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ABSTRACTThe present article analyses an infinite buffer batch size-dependent bulk service queue with multiple working vacation (MWV). The customer's arrival pattern follows the Poisson process, and they get the service in batches according to the general bulk service (GBS) rule in regular period (RP) as well as in working vacation period (WVP). After one service in RP, if the queue size is greater or equal to the lower threshold of the GBS rule, then the server performs the service in RP, otherwise, it starts the working vacation (WV) following exponential vacation time distribution. During the WVP, the server serves the customers in batches (if any) at a lower service rate than the usual service rate. The service time in the RP as well as in WVP is generally distributed. At an arbitrary epoch, the joint probabilities of the queue size and batch size with the server in RP as well as in WVP have been obtained using the supplementary variable technique (SVT) and the bivariate generating function method. Finally, some numerical observations are presented to enhance the applicability of the analytical results.

ABSTRACTWe consider an infinite buffer queueing system consisting of multiple number of identical servers and a common queue. The customers’ arrival into the system follows renewal process, whereas the service time is exponentially distributed. The servers provide service according to threshold policy where all the servers together go to an idle state when the system becomes empty and they resume service only when customers are accumulated in the queue. We perform the steady-state analysis of the model using two well-known methods namely, supplementary variable and difference equation technique, to evaluate the probability distribution of the system-content at different epochs. We also obtain the Laplace-Stieltjes transform of waiting time distribution along with other system characteristics. The expected cost model is also formulated and dealt with numerically in order to obtain the optimum threshold value. Finally, with the help of certain numerical examples, the influence of model parameters on the system behavior is studied and the managerial implications of the model is discussed.

Non-equilibrium molecular dynamics simulations are used to probe the driving forces behind the formation of highly ordered, epitaxially connected superlattices of polyhedral-shaped nanoparticles (NPs) at fluid–fluid interfaces. By explicitly modeling coarse-grained ligands that cap the NP surface, it is shown that differences in NP shapes and time-dependent facet-specific ligand densities give rise to drastically different transformation mechanisms. Our results indicate that the extent of screening of the inter-particle interactions by the surrounding solvation environment has a significant impact on reversibility and ultimately the coherence of the final two-dimensional superlattice obtained. For the particle shapes examined, a hexagonal pre-assembly and a square superlattice final assembly (upon preferential ligand desorption from {100} facets) were prevalent; however, cuboctahedral NPs formed intermediate epitaxially bonded branched clusters, which eventually grew and rearranged into a square lattice; in contrast, truncated octahedral NPs exhibited an abrupt rhombic-to-square transition driven by the clustering of their numerous {111}-ligands that favored the stacking of linear NP rods. To track the incipient order in the system, we also outline a set of novel order parameters that measure the local orientation alignment between nearest-neighbor pairs. The simulation protocols advanced in this work could pave the way forward for exploration of the vast phase space associated with the interfacial self-assembly of NPs.

This study outlines the development of an implicit-solvent model that reproduces the behavior of colloidal nanoparticles at a fluid–fluid interface. The center point of this formulation is the generalized quaternion-based orientational constraint (QOCO) method. The model captures three major energetic characteristics that define the nanoparticle configuration—position (orthogonal to the interfacial plane), orientation, and inter-nanoparticle interaction. The framework encodes physically relevant parameters that provide an intuitive means to simulate a broad spectrum of interfacial conditions. Results show that for a wide range of shapes, our model is able to replicate the behavior of an isolated nanoparticle at an explicit fluid–fluid interface, both qualitatively and often nearly quantitatively. Furthermore, the family of truncated cubes is used as a test bed to analyze the effect of changes in the degree of truncation on the potential-of-mean-force landscape. Finally, our results for the self-assembly of an array of cuboctahedra provide corroboration to the experimentally observed honeycomb and square lattices.

ABSTRACTThis paper considers a single server finite-buffer batch-size-dependent bulk service queue with queue-length dependent vacation. Customers arrive at the system according to the Poisson process and are served in batches of maximum size ‘b’ with a minimum threshold value ‘a’ following the ‘general bulk service’ rule. The service time distribution is assumed to be of general type which modulates depending on serving batch size. The server is allowed to take vacation, either single or multiple vacations, whenever permissible numbers of customers are not found in the queue at the beginning of the service. The vacation time distribution is assumed to be of general type and dynamically changes depending on the queue content at vacation initiation epoch. We use the supplementary variable and the embedded Markov chain techniques to obtain the steady-state joint distribution of the queue content service batch size, queue content and type of vacation taken by the server at various epochs. Several numerical results are presented at the end to bring out the qualitative aspect of the model, which reveals the fact that queue-length dependent vacation further reduces congestion in the batch-size-dependent bulk service queues.

