Sequential Migration Research Articles

Exploring the acid catalyzed isomerization of phenanthrene under confinement in mordenite

The isomerization reaction of 1,2-dihydrophenanthrene catalyzed by a mordenite zeolite is explored theoretically in the present study. It was found that the electrostatic adducts which resemble ion-pair and π complexes, detected for zeolite catalysts, could enable the reaction to proceed through an energy favorable channel and explain its selectivity. The reaction pathway found for the interaction of 1,2-dihydrophenanthrene with the acid site of a mordenite zeolite proceeds firstly through a hydrogen abstraction, followed by a concerted cyclization pathway with C-C bond β-scission assisted by the reagent interaction with the zeolite catalyst. Then, two sequential migrations take place over the five-ring cycled product leading to unstable carbocation intermediate species which could be hydrogenated by an H2 molecule. The Al site within the MOR zeolite framework, does not activate the H-H bond. The C-C bond scission-cyclization process is detected as the energetic limiting step that could be fostered due to the confinement effect induced by the zeolite porous structure.

Interdecadal Change in the Relationship Between the North Pacific Oscillation and the Pacific Meridional Mode and Its Impact on ENSO

Two leading but independent modes of Northern Pacific atmospheric circulation: the North Pacific Oscillation (NPO) and the Pacific Meridional Mode (PMM), are known external triggers of the El Nino-Southern Oscillation (ENSO) by the sequential migration of sea surface temperature (SST) anomalies into the tropics possibly by means of wind-evaporation-SST (WES) feedbacks. Because of the similar roles of NPO and PMM, most previous studies have explored them with no separation. Here, we investigate their independent and combined effects in triggering ENSO, and find that when the NPO and PMM occur simultaneously during spring, ENSO or ENSO-like SST anomalies are generated during the following winter; whereas when either the NPO or PMM occur alone, ENSO events rarely occur. Furthermore, the relationship between NPO and PMM shows noticeable interdecadal variability, which is related to decadal changes in the mean upper-level jet stream over the North Pacific. Changes in the upper-level jet stream modify the location of the center of the Aleutian Low, which plays a role in bridging the NPO and PMM processes, especially when it migrates to the southwest. The period when NPO and PMM are well correlated coincides somewhat with the active ENSO period, and vice versa, indicating that a more efficient trigger due to combined NPO-PMM processes results in a higher variation of ENSO. Finally, analysis of the coupled model control simulations strongly supports our observational analysis results.

GPU fuzzy c-means algorithm implementations: performance analysis on medical image segmentation

Image segmentation in the medical imagery such as MRI, is an essential step to the sensitive analysis of human tissues lesions with the objective to improve the partition of different parts of the image according to their specific characteristics. Fuzzy c-means (FCM) is one of the widely used algorithms in literature regarding image segmentation. Indeed, it offers performances to the precision level in many medical fields of applications. However, the main limitation of FCM algorithm is time consuming during the image segmentation by clustering. In order to improve and to reduce the time delay of image data processing, we implemented three methods inspired from the FCM on GPU GT 740 m by using the CUDA environment. This latter is well adapted to the new architectures of processing, and its sequential migration towards the parallel approach through the SIMD architecture as GPU cards solves this time constraint. Furthermore, we have improved, via the two current developed implementations methods, the speed up of the processing acquisition in comparison with the reference methods. The efficiency evaluation such as strengths and weaknesses of each implemented method will be evaluated on medical images segmentation according to the size of the modelled brain tumours.

Sequential Migrations between Boron and Rhodium Centers: A Cooperative Process between Rhodium and a Monosubstituted Borohydride Unit.

The sodium salt of a monosubstituted borohydride anion containing a 2-mercaptopyridyl unit (mp) is reported herein. This compound was coordinated to a rhodium(I) center providing the complex [Rh{κ3-H,H,S-H3B(mp)}(NBD)] (1) (where NBD = 2,5-norbornadiene) in which the boron-based ligand is coordinated to the rhodium center via the thione donor and two of the B-H bonds of the BH3 unit. Reaction of complex 1 with carbon monoxide results in the activation of the complex leading to the product of a formal intramolecular hydroboration reaction, where the NBD unit has, in effect, inserted into one of the B-H bonds. Three complexes were prepared in which the newly formed norbornenyl unit (nbe) is located at the boron center, namely, [Rh{κ3-H,H,S-H2B(nbe)(mp)}(CO)2] (2), [Rh{κ3-H,H,S-H2B(nbe)(mp)}(CO)(PCy3)] (3), and [Rh{κ3-H,H,S-H2B(nbe)(mp)}(CO)(PPh3)] (4). The identities of the three complexes were confirmed by spectroscopic and analytical techniques. Further confirmation was obtained via structural characterization of 3. Studies confirmed that the reactivity occurs at the metal center. A metal-ligand cooperative mechanism, involving initial migration of hydride from boron to metal center, was postulated for the formation of the new complexes based on previous investigations. The newly formed norbornenyl unit then migrates from metal center to boron.

