Proportionate Mixing Research Articles

Separable mixing: The general formulation and a particular example focusing on mask efficiency.

The aim of this short note is twofold. First, we formulate the general Kermack-McKendrick epidemic model incorporating static heterogeneity and show how it simplifies to a scalar Renewal Equation (RE) when separable mixing is assumed. A key general feature is that all information about the heterogeneity is encoded in one nonlinear real valued function of a real variable. Next, we specialize the model ingredients so that we can study the efficiency of mask wearing as a non-pharmaceutical intervention to reduce the spread of an infectious disease. Our main result affirms that the best way to protect the population as a whole is to protect yourself. This qualitative insight was recently derived in the context of an SIR network model. Here, we extend the conclusion to proportionate mixing models incorporating a general function describing expected infectiousness as a function of time since infection.

AN AGE-STRUCTURED MODEL FOR PERTUSSIS TRANSMISSION WITH MULTIPLE INFECTIONS STUDYING THE EFFECTS OF CHILDHOOD DTAP AND ADOLESCENT TDAPVACCINES

An age-structured deterministic model with multiple infections that accounts for decaying maternal antibody, waning infection-acquired and vaccine-induced immunity is formulated to study the transmission dynamics of pertussis and the effect of childhood DTaP and adolescent Tdap vaccines. The expression of the reproduction number [Formula: see text] is derived for the ODE model in the case of proportionate mixing. Estimated age-dependent transmission probability and empirical contact data are used in the simulation of the ODE model from which the basic reproduction number [Formula: see text] is estimated to be around 15. The combination of DTaP and Tdap vaccines fails to bring [Formula: see text] under one and thus pertussis remains endemic despite sustained high coverage of vaccination. While both DTaP and Tdap vaccines have remarkable effect on reducing the incidences of the age groups being directly vaccinated, the adolescent booster dose Tdap is also found to provide some indirect protection for infants though very limited ([Formula: see text] incidence reduction).

Evaluating vaccination effectiveness of group-specific fractional-dose strategies

<p style='text-indent:20px;'>In this paper, we formulate a multi-group <i>SIR</i> epidemic model with the consideration of proportionate mixing patterns between groups and group-specific fractional-dose vaccination to evaluate the effects of fractionated dosing strategies on disease control and prevention in a heterogeneously mixing population. The basic reproduction number <inline-formula><tex-math id="M1">\begin{document}$ \mathscr{R}_0 $\end{document}</tex-math></inline-formula>, the final size of the epidemic, and the infection attack rate are used as three measures of population-level implications of fractionated dosing programs. Theoretically, we identify the basic reproduction number, <inline-formula><tex-math id="M2">\begin{document}$ \mathscr{R}_0 $\end{document}</tex-math></inline-formula>, establish the existence and uniqueness of the final size and the final size relation with <inline-formula><tex-math id="M3">\begin{document}$ \mathscr{R}_0 $\end{document}</tex-math></inline-formula>, and obtain explicit calculation expressions of the infection attack rate for each group and the whole population. Furthermore, the simulation results suggest that dose fractionation policies take positive effects in lowering the <inline-formula><tex-math id="M4">\begin{document}$ \mathscr{R}_0 $\end{document}</tex-math></inline-formula>, decreasing the final size and reducing the infection attack rate only when the fractional-dose influenza vaccine efficacy is high enough rather than just similar to standard-dose. We find evidences that fractional-dose vaccination in response to influenza vaccine shortages take negative community-level effects. Our results indicate that the role of fractional dose vaccines should not be overestimated even though fractional dosing strategies could extend the vaccine coverage.</p>

A review of NiO based composite electrode materials for electrochemical energy storage

At the present era supercapacitor is widely recognized as the most promising energy-storage device to meet the challenges of high power-supply, long cycle life and reliability. From literature it has well established that the electrode material is one of the significant components to determine their performance. In this regard, the three—dimensional hierarchical mesoporous unique NiO nanocomposites with large surface area, high electrical conductivity, low equivalent series resistance and possibility of advantageous proportionate mixing of suitable components, demonstrate substantial promise for high performance supercapacitor applications, because of synergistic effect. This review summarizes the NiO based nanocomposites for supercapacitor electrode materials as well as a brief overview regarding supercapacitors active electrode materials.

