6,573 research outputs found
Investigating the Relation between Galaxy Properties and the Gaussianity of the Velocity Distribution of Groups and Clusters
We investigate the dependence of stellar population properties of galaxies on
group dynamical stage for a subsample of Yang catalog. We classify groups
according to their galaxy velocity distribution into Gaussian (G) and
Non-Gaussian (NG). Using two totally independent approaches we have shown that
our measurement of Gaussianity is robust and reliable. Our sample covers Yang's
groups in the redshift range 0.03 z 0.1 having mass
10. The new method, Hellinger Distance (HD), to determine
whether a group has a velocity distribution Gaussian or Non-Gaussian is very
effective in distinguishing between the two families. NG groups present halo
masses higher than the G ones, confirming previous findings. Examining the
Skewness and Kurtosis of the velocity distribution of G and NG groups, we find
that faint galaxies in NG groups are mainly infalling for the first time into
the groups. We show that considering only faint galaxies in the outskirts,
those in NG groups are older and more metal rich than the ones in G groups.
Also, examining the Projected Phase Space of cluster galaxies we see that
bright and faint galactic systems in G groups are in dynamical equilibrium
which does not seem to be the case in NG groups. These findings suggest that NG
systems have a higher infall rate, assembling more galaxies which experienced
preprocessing before entering the group.Comment: 55 pages, 5 Tables and 12 Figures. Accepted for publication in
Astronomical Journa
Intravenous infusion of magnesium sulfate and its effect on horses with trigeminal-mediated headshaking.
BackgroundTrigeminal-mediated headshaking results from low-threshold firing of the trigeminal nerve resulting in apparent facial pain. Magnesium may have neuroprotective effects on nerve firing that potentially dampen signs of neuropathic pain. This hypothesis has not been investigated in horses with trigeminal-mediated headshaking.ObjectiveTo investigate head-shaking behavior in affected horses after IV magnesium sulfate infusion.AnimalsSix geldings with trigeminal-mediated headshaking.MethodsProspective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextrose solution (DS; control solution at 2 mL/kg body weight [BW]) and MgSO4 50% solution (MSS at 40 mg/kg BW). Head-shaking behavior was recorded at times T0 (baseline, before infusion) and T15, T30, T60, and T120 minutes post-infusion. Venous blood variables such as pH, HCO3 - , standard base excess (SBE), Na+ , Cl- , K+ , Ca2+ , Mg2+ , total magnesium (tMg), glucose, and lactate were measured; strong ion difference (SID) and anion gap (AG) were calculated for each time point.ResultsBlood variables including pH, Na+ , Cl- , K+ , SID, AG, lactate, Ca2+ , tMg, and Mg2+ had significant changes with MSS as compared to DS treatment. Glucose, SBE, and HCO3 - did not have significant changes. A 29% reduction in head-shaking rate occurred after MSS treatment but no change occurred after DS treatment.Conclusions and clinical importanceAdministration of MSS IV increased plasma total and ionized magnesium concentrations and significantly decreased head-shaking behavior in horses with trigeminal-mediated headshaking
Luteinizing hormone concentrations in healthy horses and horses with trigeminal-mediated headshaking over an 8-hour period.
BackgroundTrigeminal-mediated headshaking results from a low threshold for firing of the trigeminal nerve. A seasonal component has been implicated in onset of clinical signs, which occur during the spring and summer months. Geldings are overrepresented in the affected population and hormonal differences as compared to a healthy control population of geldings might contribute to headshaking.Objective/hypothesisTo assess concentrations of luteinizing hormone (LH) over an 8-hour period in gelded healthy controls and horses affected with headshaking. Our hypothesis was that geldings with seasonal headshaking would have higher concentrations of LH over an 8-hour period compared to control horses during the summer when affected horses manifested headshaking.AnimalsTwelve geldings (6 controls and 6 affected).MethodsProspective controlled trial. Blood samples were drawn every 15 minutes over an 8-hour time period during summer from all horses to measure circulating LH concentrations by using a radioimmunoassay for equine LH. All affected horses were actively affected by headshaking at the time of sample collection.ResultsNo statistically significant differences in LH concentrations were found throughout the study period in headshakers as compared to control horses. Time had no significant effect, but a slight decrease in LH concentrations was observed for all horses. The main limitation of the study was the low number of horses.Conclusions and clinical importanceHorses affected with headshaking did not have significant differences in circulating LH during the late summer as compared to control horses
Recovery of platinum(IV) and palladium(II) from complex hydrochloric acid matrices by a thiodiglycolamide derivative
The solvent extraction performance of N,N’-dimethyl-N,N’-dicyclohexylthiodiglycolamide (DMDCHTDGA) towards Pt(IV) and Pd(II) in HCl solutions has recently been published. It was shown that these two platinum-group metals (PGMs) are efficiently extracted from 8 M HCl aqueous phases, being subsequently separated by sequential strippings: 1 M HCl allows Pt(IV) recovery, whereas Pd(II) is only back-extracted by thiourea in HCl. In this work, selectivity tests were carried out to evaluate the performance of DMDCHTDGA towards the recovery of both PGMs, from 8 M HCl aqueous phases, when in presence of Rh(III), Fe(III), Ni(II), Zn(II), Al(III), Ce(III) and Zr(IV), simulating the leaching solutions that may result from the hydrometallurgical treatment of spent automobile catalytic converters. It was generally observed