Atomic Resolution Structural and Chemical Imaging Revealing the Sequential Migration of Ni, Co, and Mn upon the Battery Cycling of Layered Cathode.

Layered lithium transition metal oxides (LTMO) are promising candidate cathode materials for next-generation high-energy density lithium ion battery. The challenge for using this category of cathode is the capacity and voltage fading, which is believed to be associated with the layered structure disordering, a process that is initiated from the surface or solid-electrolyte interface and facilitated by transition metal (TM) reduction and oxygen vacancy formation. However, the atomic level dynamic mechanism of such a layered structure disordering is still not fully clear. In this work, utilizing atomic resolution electron energy loss spectroscopy (EELS), we map, for the first time at atomic scale, the spatial evolution of Ni, Co and Mn in a cycled LiNi1/3Mn1/3Co1/3O2 layered cathode. In combination with atomic level structural imaging, we discovered the direct correlation of TM ions migration behavior with lattice disordering, featuring the residing of TM ions in the tetrahedral site and a sequential migration of Ni, Co, and Mn upon the increased lattice disordering of the layered structure. This work highlights that Ni ions, though acting as the dominant redox species in many LTMO, are labile to migrate to cause lattice disordering upon battery cycling, while the Mn ions are more stable as compared with Ni and Co and can act as pillar to stabilize layered structure. Direct visualization of the behavior of TM ions during the battery cycling provides insight for designing of cathode with high structural stability and correspondingly a superior performance.

Distinct Roles for Matrix Metalloproteinases 2 and 9 in Embryonic Hematopoietic Stem Cell Emergence, Migration, and Niche Colonization.

SummaryHematopoietic stem/progenitor cells (HSPCs) are formed during ontogeny from hemogenic endothelium in the ventral wall of the dorsal aorta (VDA). Critically, the cellular mechanism(s) allowing HSPC egress and migration to secondary niches are incompletely understood. Matrix metalloproteinases (MMPs) are inflammation-responsive proteins that regulate extracellular matrix (ECM) remodeling, cellular interactions, and signaling. Here, inhibition of vascular-associated Mmp2 function caused accumulation of fibronectin-rich ECM, retention of runx1/cmyb+ HSPCs in the VDA, and delayed caudal hematopoietic tissue (CHT) colonization; these defects were absent in fibronectin mutants, indicating that Mmp2 facilitates endothelial-to-hematopoietic transition via ECM remodeling. In contrast, Mmp9 was dispensable for HSPC budding, being instead required for proper colonization of secondary niches. Significantly, these migration defects were mimicked by overexpression and blocked by knockdown of C-X-C motif chemokine-12 (cxcl12), suggesting that Mmp9 controls CHT homeostasis through chemokine regulation. Our findings indicate Mmp2 and Mmp9 play distinct but complementary roles in developmental HSPC production and migration.

Naimi’s Structure and Migration: A Tissue-Specific Pattern of Organization Discovered in Normal Bladder Urothelia

Introduction: Sequential migration and organization are critical events in tissue development. The urothelium, the epithelium lining urologic tissues, is highly specialized regarding the watertight function and adaptation to large and frequent changes in urine volume. To establish the functional state of this tissue, horizontal cells growth is required to allow the vertical development into a multilayered uroepithelium. If this first step is already documented, the mechanism implicated in the switch toward the vertical growth is not yet described. Methods: We had elaborated a three-dimensional bladder model, made of bladder mesenchymal cells (BMC) seeded in a collagen matrix which can promote bladder urothelial cells (BUC) development. Results: This in vitro model allowed us to discover a behavior specific to BUC, resulting in a specific urothelial stratification and differentiation pattern. Cellular alignment into a circular arrangement, named Naimi’s structure, followed by coordinated gyratory cellular movement, named Naimi’s migration, were sequentially observed in our in vitro model and were also confirmed in native bladder Conclusion: We describe here the steps that led to Naimi’s structure and migration. Ultrastructural observations are also provided to document the remarkable organization of urothelial cells and the underlying mesenchymal rearrangement. Keywords: Urinary bladder; Urothelium; Cell migration; Extracellular matrix

