Full Merging Research Articles

Understanding the causes and consequences of the northward extension of the tropical monsoon in Asia in the Eocene

Previous geological studies have revealed that a zonal climate pattern with an arid zonal band prevailed in the mid-latitude of East Asia in the Paleogene. On the south of the arid band, a tropical monsoon climate controlled South China, Indochina, and India. In the Eocene, the boundary between the arid and the tropical monsoon climate largely moved northward. However, the reason behind this change remains unclear. Here, with the fast version of the Norwegian Earth System Model (NorESM1-F), we conduct experiments under different Eocene paleogeography conditions to analyze the evolution of the tropical Asian monsoon from the early Eocene to the late Eocene. Our results demonstrate that the northward movement of Indian plate causes a reorganization in low-level westerlies in summer. After the full merging of the India-Asia continents, modern-like low-level tropical circulations come into being and lead to the wetting in southern China.

MRINet: Multilevel Reverse-Context Interactive-Fusion Network for Detecting Salient Objects in RGB-D Images

The use of RGB-D information for salient object detection (SOD) is being increasingly explored. Traditional multilevel models handle both low- and high-level features similarly, as they use the same number of features for blending. Unlike these models, in this paper, we propose multilevel reverse-context interactive-fusion (MRI) network (MRINet) for RGB-D SOD. Specifically, first, we extract and reuse different numbers of features depending on their level; the deeper the information, the more times do we perform the extraction. Deeper information contains more semantic cues, which are important for locating salient regions. Thereafter, we use an RGB MRI block (MRIB) to merge RGB information at different levels; furthermore, we use depth features as auxiliary information and an RGB-D MRIB for full merging with RGB information. RGB and RGB-D MRIBs can reconstruct the high-level feature map in high resolution and integrate the low-level feature map to enhance boundary details. Extensive experiments demonstrate the effectiveness of the proposed MRINet and its state-of-the-art performance in RGB-D SOD.

Molecular mechanisms of mesoporous silica formation from colloid solution: Ripening-reactions arrest hollow network structures.

The agglomeration of silica nanoparticles in aqueous solution is investigated from molecular simulations. Mimicking destabilization of colloidal solutions by full removal of protective moieties or surface charge, association of SiO2/Si(OH)4 core/shell particles leads to rapid proton transfer reactions that account for local silanole → silica ripening reactions. Yet, such virtually barrier-less binding is only observed within a limited contact zone. Agglomeration hence leads to the formation of oligomers of nanoparticles, whilst full merging into a compact precipitate is hampered by the need for extended structural reorganisation. Implementing sufficiently fast supply from colloidal solution, our simulations show the development of silica networks comprised of covalently bound, yet not fully merged nanoparticles. Within the oligomerized nanoparticle network, coordination numbers range from 2 to 5 –which is far below closest packing. Our simulations hence rationalize the formation of covalently bound network structures hosting extended pores. The resulting interfaces to the solvent show water immobilization only for the immediate contact layers, whilst the inner pores exhibit solvent mobility akin to bulk water.

Full OCT anterior segment biometry: an application in cataract surgery

In vivo three-dimensional (3-D) anterior segment biometry before and after cataract surgery was analyzed by using custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT). The system was provided with custom algorithms for denoising, segmentation, full distortion correction (fan and optical) and merging of the anterior segment volumes (cornea, iris, and crystalline lens or IOL), to provide fully quantitative data of the anterior segment of the eye. The method was tested on an in vitro artificial eye with known surfaces geometry at different orientations and demonstrated on an aging cataract patient in vivo. Biometric parameters CCT, ACD/ILP, CLT/ILT Tilt and decentration are retrieved with a very high degree of accuracy. IOL was placed 400 μm behind the natural crystalline lens, The IOL was aligned with a similar orientation of the natural lens (2.47 deg superiorly), but slightly lower amounts (0.77 deg superiorly). The IOL was decentered superiorly (0.39 mm) and nasally (0.26 mm).

Soil Water Content Distributions between Two Emitters of a Subsurface Drip Irrigation System

Subsurface drip irrigation (SDI) systems are increasingly being used in agriculture in attempts to use the available water more efficiently. The proper design and management of SDI systems requires knowledge of precise distribution of water around emitters. We conducted both field and numerical experiments to evaluate the soil water content distributions between two neighboring emitters when their wetting patterns started to overlap. The experiments involved SDI systems with emitters installed at different depths and with different spacings along the drip lateral. The HYDRUS software package was used to analyze the field data, assuming modeling approaches in which emitters were represented as (i) a point source in an axisymmetrical two‐dimensional domain, (ii) a line source in a planar two‐dimensional domain, or (iii) a point source in a fully three‐dimensional domain. Results indicated that SDI systems can be accurately described using an axisymmetrical two‐dimensional model only before wetting patterns start to overlap, and a planar two‐dimensional model only after full merging of the wetting fronts from neighboring emitters. A fully three‐dimensional model appears to be required for describing subsurface drip irrigation processes in their entirety.

Merging of Globular Clusters in Inner Galactic Regions. II. Nuclear Star Cluster Formation

In this series of papers, we present the results of detailed N-body simulations of the interaction of a sample of four massive globular clusters in the inner region of a triaxial galaxy for two different sets of initial conditions that correspond to different initial density concentrations. A full merging of the clusters takes place, leading to a slowly evolving cluster that is quite similar to observed nuclear clusters. Actually, both the density and the velocity dispersion profiles match qualitatively, and also quantitatively after scaling to a larger number of merger globulars, with the observed features of many nucleated galaxies. In the case of dense initial clusters, the merger remnant shows a density profile more concentrated than that of the progenitors, with a central density higher than the sum of the progenitors' central densities and an effective radius compatible with observed nuclear values. These findings support the idea that a massive nuclear cluster may have formed in the early phases of the mother galaxy's evolution and led to the formation of a nucleus, which in many galaxies has a luminosity profile similar to that of an extended King model. A correlation with galactic nuclear activity is suggested.