Background: Endophytic fungi are taxonomically and ecologically heterogeneous group of organisms, mainly belonging to the Ascomycotina and Deuteromycotina. Endophytes usually produce the enzymes necessary for the colonization of plant tissues. Endophytes are able to utilize components of plant cells without disturbing host metabolism, which is confirmed by isozyme analysis and studies on substrate utilization. The patents related to enzymes and metabolites produced by endophytic fungi are associated with their ecological significance. Application of metabolites and growth promoting factors produced from endophytic fungi, in the pharmaceutical and agricultural industries, is now well established. The patents on secretion of extracellular enzymes in vitro by endophytic fungi needed for cell wall degradation, support the hypothesis that fungal endophytes represent a group of organisms specialized to live within plant tissue. Objective: This review presents the patents granted on different aspects of endophytic fungi for the last 11 years. This expresses the scenario and impact of these patents regarding significance in human society. Conclusion: In the last few years, research and inventions regarding the different aspects of endophytic fungi beneficial for host plant as well as for human beings have been carried out, which is supported by the increasing number of patents granted on endophytic fungi.

Generation of hydrogen by photochemical, electrochemical, and other means is a vital area of research today, and a variety of materials have been explored as catalysts for this purpose. C3N4, MoS2, and nitrogenated RGO (NRGO) are some of the important catalytic materials investigated for the hydrogen evolution reaction (HER) reaction, but the observed catalytic activities are somewhat marginal. Prompted by preliminary reports that covalent cross-linking of 2D materials to generate heteroassemblies or nanocomposites may have beneficial effect on the catalytic activity, we have synthesized nanocomposites wherein C3N4is covalently bonded to MoS2or NRGO nanosheets. The photochemical HER activity of the C3N4–MoS2nanocomposite is found to be remarkable with an activity of 12778 μmol h–1g–1and a turnover frequency of 2.35 h–1. The physical mixture of C3N4and MoS2, on the other hand, does not exhibit notable catalytic activity. Encouraged by this result, we have studied electrochemical HER activity of these composites as well. C3N4–MoS2shows superior activity relative to a physical mixture of MoS2and C3N4. Density functional theory calculations have been carried out to understand the HER activity of the nanocomposites. Charge-transfer between the components and greater planarity of cross-linked layers are important causes of the superior catalytic activity of the nanocomposites. Covalent linking of such 2D materials appears to be a worthwhile strategy for catalysis and other applications.

AbstractIn this paper we present closed-form expressions for the distribution of the virtual (actual) queueing time for the BMAP/R/1 and BMAP/D/1 queues, where `R' represents a class of distributions having rational Laplace‒Stieltjes transforms. The closed-form analysis is based on the roots of the underlying characteristic equation. Numerical aspects have been tested for a variety of arrival and service-time distributions and results are matched with those obtained using the matrix-analytic method (MAM). Further, a comparative study of computation time of the proposed method with the MAM has been carried out. Finally, we also present closed-form expressions for the distribution of the virtual (actual) system time. The proposed method is analytically quite simple and easy to implement.

The convective instability of Casson nanofluids saturating porous medium is investigated analytically and numerically. Darcy-Brinkman law is utilized to frame the momentum equation for the system. The governing equations are simplified using normal mode analysis and linear stability theory. The present study finds the expressions of thermal Rayleigh number for various boundaries and discusses the convective instability under various effects with the help of Wolfram Mathematica software. Out of all the boundaries, the instability of the layer is found to be least for both rigid boundaries. It is established that the convection in the fluid gets delayed due to porosity effects while non-Newtonian property and nano scale effects contribute significantly in making the layer unstable.

ABSTRACTAs the disease caused by Mycobacterium tuberculosiscontinues to be a burden, there is a concerted effort to find new vaccines to combat this problem. One of the important vaccine strategies is whole bacterial vaccines. This approach relies on multiple antigens and built-in adjuvanticity. Other mycobacterial strains which share cross-reactive antigens with M. tuberculosishave been considered as alternatives to M. bovisfor vaccine use. One such strain, “Mycobacterium w”, had been evaluated for its immunomodulatory properties in leprosy. A vaccine against leprosy based on killed M. wis approved for human use, where it has resulted in clinical improvement, accelerated bacterial clearance, and increased immune responses to Mycobacterium lepraeantigens. M. wshares antigens not only with M. lepraebut also with M. tuberculosis, and initial studies have shown that vaccination with killed M. winduces protection against tuberculosis in Mycobacterium bovisBCG responder, as well as BCG nonresponder, strains of mice. Hence, we further studied the protective potential of M. wand the underlying immune responses in the mouse model of tuberculosis. We analyzed the protective efficacy of M. wimmunization in both live and killed forms through the parenteral route and by aerosol immunization, compared with that of BCG. Our findings provide evidence that M. whas potential protective efficacy against M. tuberculosis. M. wactivates macrophage activity, as well as lymphocytes. M. wimmunization by both the parenteral route and aerosol adminstration gives higher protection than BCG given by the parenteral route in the mouse model of tuberculosis.

