279 research outputs found
Analysis of California surface temperature trends based on observations.
Analysis of California surface temperature based on observations has been conducted using United States Historical Climatology Network (USHCN) stations and Cooperative Weather (COOP) stations throughout California to understand spatial and temporal changes in temperature. Monthly maximum and minimum temperatures (Tmax and Tmin) were used to calculate and analyze annual and seasonal trends over the last 86 years via statistical analyses. For annual trends, Tmin is warming faster than Tmax for both 1918--2006 and 1950--2006 time periods. Since 1970, both Tmax and Tmin, however, have increased at the same rate. For seasonal trends, interestingly, by far the largest warming trends are found during spring (March--May) in both Tmax and Tmin, particularly in Southern California since 1970. While Tmin reveals a strong coherent temperature variation statewide in both annual and seasonal temperatures, Tmax shows spatial and temporal variations in finer scales. Particularly in Southern California during winter and summer, cooling and warming trends are leveled in Tmax. These regional temperature changes must be caused by different forcing mechanisms
Aspects of physics competitions in Thailand: Upsides, downsides and overcoming
Today, innovation is called for, and science competition is one of the places where new ideas are illuminated. For scientists, competition (such as for funding or resources) attracts the international talents, but it might have a detrimental effect on advances in science. This poses similar concerns about learning and the whole process of training students for science competition. For students, the science competition is an enrichment program to sharpen skills. The benefits are also for teachers as well as the teaching community. In Thailand, International Physics Olympiad (IPhO) and International Young Physicists’ Tournament (IYPT) are the two familiar competitions. The events are well-received, triggering several competitions at the national level. The high intensity of the competition identifies the brightest students. The widespread demand requires the teachers to prepare for coaching.
In this talk, I will discuss recent efforts not only to improve student performance, but also to enhance teacher skills for the physics competitions in Thailand. Despite all the merits of the competitions, there are downsides. Gender gap and lack of creativity are among some others. Ways to overcome are proposed and implemented
Characterization of cellular signalling pathways involved in the regulation of trophoblast cell functions
This publication based doctoral thesis comprises six manuscripts covering the intracellular signaling pathways activated by LIF and OSM and the functional analysis of miR-21 in trophoblastic cells. The aim of this thesis was to elucidate the signaling pathways activated by the cytokines LIF and OSM as well as the role of specific miRNAs in the control of trophoblast cell functions. The results demonstrate that LIF and OSM have similar functions in activating STAT3 and ERK1/2 by changing their phosphorylation status in four trophoblastic cell lines. However, LIF but not OSM significantly increases invasion of trophoblastic cell lines. Inhibition of STAT3 decreases the invasiveness of trophoblastic cell lines by inhibiting the secretion of matrix metalloproteinases (MMPs). These results suggest that LIF shares STAT3 and ERK1/2 activation with OSM but their resulting responses are cell type dependent. The second part of this dissertation is focused on placenta-specific miRNAs and their function on trophoblast cells. The miRNA profile of primary cells includes the expression of at three clusters which are specifically expressed in placenta tissue: C19MC, C14MC and the miR-371-3 cluster. C19MC is highly expressed in third trimester trophoblast cells and in choriocarcinoma cell lines. C14MC is highest expressed in first trimester trophoblast cells as well as in HTR-8/SVneo cells and its plasma concentration decreases with the gestational age. Both miRNA clusters are evolutionary related to the appearance of placenta and their dysregulation can be associated with pregnancy pathologies. In conclusion, this work describes the intercellular signaling pathways activated by OSM and LIF, as well as the function of miR-21 in trophoblastic cells. Moreover, it may provide novel information on their involvement in the pathogenesis of pregnancy-related disorders which may be useful for the design of future non-invasive diagnostic tools or for the development of new therapeutic approaches
The influence of entrepreneurial orientation and family business’s resources and capabilities on marketing performances
This paper uses data from the Successful Transgenerational Entrepreneurship Practices Project (STEP Project) to investigate the influence of entrepreneurial orientation (EO) and family business’s resources and capabilities towards marketing performance. Previous researches represent an evidence of a relationship between EO and firm performance. Nevertheless, there are limited studies to investigate both psychological and physical aspects of family business like EO and family business’s resources and capabilities to firm performance. The empirical analysis includes a STEP project data set of 28 countries (n = 1,008) in 4 regions of the world; Asia-Oceania (Australia, China, Hong Kong, India, Japan, Malaysia, Taiwan, Thailand), Europe (Belgium, France, Germany, Ireland, Italy, Netherlands, Spain, Sweden, Switzerland, UK, Russia), Latin America (Chile, Colombia, Dominican Republic, Peru, Puerto Rico, Venezuela), and North America (Canada, Mexico, USA) which was collected during 2013-2015. SEM is used to investigate the effect of EO and family business’s resources and capabilities on marketing performances.
