1,679 research outputs found
Farm-gate phosphorus balances and soil phosphorus concentrations on intensive dairy farms in the south-west of Ireland
peer-reviewedThis project was part funded by the European Research and Development Fund under INTERREG IIIB: Green Dairy Project Number 100 and partly by the Dairy Levy. Financial support for post-graduate students involved in this study was provided by the Teagasc Walsh Fellowship Scheme.Phosphorus (P) loss to water is a significant threat to water quality in Ireland. Agriculture is an important source of this P. There is concern about balancing agronomic requirements and environmental protection in regulations prescribing P management on farms. This study examined farm-gate (P) balances and soil test P (STP)
concentrations on 21 dairy farms in the south west of Ireland over four years, from 2003 to 2006 inclusive. Stocking density on the farms averaged 2.4 (s.d. = 0.4) livestock units (LU) per ha. Annual mean import of P onto farms was 21.6 (1.9) kg P/ha. Fertilizer P accounted for 47% (0.041), concentrates 35% (0.060) and organic manures 18% (0.034) of imported P. The mean annual P balance per farm was 9.4 (1.2) kg/ha, ranging from –3 to 47 kg/ha and mean P use efficiency was 0.71 (0.05) ranging from 0.24 to 1.37. The mean STP per farm following extraction using Morgan’s solution was 8.15 (2.9) mg/L of soil and ranged from 4.4 (2.2) to 14.7 (6.4) mg/L. There was a positive relationship
(R2 = 0.34; P < 0.01) between STP and P balance; farms with a deficit of P tended to
have agronomically sub-optimal STP and vice versa. The high between- and withinfarm
variation in STP indicates that farmers were either unaware or were not making
efficient use of STP results, and consequently there was agronomically sub-optimal soil P status in some fields and potentially environmentally damaging excesses on others (often within one farm). There was considerable potential to improve P management practices on these farms with clear agronomic and environmental benefits.European UnionTeagasc Walsh Fellowship ProgrammeDairy Levy Fun
Food waste materials appear efficient and low-cost adsorbents for the removal of organic and inorganic pollutants from wastewater
In recent studies, the adsorption capacity of several food waste materials has been assessed by performing adsorption experiments in heterogeneous operating conditions. In a latest study, the efficiency of such food waste materials for the removal of metals and metalloids from complex multi-element
solutions was evaluated in homogeneous experimental conditions, which allowed comparing the adsorption capacities of the individual adsorbents. Considering the high efficiency of the examined low-cost adsorbents for the removal of inorganic pollutants, preliminary studies were conducted in our lab for assessing the potential of the investigated food waste materials to adsorb volatile organic compounds from a real polluted matrix of leachate. Some recent
studies have shown the efficiency of low cost materials for the removal of industrial organic dyes, polycyclic aromatic hydrocarbons and phenolic compounds. However, the food waste adsorbents’ efficiency for the removal of volatile organic compounds was not investigated. Our preliminary studies showed good adsorption capacities of the examined food waste materials for aliphatic and aromatic hydrocarbons. Therefore, it is worth to carry out further studies about volatile organic compounds’ removal by food waste adsorbents
Adaptive Dispersion Compensation for Remote Fiber Delivery of NIR Femtosecond Pulses
We report on remote delivery of 25 pJ broadband near-infrared femtosecond
light pulses from a Ti:sapphire laser through 150 meters of single-mode optical
fiber. Pulse distortion due to dispersion is overcome with pre-compensation
using adaptive pulse shaping techniques, while nonlinearities are mitigated
using an SF10 rod for the final stage of pulse compression. Near transform
limited pulse duration of 130 fs is measured after the final compression.Comment: 3 pages, 4 figure
Quantum Effects in the Mechanical Properties of Suspended Nanomechanical Systems
We explore the quantum aspects of an elastic bar supported at both ends and
subject to compression. If strain rather than stress is held fixed, the system
remains stable beyond the buckling instability, supporting two potential
minima. The classical equilibrium transverse displacement is analogous to a
Ginsburg-Landau order parameter, with strain playing the role of temperature.
We calculate the quantum fluctuations about the classical value as a function
of strain. Excitation energies and quantum fluctuation amplitudes are compared
for silicon beams and carbon nanotubes.Comment: RevTeX4. 5 pages, 3 eps figures. Submitted to Physical Review Letter
Thermodynamics of Paracrystalline Silicon
Fluctuation microscopy experiments have shown that the as-deposited structure of amorphous silicon thin films is paracrystalline. A paracrystal consists of small (< 3 nm in diameter) topologically crystalline grains separated by a disordered matrix. Here the authors consider the thermodynamics of paracrystalline silicon as a function of the grain size and the temperature. They offer a simple model that qualitatively explains the observed metastability of the ordered structure at low temperature (300 K), the relaxation towards a more disordered structure at intermediate temperatures (600 K), and the recrystallization at high temperatures (1,000 K)
Intrinsic thermal vibrations of suspended doubly clamped single-wall carbon nanotubes
We report the observation of thermally driven mechanical vibrations of
suspended doubly clamped carbon nanotubes, grown by chemical vapor deposition
(CVD). Several experimental procedures are used to suspend carbon nanotubes.
The vibration is observed as a blurring in images taken with a scanning
electron microscope. The measured vibration amplitudes are compared with a
model based on linear continuum mechanics.Comment: pdf including figures, see:
http://www.unibas.ch/phys-meso/Research/Papers/2003/NT-Thermal-Vibrations.pd
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An ITPR1 gene deletion causes SCA15 and 16; a genetic, clinical and radiological description
Spinocerebellar ataxia (SCA) 15/16 is an autosomal dominantly inherited, almost pure cerebellar ataxia, which shows slow or no progression. (It has been designated variably SCA15 and SCA 16; we refer to it here as SCA15/16 to avoid confusion). Deletions in the inositol 1, 4, 5-triphosphate receptor 1 (ITPR1) on chromosome 3 have been shown to cause SCA15/16 in six families worldwide to date, with one further Japanese family identified as having an ITPR1 point mutation. We present a previously unreported SCA15/16 kindred. We describe the clinical phenotype of the family in detail; affected subjects display a remarkably slow, almost pure cerebellar syndrome. We also present genetic analyses for all subjects and longitudinal MRI data for one affected subject. Genetic analysis shows a deletion of 346,487bp in ITPR1 (the second largest ITPR1 deletion reported to date), suggesting SCA15 is due to a loss of ITPR1 function, and western blotting of lymphoblastoid cell line protein confirms reduced ITPR1 protein levels. Serial MRIs show progressive midline cerebellar atrophy with mild inferior parietal and temporal cortical volume loss in the absence of clinical disease progression. We believe that genetic testing for SCA15/16 should become a routine DNA screen available in all Neurogenetics clinics, which is likely to lead to an increased rate of the diagnosis. Familiarity with the phenotype is therefore important for all neurologists
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