As the disease caused by Mycobacterium tuberculosis continues to be a burden, there is a concerted effort to find new vaccines to combat this problem. One of the important vaccine strategies is whole bacterial vaccines. This approach relies on multiple antigens and built-in adjuvanticity. Other mycobacterial strains which share cross-reactive antigens with M. tuberculosis have been considered as alternatives to M. bovis for vaccine use. One such strain, "Mycobacterium w", had been evaluated for its immunomodulatory properties in leprosy. A vaccine against leprosy based on killed M. w is approved for human use, where it has resulted in clinical improvement, accelerated bacterial clearance, and increased immune responses to Mycobacterium leprae antigens. M. w shares antigens not only with M. leprae but also with M. tuberculosis, and initial studies have shown that vaccination with killed M. w induces protection against tuberculosis in Mycobacterium bovis BCG responder, as well as BCG nonresponder, strains of mice. Hence, we further studied the protective potential of M. w and the underlying immune responses in the mouse model of tuberculosis. We analyzed the protective efficacy of M. w immunization in both live and killed forms through the parenteral route and by aerosol immunization, compared with that of BCG. Our findings provide evidence that M. w has potential protective efficacy against M. tuberculosis. M. w activates macrophage activity, as well as lymphocytes. M. w immunization by both the parenteral route and aerosol adminstration gives higher protection than BCG given by the parenteral route in the mouse model of tuberculosis.

Experimental photoelectron and computational results show diniobium−carbon (Nb 2C n) clusters to coexist in multiple structural isomers: three-dimensional geometries, planar rings, and linear chains. Three-dimensional clusters having up to five carbons are formed preferentially with Nb−Nb bonding, whereas only Nb−C bonding is observed experimentally at six carbons. Clusters consisting of an odd number of atoms are also observed with linear geometries. The larger binary clusters ( n≥ 7) display properties similar to those of pure carbon clusters. We provide evidence for niobium substitution of carbon atoms.

ABSTRACTPyrazinamide (PZA) is an important first-line antituberculosis drug because of its sterilizing activity against semidormant tubercle bacilli. In spite of its very high in vivo activity, its in vitro activity is not apparent unless an acidic environment is available, which makes PZA susceptibility testing difficult by conventional methods. The present study was, therefore, planned to assess the performance of the colorimetric BacT/ALERT 3D system and compare the results with those from conventional tests, i.e., the Lo¨wenstein-Jensen (LJ) proportion method (pH 4.85) and Wayne's pyrazinamidase (PZase) assay, using 107 clinical isolates. The concordance among all of these tests was 89.71% after the first round of testing and reached 92.52% after resolution of the discordant results by retesting. Prolonged incubation of the PZase tube for up to 10 days was found to increase the specificity of the PZase test. The concordances between LJ proportion and BacT/ALERT 3D, LJ proportion and the PZase assay, and BacT/ALERT 3D and the PZase assay were found to be 99.06%, 93.46%, and 92.52%, respectively. Using the LJ results as the gold standard, the sensitivities of BacT/ALERT 3D and the PZase assay were 100 and 82.85%, respectively, while the specificity was 98.61% for both of the tests. The difference between the sensitivities of BacT/ALERT 3D and the PZase assay was significant (P= 0.025). The mean turnaround times for the detection of resistant and susceptible results by BacT/ALERT 3D were 8.04 and 11.32 days, respectively. While the major limitations associated with the PZase assay and the LJ proportion method are lower sensitivity in previously treated patients and a longer time requirement, respectively, the BacT/ALERT 3D system was found to be rapid, highly sensitive, and specific.

