507 research outputs found
Exploring Parameter Constraints on Quintessential Dark Energy: The Exponential Model
We present an analysis of a scalar field model of dark energy with an
exponential potential using the Dark Energy Task Force (DETF) simulated data
models. Using Markov Chain Monte Carlo sampling techniques we examine the
ability of each simulated data set to constrain the parameter space of the
exponential potential for data sets based on a cosmological constant and a
specific exponential scalar field model. We compare our results with the
constraining power calculated by the DETF using their ``''
parametrization of the dark energy. We find that respective increases in
constraining power from one stage to the next produced by our analysis give
results consistent with DETF results. To further investigate the potential
impact of future experiments, we also generate simulated data for an
exponential model background cosmology which can not be distinguished from a
cosmological constant at DETF ``Stage 2'', and show that for this cosmology
good DETF Stage 4 data would exclude a cosmological constant by better than
3.Comment: 11 pages including 10 figure
Exploring Parameter Constraints on Quintessential Dark Energy: the Albrecht-Skordis model
We consider the effect of future dark energy experiments on
``Albrecht-Skordis'' (AS) models of scalar field dark energy using the
Monte-Carlo Markov chain method. We deal with the issues of parameterization of
these models, and have included spatial curvature as a parameter, finding it to
be important. We use the Dark Energy Task Force (DETF) simulated data to
represent future experiments and report our results in the form of likelihood
contours in the chosen parameter space. Simulated data is produced for cases
where the background cosmology has a cosmological constant, as well as cases
where the dark energy is provided by the AS model. The latter helps us
demonstrate the power of DETF Stage 4 data in the context of this specific
model. Though the AS model can produce equations of state functions very
different from what is possible with the parametrization used by the
DETF, our results are consistent with those reported by the DETF.Comment: 7 pages, including 9 figure
Influence of low intensity laser irradiation on isolated human adipose derived stem cells over 72 hours and their differentiation potential into smooth muscle cells using retinoic acid
Human adipose derived stem cells (hADSCs), with their impressive differentiation potential, may be used in autologous cell therapy or grafting to replace damaged tissues. Low intensity laser irradiation (LILI) has been shown to influence the behaviour of various cells, including stem cells. This study aimed to investigate the effect of LILI on hADSCs 24, 48 or 72 h post-irradiation and their differentiation potential into smooth muscle cells (SMCs). Methodology: hADSCs were exposed to a 636 nm diode laser at a fluence of 5 J/cm2. hADSCs were differentiated into SMCs using retinoic acid (RA). Morphology was assessed by inverted light and differential interference contrast (DIC) microscopy. Proliferation and viability of hADSCs was assessed by optical density (OD), Trypan blue staining and adenosine triphosphate (ATP) luminescence. Expression of stem cell markers, β1-integrin and Thy-1, and SMC markers, smooth muscle alpha actin (SM-αa), desmin, smooth muscle myosin heavy chain (SM-MHC) and smoothelin, was assessed by immunofluorescent staining and real-time reverse transcriptase polymerase chain reaction (RT-PCR). Results: Morphologically, hADSCs did not show any differences and there was an increase in viability and proliferation post-irradiation. Immunofluorescent staining showed expression of β1-integrin and Thy-1 72 h post-irradiation. RT-PCR results showed a down regulation of Thy-1 48 h post-irradiation. Differentiated SMCs were confirmed by morphology and expression of SMC markers. Conclusion: LILI at a wavelength of 636 nm and a fluence of 5 J/cm2 does not induce differentiation of isolated hADSCs over a 72 h period, and increases cellular viability and proliferation. hADSCs can be differentiated into SMCs within 14 days using RA
The Meal Criterion Estimated in Grazing Dairy Cattle: Evaluation of Different Methods
The meal criterion (MC) has been found a useful tool to pre-treat intake behaviour data in dairy cows. It was defined as the longest interval between bouts that belong to the same meal (Tolkamp & Kyriazakis, 1999), necessary to cluster bouts to meals. The method of Yeates et al. (2001) calculating the loge-transformed intervals between bouts and using the Gaussian-Gaussian-Weibull (GGW) model to calculate the MC was found to provide the best estimation of the MC in biological as well as statistical terms. However, in grazing dairy cattle the MC-estimation has only been carried out by Rook & Huckle (1997) using a broken stick method. The aim of this study was to estimate the MC in grazing dairy cattle with the recently developed estimation methods
Buildings behaving badly:A behavioral experiment on how different motivational frames influence residential energy label adoption in the Netherlands
Heating buildings contributes to approximately 36% of Europe’s energy demand and several EU member states have adopted mandatory energy labels to improve energy efficiency by promoting home weatherization investments. This paper focuses on the perception of the energy label for residential buildings in the Netherlands and the role of different frames (egoistic, biospheric and social norms and neutral frames) in motivating adoption of energy labels for housing. We used a behavioral email experiment and an online survey to investigate these motivational factors. We find that biospheric frames are weaker than the other three motivational frames in terms of engaging interest in the energy label, but that the biospheric frame results in higher willingness to pay (WTP) for the energy label. We also find that age (rather than income) correlates with higher willingness to pay for home energy labels
Targeted photodynamic therapy as potential treatment modality for the eradication of colon cancer and colon cancer stem cells
