scholarly journals Defining priority areas for blue whale conservation and investigating overlap with vessel traffic in Chilean Patagonia, using a fast-fitting movement model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luis Bedriñana-Romano ◽  
Rodrigo Hucke-Gaete ◽  
Francisco A. Viddi ◽  
Devin Johnson ◽  
Alexandre N. Zerbini ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Species Conservation ◽  
Decisive Role ◽  
Single Step ◽  
Blue Whale ◽  
Distribution Models ◽  
Movement Model ◽  
Priority Areas ◽  
Chilean Patagonia ◽  
Order Of Magnitude

AbstractDefining priority areas and risk evaluation is of utmost relevance for endangered species` conservation. For the blue whale (Balaenoptera musculus), we aim to assess environmental habitat selection drivers, priority areas for conservation and overlap with vessel traffic off northern Chilean Patagonia (NCP). For this, we implemented a single-step continuous-time correlated-random-walk model which accommodates observational error and movement parameters variation in relation to oceanographic variables. Spatially explicit predictions of whales’ behavioral responses were combined with density predictions from previous species distribution models (SDM) and vessel tracking data to estimate the relative probability of vessels encountering whales and identifying areas where interaction is likely to occur. These estimations were conducted independently for the aquaculture, transport, artisanal fishery, and industrial fishery fleets operating in NCP. Blue whale movement patterns strongly agreed with SDM results, reinforcing our knowledge regarding oceanographic habitat selection drivers. By combining movement and density modeling approaches we provide a stronger support for purported priority areas for blue whale conservation and how they overlap with the main vessel traffic corridor in the NCP. The aquaculture fleet was one order of magnitude larger than any other fleet, indicating it could play a decisive role in modulating potential negative vessel-whale interactions within NCP.

The effect of decationation of hydroxylated HNaY zeolites on their interaction with ethylene and propylene. hydrogen complexes, oligomeration and isotope exchange

1980 ◽  
Vol 45 (11) ◽  
pp. 3101-3115 ◽  
Author(s):  
Ludmila Kubelková ◽  
Jana Nováková ◽  
Zdeněk Dolejšek ◽  
Pavel Jírů
Keyword(s):  
Isotope Exchange ◽  
Decisive Role ◽  
Single Step ◽  
Hydroxyl Groups ◽  
Isotope Exchange Reaction ◽  
Factors Affecting ◽  
Step Mechanism ◽  
Formed Hydrogen ◽  
Lower Basicity ◽  
Multiple Step

The effect of decationation on the interaction of propylene and ethylene with the hydroxylated forms of HNaY zeolites has been studied. The compounds formed in the zeolite cavities were studied using their infrared spectra, the composition of the gaseous phase was followed by mass spectrometry. The results showed that among factors affecting the interaction with propylene properties of hydroxyl groups play the decisive role. With the increasing decationation of the zeolite the strength of the OH bond in the hydrogen complex of the large-cavity hydroxyls with propylene decreased and the rate of propylene oligomeration at 310 K as well as the isotope exchange rate of propylene-d6 with the zeolite hydroxyls at 570 K increased. The propylene isotope exchange reaction proceeded by the multiple-step mechanism. In the case of ethylene only the physical sorption with a non-specific character was observed at 310 K. The adsorbed amount increased with the increasing content of Na+ ions in the zeolite (with the decreasing decationation). A part of the adsorbed molecules formed hydrogen complexes with hydroxyls of large cavities. The observed lower weakening of the OH bond was in agreement with the lower basicity of ethylene if compared with propylene. The isotope exchange of ethylene-d4 with the zeolite hydroxyls proceeded by a single-step mechanism, it had an autocatalytic character and its rate was 70 times lower than that of the isotope exchange of propylene-d6 with OH.

scholarly journals Single-Step Photochemical Formation of Near-Infrared-Absorbing Gold Nanomosaic within PNIPAm Microgels: Candidates for Photothermal Drug Delivery