Pyrazinamide (PZA) is an important first-line antituberculosis drug because of its sterilizing activity against semidormant tubercle bacilli. In spite of its very high in vivo activity, its in vitro activity is not apparent unless an acidic environment is available, which makes PZA susceptibility testing difficult by conventional methods. The present study was, therefore, planned to assess the performance of the colorimetric BacT/ALERT 3D system and compare the results with those from conventional tests, i.e., the Löwenstein-Jensen (LJ) proportion method (pH 4.85) and Wayne's pyrazinamidase (PZase) assay, using 107 clinical isolates. The concordance among all of these tests was 89.71% after the first round of testing and reached 92.52% after resolution of the discordant results by retesting. Prolonged incubation of the PZase tube for up to 10 days was found to increase the specificity of the PZase test. The concordances between LJ proportion and BacT/ALERT 3D, LJ proportion and the PZase assay, and BacT/ALERT 3D and the PZase assay were found to be 99.06%, 93.46%, and 92.52%, respectively. Using the LJ results as the gold standard, the sensitivities of BacT/ALERT 3D and the PZase assay were 100 and 82.85%, respectively, while the specificity was 98.61% for both of the tests. The difference between the sensitivities of BacT/ALERT 3D and the PZase assay was significant (P = 0.025). The mean turnaround times for the detection of resistant and susceptible results by BacT/ALERT 3D were 8.04 and 11.32 days, respectively. While the major limitations associated with the PZase assay and the LJ proportion method are lower sensitivity in previously treated patients and a longer time requirement, respectively, the BacT/ALERT 3D system was found to be rapid, highly sensitive, and specific.

We consider a finite-buffer single-server queue with Markovian arrival process (MAP ) where the server serves a limited number of customers, and when the limit is reached it goes on vacation. Both single- and multiple-vacation policies are analyzed and the queue length distributions at various epochs, such as pre-arrival, arbitrary, departure, have been obtained. The effect of certain model parameters on some important performance measures, like probability of loss, mean queue lengths, mean waiting time, is discussed. The model can be applied in computer communication and networking, for example, performance analysis of token passing ring of LAN and SVC (switched virtual connection) of ATM.

Vacation time queues with Markovian arrival process (MAP) are mainly useful in modeling and performance analysis of telecommunication networks based on asynchronous transfer mode (ATM) environment. This paper analyzes a single-server finite capacity queue wherein service is performed in batches of maximum size “b ” with a minimum threshold “a ” and arrivals are governed by MAP. The server takes a single vacation when he finds less than “a ” customers after service completion. The distributions of buffer contents at various epochs (service completion, vacation termination, departure, arbitrary and pre-arrival) have been obtained. Finally, some performance measures such as loss probability and average queue length are discussed. Numerical results are also presented in some cases.

BACKGROUND: The purpose of this study was to evaluate the effects of lasofoxifene, a selective estrogen receptor modulator (SERM), on rat and rabbit fetal development. METHODS: Lasofoxifene was administered orally to rats (1, 10, 100 mg/kg) between gestation days (GD) 6–17, and in rabbits (0.1, 1, 3 mg/kg) between GD 6–18. Maternal body weight and food consumption were monitored throughout pregnancy. Fetuses were delivered by Cesarean section on GD 21 in rats, and GD 28 in rabbits, to evaluate fetal viability, weight, and morphology. Drug concentrations in maternal plasma were measured in a separate cohort of animals at several time points commencing on GD 17 (rats) and 18 (rabbits). On GD 18 (rat) and GD 19 (rabbit) drug concentrations were measured in maternal plasma and in fetal tissue 2 hr post dosing to determine the fetal to maternal drug ratio. RESULTS: In rats, there were dose‐related declines in maternal weight gain and food consumption. Post implantation loss was significantly increased at dosages of 10 and 100 mg/kg, and the number of viable fetuses was decreased at 100 mg/kg. The placental weights increased, whereas fetal weights decreased in a dose‐dependent manner. Lasofoxifene‐related teratologic findings were noted at 10 and 100 mg/kg and included imperforate anus with hypoplastic tails, dilatation of the ureters and renal pelvis, misaligned sternebrae, hypoflexion of hindpaw, wavy ribs, and absent ossification of sternebrae. In rabbits, neither maternal weight gain nor food consumption were affected during treatment. Between GD 26–28, there was a dose‐dependent increased incidence of red discharge beneath the cages. At 1 and 3 mg/kg, resorptions and post‐implantation loss increased. There were no significant external or visceral effects, but 3 mg/kg there was an increased incidence of supernumerary ribs. Although the maternal plasma Cmax and AUC(0–24) were dose‐dependent, the exposures in the rat were many orders of magnitude greater than in the rabbit even for the same 1 mg/kg dose. The single time point fetal/maternal drug ratio was higher in the rat (1.3–0.78) than in the rabbit (0.21–0.16). CONCLUSION: In general, both maternal and fetal effects of lasofoxifene were similar to those reported with other SERMs. Although the incidence or severity of these effects was, in some instances, greater in the rat than in the rabbit, the doses and the resultant maternal and fetal exposures were many orders of magnitude higher in the rat, suggesting the rabbit to be more sensitive to the toxicological effects of lasofoxifene. Birth Defects Res B 71:161–170, 2004. © 2004 Wiley‐Liss, Inc.