Age-specific social mixing of school-aged children in a US setting using proximity detecting sensors and contact surveys

Comparisons of the utility and accuracy of methods for measuring social interactions relevant to disease transmission are rare. To increase the evidence base supporting specific methods to measure social interaction, we compared data from self-reported contact surveys and wearable proximity sensors from a cohort of schoolchildren in the Pittsburgh metropolitan area. Although the number and type of contacts recorded by each participant differed between the two methods, we found good correspondence between the two methods in aggregate measures of age-specific interactions. Fewer, but longer, contacts were reported in surveys, relative to the generally short proximal interactions captured by wearable sensors. When adjusted for expectations of proportionate mixing, though, the two methods produced highly similar, assortative age-mixing matrices. These aggregate mixing matrices, when used in simulation, resulted in similar estimates of risk of infection by age. While proximity sensors and survey methods may not be interchangeable for capturing individual contacts, they can generate highly correlated data on age-specific mixing patterns relevant to the dynamics of respiratory virus transmission.

Slu-brick – An innovative sustainable solution for solid waste management

Abstract The population of Indian cities is increasing exponentially, which results in the use of more resources and on the other side, the generation of waste will also increase. The most commonly used masonry unit of a building material is brick. To overcome this issue of resource utilization and waste generation, civil engineers have been facing challenges to find a better solution. Research was carried out to obtain a useful construction and building material in the form of slu-brick from solid waste (sludge). Improper disposal of domestic sludge causes harmful effects on the environment that poses a major problem in urban cities. This study focuses on the use of sludge in production of brick since the chemical composition of sludge is similar to that of clay. Different series of sludge and various ingredients mixture proportions were studied where in varying sludge ratios starting from 5% to 30% of the total weight of mixture was added. Various physical test were carried out such as specific gravity, compressive strength, water absorption, fineness test as well as an environmental test were also conducted such as total coliform and E-Coli content. While testing various parameters it has been observed that slu-brick is good enough to use as construction materials compared to conventional brick as its strength is similar to the conventional brick when the sludge content is 30%. It was observed that good quality slu-brick can be produced up to 30% utilization of sludge in brick making. This study confirms that the waste sludge can act as a suitable material in the manufacture of slu-brick with proportionate mix and design. Thus to an extent clay can be replaced with sludge in the brick manufacturing, which helps in the conservation of naturally available resources and improves the environmental quality.

Modelling epidemics with fractional-dose vaccination in response to limited vaccine supply

The control strategies of emergency infectious diseases are constrained by limited medical resources. The fractional dose vaccination strategy as one of feasible strategies was proposed in response to global shortages of vaccine stockpiles. Although a variety of epidemic models have been developed under the circumstances of limited resources in treatment, few models particularly investigated vaccination strategies in resource-limited settings. In this paper, we develop a two-group SIR model with incorporation of proportionate mixing patterns and n-fold fractional dose vaccination related parameters to evaluate the efficiency of fractional dose vaccination on disease control at the population level. The existence and uniqueness of the final size of the two-group SIR epidemic model, the formulation of the basic reproduction number and the relationship between them are established. Moreover, numerical simulations are performed based on this two-group vector-free model to investigate the effectiveness of n-fold fractional dose vaccination by using the emergency outbreaks of yellow fever in Angola in 2016. By employing linear and nonlinear dose-response relationships, we compare the resulting fluctuations of four characteristics of the epidemics, which are the outbreak size, the peak time of the outbreak, the basic reproduction number and the infection attack rate (IAR). For both types of dose-response relationships, dose-fractionation takes positive effects in lowering the outbreak size, delay the peak time of the outbreak, reducing the basic reproduction number and the IAR of yellow fever only when the vaccine efficacy is high enough. Moreover, five-fold fractional dose vaccination strategy may not be the optimal vaccination strategy as proposed by the World Health Organization if the dose-response relationship is nonlinear.

Population-Level Sexual Mixing According to HIV Status and Preexposure Prophylaxis Use Among Men Who Have Sex With Men in Montreal, Canada: Implications for HIV Prevention.