that the additional metal ions do not affect the recovery of Pd(II) and Pt(IV) by DMDCHTDGA. Fe(III), Zn(II) and Zr(IV) are co-extracted with Pt(IV) and Pd(II); Fe(III) and Zn(II) were efficiently scrubbed with water, whereas Zr(IV) was removed by an acidified aqueous solution. Inversely, Ni(II) is not extracted, and Rh(III) and Ce(III) appear only traceably in the loaded organic phase. Al(III) is a concern, as it is appreciably extracted, and none of the tested backextraction solutions was able to strip it
A nanoparticle comprising a micelle formed by an amphiphilic block copolymer and encapsulating a gadolinium complex
Publication number: WO2011/113616The present invention relates to a nanoparticle comprising a micelle formed by an amphophilic block-copolymer and an
agent encapsulated within said micelle. The present invention also relates to a composition comprising such nanoparticle and to
the use of such nanoparticle and/or of such composition. More particularly, in one embodiment, the invention describes a new
class of polymeric nanoparticles as smart Tl contrast agent for MR imaging for breast cancer early detection. These nanoparticles
contrast agents have the capability to remain switched off during circulation and then switch on their imaging capacity upon arrival
at the target sites (tissue of interest). These smart nanoparticles contrast agent are self-assembled from pH sensitive amphiphilic
polymer, loaded with Gadolinium (Gd3+) complex based Tl agent and then fitted with targeting biomolecules such as antibody,
small molecules or DNA to increase its specificity toward the target of interest
Prática de desidratação do azevém (Lolium multiflorum Lam.) para a confecção de silagem em terras baixas.
Marine forests of the Mediterranean-Atlantic Cystoseira tamariscifolia complex show a southern Iberian genetic hotspot and no reproductive isolation in parapatry
Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests that are undergoing population declines. The C. tamariscifolia complex, composed of C. tamariscifolia s.s., C. amentacea and C. mediterranea, have indistinct boundaries and natural hybridization is suspected. Our aims are to (1) infer the genetic structure and diversity of these species throughout their distribution ranges using microsatellite markers to identify ancient versus recent geographical populations, contact zones and reproductive barriers, and (2) hindcast past distributions using niche models to investigate the influence of past range shifts on genetic divergence at multiple spatial scales. Results supported a single, morphologically plastic species the genetic structure of which was incongruent with a priori species assignments. The low diversity and low singularity in northern European populations suggest recent colonization after the LGM. The southern Iberian genetic hotspot most likely results from the role of this area as a climatic refugium or a secondary contact zone between differentiated populations or both. We hypothesize that life-history traits (selfing, low dispersal) and prior colonization effects, rather than reproductive barriers, might explain the observed genetic discontinuities.Pew Charitable Trusts (USA); MARINERA, Spain [CTM2008-04183-E/MAR]; FCT (Portugal) [FCT-BIODIVERSA/004/2015, CCMAR/Multi/04326/2013, SFRH/BPD/107878/2015, SFRH/BPD/85040/2012]; FPU fellowship of the Spanish Ministry of Education; European Community ASSEMBLE visiting grant [00399/2012]; University of Cadi
The Role of Forests as Carbon Sinks: Land-Use and Carbon Accounting
The use of forests as carbon sinks is examined by introducing carbon sequestration benefits’ accounting in a multi-vintage land allocation model. Following the IPCC, three carbon accounting methods are considered. We compare the results in each case with those without carbon sequestration, as well as the performances of the ton-year and the average methods (second-best) to the carbon flow (first-best) concerning optimal land allocation between forestry and alternative uses, total carbon sequestered, timber production and social welfare. A full proof of long-run optimality of steady state forest is provided. Numerical simulations are performed and results discussed illustrating the setup’s potential.Land Allocation Model, Forest Vintages, Carbon Sequestration, Carbon Accounting, Optimal Rotation, Transition/steady-state
The constant-velocity highly collimated outflows of the planetary nebula He 2-90
We present high-dispersion echelle spectroscopic observations and a
narrow-band [N II] image of the remarkable jet-like features of He 2-90. They
are detected in the echelle spectra in the H-alpha and [N II] lines but not in
other nebular lines. The [N II]/H-alpha ratio is uniformly high, ~1. The
observed kinematics reveals bipolar collimated outflows in the jet-like
features and shows that the southeast (northwest) component expands towards
(away from) the observer at a remarkably constant line-of-sight velocity,
26.0+-0.5 km/s. The observed expansion velocity and the opening angle of the
jet-like features are used to estimate an inclination angle of ~5 degrees with
respect to the sky plane and a space expansion velocity of ~290 km/s. The
spectrum of the bright central nebula reveals a profusion of Fe lines and
extended wings of the H-alpha line, similar to those seen in symbiotic stars
and some young planetary nebulae that are presumed to host a mass-exchanging
binary system. If this is the case for He 2-90, the constant velocity and
direction of the jets require a very stable dynamic system against precession
and warping.Comment: 8 pages (emulate ApJ), 5 figure, 1 tabl
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