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1251
Author(s):  
Sreekar B. Marpu ◽  
Brian Leon Kamras ◽  
Nooshin MirzaNasiri ◽  
Oussama Elbjeirami ◽  
Denise Perry Simmons ◽  
...  
Keyword(s):  
Near Infrared ◽  
Dimethyl Sulfide ◽  
Test Sample ◽  
Single Step ◽  
Step Method ◽  
Photochemical Reduction ◽  
Order Of Magnitude ◽  
Post Synthesis ◽  
Lamp Source ◽  
Hybrid Microgels

This work demonstrates the dynamic potential for tailoring the surface plasmon resonance (SPR), size, and shapes of gold nanoparticles (AuNPs) starting from an Au(I) precursor, chloro(dimethyl sulfide)gold (I) (Au(Me2S)Cl), in lieu of the conventional Au(III) precursor hydrogen tetrachloroaurate (III) hydrate (HAuCl4). Our approach presents a one-step method that permits regulation of an Au(I) precursor to form either visible-absorbing gold nanospheres or near-infrared-window (NIRW)-absorbing anisotropic AuNPs. A collection of shapes is obtained for the NIR-absorbing AuNPs herein, giving rise to spontaneously formed nanomosaic (NIR-absorbing anisotropic gold nanomosaic, NIRAuNM) without a dominant geometry for the tesserae elements that comprise the mosaic. Nonetheless, NIRAuNM exhibited high stability; one test sample remains stable with the same SPR absorption profile 7 years post-synthesis thus far. These NIRAuNM are generated within thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) microgels, without the addition of any growth-assisting surfactants or reducing agents. Our directed-selection methodology is based on the photochemical reduction of a light-, heat-, and water-sensitive Au(I) precursor via a disproportionation mechanism. The NIRAuNM stabilized within the thermoresponsive microgels demonstrates a light-activated size decrease of the microgels. On irradiation with a NIR lamp source, the percent decrease in the size of the microgels loaded with NIRAuNM is at least five times greater compared to the control microgels. The concept of photothermal shrinkage of hybrid microgels is further demonstrated by the release of a model luminescent dye, as a drug release model. The absorbance and emission of the model dye released from the hybrid microgels are over an order of magnitude higher compared to the absorbance and emission of the dye released from the unloaded-control microgels.

scholarly journals Transient Model for CW and Pulsed Laser Machining of Ablating/Decomposing Materials—Approximate Analysis

1996 ◽  
Vol 118 (3) ◽  
pp. 774-780 ◽  
Author(s):  
M. F. Modest
Keyword(s):  
Three Dimensional ◽  
Pulsed Laser ◽  
Computer Time ◽  
Single Step ◽  
Laser Source ◽  
Laser Machining ◽  
Transient Model ◽  
One Dimensional ◽  
Cpu Time ◽  
Order Of Magnitude

Approximate, quasi-one-dimensional conduction models have been developed to predict the changing shape of holes, single grooves, or overlapping grooves carved by ablation into a thick solid that is irradiated by a moving laser source. For CW or pulsed laser operation a simple integral method is presented, which predicts shapes and removal rates with an accuracy of a few percent, while requiring one order of magnitude less CPU time than a three-dimensional, numerical solution. For pulsed operation a “full-pulse” model is presented, computing the erosion from an entire pulse in a single step, and reducing computer time by another order of magnitude.

Kimberlite magmatism and origin of K-rich metasomatic melt-fluid

2020 ◽  
Author(s):  
Lia Kogarko
Keyword(s):  
Partition Coefficient ◽  
Transition Zone ◽  
Lower Mantle ◽  
Decisive Role ◽  
Fluid Phase ◽  
Thermodynamic Activity ◽  
Depth Interval ◽  
Element Partitioning ◽  
Mantle Diapir ◽  
Order Of Magnitude