Sequential transmigration of polymorphonuclear cells and naive CD3+ T lymphocytes across the blood-cerebrospinal-fluid barrier in vitro following infection with Echovirus 30

Viral meningitis by non-polio enteroviruses (NPEV) is a major public health burden causing fatal outcomes especially in the younger population. Strong evidence exists that the blood-cerebrospinal-fluid (CSF) barrier (BCSFB) serves as an entry point for enterovirus and leucocytes into the central nervous system (CNS). Moreover, analysis of clinical CSF specimens of patients with a NPEV infection revealed a predominance of polymorphonuclear granulocytes (PMN) in the early phase and mononuclear cells in the later course of meningitis. By applying a functional in vitro model of the BCSFB consisting of human choroid plexus papilloma (HIBCPP) cells, we aimed to analyse the mechanisms of sequential migration of PMN and naive CD3+ T lymphocytes following infection with Echovirus 30 (EV30). EV30 infection led to increased transmigration of PMN and naive CD3+ T lymphocytes. Transmigration of PMN was significantly enhanced in the presence of naive CD3+ T lymphocytes, but not vice versa. The barrier function was not differentially altered under the respective conditions. Infection with EV30 led to an upregulation of CXCL3 and CXCL11 on the RNA-level. Additional analysis of cytokine secretion revealed relatively high concentrations of IL-8, CCL20, CXCL3, CXCL10 and M-CSF. Overall, there was a predominantly polar direction of cytokine secretion to the basolateral side. IL-7 was the only cytokine which was strongly secreted to the apical side and that was enhanced following EV30 infection in our model. In conclusion, this study highlights the role of the choroid plexus and cytokines in regulating leucocyte entry into the CNS in the context of EV30 infection.

Beyond the artisanal mining site: migration, housing capital accumulation and indirect urbanization in East Africa

ABSTRACTDuring the past 30 years, Tanzania has experienced successive precious mineral rushes led by artisanal miners. Their settlement, livelihood and housing strategies have evolved amidst high mobility in pursuit of mineral wealth. Cumulatively, the spatial movement of artisanal miners and an associated following of economically motivated migrant service providers have catalysed large-scale “direct urbanization” at artisanal mine sites-cum-small towns. These settlements have been generally characterized by relatively makeshift accommodation, which may mask accumulated savings of in situ earnings for housing investment elsewhere. In this article, in addition to documenting the mine-led direct urbanization process, we draw attention to a subsequent “indirect urbanization” phenomenon, whereby many successful artisanal miners and other entrepreneurial mining settlement residents make strategic house building investments in larger towns and cities. In anticipation of declining mineral yields and retirement from days of “roughing it” in mining sites, they endeavour to channel savings into housing in more urbanized locations, aiming to diversify into profitable business activities, living a life with better physical and social amenities. Their second-wave onward migration from mine sites encompasses more diverse destinations, particularly regional towns and cities, which accommodate their work and family life cycle needs and lifestyle preferences. Such mine-led direct and indirect urbanization processes arise from sequential migration decision-making of participants in Tanzania’s artisanal mining sector. In this article, we interrogate mining settlement residents’ locational choices on the basis of fieldwork survey findings from four artisanal gold and diamond mining settlements in Tanzania’s mineral-rich regions of Geita, Mwanza and Shinyanga, and from in-depth interviews with miners-cum-entrepreneurs residing in Mwanza, Tanzania’s second largest city, situated in the heart of Tanzania’s gold fields.

Fundamental Pathways for the Adsorption and Transport of Hydrogen on TiO2 Surfaces: Origin for Effective Sensing at about Room Temperature.

Effective detection of hydrogen at lowered temperature is highly desirable in promoting safety in using this abundant gas as a clean energy source. Through first-principle calculations in the framework of density functional theory, we find that the high-energy (002) surface for rutile TiO2 is significantly more effective in adsorbing hydrogen atoms through dissociating hydrogen molecules. The pathways for the dissociation of hydrogen molecules and sequential migration of hydrogen atoms are identified through searching along various transitional states. Pathways of low potential barriers indicate promise for hydrogen sensing, even close to room temperature. This has been proven through sensors made of thin films of well-aligned rutile nanorods, wherein the high-energy (002) surface dictates the top surface of the active layer of the sensors.

