310 research outputs found
Opportunities for investment in the societal values provided by Sanjay Gandhi National Park, India
Sanjay Gandhi National Park (SGNP), surrounded by the megacity of Mumbai, India, is subject to high anthropogenic pressures. However, it constitutes an important âgreen lungâ and water source, supporting biodiversity, tourism, recreation and additional benefits both locally and remotely. To safeguard and enhance the Park ecosystem, there is a need to recognise and demonstrate the diversity of values associated with these multiple benefits, potential conflicts, and management measures necessary to protect them. This study explores outcomes from SGNP across a systemically connected range of ecosystem services, and the geographical scales over which service benefits accrue. This informs potential novel âpayment for ecosystem servicesâ (PES) opportunities. The protected status of the landscape is reflected in low values from provisioning services (material or energy exploitation), but substantial values from supporting (such as habitat for wildlife), regulating (including global climate, microclimate and hydrological regulation) and cultural (particularly tourism) services. However, direct resource exploitation by communities inhabiting the Park is limited. Some ecosystem services were identified as ready for PES implementation (for example water supply), others require further development (including contributions to peripheral urban microclimate), through many services have no or limited PES potential (such as wood or aggregate extraction, prohibited under Park regulations)
Honeypot Allocation for Cyber Deception in Dynamic Tactical Networks: A Game Theoretic Approach
Honeypots play a crucial role in implementing various cyber deception
techniques as they possess the capability to divert attackers away from
valuable assets. Careful strategic placement of honeypots in networks should
consider not only network aspects but also attackers' preferences. The
allocation of honeypots in tactical networks under network mobility is of great
interest. To achieve this objective, we present a game-theoretic approach that
generates optimal honeypot allocation strategies within an attack/defense
scenario. Our proposed approach takes into consideration the changes in network
connectivity. In particular, we introduce a two-player dynamic game model that
explicitly incorporates the future state evolution resulting from changes in
network connectivity. The defender's objective is twofold: to maximize the
likelihood of the attacker hitting a honeypot and to minimize the cost
associated with deception and reconfiguration due to changes in network
topology. We present an iterative algorithm to find Nash equilibrium strategies
and analyze the scalability of the algorithm. Finally, we validate our approach
and present numerical results based on simulations, demonstrating that our game
model successfully enhances network security. Additionally, we have proposed
additional enhancements to improve the scalability of the proposed approach.Comment: This paper accepted in 14th International Conference on Decision and
Game Theory for Security, GameSec 202
Semi-analytical Solution for Multiphase Fluid Flow Applied to CO2 Sequestration in Geologic Porous Media
The increasing concentration of CO_(2) has been linked to global warming and changes in climate. Geologic sequestration of CO_(2) in deep saline aquifers is a proposed greenhouse gas mitigation technology with potential to significantly reduce atmospheric emissions of CO_(2). Feasibility assessments of proposed sequestration sites require realistic and computationally efficient models to simulate the subsurface pressure response and monitor the injection process, and quantify the risks of leakage if there is any. This study investigates the possibility of obtaining closed form expressions for spatial distribution of CO_(2) injected in brine aquifers and gas reservoirs.
Four new semi-analytical solutions for CO_(2) injection in brine aquifers and gas reservoirs are derived in this dissertation. Both infinite and closed domains are considered in the study. The first solution is an analysis of CO_(2) injection into an initially brine-filled infinite aquifer, exploiting selfâsimilarity and matched asymptotic expansion. The second is an expanding to the first solution to account for CO_(2) injection into closed domains. The third and fourth solutions are analyzing the CO_(2) injection in infinite and closed gas reservoirs. The third and fourth solutions are derived using Laplace transform. The brine aquifer solutions accounted for both Darcyian and non-Darcyian flow, while, the gas reservoir solutions considered the gas compressibility variations with pressure changes.