BACKGROUND: Lasofoxifene is a nonsteroidal selective estrogen receptor modulator (SERM). With high affinity to the α and β human estrogen receptors and greater potency than other SERMs, lasofoxifene is potentially a superior treatment for postmenopausal osteoporosis. In light of the known effects of estrogen‐modulating compounds on female reproductive indices, two studies were conducted to evaluate the effects of lasofoxifene on female rat cyclicity, reproduction, and parturition. METHODS: One study evaluated effects of lasofoxifene on estrous cyclicity, and the second study assessed effects on implantation and parturition. In the cyclicity study, lasofoxifene was administered to female rats at doses of 0.1, 0.3, and 1.0 mg/kg/day for 14 consecutive days. After treatment, there was a 3‐week reversibility phase followed by a mating phase. In the implantation study, lasofoxifene was administered to pregnant female rats at doses of 0.01, 0.03, and 0.1 mg/kg/day for 7 consecutive days (gestation day [GD] 0–6). Some animals were euthanized on GD 21, and the remainder of the group was allowed to deliver the F1 generation. Several developmental indices were evaluated in the F1 pups through post‐natal day (PND) 21. RESULTS: In the cyclicity study, all lasofoxifene‐treated females were anestrous by Study Day 7 (1.0 mg/kg) or 9 (0.3 and 0.1 mg/kg). The reversibility phase resulted in restoration of normal estrous cycles by the end of 1 (0.1 mg/kg) or 2 weeks (0.3 and 1.0 mg/kg). During the mating phase, no adverse effects occurred in pregnancy success or reproductive parameters. In the implantation study, all doses of lasofoxifene increased pre‐ and post‐implantation losses, increased gestation length, and reduced litter size. None of the developmental parameters measured on the F1 generation was adversely affected. CONCLUSION: Lasofoxifene reversibly altered the estrous cycle and inhibited implantation, consistent with what would be expected from a member of the SERM class. Birth Defects Res B 71:150–160, 2004. © 2004 Wiley‐Liss, Inc.

BACKGROUND: A review of the nonsteroidal anti‐inflammatory drug (NSAID) literature suggested occurrences of low‐level incidences of cardiovascular and midline defects in rabbit fetuses exposed in utero. Aspirin (acetylsalicylic acid, ASA) is a widely used NSAID that irreversibly inhibits cyclooxygenases (COXs) 1 and 2. ASA has been studied extensively in rats and has consistently increased low‐incidence cardiovascular malformations and defects in midline closure. The objectives of the current study were to comprehensively define the developmental toxicology profile of ASA in rabbits by using a dosing paradigm encompassing the period of organogenesis and to test the hypothesis that maternal gastrointestinal toxicity after repeated dose administrations hampers the detection of low‐incidence malformations with ASA in rabbits by limiting ASA administration to sensitive windows for cardiovascular development and midline closure. METHODS: ASA was administered to pregnant New Zealand White rabbits from gestation days (GDs) 7 to 19 at dose levels of 125, 250, and 350 mg/kg per day and as single doses of 500, 750, or 1000 mg/kg on GD 9, 10, or 11. Cesarean sections were performed on GD 29, and the fetuses were examined for external, visceral, and skeletal development. RESULTS: In the repeated dose study, maternal toxicity was exhibited in the 250‐ and 350‐mg/kg per day groups by mortality and decreased food consumption and body weight gain. In the single dose studies, maternal toxicity was exhibited at all doses by reductions in body weight gain and food consumption for 3 days after treatment. Fetal body weight was significantly reduced in the repeated dose study at 350 mg/kg per day. Fetal weights were not affected by single doses of ASA on GD 9, 10, or 11. There were no treatment‐related external, visceral, or skeletal malformations associated with ASA administration throughout organogenesis or with single doses administered during critical developmental windows. CONCLUSION: These findings supported previous work demonstrating that ASA is not teratogenic in rabbits, as opposed to rats, even when large doses are administered on single days during specific windows of development. Birth Defects Research (Part B) 68:38–46, 2003. © 2003 Wiley‐Liss, Inc.