Using cross-sectional survey data (Engage, 2017–2018) from 1,137 men who have sex with men, ≥16 years old, in Montreal, we compared observed human immunodeficiency virus (HIV) seroconcordance in previous-6-months’ sexual partnerships with what would have been observed by chance if zero individuals serosorted. Of 5 recent partnerships where both individuals were HIV-negative, we compared observed concordance in preexposure prophylaxis (PrEP) use with the counterfactual if zero individuals selected partners based on PrEP use. We estimated the concordance by chance using a balancing-partnerships approach assuming proportionate mixing. HIV-positive respondents had a higher proportion of HIV-positive partners (66.4%, 95% confidence interval (CI): 64.0, 68.6) than by chance (23.9%, 95% CI: 23.1, 24.7). HIV-negative respondents (both on and not on PrEP) had higher proportions of HIV-negative partners (82.9% (95% CI: 81.1, 84.7) and 90.7% (95% CI: 89.6, 91.7), respectively) compared with by chance (76.1%, 95% CI: 75.3, 76.9); however, those on PrEP had a higher proportion of HIV-positive partners than those not on PrEP (17.1% (95% CI: 15.3, 18.9) vs. 9.3% (95% CI: 8.3, 10.4). Those on PrEP also had a higher proportion of partners on PrEP among their HIV-negative partners (50.6%, 95% CI: 42.5, 58.8) than by chance (28.5%, 95% CI: 27.5, 29.4). The relationship between PrEP and sexual-mixing patterns demonstrated by less population-level serosorting among those on PrEP and PrEP-matching warrants consideration during PrEP roll-out.

Mycotoxins in uncooked and plate-ready household food from rural northern Nigeria

In order to understand the changes in toxic metabolite profiles in uncooked and cooked foods, samples of flour/grain (n = 40) and their corresponding plate-ready food (n = 39) were collected from 40 households in two states of northern Nigeria. The food samples were analyzed for multiple fungal metabolites by LC-MS/MS and daily intakes of mycotoxins in the diets were estimated and compared to established margin of exposure (MOE) and tolerable daily intake (TDI) values. Both food groups contained 65 fungal and plant metabolites, inclusive of 23 mycotoxins. The mean concentrations of aflatoxin B1, beauvericin, fumonisin B1 (FB1), FB2, FB3, hydrolysed FB1, moniliformin and nivalenol were significantly (p < 0.05) higher in flour than in the plate-ready food samples. The levels of several mycotoxins were higher in the flour samples than in plate-ready meals by 129–383%. The dilution effect from proportionate mixing of flour samples with water led to 48–100% reduction in detectable mycotoxins in flour to plate-ready meals. Aflatoxins and fumonisins co-occurred in 36% of the plate-ready foods. Exposures of households to aflatoxins and fumonisins based on 95% CI concentration of mycotoxins in the meals were high, suggesting potential health risks based on calculated low MOE and exceedence of stipulated TDI value, respectively.

Is it time for Universal Varicella Vaccination in Chile? A health economic analysis

Background: Although the Latin American Society of Pediatric Infectious Diseases (SLIPE) recommended adoption of Universal Varicella Vaccination (UVV) in 2016, UVV is not offered in Chile. In this study, we evaluate the health and economic impact of introducing UVV in Chile. Methods & Materials: A dynamic transmission model of varicella infection with proportionate mixing in a static population and force of infection varying over age, time, and vaccination status was adapted. Seroprevalence data from Argentina, indicating relatively low varicella virus transmission (with 15% of adults never been exposed to natural varicella), were used for calibration in the absence of available Chilean data. Healthcare resource utilization and costs were estimated from a recent study of the clinical characteristics and economic costs of hospitalized varicella patients in Chile. The Chilean immunization schedule currently has vaccination visits at 12 months, 18 months, and 6 years of age during which varicella vaccination could be offered; the following one- (1D) and two-dose (2D) vaccination strategies were considered (age at vaccination/vaccination coverage %): 1D-Early (12m/90%); 1D-Late (18m/85%); 2D-Early-Short (12m/90%, 18m/85%); 2D-Early-Long (12m/90%, 6y/85%); 2D-Late-Long (18m/85%, 6y/85%). Costs were evaluated in 2017 United States Dollars (USD) (1 USD = 633.527 Chilean Pesos). Costs and benefits were discounted at 3%; a 25-year time horizon was used. Results: The model estimates 185,419 varicella cases/year (incidence rate 1023/100,000) in Chile in the absence of UVV with 28 deaths per year. All vaccination strategies were cost saving. The most cost-saving strategy is 1D-Early. 1D-Early UVV will reduce the varicella case load by 87%/99.4%/99.5%/99.7% at 1/5/10/25 years after vaccination, and is estimated to save 3.6M/52M/109M/269M USD (discounted) respectively. Two-dose strategies are more effective, but more costly. Although two-dose strategies are cost effective compared to not vaccinating, the marginal incremental cost effectiveness compared to one-dose strategies is very high. 2D-short is the most effective and cost effective of the two-dose strategies, and can reduce breakthrough varicella by 65-75% compared to one-dose strategies. Conclusion: Both one- or two-dose UVV is estimated to be cost-saving in Chile. Because of historically low varicella transmission rates, UVV can rapidly and sustainably reduce the burden of varicella in Chile.