Abstract: Colorectal cancer is commonly treated by tumour resection, as chemotherapy and radiation have proven to be less effective, especially if the tumour has metastasized. Resistance to therapies occurs in almost all patients with colorectal cancer, especially in those with metastatic tumours. Cancer stem cells have the ability to self-renew, and their slow rate of cycling enhances resistance to treatment and increases the likelihood of tumour recurrence. Most metastatic tumours are unable to be surgically removed, thus creating a need for treatment modalities that target cancers directly and destroy cancer stem cells. Photodynamic therapy involves a photosensitizer that when exposed to a light source of a particular wavelength becomes excited and produces a form of oxygen that kills cancer cells. Photodynamic therapy is currently being investigated as a treatment modality for colorectal cancer, and new studies are exploring enhancing photodynamic therapy efficacy with the aid of drug carriers and immune conjugates. These modifications could prove effective in targeting cancer stem cells that are thought to be resistant to photodynamic therapy. In order for photodynamic therapy to be an effective treatment in colorectal cancer, it requires treatment of both primary tumours and the metastatic secondary disease that is caused by colon cancer stem cells. This review focuses on current photodynamic therapy treatments available for colorectal cancer and highlights proposed actively targeted photosynthetic drug uptake mechanisms specifically mediated towards colon cancer stem cells, as well as identify the gaps in research which need to be investigated in order to develop a combinative targeted photodynamic therapy regime that can effectively control colorectal cancer primary and metastatic tumour growth by eliminating colon cancer stem cells. Tumor Biology, DOI: 10.1177/101042831773469
Photometric Redshift Probability Distributions for Galaxies in the SDSS DR8
We present redshift probability distributions for galaxies in the SDSS DR8
imaging data. We used the nearest-neighbor weighting algorithm presented in
Lima et al. 2008 and Cunha et al. 2009 to derive the ensemble redshift
distribution N(z), and individual redshift probability distributions P(z) for
galaxies with r < 21.8. As part of this technique, we calculated weights for a
set of training galaxies with known redshifts such that their density
distribution in five dimensional color-magnitude space was proportional to that
of the photometry-only sample, producing a nearly fair sample in that space. We
then estimated the ensemble N(z) of the photometric sample by constructing a
weighted histogram of the training set redshifts. We derived P(z) s for
individual objects using the same technique, but limiting to training set
objects from the local color-magnitude space around each photometric object.
Using the P(z) for each galaxy, rather than an ensemble N(z), can reduce the
statistical error in measurements that depend on the redshifts of individual
galaxies. The spectroscopic training sample is substantially larger than that
used for the DR7 release, and the newly added PRIMUS catalog is now the most
important training set used in this analysis by a wide margin. We expect the
primary source of error in the N(z) reconstruction is sample variance: the
training sets are drawn from relatively small volumes of space. Using
simulations we estimated the uncertainty in N(z) at a given redshift is 10-15%.
The uncertainty on calculations incorporating N(z) or P(z) depends on how they
are used; we discuss the case of weak lensing measurements. The P(z) catalog is
publicly available from the SDSS website.Comment: 29 pages, 9 figures, single colum
30 Yan-nhanu language documentation and revitalisation
Breastfeeding may have a protective effect on the development of obesity in later life. Not much is known about the effects of infant feeding on more-specific fat measures.We examined associations of breastfeeding duration and exclusiveness and age at the introduction of solid foods with general and abdominal fat outcomes in children.We performed a population-based, prospective cohort study in 5063 children. Information about infant feeding was obtained by using questionnaires. At the median age of 6.0 y (90\% range: 5.7\%, 6.8\%), we measured childhood anthropometric measures, total fat mass and the android:gynoid fat ratio by using dual-energy X-ray absorptiometry and preperitoneal abdominal fat by using ultrasound.We observed that, in the models adjusted for child age, sex, and height only, a shorter breastfeeding duration, nonexclusive breastfeeding, and younger age at the introduction of solid foods were associated with higher childhood general and abdominal fat measures (P-trend < 0.05) but not with higher childhood body mass index. The introduction of solid foods at a younger age but not breastfeeding duration or exclusivity was associated with higher risk of overweight or obesity (OR: 2.05; 95\% CI: 1.41, 2.90). After adjustment for family-based sociodemographic, maternal lifestyle, and childhood factors, the introduction of solid food between 4-4.9 mo of age was associated with higher risks of overweight or obesity, but the overall trend was not significant.Associations of infant breastfeeding and age at the introduction of solid foods with general and abdominal fat outcomes are explained by sociodemographic and lifestyle-related factors. Whether infant dietary composition affects specific fat outcomes at older ages should be further studied
Treatment experiences of Latinas after diagnosis of breast cancer
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138310/1/cncr30702.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138310/2/cncr30702_am.pd
М.К. Янгель біля витоків вітчизняного ракетобудування
Висвітлено життєвий шлях академіка М.К.Янгеля, його внесок у розвиток вітчизняного ракетобудування, забезпечення обороноздатності СРСР.Освещены жизненный путь академика М.К.Янгеля и его вклад в развитие отечественного ракетостроения, обеспечение обороноспособности СССР.An account of the life path of the academician М. К. Yangel, his contribution in the national spacecraft and of defense capacity building of the USSR is contained
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