The findings support the relationship of EO and family business’s resources and capabilities on entrepreneurial performances. The results of the study show that both EO and family business’s resources and capabilities affect positively to the entrepreneurial performance. This study provides insights to researchers, practitioners and managers on the significance of both entrepreneurial orientations and firms’ resources and capabilities for the survival and growth of family businesses.peer-reviewe
Force on a moving object in an ideal quantum gas
We consider a heavy external object moving in an ideal gas of light
particles. Collisions with the gas particles transfer momentum to the object,
leading to a force that is proportional to the object's velocity but in the
opposite direction. In an ideal classical gas at temperature , the force
acting on the object is proportional to . Quantum statistics causes a
deviation from the -dependence and shows that the force scales with
at low temperatures. At , the force vanishes in a Bose gas but is
finite in a Fermi gas.Comment: 11 pages, 4 figures; This material has been submitted to/accepted by
the American Journal of Physics. After it is published, it will be found at
(https://pubs.aip.org/aapt/ajps
What skills do nascent entrepreneurs need? The evidence from Thailand
The purposes of this study are (1) to investigate the entrepreneurial skills situation of Thai nascent entrepreneurs (2) to study the influence of entrepreneurial skills towards business growth expectation of Thai nascent entrepreneurs.
The sample consisted of 1,000 Thai entrepreneurs having been juristic person or commercial registered less than 2 years. Multi-stage sampling method was used to collect the data by using questionnaire as the research instrument.
The result shows that Thai nascent entrepreneurs have the highest level of readiness in technological skill (4.08), marketing skill (3.99), managerial skill (3.96), human resource skill (3.66) and accounting and financial skill (3.41) ranked lowest.
Additionally, the results of hypothesis testing show that (1) entrepreneurial skills statistically significantly influence on business growth expectation of Thai nascent entrepreneurs. (2) High entrepreneurial skill entrepreneurs have significantly higher level of business growth expectation than counterparts.peer-reviewe
Cosmic evolution in DHOST theories with scaling solutions
We study cosmic evolution based on the fixed points in the dynamical analysis
of the Degenerate Higher-Order Scalar-Tensor (DHOST) theories. We consider the
DHOST theories in which the propagation speed of gravitational waves is equal
to the speed of light, the tensor perturbations do not decay to dark energy
perturbations, and the scaling solutions exist. The scaling fixed point
associated with late time acceleration of universe can be either stable or
saddle depending on the parameters of the theory. For some ranges of the
parameters, the accelerated scaling point and the field dominated point can be
simultaneously stable. Cosmic evolution will reach the accelerated scaling
point if the time derivative of the scalar field in the theory is positive
during the matter domination. If the time derivative of the scalar field is
negative during the matter domination, the background universe will evolve
towards the field dominated point. The density parameter of the matter can be
larger than unity before reaching the scaling fixed point if the deviation from
the Einstein theory of gravity is too large and the initial conditions for the
dynamical variables during the matter domination are significantly different
from the accelerated scaling point. The stabilities of MDE fixed point
are similar to the coupled dark energy models. In our consideration, the
universe can only evolve from the MDE to the field dominated point.Comment: 19 pages, 3 figures, 1 tabl
The Impact of Dietary Compounds in Functional Foods on MicroRNAs Expression
MicroRNAs (miRNAs) are a class of non-coding endogenous RNA molecules that are involved in post-transcriptional gene silencing via binding to their target messenger RNA, leading to mRNA degradation or translational repression. MicroRNAs can be modulated by several factors including hormones, transcription factors, and dietary compounds. These biologically active compounds have positive impact on the progression of human pathology including non-communicable diseases, which indicating that administration of diet may have potential as therapeutic agents in modulating the risk of chronic diseases. Interestingly, evidence emerging in recent years suggests that dietary miRNAs can be absorbed in human circulation, modulated human gene expression and biological functions. The exploitation of the miRNA functioning within different origins, cellular miRNAs and dietary miRNAs will help us to understand the molecular machinery as well as the regulatory mechanisms involved in fundamentally important biological processes. Therefore, this knowledge may be applied of natural bioactive compounds in preventive or therapeutic approaches
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