Use of Sludge Waste as Ingredient in Making of Brick

Waste may be defined as an unwanted material generated after the manufacturing process from industry, agriculture, or from house hold activity. Waste causes many nuisances in the environment. It produces many types of infection, for human and animal. The sludge from tannery effluent plants has problem of disposal. Dewatered sludge is disposed off by land filling. However, it is not an appropriate solution, due to the land limitation. The production of sludge in tannery effluent plant is about to increase every year. In addition, the constraint to treat sludge is very high in cost and time-consuming, which is the disadvantage to the responsible parties. Therefore, this study was carried out to utilize those sludge waste (SW) produced from the tannery effluent plant as a brick. The sludge brick (SB) mixtures were incorporated with many ratios of SW. Tests were conducted such as fineness test, specific gravity, water absorption and compressive strength. As the conclusion, brick with 20% utilization of SW is acceptable to produce good quality of brick. This study shows that the disposal of tannery sludge TSW would act as a suitable material for manufacturing of bricks with proportionate mix and design.

A Study on Compressive Strength Attributes of Jute Fiber Reinforced Cement Concrete Composites

The primary objective of this study is to investigate the effect of reinforcing raw jute fibers on the mechanical properties of cement concrete composites. The investigation helps to explore more on the variation of properties of concrete with jute fibers, its effective usage and to reduce the usage of polymer fibers which interns an environmental harm. In the present study, raw jute fibers cut to 10 mm were used with the proportionate mix of cement, coarse aggregate and sand with the water-cement ratio of 0.45. The mixed specimens are casted for different volume content of jute fibers (0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6% and 1.8%) and cured for 3, 7 and 28 days. It is observed that the compressive strength of casted concrete coupon is increased from 8.8 N/mm2 to a maximum of 44.44 N/mm2 due to the addition of jute fibers. The maximum compressive strength is obtained for a concrete coupon of fiber content 0.4%. As the fiber content increased from 0.4 % the compressive strength get reduced, causing poor workability of concrete.

PSS10 - The Benefits and Costs Of Different Scenarios for Varicella Vaccination in Chile

Universal childhood vaccination (UVV) against varicella has not been implemented in Chile. The benefits and costs of introducing UVV under various possible vaccination scenarios were explored through modelling. A dynamic transmission model of varicella infection, with proportionate mixing in a static population, and with time, age, and vaccination-status varying force of infection, was calibrated based on the Chilean population and Argentinean seroprevalence data. Rates of healthcare utilization and costs were from a recent observational study. Five vaccination strategies based on the current vaccination visits in the pediatric vaccination programme were considered, with first dose given at either 12 months (90% coverage) or 18 months (85% coverage), and a second dose either not administered, or given at 18 months (85% coverage)or 6 years (85% coverage). Three different types of varicella vaccines (highly-, moderately-, and weakly-effective) were hypothesized. The resulting 15 vaccination scenarios were compared to a no-vaccination scenario. Benefits and costs were calculated from the payer and societal perspectives over a 25-year time horizon, and discounted at 3% annually. The model estimated over 200,000 varicella cases annually in Chile in the absence of varicella vaccination. All vaccination scenarios reduced the number of cases by 86.0-99.7% and all were cost-saving. One-dose strategies with a highly- or moderately-effective vaccine were the most cost-saving scenarios, saving $239M-$252M over 25 years. Cost-benefit ratios were 2.63-3.53 for one-dose and 1.92-2.52 for two-dose scenarios. The optimum vaccination scenario from a cost perspective was one dose at 12 months with 90% coverage; two doses given at 12 and 18 months reduced morbidity and mortality the most. Both one- and two-dose UVV programs are predicted to be cost-saving in Chile. The optimum strategy based on cost-benefit ratios from a societal perspective is vaccination with a single dose of a highly- or moderately-effective varicella vaccine at 12 months.

Constrained minimization problems for the reproduction number in meta-population models.

