2,326 research outputs found
Clover species cover on summer dry hill country in Central Otago
The prevalence of annual clover species and white
clover (Trifolium repens) during the critical late winter
to early summer period (mid Aug – Dec) are compared
in relation to aspect, altitude, temperature and rainfall on
Mt Grand at Hawea Flat. Measurements were at four
north facing sites (450, 620, 750, 910 m a.s.l.) and one
shady site at 630 m a.s.l. The rainfall was similar for all
altitudes and aspects but annual clovers dominated on
sunny faces and the perennial white clover dominated on
the shady face with suckling (T. dubium) the only
adventive annual clover present. Annual cluster clover
(T. glomeratum) dominated on the lower sunny faces at
450 and 620 m and sub clover (T. subterraneum)
dominated at 750 m. Suckling and striated clover (T.
striatum) were present on all sunny aspect sites and
were unaffected by altitude while haresfoot (T. arvense)
presence increased with altitude. Air thermal time
accumulation for the mid Aug-Dec period was 1440 °Cd
at the 450 m site and declined at 100 °Cd per 100 m of
elevation (r² = 0.99). Thermal time at 910 m was <1000
°Cd and may limit seed production of some annual
clover species at or above this altitude. The dominance
of adventive annual clovers on the sunny aspects
indicates areas that are probably suitable for
introduction of improved annual species such as balansa
clover (T. michelianum) or modern cultivars of sub.
Productivity of perennial white clover which has
persisted on the shady faces may be increased by more
intensive grazing management
Phonon Density of States of LaFeAsO1-xFx
We have studied the phonon density of states (PDOS) in LaFeAsO1-xFx with
inelastic neutron scattering methods. The PDOS of the parent compound(x=0) is
very similar to the PDOS of samples optimally doped with fluorine to achieve
the maximum Tc (x~0.1). Good agreement is found between the experimental PDOS
and first-principle calculations with the exception of a small difference in Fe
mode frequencies. The PDOS reported here is not consistent with conventional
electron-phonon mediated superconductivity
Radio continuum observations of Class I protostellar disks in Taurus: constraining the greybody tail at centimetre wavelengths
We present deep 1.8 cm (16 GHz) radio continuum imaging of seven young
stellar objects in the Taurus molecular cloud. These objects have previously
been extensively studied in the sub-mm to NIR range and their SEDs modelled to
provide reliable physical and geometrical parametres.We use this new data to
constrain the properties of the long-wavelength tail of the greybody spectrum,
which is expected to be dominated by emission from large dust grains in the
protostellar disk. We find spectra consistent with the opacity indices expected
for such a population, with an average opacity index of beta = 0.26+/-0.22
indicating grain growth within the disks. We use spectra fitted jointly to
radio and sub-mm data to separate the contributions from thermal dust and radio
emission at 1.8 cm and derive disk masses directly from the cm-wave dust
contribution. We find that disk masses derived from these flux densities under
assumptions consistent with the literature are systematically higher than those
calculated from sub-mm data, and meet the criteria for giant planet formation
in a number of cases.Comment: submitted MNRA
Flavones induce neutrophil apoptosis by down-regulation of Mcl-1 via a proteasomal-dependent pathway
Neutrophil apoptosis and subsequent nonphlogistic clearance by surrounding phagocytes are key to the successful resolution of neutrophilic inflammation, with dysregulated apoptosis reported in multiple human inflammatory diseases. Enhancing neutrophil apoptosis has proresolution and anti-inflammatory effects in preclinical models of inflammation. Here we investigate the ability of the flavones apigenin, luteolin, and wogonin to induce neutrophil apoptosis in vitro and resolve neutrophilic inflammation in vivo. Human neutrophil apoptosis was assessed morphologically and by flow cytometry following incubation with apigenin, luteolin, and wogonin. All three flavones induced time- and concentration-dependent neutrophil apoptosis (apigenin, EC(50)=12.2 μM; luteolin, EC(50)=14.6 μM; and wogonin, EC(50)=28.9 μM). Induction of apoptosis was caspase dependent, as it was blocked by the broad-spectrum caspase inhibitor Q-VD-OPh and was associated with both caspase-3 and caspase-9 activation. Flavone-induced apoptosis was preceded by down-regulation of the prosurvival protein Mcl-1, with proteasomal inhibition preventing flavone-induced Mcl-1 down-regulation and apoptosis. The flavones abrogated the survival effects of mediators that prolong neutrophil life span, including lipoteichoic acid, peptidoglycan, dexamethasone, and granulocyte-macrophage colony stimulating factor, by driving apoptosis. Furthermore, wogonin enhanced resolution of established neutrophilic inflammation in a zebrafish model of sterile tissue injury. Wogonin-induced resolution was dependent on apoptosis in vivo as it was blocked by caspase inhibition. Our data show that the flavones induce neutrophil apoptosis and have potential as neutrophil apoptosis-inducing anti-inflammatory, proresolution agents.—Lucas, C. D., Allen, K. C., Dorward, D. A., Hoodless, L. J., Melrose, L. A., Marwick, J. A., Tucker, C. S., Haslett, C., Duffin, R., Rossi, A. G. Flavones induce neutrophil apoptosis by down-regulation of Mcl-1 via a proteasomal-dependent pathway