Forced axi-symmetric vibrations of polar orthotropic linearly tapered circular plates are discussed on the basis of classical plate theory. Ritz method has been employed to obtain the solutions. The deflection function and the bending moments for forced vibrations of the plate are presented for various values of taper parameter and rigidity ratio. A comparison of results with those available in literature shows an excellent agreement.

We have studied the geographic and ethinic distribution of mutations in 376 subjects who were carriers of β-thalassemia, and identified the mutations in 365 chromosomes. The majority of the β-thalassemia carriers were of Uttar Pradesh (India) origin. Their pattern of mutations differed from the other states of India and from those families who had migrated from Pakistan. The frequency of the NS-I-5 (G→C) and 619 bp deletion mutations were 64.3 and 2.5%, respectively, among families originating from Uttar Pradesh, compared to a prevalence of 37.5 and 27.5%, respectively in the population of Pakistani immigrants. Of the 10 common Asian Indian mutations, only eight were observed in subjects studied from different parts of India. By use of the amplification refractory mutation system along with DNA sequencing techniques, the mutations were successfully identified in 97.1% of subjects, while 11 cases (2.9%) still remain to be characterized by single strand conformation polymorphism and sequencing analyses. The application of this knowledge has facilitated the successful implementation of the program of genetic counseling and prenatal diagnosis of β-tbalassemia, thus helping to avoid the birth of an affected child in India.

A new inorganic ion exchange sorbent, zirconium aluminophosphate, has been prepared with Na⁺ ion exchange capacity (iec) equal to 2.10 mequiv/dry g. Its X-ray diffraction studies suggest that it is amorphous in nature. Its characterization has also been done by IR, TGA, and DSC so as to identify various functional groups and ion exchange sites present in the material. Further, various ion exchange studies such as determination of iec, elution behavior, pH titration, and distribution behavior have been performed on this material. Distribution coefficients for some heavy metal ions have also been determined to explore its separation potential. This material shows a high selectivity for Pb(II). On this basis some possible binary separations may be Pb(II)−Cd(II) and Pb(II)−Mg(II) on a column of this material.

Objective:This study was conducted to document the prevalence of maternal genital tract colonization by Ureaplasma urealyticumand Mycoplasma hominis, and to assess its association with low birth weight (LBW) and prematurity. Methods:The high vaginal swabs of pregnant women in spontaneous labor after 26 weeks of gestation were cultured for U. urealyticumand M. hominis. Clinical details and perinatal outcomes including birth weight and gestation were documented. Results:Of a total of 303 women enrolled, 148 (48.8%) had positive vaginal cultures for U. urealyticum, while only five (1.6%) grew M. hominis. The mean birth weight and the incidences of LBW and preterm neonates among ureaplasma positive and ureaplasma negative mothers were statistically comparable. Conclusions:U. urealyticumemerged as a common inhabitant of the lower genital tract of women in labor, being present in nearly half of them. Its presence was not a risk factor of LBW or prematurity. Maternal colonization with M. hominiswas uncommon.

In this paper we discuss the performance analysis of a single server queue with Poisson arrivals and arbitrary service times which are conditioned on the number of customers (units) in the system at the beginning of the service of a customer. The system has a finite capacity K. The model is denoted by M/Gn/K, and has wide applications in computer-communication systems. An algorithm has been developed to compute the steady-state probabilities at departure and arbitrary epochs. Numerical results have been presented for various special cases: two-state service rates; two-state mixed service; and many-state service rates. The algorithm is computationally efficient, accurate and reliable for both high and low values of the model parameters and works for all the service time distributions including the non-phase type. Some comparative studies have been presented in the form of tables and graphs.

Asymmetric vibrations of polar orthotropic circular plates of linearly varying thickness with elastic/rigid support are discussed on the basis of the classical plate theory. An approximate solution of the problem is obtained by the Rayleigh–Ritz method using functions based on static deflection of polar orthotropic circular plates. This type of approximating functions has a faster rate of convergence as compared to the polynomial co-ordinate functions. Frequency parameters of the plate have been obtained for different values of taper parameter, flexibility parameter and rigidity ratio in the first three modes of vibration. A comparison of results for special cases of isotropy, uniform thickness and of axisymmetric vibrations obtained by other techniques such as the finite element method and the Receptance method shows excellent agreement.

The instability of two superposed fluids in the presence of suspended particles is studied. It is found that the system is unstable for sufficiently long waves, however large the applied magnetic field may be, provided the initial configuration is top-heavy density wise. Also, the potentially stable system remains stable for the case of two superposed fluids in the presence of a variable magnetic field and suspended particles.