<p>The experimental study indicates that high-K magmas and kimberlites are in equilibrium with metasomatic minerals, such as phlogopite, richterite, and apatite during their formation in the mantle; i.e., metasomatic processes played a decisive role in their genesis.</p><p>In the uppermost part of the mantle, K is entirely concentrated in plagioclase. With increasing depth the K budget is determined mainly by clinopyroxene and, to a lesser extent, garnet A further increase in pressure causes pyroxene and garnet to react to form majorite, which has K and Na partition coefficients equal to 0.015 and 0.39, respectively [1]. In the depth interval of 410–660 km, majorite is associated with wadsleyite (410–500 km) and ringwoodite (500–660 km), neither of which incorporate K or Na into their structures. At deeper levels, below 660 km, the majorite–ringwoodite assemblage is replaced by the ferropericlase–bridgmanite–Ca-perovskite paragenesis. Here, the modal content of Ca-perovskite  is ~8%. The K partition coefficient for Ca-perovskite is relatively high (0.39), and that of Na is even higher (2.0) [2].The.hexagonal NAL phase content up to 1.1 and  6.2wt% K2O and Na2O respectively Thus, practically all K and Na will be concentrated in Ca-perovskite and  the NALphase in the upper parts of the lower mantle. When a mantle diapir ascends from a depth  more then of ~660 km, Ca-perovskite and NAL becomes unstable and reacts with bridgmanite and ferripericlase to produce majorite and ringwoodite, and, with a further decrease in pressure wadsleyite becomes stable. The K partition coefficient in Ca-perovskite is 26 times higher compared with that of majorite The K partition coefficient of NAL is unknown. The remaining K likely remains excluded from the lattices of minerals in this mantle zone .Majorite may be an important concentrator of Na in the uppermost part of the lower mantle and transition zone. Experimental data indicate that 12 molar % sodium can be incorporated in majorite solid solutions. The chemical composition of the natural majorite contains 0.27-1.12 wt % Na<sub>2</sub>O Taking into consideration values of the K partition coefficient for Ca-perovskite and majorite, it can be confidently stated that the thermodynamic activity of K<sub>2</sub>O in the system increases by more than an order of magnitude with the transition of the bridgmanite–Ca-perovskite–ferripericlase – NAL association to the majorite–ringwoodite paragenesis. This is evidence that majorite will markedly fractionate K and Na, resulting in conditions favorable for the transfer of K into a melt or fluid phase at the boundary between the lower mantle and the transition zone.</p><p>1 Corgne A. and Wood B.J., Trace element partitioning between majoritic garnet and silicate melt at 25 GPa. Physics of the Earth and Planetary Interiors, 2004, 143–144, 407-419.</p><p>2 Liebske C., Wood B.J., Rubie D.C., Frost D.J., Silicate perovskite-melt partitioning of trace elements and geochemical signature of a deep perovskitic reservoir. Geochimica et Cosmochimica Acta, 2005, 69(2), 485-496. </p>

scholarly journals New closed analytical solutions for geometrically thick fluid tori around black holes

2018 ◽  
Vol 614 ◽  
pp. A75 ◽  
Author(s):  
V. Witzany ◽  
P. Jefremov
Keyword(s):  
Black Hole ◽  
Initial Conditions ◽  
Rest Mass ◽  
Decisive Role ◽  
Rotational Instability ◽  
Asymptotic State ◽  
Rotation Curves ◽  
Perfect Fluids ◽  
Order Of Magnitude ◽  
Orbital Periods

Context. When a black hole is accreting well below the Eddington rate, a geometrically thick, radiatively inefficient state of the accretion disk is established. There is a limited number of closed-form physical solutions for geometrically thick (nonselfgravitating) toroidal equilibria of perfect fluids orbiting a spinning black hole, and these are predominantly used as initial conditions for simulations of accretion in the aforementioned mode. However, different initial configurations might lead to different results and thus observational predictions drawn from such simulations. Aims. We aim to expand the known equilibria by a number of closed multiparametric solutions with various possibilities of rotation curves and geometric shapes. Then, we ask whether choosing these as initial conditions influences the onset of accretion and the asymptotic state of the disk. Methods. We have investigated a set of examples from the derived solutions in detail; we analytically estimate the growth of the magneto-rotational instability (MRI) from their rotation curves and evolve the analytically obtained tori using the 2D magneto-hydrodynamical code HARM. Properties of the evolutions are then studied through the mass, energy, and angular-momentum accretion rates. Results. The rotation curve has a decisive role in the numerical onset of accretion in accordance with our analytical MRI estimates: in the first few orbital periods, the average accretion rate is linearly proportional to the initial MRI rate in the toroids. The final state obtained from any initial condition within the studied class after an evolution of ten or more orbital periods is mostly qualitatively identical and the quantitative properties vary within a single order of magnitude. The average values of the energy of the accreted fluid have an irregular dependency on initial data, and in some cases fluid with energies many times its rest mass is systematically accreted.

