546 research outputs found
The effects of calcium and boron on apple trees when applied through microjet irrigation
Two experiments were performed to study the effects of calcium (Ca) and boron (B) applied as calcium chloride {CaCl2*2H20(27% Ca)} and Solubor {Na2B407(20% B)} through microjet irrigation to young apple trees (Malus domestica Borkh). The effects of CaCl2 and Solubor treatments on both soil and foliar nutrient levels were measured when Ca and B were applied in irrigation water with and without foliar applications of Ca as CaCl2 (Exp 1). Additionally, the effects of Ca and B fertilization with and without irrigation were investigated (Exp 2). No differences in foliar or soil test extractable Ca concen-trations were found with any CaCl2 treatments for either experiment. Treatments providing 0.25 and 0.50 g/day/tree Solubor (1982) and 0.50 and 0.10 g/day/tree of Solubor (1983) significantly increased both soil and foliar B levels (Exp 1). Applications of 0.50 g/day/tree of Solubor in experiment 2 increased the levels of B in the soil but not in the leaves. No differences were found between the irrigated and non-irrigated treatments. The addition of CaCl2 to irrigation water did not influence volume output but did influence the irriga-tion spray pattern
Data Sharing in Clinical Trials – Practical guidance on anonymizing trial datasets
There is an increasing demand by non-commercial funders that trialists should provide access to trial data once the primary analysis is completed. This has to take into account concerns about identifying individual trial participants, and the legal and regulatory requirements.
Using the good practice guidelines on data sharing laid out by the work funded by the MRC Network of Hubs for Trials Methodology Research, we have devised a processes and mechanisms for user access control, anonymisation and sharing of clinical trial data.
As part of this, we have anonymised a dataset from the TOPPIC trial. Using this example, we will present practical guidance on how to anonymise a dataset, and describe rules that could be used on other trial datasets. We will describe how these might differ if the trial was to be made freely available to all, or if the data could only be accessed with specific permission and data usage agreements in place
SN2013fs and SN2013fr: Exploring the circumstellar-material diversity in Type II supernovae
We present photometry and spectroscopy of SN2013fs and SN2013fr in the first
100 days post-explosion. Both objects showed transient, relatively narrow
H emission lines characteristic of SNeIIn, but later resembled normal
SNeII-P or SNeII-L, indicative of fleeting interaction with circumstellar
material (CSM). SN2013fs was discovered within 8hr of explosion. Its light
curve exhibits a plateau, with spectra revealing strong CSM interaction at
early times. It is a less luminous version of the transitional SNIIn PTF11iqb,
further demonstrating a continuum of CSM interaction intensity between SNeII-P
and IIn. It requires dense CSM within 6.510~cm of the
progenitor, from a phase of advanced pre-SN mass loss shortly before explosion.
Spectropolarimetry of SN2013fs shows little continuum polarization, but
noticeable line polarization during the plateau phase. SN2013fr morphed from a
SNIIn at early times to a SNII-L. After the first epoch its narrow lines
probably arose from host-galaxy emission, but the bright, narrow H
emission at early times may be intrinsic. As for SN2013fs, this would point to
a short-lived phase of strong CSM interaction if proven to be intrinsic,
suggesting a continuum between SNeIIn and II-L. It is a low-velocity SNII-L,
like SN2009kr but more luminous. SN2013fr also developed an IR excess at later
times, due to warm CSM dust that require a more sustained phase of strong
pre-SN mass loss.Comment: MNRAS accepted. 28 pages, 23 figures, 8 table
A spontaneous increase in intracellular Ca2+ in metaphase II human oocytes in vitro can be prevented by drugs targeting ATP-sensitive K+ channels
