under
action of loading. The imagines can be picked from real time
monitoring process to analyze the strain change of each loading stage.
The proposed 3-Dimensional digital image correlation method,
developed in the study, is applied to analyze the post-buckling
phenomenon and buckling tendency of welded steel plate with crack.
Then, the stress intensity of 3-dimensional analysis of different
materials and enhanced materials in steel plate has been analyzed in
this paper. The test results show that this proposed three-dimensional
DIC method can precisely detect the crack variation of welded steel
plate under different loading stages. Especially, this proposed DIC
method can detect and identify the crack position and the other flaws
of the welded steel plate that the traditional test methods hardly detect
these kind phenomena. Therefore, this proposed three-dimensional
DIC method can apply to observe the mechanics phenomena of
composite materials subjected to loading and operating.