Field studies were conducted at Bouctouche Research Farm in New Brunswick, Canada to determine the effect of zinc (Zn) and nitrogen (N) on silage corn. Soils at these sites are coarse texture loamy sand with pH values of 6.0-6.3 and organic matter content of 2.6 to 2.7 mg·g-1. In Experiment 1, Zn application at 0.5 to 1.0 kg·ha-1 foliar or 10 to 20 kg·ha-1 soil applied significantly increased the silage corn dry matter yield. Leaf Zn levels of 8.8 to 10.1 mg·kg-1 and available soil Zn at 0.8 mg·kg-1 in the check treatments were related to Zn deficiency in corn. No response to Zn was noted in Experiment 2 and this was associated with leaf Zn levels of 15 to 16 mg·kg-1 in the control treatment. In the Zn x N field study, a significant dry matter yield response to N and Zn was obtained. Nitrogen applications with or without added Zn increased leaf Zn. Leaf Zn increases were highest at the highest rate of added N. Corn leaf Zn levels at 9 mg·kg-1 were associated with lower yield. Zinc deficiency in corn can be controlled by 1 kg Zn ha-1 foliar or 10 to 20 kg Zn ha-1 soil applied.

Test grouting has been carried out in the three different rock units (phyllites grade I, II & III) exposed around Tehri Dam Project to evaluate the groutability of these rocks and to evolve optimum spacing of grout holes to be adopted for the grout, curtain. Since it has been observed that permeability of the rock mass is essentially secondary and is mainly joint and fissure controlled, the structural discontinuities observed in the rock types have been analysed for finding out the direction of grout holes that can intersect the maximum numbers of discontinuities and hence seal the rock mass properly. The grouting has been carried out through grou holes and its effectiveness has been observed through inspection holes drilled in between and depending upon the effectiveness, secondary and tertiary holes were drilled in between to reduce the spacing of holes from inspection holes. Finally, when the permeability values of inspection holes were reduced to 1 lugeon or less after grouting through tertiary holes, it has been considered to have achieved optimum grouting efficiency. The effective grout travel distance in the phyllites has been proved to be 0.75 m. It has been inferred that adoption of high grout pressures while emplacing the grout curtain might change the spacing to around 1.5 m apart. Des essais d'injection ont été réalisés dans trois types différents de roches (phyllites I, II et III) sur le site du projet de barrage de Tehri, afin d'évaluer les capacités d'absorption de ces roches et pour calculer l'espacement optimal des forages d'injection pour réalisation du rideau d'étanchéité. On a observé que la perméabilité du massif rocheux est essentiellement secondaire et dépend surtout des joints et fissures. Les discontinuités de structure ont donc été analysées pour trouver les meilleures orientations possibles pour les forages d'injection, de façon à recouper le plus grand nombre possible de ces discontinuités et ainsi sceller au mieux le massif. L'injection a été réalisée dans des forages d'injection et son efficacité a été observée à l'aide de forages d'inspection intercalaires et dans certains cas des forages supplémentaires ont été rajoutés, en fonction des résultats observés. Finalement, on a considérés que lorsque la valeur de la perméabilité a été réduite à moins de 1 lugeon après injection dans les forages supplémentaires, l'efficacité optimale était atteinte. L'écartement optimal des forages d'injection dans les phyllites s'est avéré être de 0,75 m. On en a déduit que l'adoption de pressions d'injection élevées lors de la mise en place du rideau pourrait permettre d'adopter un espacement de 1,5 mètre.

Micronutrients can be limiting for crop production and quality in fine sandy loam Podzolic soils in the cool, humid climate of Atlantic Canada. This study was conducted to determine the effect of mimimum tillage practices, in three long-term animal feed crop rotations, on micronutrient (B, Cu, Zn, Mn, Fe and Mo) content and grain quality of spring barley (Hordeum vulgare L.) and soybean (Glycine max L. Merrill). Reductions in soil tillage had various effects on micronutrient concentration in plant parts, especially for Cu, Zn, Mn, and Mo, which were probably related to pH changes at the soil surface. Grain micronutrient concentrations, however, for crop yield potential tended to be in the sufficiency range and were not limiting for crop growth or feed quality. Evidence suggesting a decline in Mo concentration over time underlines the need for periodic assessment of micronutrient assimilation in conservation tillage systems.

Asymmetric vibration of polar orthotropic circular plates of linearly varying thickness subjected to hydrostatic in-plane force are discussed on the basis of classical plate theory. An approximate solution of the problem has been obtained by the Ritz method, which employs functions based upon the static deflection of polar orthotropic plates. This method has a faster rate of convergence as compared to the polynomial co-ordinate functions. Frequency parameters of the plate with elastically restrained edge conditions are presented for the three modes of vibrations for various values of taper parameter, rigidity ratio, flexibility parameter and buckling load parameter. The critical buckling loads for elastically restrained edge conditions have been obtained. A comparison of results with those available in the literature shows an excellent agreement.