STUDY QUESTION: Could drugs targeting ATP-sensitive K+ (KATP) channels prevent any spontaneous increase in intracellular Ca2+ that may occur in human metaphase II (MII) oocytes under in vitro conditions? SUMMARY ANSWER: Pinacidil, a KATP channel opener, and glibenclamide, a KATP channel blocker, prevent a spontaneous increase in intracellular Ca2+ in human MII oocytes. WHAT IS KNOWN ALREADY: The quality of the oocyte and maintenance of this quality during in vitro processing in the assisted reproductive technology (ART) laboratory is of critical importance to successful embryo development and a healthy live birth. Maintenance of Ca2+ homeostasis is crucial for cell wellbeing and increased intracellular Ca2+ levels is a well-established indicator of cell stress. STUDY DESIGN, SIZE, DURATION: Supernumerary human oocytes (n = 102) collected during IVF/ICSI treatment that failed to fertilize were used from October 2013 to July 2015. All experiments were performed on mature (MII) oocytes. Dynamics of intracellular Ca2+ levels were monitored in oocytes in the following experimental groups: (i) Control, (ii) Dimethyl sulfoxide (DMSO; used to dissolve pinacidil, glibenclamide and 2,4-Dinitrophenol (DNP)), (iii) Pinacidil, (iv) Glibenclamide, (v) DNP: an inhibitor of oxidative phosphorylation, (vi) Pinacidil and DNP and (vii) Glibenclamide and DNP. PARTICIPANTS/MATERIALS/SETTINGS/METHODS: Oocytes were collected under sedation as part of routine treatment at an assisted conception unit from healthy women (mean ± SD) age 34.1 ± 0.6 years, n = 41. Those surplus to clinical use were donated for research. Oocytes were loaded with Fluo-3 Ca2+-sensitive dye, and monitored by laser confocal microscopy for 2 h at 10 min intervals. Time between oocyte collection and start of Ca2+ monitoring was 80.4 ± 2.1 h. MAIN RESULTS AND THE ROLE OF CHANCE: Intracellular levels of Ca2+ increased under in vitro conditions with no deliberate challenge, as shown by Fluo-3 fluorescence increasing from 61.0 ± 11.8 AU (AU = arbitrary units; n = 23) to 91.8 ± 14.0 AU (n = 19; P <0.001) after 2 h of monitoring. Pinacidil (100 µM) inhibited this increase in Ca2+ (85.3 ± 12.3 AU at the beginning of the experiment, 81.7 ± 11.0 AU at the end of the experiment; n = 13; P = 0.616). Glibenclamide (100 µM) also inhibited the increase in Ca2+ (74.7 ± 10.6 AU at the beginning and 71.8 ± 10.9 AU at the end of the experiment; n = 13; P = 0.851. DNP (100 mM) induced an increase in intracellular Ca2+ that was inhibited by glibenclamide (100 µM; n = 9) but not by pinacidil (100 µM; n = 5). LIMITATIONS, REASONS FOR CAUTION: Owing to clinical and ethical considerations, it was not possible to monitor Ca2+ in MII oocytes immediately after retrieval. MII oocytes were available for our experimentation only after unsuccessful IVF or ICSI, which was, on average, 80.4 ± 2.1 h (n = 102 oocytes) after the moment of retrieval. As the MII oocytes used here were those that were not successfully fertilized, it is possible that they may have been abnormal with impaired Ca2+ homeostasis and, furthermore, the altered Ca2+ homeostasis might have been associated solely with the protracted incubation. WIDER IMPLICATIONS OF THE FINDINGS: These results show that maintenance of oocytes under in vitro conditions is associated with intracellular increase in Ca2+, which can be counteracted by drugs targeting KATP channels. As Ca2+ homeostasis is crucial for contributing to a successful outcome of ART, these results suggest that KATP channel openers and blockers should be tested as drugs for improving success rates of ART
Multi-Epoch Spectropolarimetry for a Sample of Type IIn Supernovae: Persistent Asymmetry in Dusty Circumstellar Material
We present multi-epoch spectropolarimetry and spectra for a sample of 14 Type
IIn supernovae (SNe IIn). We find that after correcting for likely interstellar
polarization, SNe IIn commonly show intrinsic continuum polarization of 1--3%
at the time of peak optical luminosity, although a few show weaker or
negligible polarization. While some SNe IIn have even stronger polarization at
early times, their polarization tends to drop smoothly over several hundred
days after peak. We find a tendency for the intrinsic polarization to be
stronger at bluer wavelengths, especially at early times. While polarization
from an electron scattering region is expected to be grey, scattering of SN
light by dusty circumstellar material (CSM) may induce such a
wavelength-dependent polarization. For most SNe IIn, changes in polarization
degree and wavelength dependence are not accompanied by changes in the position
angle, requiring that asymmetric pre-SN mass loss had a persistent geometry.