The basic reproduction number ([Formula: see text]) can be considerably higher in an SIR model with heterogeneous mixing compared to that from a corresponding model with homogeneous mixing. For example, in the case of measles, mumps and rubella in San Diego, CA, Glasser et al. (Lancet Infect Dis 16(5):599-605, 2016. https://doi.org/10.1016/S1473-3099(16)00004-9 ), reported an increase of 70% in [Formula: see text] when heterogeneity was accounted for. Meta-population models with simple heterogeneous mixing functions, e.g., proportionate mixing, have been employed to identify optimal vaccination strategies using an approach based on the gradient of the effective reproduction number ([Formula: see text]), which consists of partial derivatives of [Formula: see text] with respect to the proportions immune [Formula: see text] in sub-groups i (Feng et al. inJ Theor Biol 386:177-187,2015. https://doi.org/10.1016/j.jtbi.2015.09.006 ; Math Biosci 287:93-104,2017. https://doi.org/10.1016/j.mbs.2016.09.013 ). These papers consider cases in which an optimal vaccination strategy exists. However, in general, the optimal solution identified using the gradient may not be feasible for some parameter values (i.e., vaccination coverages outside the unit interval). In this paper, we derive the analytic conditions under which the optimal solution is feasible. Explicit expressions for the optimal solutions in the case of [Formula: see text] sub-populations are obtained, and the bounds for optimal solutions are derived for [Formula: see text] sub-populations. This is done for general mixing functions and examples of proportionate and preferential mixing are presented. Of special significance is the result that for general mixing schemes, both [Formula: see text] and [Formula: see text] are bounded below and above by their corresponding expressions when mixing is proportionate and isolated, respectively.

Evolution of chemical and biological characterization during agitated pile composting of flower waste

PurposeFlower waste dumping in landfills and other disposal sites is causing major environmental issues due to its highly biodegradable nature. Instead, flower waste can be successfully composted for its higher nutrient value. Therefore, this study evaluated the pile composting of flower waste with different combinations of cow dung and saw dust to produce stabilized compost.MethodsFive agitated piles of flower waste mixture were formed in trapezoidal shape to perform the composting. Pile (P0) was a control experiment, which contained 100 kg flower waste. The quantity of flower waste mixture with cow dung and saw dust in the other Piles was a total of 100 kg i.e. P1 (50:40:10) kg, P2 (60:30:10) kg, P3 (70:20:10) kg and P4 (80:10:10) kg, respectively.ResultsTemperature above 50 °C was observed in all the piles except in P0. Physico-chemical characteristics of compost showed a stabilized compost obtained by proportionate mix of flower waste, cow dung and saw dust. Pile P2 was observed with pH 7.23 and electrical conductivity 3.98 mS cm−1, total organic carbon 30.9%, total nitrogen 2.31% and C:N ratio 14, thus a good proportion for compost amongst all the piles.ConclusionsAppropriate proportion of waste mixture played an important role in providing favorable conditions for the microbial transformation of flower waste to stabilized compost. Temperature influenced the growth of microbes and maximum temperature was helpful in fast degradation of organic matter. Finally, flower waste with a combination of cow dung and saw dust was found to be successful during pile composting.

Modeling optimal treatment strategies in a heterogeneous mixing model.

BackgroundMany mathematical models assume random or homogeneous mixing for various infectious diseases. Homogeneous mixing can be generalized to mathematical models with multi-patches or age structure by incorporating contact matrices to capture the dynamics of the heterogeneously mixing populations. Contact or mixing patterns are difficult to measure in many infectious diseases including influenza. Mixing patterns are considered to be one of the critical factors for infectious disease modeling.MethodsA two-group influenza model is considered to evaluate the impact of heterogeneous mixing on the influenza transmission dynamics. Heterogeneous mixing between two groups with two different activity levels includes proportionate mixing, preferred mixing and like-with-like mixing. Furthermore, the optimal control problem is formulated in this two-group influenza model to identify the group-specific optimal treatment strategies at a minimal cost. We investigate group-specific optimal treatment strategies under various mixing scenarios.ResultsThe characteristics of the two-group influenza dynamics have been investigated in terms of the basic reproduction number and the final epidemic size under various mixing scenarios. As the mixing patterns become proportionate mixing, the basic reproduction number becomes smaller; however, the final epidemic size becomes larger. This is due to the fact that the number of infected people increases only slightly in the higher activity level group, while the number of infected people increases more significantly in the lower activity level group. Our results indicate that more intensive treatment of both groups at the early stage is the most effective treatment regardless of the mixing scenario. However, proportionate mixing requires more treated cases for all combinations of different group activity levels and group population sizes.ConclusionsMixing patterns can play a critical role in the effectiveness of optimal treatments. As the mixing becomes more like-with-like mixing, treating the higher activity group in the population is almost as effective as treating the entire populations since it reduces the number of disease cases effectively but only requires similar treatments. The gain becomes more pronounced as the basic reproduction number increases. This can be a critical issue which must be considered for future pandemic influenza interventions, especially when there are limited resources available.