On optimal computation of MPLS label binding for multipoint-to-point connections

Most network operators have considered reducing Label Switched Routers (LSR) label spaces (i.e. the number of labels that can be used) as a means of simplifying management of underlaying Virtual Private Networks (VPNs) and, hence, reducing operational expenditure (OPEX). This letter discusses the problem of reducing the label spaces in Multiprotocol Label Switched (MPLS) networks using label merging - better known as MultiPoint-to-Point (MP2P) connections. Because of its origins in IP, MP2P connections have been considered to have tree- shapes with Label Switched Paths (LSP) as branches. Due to this fact, previous works by many authors affirm that the problem of minimizing the label space using MP2P in MPLS - the Merging Problem - cannot be solved optimally with a polynomial algorithm (NP-complete), since it involves a hard- decision problem. However, in this letter, the Merging Problem is analyzed, from the perspective of MPLS, and it is deduced that tree-shapes in MP2P connections are irrelevant. By overriding this tree-shape consideration, it is possible to perform label merging in polynomial time. Based on how MPLS signaling works, this letter proposes an algorithm to compute the minimum number of labels using label merging: the Full Label Merging algorithm. As conclusion, we reclassify the Merging Problem as Polynomial-solvable, instead of NP-complete. In addition, simulation experiments confirm that without the tree-branch selection problem, more labels can be reduced.

Aluminum and carbon substitution in MgB2. Electron doping and scattering effects

The point-contact spectroscopy is used to address the evolution of two superconducting energy gaps in the Al- and C-doped magnesium diboride polycrystals and single crystals with Tc’s from 39 to 22K prepared by different techniques. The obtained evolution of two gaps does not show any anomalous behavior but can be consistently described by the combination of the (prevailing) band filling effect and a (minor) increased interband scattering as proposed by Kortus et al. [Kortus et al., Phys. Rev. Lett. 94 (2005) 027002]. The approaching of two gaps is stronger in the Al-doped systems but interband scattering is still not large enough to merge two gaps. The full merging can expected only for higher dopings with Tc’s below 10–15K. In-magnetic-field measurements are used to analyze the intraband scatterings introduced by these two substitutions. It is shown that the carbon doping introduces significant disorder mainly by decreasing the diffusion coefficient in the π band while the Al substitution leaves the samples in the clean limit.

Reynolds number dependence of two-dimensional laminar co-rotating vortex merging

The paper reports unsteady Navier–Stokes calculations of laminar two-dimensional co-rotating vortex merging for various Reynolds numbers. The unsteady, incompressible two-dimensional Navier–Stokes equations were solved with fourth-order Runge–Kutta temporal discretization and fourth-order symmetric compact schemes for spatial discretization. Calculations of the unsteady Taylor vortex benchmark showed that fourth-order accurate solutions for all primitive variables were indeed achieved. Calculations for a pair of equal-strength co-rotating vortices show good agreement with reported direct numerical simulation and experiments for the evolution of the separation distance and core radius. It is found that the time required for merging is inversely proportional to the square root of the Reynolds number. According to previous experimental research, it was also found that complete merging in laminar regime undergoes four stages with physical meaning. The physical mechanism responsible for the merging process is investigated and it is found that the antisymmetric vorticity dynamics plays an important role until full merging.

A bispericyclic transition structure allows for efficient relief of antiaromaticity enhancing reactivity and endo stereoselectivity in the dimerization of the fleeting cyclopentadienone.

B3LYP/6-31G calculations account for the enhanced reactivity and endo stereoselectivity in the dimerization of the fleeting antiaromatic cyclopentadienone. Secondary orbital interactions promote endo stereoselectivity and a full merging of 4+2 and 2+4 allowed paths in an endo bispericyclic transition structure. Electrostatic effects increase reactivity and selectivity but the driving force to enhanced reactivity is the loss of antiaromaticity in the dimerization TSs while enhanced selectivity derives from the more efficient relief of antiaromaticity in the bispericyclic array.

Fractal modelling of carbonaceous aerosols—application to car exhaust plumes

Most commonly, atmospheric aerosol particles are ideally modelled as spheres allowing for straightforward calculations of their geometrical properties (diameter, surface and volume) and ensuing radiative, dynamical and chemical characteristics. However, particles issued particularly from combustion processes display various structural types, from linear clusters to quasi-spherical ones. Such various shapes result in quite different physical and chemical particle characteristics: e.g. the processes of absorption, coagulation/sintering and deposition are strongly affected by the fractal morphology of such aerosols. Whereas only one discretization parameter (diameter, d) is required for the spectral distribution n( d) of spherical particles, it is necessary to use a 2D distribution n( v, a) for fractal ones, v and a being, respectively, the volume and area of particles. For the coagulation process the associated governing aerosol population balance equation not only involves a collision term but also another term for more or less complete coalescence (sintering). For example, in view of the general texture of carbonaceous aerosols proposed by Strommen and Kamens (Environmental Science and Technology 31 (1997) 2983), let us consider two colliding particles each made of elementary carbon spherules immersed within a viscous organic liquid. They tend to more or less rapidly and completely merge, according to their bulk viscosities and surface tensions. In a first limit case, particles only stick together, displaying a maximum overall area. The other limit case is obtained through full particle merging into spherical structures. The new fractal model proposed, appropriate for describing such diverse particle morphologies, is then applied to car exhaust plumes.