WAYFINDER: parallel virtual machine reallocation through A* search

Modern virtual machine (VM) management software enables consolidation of VMs for power savings or load-balancing for performance. While existing literature provides various methods for computing a better load-balanced, or consolidated goal state, it fails to adequately suggest the best path from the system’s current state to the desired goal allocation. This paper discusses an approach to efficient path finding in VM placement problems for cloud computing environments of moderate scale with results indicating the solution is reasonable for managing hundreds of VMs. We present an overview of known approaches to dynamic VM placement and discuss their shortcomings with respect to dynamic reallocation. We then describe a novel design and implementation of a heuristic search algorithm to determine optimal sequential migration plans to transition from a given VM-to-host allocation to an arbitrary desired allocation state. We then elaborate nuances of A* application to this domain along with our simulation-based validation approach. Finally, this work demonstrates a novel and highly effective technique for exploiting migration parallelism in order to rapidly achieving VM reallocation convergence suitable for continual workload rebalancing in cloud data centers.

International Trade, Migration and Unemployment – The Role of Informal Sector

This paper provides an elaborate general equilibrium framework by including informal economic activities in a model of trade, migration and unemployment. Existence of informal activities is critical in generating positive employment effects of liberal trade policies. Following a tariff cut informal wage increases and rate of unemployment goes down under reasonable conditions. Next we generalize the benchmark model to capture the phenomenon of sequential migration: from agriculture to urban informal sector, and then to urban formal sector. Positive employment effect of reformatory trade policy partly owes to the fact that the presence of informal sector directly reduces the cost of migration and, hence, further induces the process of outmigration from agricultural sector. The paper also extends the benchmark model to include both informal intermediate and final good.

Forward Curve Shifts and Return Convergence

Most investment-grade bond portfolios have a relatively stable duration that shapes their multiyear returns. These returns are impacted by the wide variety of yield paths that can result from sequential migrations to implied forward yield curves, accompanied by parallel trend line shifts. Under these theoretical conditions, the annualized return converges, over an investment horizon that is roughly twice the portfolio’s duration, toward a starting yield curve value whose maturity just coincides with this specific horizon. Thus, a stable duration portfolio return will converge, with surprisingly minimal dispersions, back to a yield curve value that prevailed at the outset—regardless of the direction or volatility of intervening yields. These results have important implications for multiyear return estimation and for volatility assumptions involved in asset allocation. <b>TOPICS:</b>Portfolio management/multi-asset allocation, in portfolio management, commodities

Does University Quality Influence the Interregional Mobility of Students and Graduates? The Case of Italy

Ciriaci D. Does university quality influence the interregional mobility of students and graduates? The case of Italy, Regional Studies. This paper analyses the role that university quality holds, among other socio-economic factors, in the sequential migration behaviour of Italian students and graduates. Regardless of the recognition of universities as key drivers of economic development, empirical evidence on the effects of their quality on the attraction and retention of students and graduates is still limited, and mainly related to Anglo-Saxon countries. This study aims at partly filling this knowledge gap. Its results indicate that both university research and teaching quality influence migration choices and, consequently, affirm that universities are ‘supply’ tools for policy-makers, in order to counterbalance the negative effects of brain drain on regional human capital accumulation.

Photo‐Activatable Surfaces for Cell Migration Assays

AbstractA simple material platform for advanced cell migration studies is presented. It relies on surfaces modified with photo‐activatable adhesion peptides and two light exposure steps to independently trigger attachment and migration. The light‐controlled exposure of adhesive ligands allows precise and selective control over integrin‐mediated adhesion and migration events, including their dynamic variation. By using a microscope‐coupled scanning laser, user‐defined geometry, size and composition of the adhesion and migration spaces are possible and simply defined by the laser scanning parameters. Time lapse and high resolution microscopy are possible during the complete process. The miniaturization capabilities of this assay also allow (i) parallel or sequential migration experiments and controls on the same view field of the microscope, (ii) migration studies in confined and unconventional geometries or (iii) activation of migration spaces at subcellular resolution, all of these with minimum material and time consumption. The photo‐activatable surfaces will allow studies of the dynamics of integrin‐dependent migration processes with unprecedented flexibility, multiplexing, reproducibility, and spatiotemporal resolution.