While 2--3% polarization is typical, about 30% of SNe IIn have very low or
undetected polarization. Under the simplifying assumption that all SN IIn
progenitors have axisymmetric CSM (i.e. disk/torus/bipolar), then the
distribution of polarization values we observe is consistent with similarly
asymmetric CSM seen from a distribution of random viewing angles. This
asymmetry has very important implications for understanding the origin of
pre-SN mass loss in SNe IIn, suggesting that it was shaped by binary
interaction.Comment: 76 pages, 54 figures (13 in main text, 41 in appendix A
SN2012ab: A Peculiar Type IIn Supernova with Aspherical Circumstellar Material
We present photometry, spectra, and spectropolarimetry of supernova (SN)
2012ab, mostly obtained over the course of days after discovery. SN
2012ab was a Type IIn (SN IIn) event discovered near the nucleus of spiral
galaxy 2MASXJ12224762+0536247. While its light curve resembles that of SN
1998S, its spectral evolution does not. We see indications of CSM interaction
in the strong intermediate-width emission features, the high luminosity (peak
at absolute magnitude ), and the lack of broad absorption features in
the spectrum. The H emission undergoes a peculiar transition. At early
times it shows a broad blue emission wing out to km
and a truncated red wing. Then at late times (
100days) it shows a truncated blue wing and a very broad red emission wing
out to roughly km . This late-time broad red wing
probably arises in the reverse shock. Spectra also show an asymmetric
intermediate-width H component with stronger emission on the red side
at late times. The evolution of the asymmetric profiles requires a density
structure in the distant CSM that is highly aspherical. Our spectropolarimetric
data also suggest asphericity with a strong continuum polarization of % and depolarization in the H line, indicating asphericity in the
CSM at a level comparable to that in other SNe IIn. We estimate a mass-loss
rate of for km extending back at least 75yr prior to the
SN. The strong departure from axisymmetry in the CSM of SN 2012ab may suggest
that the progenitor was an eccentric binary system undergoing eruptive mass
loss.Comment: 18 pages, 12 figure
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Early Observations And Analysis Of The Type Ia SN 2014J In M82
We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (-10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I lambda 1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for OI, Mg II, Si II, S Ca a, and Fell suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from -10d to +29d, in the UBVRIJH and K-s bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using R-v = 1.46, which is consistent with previous studies, SNooPy finds that A(v) = 1.80 for E(B - V)(host) = 1.23 +/- 0.06 mag. The maximum B-band brightness of -19.19 +/- 0.10 mag was reached on February 1.74 UT +/- 0.13 days and the supernova has a decline parameter, Delta m(15), of 1.12 +/- 0.02 mag.Department of Space, Government of IndiaHungarian OTKA NN-107637NSF AST-1109801, AST-1151462, AST-1211196NSF Astronomy and Astrophysics Postdoctoral Fellowship AST-1302771NASA through a grant from the Space Telescope Science Institute GO-12540NASA NAS5-26555Swedish Research CouncilSwedish National Space BoardDanish Agency for Science and Technology and Innovation realized through a Sapere Aude Level 2 grantAstronom
Communicating uncertainties in spatial predictions of grain micronutrient concentration
The concentration of micronutrients in staple crops varies spatially. Quantitative information about this can help in designing efficient interventions to address micronutrient deficiency. Concentration of a micronutrient in a staple crop can be mapped from limited samples, but the resulting statistical predictions are uncertain. Decision makers must understand this uncertainty to make robust use of spatial information, but this is a challenge due to the difficulties in communicating quantitative concepts to a general audience. We proposed strategies to communicate uncertain information and present a systematic evaluation and comparison in the form of maps. We proposed testing five methods to communicate the uncertainty about the conditional mean grain concentration of an essential micronutrient, selenium (Se). Evaluation of the communication methods was done through a questionnaire by eliciting stakeholder opinions about the usefulness of the methods of communicating uncertainty. We found significant differences in how participants responded to the different methods. In particular, there was a preference for methods based on the probability that concentrations are below or above a nutritionally significant threshold compared with general measures of uncertainty such as the prediction interval. There was no evidence that methods which used pictographs or calibrated verbal phrases to support the interpretation of probabilities made a different impression than probability alone, as judged from the responses to interpretative questions, although these approaches were ranked most highly when participants were asked to put the methods in order of preference
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A Metabolomic Analysis of Omega-3 Fatty Acid-Mediated Attenuation of Western Diet-Induced Nonalcoholic Steatohepatitis in LDLR[superscript -/-] Mice
Background: Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease and a risk
factor for cirrhosis, hepatocellular carcinoma and liver failure. Previously, we reported that dietary docosahexaenoic
acid (DHA, 22:6,n-3) was more effective than eicosapentaenoic acid (EPA, 20:5,n-3) at reversing western diet (WD)
induced NASH in LDLR-/- mice.