A Note on Proportionate Mixing Assumption Revisited for a Model with Vertical Transmission

We conditionally extend formulas of(Dietz and Schenzle, J. Math. Biol. 22: 117-120,1995) for the ”transmission potential” of an immunizing infection with pre-infection possible before birth and vertical transmission admitted. We look for minimum proportion to be covered to reduce basic reproduction rate below 1 by acting through vaccination. We present also a new criterion allowing the selection of an immunizing vaccination strategy by bringing the reproduction number below 1. We find that reduce vertical transmission, adds chances to eradicate disease. Moreover reduce age of vaccination reduces the minimum vaccination coverage inducing global immunization against disease by bringing down the basic reproduction number.

The social benefits of private infectious disease-risk mitigation

Does society benefit from private measures to mitigate infectious disease risks? Since mitigation reduces both peak prevalence and the number of people who fall ill, the answer might appear to be yes. But mitigation also prolongs epidemics and therefore the time susceptible people engage in activities to avoid infection. These avoidance activities come at a cost—in lost production or consumption, for example. Whether private mitigation yields net social benefits depends on the social weight given to the costs of illness and illness avoidance, now and into the future. We show that, for a large class of infectious diseases, private risk mitigation is socially beneficial. However, in cases where society discounts the future at either very low or very high rates relative to private individuals, or where it places a low weight on the private cost of illness, the social cost of illness under proportionate mixing (doing nothing) may be lower than the social cost of illness under preferential mixing (avoiding infectious individuals). That is, under some circumstances, society would prefer shorter, more intense epidemics without avoidance costs over longer, less intense epidemics with avoidance costs. A sobering (although not surprising) implication of this is that poorer societies should be expected to promote less private disease-risk mitigation than richer societies.

Estimation of the HIV Basic Reproduction Number in Rural South West Uganda: 1991–2008

BackgroundThe basic reproduction number, , is one of the many measures of the epidemic potential of an infection in a population. We estimate HIV over 18 years in a rural population in Uganda, examine method-specific differences in estimated , and estimate behavioural changes that would reduce below one.MethodsData on HIV natural history and infectiousness were collated from literature. Data on new sexual partner count were available from a rural clinical cohort in Uganda over 1991–2008. was estimated using six methods. Behavioural changes required to reduce below one were calculated.ResultsReported number of new partners per year was 0 to 16 (women) and 0 to 80 (men). When proportionate sexual mixing was assumed, the different methods yielded comparable estimates. Assuming totally assortative mixing led to increased estimates in the high sexual activity class while all estimates in the low-activity class were below one. Using the “effective” partner change rate introduced by Anderson and colleagues resulted in estimates all above one except in the lowest sexual activity class. could be reduced below one if: (a) medium risk individuals reduce their partner acquisition rate by 70% and higher risk individuals reduce their partner acquisition rate by 93%, or (b) higher risk individuals reduce the partner acquisition rate by 95%.ConclusionsThe estimated depended strongly on the method used. Ignoring variation in sexual activity leads to an underestimation of . Relying on behaviour change alone to eradicate HIV may require unrealistically large reductions in risk behaviour, even though for a small proportion of the population. To control HIV, complementary prevention strategies such as male circumcision and HIV treatment services need rapid scale up.

Impact of Bundle Structure on Performance of on-Chip CNT Interconnects

CNTs are proposed as a promising candidate against copper in deep submicron IC interconnects. Still this technology is in its infancy. Most available literatures on performance predictions of CNT interconnects, have focused only on interconnect geometries using segregated CNTs. Yet during the manufacturing phase, CNTs are obtained usually as a mixture of single-walled and multi-walled CNTs (SWCNTs and MWCNTs). Especially in case of SWCNTs; it is usually available as a mixture of both Semi conducting CNTs and metallic CNTs. This paper attempts to answer whether segregation is inevitable before using them to construct interconnects. This paper attempt to compare the performance variations of bundled CNT interconnects, where bundles are made of segregated CNTs versus mixed CNTs, for future technology nodes using electrical model based analysis. Also a proportionate mixing of different CNTs has been introduced so as to yield a set of criteria to aid the industry in selection of an appropriate bundle structure for use in a specific application with optimum performance. It was found that even the worst case performance of geometries using a mixture of SWCNTs and MWCNTs was better than copper. These results also reveal that, for extracting optimum performance vide cost matrix, the focus should be more on diameter controlled synthesis than on segregation.