Existing analytical solutions assume injection under constant rate at the wellbore. This assumption is problematic because injection under constant rate is hard to maintain, especially for gases. The modeled injection processes in all aforementioned solutions are carried out under constant pressure injection at the wellbore (i.e. Dirichlet boundary condition). One major difïŹculty in developing an analytical or semi-analytical solution involving injection of CO_(2) under constant pressure is that the flux of CO_(2) at the wellbore is not known. The way to get around this obstacle is to solve for the pressure wave first as a function of flux, and then solve for the flux numerically, which is subsequently plugged back into the pressure formula to get a closed form solution of the pressure. While there is no simple equation for wellbore flux, our numerical solutions show that the evolution of flux is very close to a logarithmic decay with time. This is true for a large range of the reservoir and CO_(2) properties.
The solution is not a formation specific, and thus is more general in nature than formation-specific empirical relationships. Additionally, the solution then can be used as the basis for designing and interpreting pressure tests to monitor the progress of CO_(2) injection process. Finally, the infinite domain solution is suitable to aquifers/reservoirs with large spatial extent and low permeability, while the closed domain solution is applicable to small aquifers/reservoirs with high permeability
Influence of Using Fly ash and Silica Fume on the Concrete Performance against Chloride Attack
This paper is part of a research project deals with the study of the possible use of by-product materials such as fly ash (FA) and silica fume (SF) with Ordinary Portland Cement (OPC) in ternary system in different applicable measured properties of concrete. In this research, six concrete mixtures with water/cement ratios 0.4 and 0.5 have been investigated. Trial mixes were carried out to produce concrete with same slump and air content percentage. Also the influence of using fly ash and silica fume with Portland cement on the concrete performance against chloride attack has been studied. The potentiometric apparatus was used to measure the chloride concentrations through the concrete samples by titration chemical analysis. In addition, the diffusion coefficients were determined for the tested specimens. It is concluded that the addition of fly ash and silica fume to Portland cement in ternary system improved concrete resistance to chloride attack and reduced its diffusion coefficient as well as can be reasonably used in concrete industry with considerable proportions. Moreover, the change in the cementitious materials content, type and their replacement percent has significant effect in the studied properties of concrete. Furthermore, results show that the total and soluble chloride content for zone 10~20 mm and zone 20~30 mm are very low .This results leads that such type of concrete needs less concrete cover depth which leads to protect the reinforcement
Screw nail medialization of arytenoid in unilateral adductor vocal cord paralysis: A new office procedure
AbstractObjectivesThe aim of this study is to describe and evaluate new technique for treatment of unilateral vocal cord paralysis giving the same results of the standard procedure but minimizing the surgical trauma.Patients and methodsA prospective study was carried out between November 2009 and November 2011 in the Otorhinolaryngology Department, Zagazig University Hospitals, Egypt. It included 12 patients with unilateral idiopathic vocal cord paralysis who were managed by this new technique. Preoperative and postoperative video-laryngoscopy was done, maximal phonation time was calculated and ratings grade of dysphonia was compared.ResultsPostoperative video-laryngoscopy relieved complete glottic gap closure in 83.3% of cases and partial glottic gap in the remaining 16.7% of cases. The mean preoperative maximal phonation time was 9.42s and the postoperative value was 21.5s with a mean difference of 11.6s. The rating of the grade of dysphonia showed great improvement in the patientâs voice quality from severe dysphonia preoperatively to normal or near-normal voice postoperatively. All patients were satisfied with the results of the procedure except one patient (8.3%).ConclusionThe screw nail medialization technique gives a good reliable and easy procedure under local anesthesia for managing unilateral vocal cord paralysis and avoids the disadvantages of infection laryngoplasty and medialization thyroplasty using implants
