254 research outputs found
Determinants of Online Purchase Decisions by Online Users
This study was focused on evaluating the determinants of online purchase decisions by thoroughly focusing on the key variables such as need recognition, information search, evaluation of alternatives, cost and time efficiency. The study adopted a quantitative approach, and primary data was collected through a survey technique. The respondents were randomly selected based on their likelihood of using the internet to purchase. The need recognition, information search, evaluation of alternatives, cost and time efficiency were regarded as the independent variables of this study; while purchase decision was treated as a dependent variable. Based on the findings of this study, all the proposed hypotheses are proven substantial. The need recognition, information search, evaluation of alternatives, cost and time efficiency have a positive effect on consumers’ online purchase decisions. The internet has been regarded and used as the prime source of information by a wide range of consumers. Therefore, it is recommended that companies should use a customer centric approach that seeks to engage and prioritize customers, and their needs, through the use of the internet and online means. Keywords: Need recognition, Informative search, Evaluation of alternatives ,Cost and time efficiency Online purchase decisions DOI: 10.7176/JMCR/86-04 Publication date:September 30th 2022
BeiDou-3 orbit and clock quality of the IGS Multi-GNSS Pilot Project
Within the Multi-GNSS Pilot Project (MGEX) of the International GNSS Service
(IGS), precise orbit and clock products for the BeiDou-3 global navigation
satellite system (BDS-3) are routinely generated by a total of five analysis
centers. The processing standards and specific properties of the individual
products are reviewed and the BDS-3 orbit and clock product performance is
assessed through direct inter-comparison, satellite laser ranging (SLR)
residuals, clock stability analysis, and precise point positioning solutions.
The orbit consistency evaluated by the signal-in-space range error is on the
level of 4-8 cm for the medium Earth orbit satellites whereas SLR residuals
have RMS values between 3 and 9 cm. The clock analysis reveals sytematic
effects related to the elevation of the Sun above the orbital plane for all ACs
pointing to deficiencies in solar radiation pressure modeling. Nevertheless,
precise point positioning with the BDS-3 MGEX orbit and clock products results
in 3D RMS values between 7 and 8 mm.Comment: 13 pages, 5 figure
Investigation of a three-phase thermochemical reactor through an experimentally validated numerical modelling
Proteomic analysis of anthers from wild-type and photosensitive genetic male sterile mutant cotton (Gossypium hirsutum L.)
Association between serum cystatin C level and cognition in older adults: a cross-sectional analysis
IntroductionSerum Cystatin C level, an indication of kidney function, has been implicated in the pathogenesis of Alzheimer’s disease and cognitive impairment. In this cross-sectional study, we looked into the relation between serum Cystatin C levels and cognition in a group of U.S. older adults.MethodThe data of this study were from the National Health and Nutrition Examination Survey (NHANES) 1999–2002. A total of 4,832 older adults aged ≥60 who met the inclusion criteria were included. The Dade Behring N Latex Cystatin C assay, which is a particle-enhanced nephelometric assay (PENIA), was utilized to assess Cystatin C levels in participants’ blood samples. Participants’ cognition was examined using the digit symbol substitution test (DSST). Z-scores of the DSST were calculated based on sample means and standard deviations (SD). To investigate the relationships between the quartiles of serum Cystatin C level and DSST z scores, multiple linear regression models were developed while controlling for age, sex, race/ethnicity, and education.ResultsThe average age of the participants was 71.1 (SD 7.8). The participants were about half female (50.5%), non-Hispanic White (61.2%), and (36.1%) who had completed at least some college. They had an average serum Cystatin C level of 1.0 mg/dl (SD 0.44). After performing multiple linear regression with a reference group consisting of participants in quartile one of plasma Cystatin C levels, we found that serum Cystatin C levels in quartiles three and four were independently associated with lower DSST z scores (β = −0.059, 95% CI −0.200 to −0.074 and β = −0.108, 95% CI −0.319 to −0.184, respectively).ConclusionHigher serum Cystatin C level is associated with worse processing speed, sustained attention, and working memory in older adults. Cystatin C level may be a biomarker for cognitive decline in older adults
Approximate solutions to large nonsymmetric differential Riccati problems with applications to transport theory
In the present paper, we consider large scale nonsymmetric differential
matrix Riccati equations with low rank right hand sides. These matrix equations
appear in many applications such as control theory, transport theory, applied
probability and others. We show how to apply Krylov-type methods such as the
extended block Arnoldi algorithm to get low rank approximate solutions. The
initial problem is projected onto small subspaces to get low dimensional
nonsymmetric differential equations that are solved using the exponential
approximation or via other integration schemes such as Backward Differentiation
Formula (BDF) or Rosenbrok method. We also show how these technique could be
easily used to solve some problems from the well known transport equation. Some
numerical experiments are given to illustrate the application of the proposed
methods to large-scale problem
Recovery of an embedded obstacle and the surrounding medium for Maxwell's system
In this paper, we are concerned with the inverse electromagnetic scattering
problem of recovering a complex scatterer by the corresponding electric
far-field data. The complex scatterer consists of an inhomogeneous medium and a
possibly embedded perfectly electric conducting (PEC) obstacle. The far-field
data are collected corresponding to incident plane waves with a fixed incident
direction and a fixed polarisation, but frequencies from an open interval. It
is shown that the embedded obstacle can be uniquely recovered by the
aforementioned far-field data, independent of the surrounding medium.
Furthermore, if the surrounding medium is piecewise homogeneous, then the
medium can be recovered as well. Those unique recovery results are new to the
literature. Our argument is based on low-frequency expansions of the
electromagnetic fields and certain harmonic analysis techniques.Comment: 15 page
Polymorphism of the PEMT gene and susceptibility to nonalcoholic fatty liver disease (NAFLD)
Phosphatidylethanolamine N-methyltransferase (PEMT) catalyzes phosphatidylcholine synthesis. PEMT knockout mice have fatty livers, and it is possible that, in humans, nonalcoholic fatty liver disease (NAFLD) might be associated with PEMT gene polymorphisms. DNA samples from 59 humans without fatty liver and from 28 humans with NAFLD were genotyped for a single nucleotide polymorphism in exon 8 of PEMT which leads to a V175M substitution. V175M is a loss of function mutation, as determined by transiently transfecting McArdle-RH7777 cells with constructs of wildtype PEMT open reading frame or the V175M mutant. Met/Met at residue 175 (loss of function SNP) occurred in 67.9% of the NAFLD subjects and in only 40.7% of control subjects (p< 0.03). For the first time we report that a polymorphism of the human PEMT gene (V175M) is associated with diminished activity and may confer susceptibility to NAFLD
- …