509 research outputs found
A note on the conservation characteristics of baled grass silages ensiled with different additives.
peer-reviewedThe effects of contrasting conventional silage additives on chemical composition,
aerobic stability and deterioration, and mould development in baled silage were investigated.
Herbage from a grassland sward was wilted for 24 h and treated with acid (formic
or sulphuric), sugar (molasses), bacterial (Lactobacillus plantarum, L. plantarum + Serratia
rubidaea + Bacillus subtilis, or L. buchneri) or sugar + bacterial (molasses + L. plantarum)
additives prior to baling and wrapping. Silage made without an additive preserved
well and had a low incidence of mould growth, and the effects of additives were minor or
absent. It is concluded that little practical benefit was realised when conventional additives
were applied to wilted, leafy, easy-to-ensile grass prior to baling and ensilage
Conservation characteristics of baled grass silages differing in duration of wilting, bale density and number of layers of plastic stretch-film
peer-reviewedThe effects of duration of wilting, bale density and number of layers of plastic stretchfilm used to wrap bales on the conservation characteristics of baled grass silage was
investigated. Grass from the primary growth of a Lolium perenne dominant sward was
wilted for 24, 48 or 72 h. For each duration of wilting, 54 cylindrical bales (1.2 m nominal
diameter) were made with the baler at a high or low density setting for alternate bales.
Bales were wrapped with 2, 4 or 6 layers of plastic stretch-film and stored outdoors
for 295 days. Two layers of plastic stretch-film resulted in inferior preservation, lower
digestibility and extensive mould growth and deteriorated silage. Substantial improvement
occurred to each of these characteristics from applying four layers of stretch-film
(P<0.05), while six layers of stretch-film brought little further improvement. When
four or six layers of stretch-film were used, extensive wilting restricted fermentation
and improved the standard of preservation with the apparently difficult-to-preserve
herbage used in this experiment. However, under the anaerobic conditions provided
by four or six layers of stretch-film neither progressive wilting nor bale density had
a major effect on digestibility, or the extent of surface mould growth or deteriorated
silage. It can be concluded that a minimum of four layers of conventional black plastic
stretch-film were required to achieve suitably anaerobic conditions, and that the additional
benefits from six layers were small. Once anaerobic conditions were achieved,
extensive wilting improved the conservation characteristics of baled grass silage made
from a difficult-to-preserve crop, whereas bale density had little impact
Role of the impact parameter in exoplanet transmission spectroscopy
Transmission spectroscopy is a promising tool for the atmospheric
characterization of transiting exoplanets. Because the planetary signal is
faint, discrepancies have been reported regarding individual targets. We
investigate the dependence of the estimated transmission spectrum on deviations
of the orbital parameters of the star-planet system that are due to the
limb-darkening effects of the host star. We describe how the uncertainty on the
orbital parameters translates into an uncertainty on the planetary spectral
slope. We created synthetic transit light curves in seven different wavelength
bands, from the near-ultraviolet to the near-infrared, and fit them with
transit models parameterized by fixed deviating values of the impact parameter
. Our simulations show a wavelength-dependent offset that is more pronounced
at the blue wavelengths where the limb-darkening effect is stronger. This
offset introduces a slope in the planetary transmission spectrum that becomes
steeper with increasing values. Variations of by positive or negative
values within its uncertainty interval introduce positive or negative slopes,
thus the formation of an error envelope. The amplitude from blue optical to
near-infrared wavelength for a typical uncertainty on corresponds to one
atmospheric pressure scale height and more. This impact parameter degeneracy is
confirmed for different host types; K stars present prominently steeper slopes,
while M stars indicate features at the blue wavelengths. We demonstrate that
transmission spectra can be hard to interpret, basically because of the
limitations in defining a precise impact parameter value for a transiting
exoplanet. This consequently limits a characterization of its atmosphere
ChIP-on-chip significance analysis reveals large-scale binding and regulation by human transcription factor oncogenes
ChIP-on-chip has emerged as a powerful tool to dissect the complex network of regulatory interactions between transcription factors and their targets. However, most ChIP-on-chip analysis methods use conservative approaches aimed to minimize false-positive transcription factor targets. We present a model with improved sensitivity in detecting binding events from ChIP-on-chip data. Biochemically validated analysis in human T-cells reveals that three transcription factor oncogenes, NOTCH1, MYC, and HES1, bind one order of magnitude more promoters than previously thought. Gene expression profiling upon NOTCH1 inhibition shows broad-scale functional regulation across the entire range of predicted target genes, establishing a closer link between occupancy and regulation. Finally, the resolution of a more complete map of transcriptional targets reveals that MYC binds nearly all promoters bound by NOTCH1. Overall, these results suggest an unappreciated complexity of transcriptional regulatory networks and highlight the fundamental importance of genome-scale analysis to represent transcriptional programs