Cost-effectiveness of malaria diagnosis using rapid diagnostic tests compared to microscopy or clinical symptoms alone in Afghanistan
Background
Improving access to parasitological diagnosis of malaria is a central strategy for control and elimination of the disease. Malaria rapid diagnostic tests (RDTs) are relatively easy to perform and could be used in primary level clinics to increase coverage of diagnostics and improve treatment of malaria.<p></p>
Methods
A cost-effectiveness analysis was undertaken of RDT-based diagnosis in public health sector facilities in Afghanistan comparing the societal and health sector costs of RDTs versus microscopy and RDTs versus clinical diagnosis in low and moderate transmission areas. The effect measure was âappropriate treatment for malariaâ defined using a reference diagnosis. Effects were obtained from a recent trial of RDTs in 22 public health centres with cost data collected directly from health centres and from patients enrolled in the trial. Decision models were used to compare the cost of RDT diagnosis versus the current diagnostic method in use at the clinic per appropriately treated case (incremental cost-effectiveness ratio, ICER).<p></p>
Results
RDT diagnosis of Plasmodium vivax and Plasmodium falciparum malaria in patients with uncomplicated febrile illness had higher effectiveness and lower cost compared to microscopy and was cost-effective across the moderate and low transmission settings. RDTs remained cost-effective when microscopy was used for other clinical purposes. In the low transmission setting, RDTs were much more effective than clinical diagnosis (65.2% (212/325) vs 12.5% (40/321)) but at an additional cost (ICER) of US2.5 and household cost of US$2.0. Sensitivity analysis, which varied drug costs, indicated that RDTs would remain cost-effective if artemisinin combination therapy was used for treating both P. vivax and P. falciparum. Cost-effectiveness of microscopy relative to RDT is further reduced if the former is used exclusively for malaria diagnosis. In the health service setting of Afghanistan, RDTs are a cost-effective intervention compared to microscopy.<p></p>
Conclusions
RDTs remain cost-effective across a range of drug costs and if microscopy is used for a range of diagnostic services. RDTs have significant advantages over clinical diagnosis with minor increases in the cost of service provision.<p></p>
Malaria "diagnosis" and diagnostics in Afghanistan.
In many malaria-endemic areas, including Afghanistan, overdiagnosis of malaria is common. Even when using parasite-based diagnostic tests prior to treatment, clinicians commonly prescribe antimalarial treatment following negative test results. This practice neglects alternative causes of fever, uses drugs unnecessarily, and might contribute to antimalarial drug resistance. We undertook a qualitative study among health workers using different malaria diagnostic methods in Afghanistan to explore perceptions of malaria diagnosis. Health workers valued diagnostic tests for their ability to confirm clinical suspicions of malaria via a positive result, but a negative result was commonly interpreted as an absence of diagnosis, legitimizing clinical diagnosis of malaria and prescription of antimalarial drugs. Prescribing decisions reflected uncertainty around tests and diagnosis, and were influenced by social- and health-system factors. Study findings emphasize the need for nuanced and context-specific guidance to change prescriber behavior and improve treatment of malarial and nonmalarial febrile illnesses
Routine versus selective plasma exchange before thymectomy in myasthenia gravis
Background: Prethymectomy plasma exchange may improve the outcome of surgery; however, the technique is associated with an increased risk of complications. Therefore, the objective of this study was to compare selective versus routine plasma exchange before thymectomy in patients with myasthenia gravis.
Method: We conducted a prospective multi-center cohort study to compare two protocols for plasma exchange before thymectomy. We compared the routine plasma exchange in all patients undergoing thymectomy for myasthenia gravis (group I; n= 30) versus selective exchange (Group II; n= 30). Endpoints were the duration of postoperative mechanical ventilation, plasma exchange, and operative complications.