scholarly journals An animal movement model incorporating home range and habitat selection

2007 ◽  
Vol 15 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Aaron Christ ◽  
Jay Ver Hoef ◽  
Dale L. Zimmerman
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Animal Movement ◽  
Movement Model

Geographic distribution of Rhyncholestes raphanurus Osgood, 1924 (Paucituberculata:Caenolestidae), an endemic marsupial of the Valdivian Temperate Rainforest

2011 ◽  
Vol 59 (2) ◽  
pp. 118 ◽  
Author(s):  
Gabriel M. Martin
Keyword(s):  
Potential Distribution ◽  
Species Conservation ◽  
Forest Types ◽  
Distribution Models ◽  
Biogeographic Patterns ◽  
Ecological Requirements ◽  
The Andes ◽  
Critical Areas ◽  
The Family ◽  
High Prediction

The Chilean shrew opossum (Rhyncholestes raphanurus) is the southernmost representative of the family Caenolestidae (Marsupialia : Paucituberculata). The species lives in temperate forests of southern Chile and Argentina and is currently known from <25 localities, spanning a latitudinal and longitudinal range of 2°44′ (~320 km) and 2°20′ (~190 km), respectively. Species distribution was analysed in a historical, geographic and biogeographic context, with the use of maps at different scales (region, subregion, province, ecoregion, forest types), and two potential distribution models were generated with MaxEnt. The models show a few isolated areas of high prediction values (>50%) in coastal Chile and the Andes from 39°30′ to ~42°S, and most of Chiloé Island, plus a northern and southern expansion of medium to low (<50%) prediction values. The most important environmental variables identified from the models include precipitation and some temperature-related variables. The species occurrence lies within the Andean region, Subantarctic subregion, and Valdivian biogeographic province. At a smaller scale, most of the localities occur in eight of the 22 forest types described for the Valdivian ecoregion, implying narrow ecological requirements. Identification of critical areas through potential distribution modelling may have implications for species conservation and identification of biogeographic patterns.

Population productivity and late breeding habitat selection by the threatened Little Bustard: the importance of grassland management

2017 ◽  
Vol 28 (4) ◽  
pp. 521-533 ◽  
Author(s):  
NUNO FARIA ◽  
MANUEL B. MORALES
Keyword(s):  
Habitat Selection ◽  
Species Conservation ◽  
Grassland Management ◽  
Breeding Habitat ◽  
Breeding Period ◽  
Tetrax Tetrax ◽  
Species Population ◽  
Suitable Habitats ◽  
Stocking Rates ◽  
The Relationship

SummaryWe investigated population productivity and habitat selection of the Little BustardTetrax tetraxin the late breeding period, in grassland-dominated landscapes of south-west Iberia. Specifically, our goals were to investigate how these parameters are influenced by the management of (1) grazing and (2) hay production. We conducted bird counts from 22 June to 4 July (2012 to 2016) using low speed 4x4 car surveys. The relationship between the density of the species, population productivity and farm management (grazing and haying) was evaluated using Generalized Linear Mixed Models and Kruskal-Wallis tests. Male and female densities were significantly higher in short vegetation compared to all other types of vegetation considered, but population productivity was similar in short and medium vegetation. Hay stubbles were found to be unattractive for the species. The availability of suitable habitats depends on the timing of grazing, notably of seasonal (spring) grazing. Species density was higher in fields ungrazed during winter and with moderate to high stocking rates in spring (around 0.8 LU/ha or higher), depending, at least for males and females, on each year’s weather characteristics. We conclude that low to moderate stocking rates during winter and spring are essential to ensure successful breeding and thus population persistence. Current levels of haying in our study area are detrimental for the species’ conservation.

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