Genetics and epigenetics of liver cancer
Hepatocellular carcinoma (HCC) represents a major form of primary liver cancer in adults. Chronic infections with hepatitis B (HBV) and C (HCV) viruses and alcohol abuse are the major factors leading to HCC. This deadly cancer affects more than 500,000 people worldwide and it is quite resistant to conventional chemo- and radiotherapy. Genetic and epigenetic studies on HCC may help to understand better its mechanisms and provide new tools for early diagnosis and therapy. Recent literature on whole genome analysis of HCC indicated a high number of mutated genes in addition to well-known genes such as TP53, CTNNB1, AXIN1 and CDKN2A, but their frequencies are much lower. Apart from CTNNB1 mutations, most of the other mutations appear to result in loss-of-function. Thus, HCC-associated mutations cannot be easily targeted for therapy. Epigenetic aberrations that appear to occur quite frequently may serve as new targets. Global DNA hypomethylation, promoter methylation, aberrant expression of non-coding RNAs and dysregulated expression of other epigenetic regulatory genes such as EZH2 are the best-known epigenetic abnormalities. Future research in this direction may help to identify novel biomarkers and therapeutic targets for HCC. © 2013 Elsevier B.V
Probing the atmosphere of HD189733b with the Na I and K I lines
High spectral resolution transmission spectroscopy is a powerful tool to
characterize exoplanet atmospheres. Especially for hot Jupiters, this technique
is highly relevant, due to their high altitude absorption e.g. from resonant
sodium (Na I) and potassium (K I) lines. We resolve the atmospheric K
I-absorption on HD189733b with the aim to compare the resolved K I -line and
previously obtained high resolution Na I-D-line observations with synthetic
transmission spectra. The line profiles suggest atmospheric processes leading
to a line broadening of the order of 10 km/s for the Na I-D-lines, and only a
few km/s for the K I-line. The investigation hints that either the atmosphere
of HD189733b lacks a significant amount of K I or the alkali lines probe
different atmospheric regions with different temperature, which could explain
the differences we see in the resolved absorption lines
Platelet-activating factor levels of serum and gingival crevicular fluid in nonsmoking patients with periodontitis and/or coronary heart disease
The purpose of the present study was to investigate systemic and local levels of platelet-activating factor (PAF), a potent proinflammatory mediator implicated in cardiovascular pathophysiology in adult nonsmoking patients with periodontitis with or without coronary heart disease (CHD). Eighty-seven volunteers, 25 periodontitis patients, 19 periodontitis with CHD patients, 19 CHD patients, and 24 healthy controls were included, and periodontal conditions were assessed. Gingival crevicular fluid (GCF) and venous blood were collected, and PAF levels were measured by enzyme-linked immunosorbent assay. PAF levels in serum (303.3 ± 204 pg/ml) and in GCF (26.3 ± 6 pg/μl) of the periodontitis group with CHD, the periodontitis group (serum, 302.4 ± 241 pg/ml and GCF, 26.3 ± 8 pg/μl) and the CHD group (serum, 284.7 ± 192 pg/ml and GCF, 20.8 ± 6 pg/μl) were significantly higher than the healthy control group (serum, 65.4 ± 35 pg/ml and GCF, 7.7 ± 3 pg/μl; p < 0.05). In summary, the present study could demonstrate that in patients with periodontitis, the inflammatory mediator PAF is released into serum at least in the same range as for patients with coronary heart disease. However, no additive effects were seen when both conditions were present
Sense of place in the changing process of house form: Case studies from Ankara, Turkey
This paper aims to investigate the impact of typomorphological changes of residential environments on residents’ sense of place’. Seven housing developments representing different types introduced in Ankara, Turkey since the late 19th-century are selected as case studies. Their morphological characters at the building, street and neighbourhood scales are examined, and typological transformations among the cases in terms of the degrees of continuity are identified. The paper proposes a conceptual model consisting of ten indicators to assess sense of place at the building, street and neighbourhood scales of the residents of the seven cases. The scores of sense of place are generated through structured interviews with the residents and analysed in SPSS. The results show that sense of place is negatively affected by typomorphological changes over time, particularly when mutational changes occur. Continuity in typomorphological transformation helps to maintain sense of place at a desirable level. Furthermore, physical changes at the street and neighbourhood scales have larger impact on sense of place than that at the building scale. The research thus suggests that planning and design should be responsive to traditional types in residential development, particularly at the street and neighbourhood scales to maintain residents’ sense of place
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