Methods: Using livers from our previous study, we carried out a global non-targeted metabolomic approach to
quantify diet-induced changes in hepatic metabolism.
Results: Livers from WD + olive oil (WD + O)-fed mice displayed histological and gene expression features
consistent with NASH. The metabolomic analysis of 320 metabolites established that the WD and n-3
polyunsaturated fatty acid (PUFA) supplementation had broad effects on all major metabolic pathways. Livers from
WD + O-fed mice were enriched in saturated (SFA) and monounsaturated fatty acids (MUFA), palmitoylsphingomyelin,
cholesterol, n-6 PUFA, n-6 PUFA-containing phosphoglycerolipids, n-6 PUFA-derived oxidized lipids
(12-HETE) and depleted of C20-22 n-3 PUFA-containing phosphoglycerolipids, C20-22 n-3 PUFA-derived oxidized lipids
(18-HEPE, 17,18-DiHETE) and S-lactoylglutathione, a methylglyoxal detoxification product. WD + DHA was more
effective than WD + EPA at attenuating WD + O-induced changes in NASH gene expression markers, n-6 PUFA and
oxidized lipids, citrate and S-lactosyl glutathione. Diet-induced changes in hepatic MUFA and sphingolipid content
were associated with changes in expression of enzymes involved in MUFA and sphingolipid synthesis. Changes in
hepatic oxidized fatty acids and S-lactoylglutathione, however, correlated with hepatic n-3 and n-6 C20-22 PUFA
content. Hepatic C20-22 n-3 PUFA content was inversely associated with hepatic α-tocopherol and ascorbate content
and positively associated with urinary F2- and F3-isoprostanes, revealing diet effects on whole body oxidative stress.
Conclusion: DHA regulation of hepatic SFA, MUFA, PUFA, sphingomyelin, PUFA-derived oxidized lipids and Slactoylglutathione
may explain the protective effects of DHA against WD-induced NASH in LDLR-/- mice
The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?
We present extensive u'g'r'i'BVRIYJHKs photometry and optical spectroscopy of
SN 2005hk. These data reveal that SN 2005hk was nearly identical in its
observed properties to SN 2002cx, which has been called ``the most peculiar
known type Ia supernova.'' Both supernovae exhibited high ionization SN
1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The
spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities
that were roughly half those of typical type Ia supernovae. The R and I light
curves of both supernovae were also peculiar in not displaying the secondary
maximum observed for normal type Ia supernovae. Our YJH photometry of SN 2005hk
reveals the same peculiarity in the near-infrared. By combining our optical and
near-infrared photometry of SN 2005hk with published ultraviolet light curves
obtained with the Swift satellite, we are able to construct a bolometric light
curve from ~10 days before to ~60 days after B maximum. The shape and unusually
low peak luminosity of this light curve, plus the low expansion velocities and
absence of a secondary maximum at red and near-infrared wavelengths, are all in
reasonable agreement with model calculations of a 3D deflagration which
produces ~0.25 M_sun of 56Ni.Comment: Accepted by PASP, to appear in April 2007 issue, 63 pages, 16
figures, 11 table
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