Spatial and Temporal Aspects of Occurrence ofMogeraSpecies in the Japanese Islands Inferred from Mitochondrial and Nuclear Gene Sequences

We assessed dispersal and vicariant events in four species of Japanese moles in the genera Mogera and Euroscaptor to better understand the factors shaping intra- and interspecific differentiation in Japanese moles. We used the combined viewpoints of molecular phylogeny and historical geology using nucleotide sequences of mitochondrial (cytochrome b; Cytb) and nuclear (A2ab, Bmp4, Tcf25, vWf) genes. The divergence times estimated from the molecular data were verified with available geological data on the chronology of fluctuations in sea level in the Korea Strait, assuming sequential migration and speciation events. This produced possible migration times of 5.6, 3.5, 2.4, and 1.3 million years ago for four species of Japanese moles, Euroscaptor mizura, Mogera tokudae, M. imaizumii, and M. wogura, respectively. For the western Japanese mole M. wogura, Cytb sequences revealed four major phylogroups with strong geographic affinities in southwestern Central Honshu (I), western Honshu/Shikoku (II), Kyushu/westernmost Honshu (III), and Korea/Russian Primorye (IV). The nuclear gene sequences supported the distinctiveness of phylogroups I and IV, indicating long, independent evolutionary histories. In contrast, phylogroups II and III were merged into a single geographic group based on the nuclear gene data. Intraspecific divergences in M. imaizumii and M. tokudae were rather apparent in Cytb but not in nuclear gene sequences. The results suggest that repeated dispersal events have occurred between the Asian continent and the Japanese Islands, and intensive vicariant events associated with abiotic and biotic factors have created higher levels of species and genetic diversities in moles occurring on the Japanese Islands.

Lineage-specific fragmentation and nuclear relocation of the mitochondrial cox2 gene in chlorophycean green algae (Chlorophyta)

In most eukaryotes the subunit 2 of cytochrome c oxidase (COX2) is encoded in intact mitochondrial genes. Some green algae, however, exhibit split cox2 genes (cox2a and cox2b) encoding two polypeptides (COX2A and COX2B) that form a heterodimeric COX2 subunit. Here, we analyzed the distribution of intact and split cox2 gene sequences in 39 phylogenetically diverse green algae in phylum Chlorophyta obtained from databases (28 sequences from 22 taxa) and from new cox2 data generated in this work (23 sequences from 18 taxa). Our results support previous observations based on a smaller number of taxa, indicating that algae in classes Prasinophyceae, Ulvophyceae, and Trebouxiophyceae contain orthodox, intact mitochondrial cox2 genes. In contrast, all of the algae in Chlorophyceae that we examined exhibited split cox2 genes, and could be separated into two groups: one that has a mitochondrion-localized cox2a gene and a nucleus-localized cox2b gene (“Scenedesmus-like”), and another that has both cox2a and cox2b genes in the nucleus (“Chlamydomonas-like”). The location of the split cox2a and cox2b genes was inferred using five different criteria: differences in amino acid sequences, codon usage (mitochondrial vs. nuclear), codon preference (third position frequencies), presence of nucleotide sequences encoding mitochondrial targeting sequences and presence of spliceosomal introns. Distinct green algae could be grouped according to the form of cox2 gene they contain: intact or fragmented, mitochondrion- or nucleus-localized, and intron-containing or intron-less. We present a model describing the events that led to mitochondrial cox2 gene fragmentation and the independent and sequential migration of cox2a and cox2b genes to the nucleus in chlorophycean green algae. We also suggest that the distribution of the different forms of the cox2 gene provides important insights into the phylogenetic relationships among major groups of Chlorophyceae.

Prostaglandin D2 Regulates CD4+ Memory T Cell Trafficking across Blood Vascular Endothelium and Primes These Cells for Clearance across Lymphatic Endothelium