Results: There was no difference in age between both groups (30± 10.1 vs. 29± 9.2 years in Group I and II, respectively; p= 0.69). There were 17 females in Group I (56.67%) vs. 16 in group II (53.33%) (p= 0.8). Comorbidities are comparable between groups. All patients preoperative pyridostigmine, and 27 patients (90%) in Group I and 26 patients (87%) in Group II received glucocorticoids. There was no difference in pulmonary function tests between groups. Plasma exchange related complications were not different between groups. Immediate extubation was achieved in 29 patients (97%) in Group II, and after 6 hours in one patient (3.33%). In Group I, 28 patients (93%) extubated immediately, and two patients were ventilated for 7-12 hours. The mean ICU stay was 1.5 days in Group I and 1.4 days in group II (p= 0.615). The mean hospital stay was 8.5 days in Group I and 9.2 days in group II (p= 0.118). There was no significant difference in pathology between groups (p= 0.137).
Conclusion: Selective plasma exchange is feasible before thymectomy for myasthenia gravis. Selective plasma exchange may decrease exchange related complications without affecting the operative outcomes
The Implicit Keller Box Scheme for Combined Heat and Mass Transfer of BrinkmanâType Micropolar Nanofluid with Brownian Motion and Thermophoretic Effect Over an Inclined Surface
The main purpose of the present analysis is to report the numerical solution of the thermal radiations and magnetohydrodynamic (MHD) effect on the flow of micropolar nanofluid. Further, the effect of Brownian motion and thermophoresis on the flow field are also elucidated. The combined phenomenon of heat and mass transfer is considered. Compatible similarities are implemented for the conversion of nonlinear ordinary differential equations from nonlinear partial differential equations. The numerical solution of the governing differential equations is obtained via the implicit Keller box technique. This is an efficient scheme based on the finite difference method. Findings demonstrate that the heat and mass exchange reduce with growth of the Brinkman parameter, whereas the wall shear stress enhances with improving the magnitude of the Brinkman factor. The temperature contour enhances when the radiation parameter reaches its peak, which is useful for industrial processes. The heat and mass flow rates decrease against higher magnitudes of inclinatio
Cost-effectiveness of malaria diagnosis using rapid diagnostic tests compared to microscopy or clinical symptoms alone in Afghanistan.
BACKGROUND: Improving access to parasitological diagnosis of malaria is a central strategy for control and elimination of the disease. Malaria rapid diagnostic tests (RDTs) are relatively easy to perform and could be used in primary level clinics to increase coverage of diagnostics and improve treatment of malaria. METHODS: A cost-effectiveness analysis was undertaken of RDT-based diagnosis in public health sector facilities in Afghanistan comparing the societal and health sector costs of RDTs versus microscopy and RDTs versus clinical diagnosis in low and moderate transmission areas. The effect measure was 'appropriate treatment for malaria' defined using a reference diagnosis. Effects were obtained from a recent trial of RDTs in 22 public health centres with cost data collected directly from health centres and from patients enrolled in the trial. Decision models were used to compare the cost of RDT diagnosis versus the current diagnostic method in use at the clinic per appropriately treated case (incremental cost-effectiveness ratio, ICER). RESULTS: RDT diagnosis of Plasmodium vivax and Plasmodium falciparum malaria in patients with uncomplicated febrile illness had higher effectiveness and lower cost compared to microscopy and was cost-effective across the moderate and low transmission settings. RDTs remained cost-effective when microscopy was used for other clinical purposes. In the low transmission setting, RDTs were much more effective than clinical diagnosis (65.2% (212/325) vs 12.5% (40/321)) but at an additional cost (ICER) of US2.5 and household cost of US$2.0. Sensitivity analysis, which varied drug costs, indicated that RDTs would remain cost-effective if artemisinin combination therapy was used for treating both P. vivax and P. falciparum. Cost-effectiveness of microscopy relative to RDT is further reduced if the former is used exclusively for malaria diagnosis. In the health service setting of Afghanistan, RDTs are a cost-effective intervention compared to microscopy. CONCLUSIONS: RDTs remain cost-effective across a range of drug costs and if microscopy is used for a range of diagnostic services. RDTs have significant advantages over clinical diagnosis with minor increases in the cost of service provision. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov under identifier NCT00935688
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