An analysis and numerical results are presented for free transverse vibrations of orthotropic rectangular plates of linearly varying thickness along one direction and resting on an elastic foundation of the Winkler type on the basis of classical plate theory. Following the Le´vy approach i.e., two parallel edges being simply supported, the fourth order differential equation governing the motion of such plates has been solved by using the quintic splines interpolation technique for three different combinations of clamped, simply supported and free boundary conditions at the other two edges. The effect of the elastic foundation together with the orthotropy, aspect ratio and thickness variation on the natural frequencies of vibration is illustrated for the first three modes of vibration. Normalized displacements are presented for two different values of the taper constant keeping other plate parameters fixed for all the three boundary conditions. A comparison of the results with those available in literature is presented.

Moving Boundary Formulation is used to analyze one dimensional model of magma chamber which gradually cools and solidifies after emplacement in the region. Cooling of a layer of pure melt (magma chamber) from above leads to a temperature profile that increases with depth and is thermally unstable. The vigor of convection thus produced, is determined by Rayleigh-Nusselt number based on the finite depth of liquid layer remaining at a particular time and some other parameters like initial heat flow and Stefan number etc. We solve the nonlinear coupled set of differential equations by Runge-Kutta-Fehlberg method and results for different parameters are compared for phase boundary movement.

To determine the association of trace elements and magnesium with risk of coronary artery disease (CAD) in rural and urban populations of India.Cross-sectional surveys on the randomly selected municipal streets in Moradabad city and one village in Moradabad tahsil in North India.There were 162 rural (86 men and 96 women) and 152 urban (80 men and 72 women) subjects between 26 to 65 years of age. Evaluations were obtained by physician- and dietitian-administered, validated questionnaires, physical examination, electrocardiogram and blood examination.The prevalence of CAD and coronary risk factors was 2.5 times higher in the urban population compared to rural subjects (8.6 vs. 3.0%). In rural subjects, dietary intakes and plasma levels of vitamins and minerals were comparable with those of urban subjects except for higher dietary intake of magnesium in rural subjects and higher plasma vitamin A level in urban subjects. In both rural and urban subjects, low serum zinc (80 +/− 82 vs. 110 +/− 11.0 micrograms/dl, p < 0.05) and magnesium levels (1.60 +/− 0.36 vs. 1.71 +/− 0.41 mEQ/L, p < 0.05) and lower zinc/copper ratio (0.58 +/− 0.08 vs. 1.11 +/− 0.25 p < 0.50) were inversely associated with CAD. Serum levels of copper and iron were significantly higher and plasma levels of antioxidant vitamins A, E and C and beta-carotene were significantly lower in patients with CAD compared to the rest of the subjects. In both rural (7.1 +/− 1.2 mg/day) and urban subjects (8.6 +/− 1.6 mg/day), zinc consumption was half of the recommended dietary allowances. Higher prevalence of CAD in urban compared to rural subjects was attributed to higher dietary fat intake and higher prevalence of risk factors in urban subjects.The findings suggest that lower serum levels of zinc and magnesium and lower zinc copper ratio were inversely associated with CAD. It is possible that urban populations with higher risk of CAD may benefit by decreasing dietary fat intake and by increasing their intake of foods rich in zinc and magnesium.

This paper presents a simple method for computing steady state probabilities at arbitrary and departure epochs of theM/G/1/K queue. The method is recursive and works efficiently for all service time distributions. The only input required for exact evaluation of state probabilities is the Laplace transform of the probability density function of service time. Results for theGI/M/1/K -1 queue have also been obtained from those ofM/G/1/K queue.

This paper presents a unified approach for the numerical solutions of anM/G/1 queue. On the assumption that the service-time distribution has a rational Laplace-Stieltjes transform (LST), explicit closed-form expressions have been obtained for moments, distributions of system length and waiting time (in queue) in terms of the roots of associated characteristic equations (c.e.'s). Approximate analyses for the tails of the distributions based on one or more roots are also discussed. Numerical aspects have been tested for a variety of complex service-time distributions including but not restricted to only mixed generalized Erlang and generalized hyperexponential. A sample of numerical computations is also included. It is hoped that the results obtained would prove to be beneficial to both practitioners and theorists dealing with bounds, inequalities, approximations, and other aspects.