Translating the Dutch walking stairs, walking ability and rising and sitting questionnaires into German and assessing their concurrent validity with VAS measures of pain and activities in daily living
<p>Abstract</p> <p>Background</p> <p>The Dutch Walking Stairs, Walking Ability and Rising and Sitting Questionnaires are three validated instruments to measure physical activity and limitations in daily living in patients with lower extremity disorders living at home of which no German equivalents are available. Our scope was to translate the Walking Stairs, Walking Ability and Rising and Sitting Questionnaires into German and to verify its concurrent validity in the two domains pain and activities in daily living by comparing them with the corresponding measures on the Visual Analogue Scale.</p> <p>Methods</p> <p>We translated the Walking Stairs, Walking Ability and Rising and Sitting Questionnaires according to published guidelines. Demographic data and validity were assessed in 52 consecutive patients with Complex Regional Pain Syndrome 1 of the lower extremity. Information on age, duration of symptoms, type of Complex Regional Pain Syndrome 1 and type of initiating event were obtained. We assessed the concurrent validity in the two domains pain and activities in daily living by comparing them with the corresponding measures on the Visual Analogue Scale.</p> <p>Results</p> <p>We found that variability in the German Walking Stairs, Walking Ability and Rising and Sitting Questionnaires was largely explained by measures of pain and activities in daily living on the Visual Analogue Scale.</p> <p>Conclusion</p> <p>Our study shows that the domains pain and activities in daily living are properly represented in the German versions of the Walking Stairs, Walking Ability and Raising and Sitting Questionnaires. We would like to propagate their use in clinical practice and research alike.</p
Chemoreceptor responsiveness at sea level does not predict the pulmonary pressure response to high altitude
The hypoxic ventilatory response (HVR) at sea level (SL) is moderately predictive of the
change in pulmonary artery systolic pressure (PASP) to acute normobaric hypoxia. However, because of
progressive changes in the chemoreflex control of breathing and acid-base balance at high altitude (HA),
HVR at SL may not predict PASP at HA. We hypothesized that resting peripheral oxyhemoglobin
saturation (SpO2) at HA would correlate better than HVR at SL to PASP at HA. In 20 participants at SL,
we measured normobaric, isocapnic HVR (L/min·-%SpO2
-1) and resting PASP using echocardiography.
Both resting SpO2 and PASP measures were repeated on day 2 (n=10), days 4-8 (n=12), and 2-3 weeks
(n=8) after arrival at 5050m. These data were also collected at 5050m on life-long HA residents (Sherpa;
n=21). Compared to SL, SpO2 decreased from 98.6 to 80.5% (P<0.001), while PASP increased from
21.7 to 34.0mmHg (P<0.001) after 2-3 weeks at 5050m. Isocapnic HVR at SL was not related to SpO2
or PASP at any time point at 5050m (all P>0.05). Sherpa had lower PASP (P<0.01) than lowlanders on
days 4-8 despite similar SpO2. Upon correction for hematocrit, Sherpa PASP was not different from
lowlanders at SL, but lower than lowlanders at all HA time points. At 5050m, whilst SpO2 was not
related to PASP in lowlanders at any point (all R2=0.50), there was a weak relationship in the
Sherpa (R2=0.16; P=0.07). We conclude that neither HVR at SL nor resting SpO2 at HA correlates with
elevations in PASP at HA
Alterations in cerebral blood flow and cerebrovascular reactivity during 14 days at 5050 m
Upon ascent to high altitude, cerebral blood flow (CBF) rises substantially before returning to sea-level values. The underlying mechanisms for these changes are unclear. We examined three hypotheses: (1) the balance of arterial blood gases upon arrival at and across 2 weeks of living at 5050 m will closely relate to changes in CBF; (2) CBF reactivity to steady-state changes in CO2 will be reduced following this 2 week acclimatisation period, and (3) reductions in CBF reactivity to CO2 will be reflected in an augmented ventilatory sensitivity to CO2. We measured arterial blood gases, middle cerebral artery blood flow velocity (MCAv, index of CBF) and ventilation () at rest and during steady-state hyperoxic hypercapnia (7% CO2) and voluntary hyperventilation (hypocapnia) at sea level and then again following 2–4, 7–9 and 12–15 days of living at 5050 m. Upon arrival at high altitude, resting MCAv was elevated (up 31 ± 31%; P < 0.01; vs. sea level), but returned to sea-level values within 7–9 days. Elevations in MCAv were strongly correlated (R2= 0.40) with the change in ratio (i.e. the collective tendency of arterial blood gases to cause CBF vasodilatation or constriction). Upon initial arrival and after 2 weeks at high altitude, cerebrovascular reactivity to hypercapnia was reduced (P < 0.05), whereas hypocapnic reactivity was enhanced (P < 0.05 vs. sea level). Ventilatory response to hypercapnia was elevated at days 2–4 (P < 0.05 vs. sea level, 4.01 ± 2.98 vs. 2.09 ± 1.32 l min−1 mmHg−1). These findings indicate that: (1) the balance of arterial blood gases accounts for a large part of the observed variability (∼40%) leading to changes in CBF at high altitude; (2) cerebrovascular reactivity to hypercapnia and hypocapnia is differentially affected by high-altitude exposure and remains distorted during partial acclimatisation, and (3) alterations in cerebrovascular reactivity to CO2 may also affect ventilatory sensitivity
Racism and bullying in rural primary schools: protecting White identities post Macpherson
- …