Memory lymphocytes support inflammatory and immune responses. To do this, they enter tissue via blood vascular endothelial cells (BVEC) and leave tissue via lymphatic vascular endothelial cells (LVEC). In this study, we describe a hierarchy of signals, including novel regulatory steps, which direct the sequential migration of human T cells across the blood and the lymphatic EC. Cytokine-stimulated (TNF and IFN) human BVEC preferentially recruited memory T cells from purified PBL. Lymphocyte recruitment from flow could be blocked using a function-neutralizing Ab against CXCR3. However, a receptor antagonist directed against the PGD(2) receptor DP2 (formerly chemoattractant receptor-homologous molecule expressed on Th2 cells) inhibited transendothelial migration, demonstrating that the sequential delivery of the chemokine and prostanoid signals was required for efficient lymphocyte recruitment. CD4(+) T cells recruited by BVEC migrated with significantly greater efficiency across a second barrier of human LVEC, an effect reproduced by the addition of exogenous PGD(2) to nonmigrated cells. Migration across BVEC or exogenous PGD(2) modified the function, but not the expression, of CCR7, so that chemotaxis toward CCL21 was significantly enhanced. Thus, chemokines may not regulate all stages of lymphocyte migration during inflammation, and paradigms describing their trafficking may need to account for the role of PGD(2).

Wnt Ligand Expression and Regulation of Stem Cells During Postnatal Growth of the Small Intestine in Rats

Background: The sequential proliferation, lineage-specific differentiation, crypt-villus migration, and cell death of the epithelial cells of the intestinal mucosa is tightly regulated by regulatory peptides, differentiation signals, and luminal stimuli, including nutrients and pathogenic/commensal organisms. Despite its importance for understanding normal homeostasis and pathogenesis of disease states, the intracellular signal transduction mechanisms involved remain incompletely understood. Here, we tested the hypothesis that PKD1 plays a key role in intestinal crypt cell proliferation In Vivo. Results: To clarify the role of PKD1 in intestinal epithelial cell proliferation In Vivo, we generated transgenic mice that express elevated PKD1 protein in the distal small intestinal and proximal colonic epithelium. The catalytic activity and multi-site phosphorylation (Ser744, Ser748 and Ser916) of PKD1 was strikingly higher in extracts from ileal mucosa of transgenic mice as compared with non-transgenic littermates. These results indicate that transgenic PKD1 is functional in the intestinal epithelium. PKD1 signaling stimulated intestinal cell proliferation, as shown by detection of 5-bromo-2-deoxyuridine (BrdU) incorporated into the cell nuclei of crypt cells of the ileum and proximal colon, where PKD1 protein is maximally expressed. Our results demonstrated a highly statistically significant increase (p<0.005) in DNA synthesizing cells in the crypts of the PKD1 transgenic mice as compared with non-transgenic littermates. In the intestine, normal cell numbers are maintained by balancing rates of cell proliferation, differentiation, migration and apoptosis. Consequently, we determined whether transgenic PKD1 leads to a change in tissue architecture, manifested by an increase in the size and total number of epithelial cells in the crypts. We measured crypt height (in micrometer and cell number) and crypt circumference (in micrometer and cell number) in histological sections of control and PKD1 transgenic mice. The data was used to calculate the size of individual cells and the total number of cells per crypt. Our results show a significant increase in the depth (either in μm or in number of cells) and in the total number of cells per crypt in the transgenic PKD1 mice as compared with the nontransgenic littermates (276 total cells per ileal crypt in transgenic mice versus 192 in nontransgenic mice; p< 0.005). These results indicate that the expression of the PKD1 transgene led to a marked increase (44%) in the total number of intestinal epithelial cells per crypt. Conclusion: Transgenic PKD1 expression increases the number of cells per crypt by stimulating the rate of crypt cell proliferation. These results support the hypothesis that PKD1 signaling plays a role in a pathway leading to proliferation in intestinal epithelial cells.

The Migration of Mobile Agent using the Object Replication

The migration method of a mobile agent affects the entire performance of the distributed system. Most of the existing migration methods have the slow-witted structures due to the fixed order migration that cause the subsequent accumulation of the task results. They can induce various problems such as the failure of host, network obstacles, service absence, and increased traffic resulting in the inefficient operation of the mobile agent. In this paper, we propose the new migration method using the object replication to solve these problems. The proposed model is simply composed of three components: the Mobile Agent Client, Naming Agent Server, and Mobile Agent Server. The Mobile Agent Client performs the object replication according to the furnished object information (the number of replication) from the Naming Service Management Module. The main function of the naming service given by the naming agent is to provide information regarding the object replication and the location transparency of servers in the distributed network environment. We also suggest the replication algorithm and the migration model of the replicated mobile agent object using the naming service. The experiments analyzing the performance of our method, the sequential migration method, and the Locker pattern method are performed and the results are compared to guarantee the effectiveness of our approach.