4,989 research outputs found
Rainfall as a cause of mechanical damage to Pseudocyphellaria rufovirescens in a New Zealand temperate rainforest
Lichens, like all poikilohydric plants, have a metabolism that is dependent on external moistening from their environment. In the case of green algal lichens high humidities may be sufficient for positive net photosynthesis to occur (Lange et al. 1993a). For these plants water stress is usually taken to mean a lack of water (Kappen 1988; Rundel 1988) but it can also mean an excess of water that leads to depressed CO2 exchange because of increased diffusion resistances at high thallus water contents (Lange & Tenhunen 1981; Kershaw 1985). Rather than this being an unusual occurrence, Lange et al. (19936) found reduced CO2 exchange at thallus supra-saturation to be present over long periods in the temperate rainforest of north-eastern New Zealand
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Electrical Conductivity in Thin Films
This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method
A Profile of the Iowa Pork Industry, Its Producers, and Implications for the Future
In March and April of 1993, a random sample of 334 Iowa pork producers participated in a survey regarding their production practices, facilities, and purchasing patterns. The sample, was divided into three groups by size: 113 farms marketing under 700 head of hogs, 141 farms marketing 700 - 2,000 head, and 90 marketing over 2,000 head. A few of the key findings include;Producer profile Is forty-five years old; has 13 years of formal education, 22 years of pork production experience; and plans to produce hogs for an additional 17 ye^s. Has annual marketings of 1,743 market hogs and 447 feeder pigs from 128 sows
Моделирование условий протекания реакции для составов на основе оксида железа с помощьюпрограммного комплекса Астра - 4
Работа посвящена исследованию установление возможности протекания реакции элементов на основе оксида железа. По результатам моделирования в программном комплексе Астра - 4 получены показатели, при которых возможно протекании реакции Fe2O3 + Al+ Cr= Al2O3+Fe+ Cr а также данные температуры (2430 К) и наибольшей внутренней энергией S (4076,2 кДж/(кг*К)).The study was devoted to establishing the possibility of reaction elements on the basis of iron oxide. The results of the simulations in the software package Astra - 4 the obtained values allow the reaction Fe2O3 + Al+ Cr= Al2O3+Fe+ Cr and the temperature data (2430) and the greatest internal energy S (4076,2 kJ/(kg*K))
Exploring the mechanisms that regulate CaV2.2 trafficking and function
N-type calcium channels (CaV2.2) are pseudotetrameric voltage-gated calcium channels (VGCCs) predominantly expressed at the presynaptic terminals in the peripheral and central nervous system. CaV2.2 channels are highly calcium selective and play a crucial role in neurotransmitter release, coupling extracellular calcium entry to neurotransmitter exocytosis. The activity of CaV2.2 has multiple forms of regulation including: post-translational modifications (PMTs), proteolytic degradation and subcellular localisation. In addition, the behaviour of VGCCs is modulated by their auxiliary α2δ and β subunits. In this study, I first examine the role of proteolytic α2δ processing on CaV2.2. I find that unprocessed α2δ subunits, while unable to enhance whole-cell CaV2.2 currents, retain the ability to promote cell-surface expression of CaV2.2 in cell lines. Subsequent restoration of α2δ processing did not influence the protein expression of α2δ or of coexpressed CaV2.2. Thereafter, I examined the properties of CaV2.2 mutants featuring substitutions of crucial P-loop glutamate residues within the selectivity filter. I find that mutation of these glutamate residues renders these channels deficient in trafficking both in non-neuronal cell lines and primary neuronal cultures. These data are pertinent given the use of P-loop CaV mutants as dominant negative channels in previous studies. Finally, I compare the influence of α2δ-1, α2δ-2 and α2δ-3 subtypes on the cell-surface and total expression of CaV2.2. Both cell-surface and total expression of CaV2.2 was found to be enhanced by all three subtypes albeit to differing degrees. Further investigation reveals that α2δ-1 and α2δ-2 promote the net forward trafficking of CaV2.2 through Rab11a-dependent recycling. CaV2.2 does not appear to participate in Rab11a-dependent recycling when expressed in the absence of α2δ or with α2δ-3. This study reveals differential regulation of CaV2.2 channels among α2δ subtypes through targeted endosomal trafficking
Evaluation of the Performance of Vortex Generators on the DU 91-W2-250 Profile using Stereoscopic PIV
Stereoscopic PIV measurements investigating the effect of Vortex Generators on the lift force near stall and on glide ratio at best aerodynamic performance have been carried out in the LM Glasfiber wind tunnel on a DU 91-W2-250 profile. Measurements at two Reynolds numbers were analyzed; Re=0.9·10 6 and 2.4·10 6 . The results show that one can resolve the longitudinal vortex structures generated by the devices and that mixing is created close to the wall, transferring high momentum fluid into the near wall region. It is also seen that the vortex generators successfully can obstruct separation near stall
Impact of antibiotic restriction on resistance levels of Escherichia coli:a controlled interrupted time series study of a hospital-wide antibiotic stewardship programme
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