160 research outputs found
The use of tensiometers to control the irrigation of nursery stock in containers.
End of Project ReportThe use of digital tensiometers to control the irrigation of nursery stock in
containers was studied over a three year period. Over this time the tensiometers
performed satisfactorily and successfully automated the irrigation of the plants.
The results indicate the feasibility of using them to control nursery stock irrigation
under Irish conditions. An irrigation tension of 50 hPa to trigger an irrigation period resulted in larger
plants than those grown under drier regimes with irrigation tensions of 100 and
200 hPa. Measurements of stomatal resistance indicated that the plants in the
drier regimes were growing under greater moisture stress.
The drier regimes reduced the number of irrigations and also the overall usage of
water. They reduced plant size but did not impair plant appearance. It may be
possible to use this approach in the future to control plant growth.
There was no difference in performance between plants gown with ebb and flood
irrigation and those irrigated via overhead spraylines. The ebb and flood system
gave a considerable reduction in water use.European Union Structural Funds
(EAGGF
Optimising Nutrition Of Containerised Nursery Stock
End of Project ReportIrish peat, used as a growing medium in horticulture, tends to have a higher state
of decomposition and a higher potential buffering capacity than some of the
younger peats from Scandinavian or Baltic countries. Particularly where hard
water, with high bicarbonate content, is used for irrigation this could be an
important property in giving the peat greater stability with respect to pH levels throughout the cropping period. It may also influence the optimum rate of lime to
be applied to adjust the pH prior to cropping.
The effect of peat type on the performance of nursery stock plants, Azalea and
Hebe in 2-litre containers, was studied when irrigated with both soft and hard
water and with different rates of lime in the peat growing medium.
When irrigated with hard water, the rate of pH increase was less with relatively
decomposed Irish peat than with younger Baltic peats. Using Irish peat, a rate of
dolomitic lime addition to the peat of 4 kg/m3 was best for Hebe when irrigated
with soft water. Irrigating with hard water the lime rate could vary between 2 and
4 kg/m3 without affecting plant performance. With the Baltic peats, increasing the
rate of lime addition above 2 kg/m3 tended to reduce growth of Hebe.
Azalea gave better results when irrigated with soft water. In hard water areas
therefore it is advisable, if possible, to collect rain water from a greenhouse roof
for irrigation purposes. A zero rate of lime gave inferior results with Azalea. With
hard water a rate of 1 kg/m3 was optimum. With soft water this could be
increased to 2 kg/m3 without damage.
New formulations of the controlled release fertiliser (CRF) have been introduced
recently. An experiment was carried out to evaluate the CRFs available in Ireland
for the production of containerised nursery stock over a 12 month period. The
effect of rate of CRF was also studied. Experiments were also located in the
Colleges of Horticulture in Warrenstown and Kildalton.
All the CRFs in these experiments produced acceptable results in terms of plant
performance. There were differences between the CRFs but these were not
consistent between the experiments. The vigorous species Lonicera pileata and
Escallonia macrantha responed positively to rates of CRF up to 8 kg/m3. The
conifer, Thuja plicata gave no response to rates above 6 kg/m3.
In an experiment over two seasons using 20 nursery stock species, a liquid
feeding system resulted in heavier plants of most species than did one based on
a controlled release fertiliser.European Union Structural Funds (EAGGF
Imaging current-induced switching of antiferromagnetic domains in CuMnAs
The magnetic order in antiferromagnetic materials is hard to control with external magnetic fields. Using X-ray Magnetic Linear Dichroism microscopy, we show that staggered effective fields generated by electrical current can induce modification of the antiferromagnetic domain structure in microdevices fabricated from a tetragonal CuMnAs thin film. A clear correlation between the average domain orientation and the anisotropy of the electrical resistance is demonstrated, with both showing reproducible switching in response to orthogonally applied current pulses. However, the behavior is inhomogeneous at the submicron level, highlighting the complex nature of the switching process in multi-domain antiferromagnetic films
Single-Band Model for Diluted Magnetic Semiconductors: Dynamical and Transport Properties and Relevance of Clustered States
Dynamical and transport properties of a simple single-band spin-fermion
lattice model for (III,Mn)V diluted magnetic semiconductors (DMS) is here
discussed using Monte Carlo simulations. This effort is a continuation of
previous work (G. Alvarez, Phys. Rev. Lett. 89, 277202 (2002)) where the static
properties of the model were studied. The present results support the view that
the relevant regime of J/t (standard notation) is that of intermediate
coupling, where carriers are only partially trapped near Mn spins, and locally
ordered regions (clusters) are present above the Curie temperature T_C. This
conclusion is based on the calculation of the resistivity vs. temperature, that
shows a soft metal to insulator transition near T_C, as well on the analysis of
the density-of-states and optical conductivity. In addition, in the clustered
regime a large magnetoresistance is observed in simulations. Formal analogies
between DMS and manganites are also discussed.Comment: Revtex4, 20 figures. References updated, minor changes to figures and
tex
International study on inter-reader variability for circulating tumor cells in breast cancer
Introduction: Circulating tumor cells (CTCs) have been studied in breast cancer with the CellSearch® system. Given the low CTC counts in non-metastatic breast cancer, it is important to evaluate the inter-reader agreement.Methods: CellSearch® images (N = 272) of either CTCs or white blood cells or artifacts from 109 non-metastatic (M0) and 22 metastatic (M1) breast cancer patients from reported studies were sent to 22 readers from 15 academic laboratories and 8 readers from two Veridex laboratories. Each image was scored as No CTC vs CTC HER2- vs CTC HER2+. The 8 Veridex readers were summarized to a Veridex Consensus (VC) to compare each academic reader using % agreement and kappa (κ) statistics. Agreement was compared according to disease stage and CTC counts using the Wilcoxon signed rank test.Results: For CTC definition (No CTC vs CTC), the median agreement between academic readers and VC was 92% (range 69 to 97%) with a median κ of 0.83 (range 0.37 to 0.93). Lower agreement was observed in images from M0 (median 91%, range 70 to 96%) compared to M1 (median 98%, range 64 to 100%) patients (P < 0.001) and from M0 and <3CTCs (median 87%, range 66 to 95%) compared to M0 and ≥3CTCs samples (median 95%, range 77 to 99%), (P < 0.001). For CTC HER2 expression (HER2- vs HER2+), the median agreement was 87% (range 51 to 95%) with a median κ of 0.74 (range 0.25 to 0.90).Conclusions: The inter-reader agreement for CTC definition was high. Reduced agreement was observed in M0 patients with low CTC counts. Continuous training and independent image review are required
Age at first birth in women is genetically associated with increased risk of schizophrenia
Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe
Limits on the production of scalar leptoquarks from Z (0) decays at LEP
A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
Blood metabolomics uncovers inflammation-associated mitochondrial dysfunction as a potential mechanism underlying ACLF (vol 72, pg 688, 2020)
Cellular mechanisms in basic and clinical gastroenterology and hepatolog
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