225 research outputs found

    AN ADVECTION–DILUTION MODEL TO ESTIMATE CONDUIT GEOMETRY AND FLOW

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    As conduit water carries pollutants introduced from a point recharge downgradient, a contaminant-free seepage from the surrounding limestone is added into the conduit water and actively dilutes the pollutants. In this study, the transport with advection and this active dilution but no dispersion, is solved using the method of characteristics. The complete solution considering initial condition, boundary condition, and production is presented. Scale analysis reveals that the model is applicable when injection of pollutants at sinkholes persists long enough but unsuitable for analysis of dye tracing experiments. An approach combining the model with dye tracing experiment is used to quickly estimate the geometry and flow of a major conduit from Ames Sink to Wakulla Spring, Northwest Florida

    A simple diagnostic model to estimate total sink recharge based on dye tracing experiments

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    Dye tracing experiments are an active, effective and promising approach to investigate karst aquifers. In this paper, we develop a simple diagnostic model for calculating total recharge of sinks using dye tracing results. The conceptual model is that all sinks are convergent to a major conduit which then branches into several conduits and finally to several springs. Under the assumption that advection is dominant over dispersion at springs, breakthrough curve at a single spring can be used to calculate total recharge. The model is advantageous in that for such a conduit network, it is not necessary to measure breakthrough curves at all springs. Then the model with two dye tracing experiments is used to infer the conduit network in a karst aquifer in Luxi, southwest China. This paper represents a preliminary effort aiming to using dye tracing results to calculate the total recharge of sinks and infer the network of conduits.Preprost model izračuna celokupnega napajanja kraškega sistema na osnovi sledilne krivuljeSledenje podzemnih voda z umetnimi barvili je učinkovita tehnika raziskav kraških vodonosnikov. V članku razvijemo enostaven model za izračun celokupnega napajanja ponorov iz rezultatov sledenj. Model predpostavlja, da se voda, ki v sistem vstopa skozi več ponornih točk, najprej združi v glavnem prevodniku in kasneje razteka na več izvirov. Če predpostavimo prevladujoč advekcijski prenos sledila, lahko celokupen dotok v sistem izračunamo iz sledilne krivulje enega samega izvira. Model uporabimo pri obravnavi dveh sledenj na območju Luxi v JZ Kitajski. V članku predstavimo prve rezultate raziskav, s katerimi na osnovi sledenj poskušamo določiti celotni dotok v kraški sistem in sklepati o geometriji mreže kraških kanalov.

    Gaussian filter to process tracer breakthrough curves

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    Breakthrough curves in hydrogeology are similar to seismograms in containing a variety of undesired noises and regular interferences characterized with high frequency. In this paper, Gaussian filter for processing seismic waves is used to retain low-frequency trend of breakthrough curves and remove away high-frequency fluctuations. At first, the mathematical fundamental of the filter is introduced. Then the filter is applied to process four breakthrough curves measured in laboratory experiments, in which Gaussian parameter is set to be 0.2 and 0.5. Finally, a breakthrough curve in field test is processed with different Gaussian parameters. The results demonstrate how the parameter controls the cutting-off frequency and the filter is well controllable and very efficient in acquiring the primary trend of the curves.Key words: Gaussian filter; convolution; breakthrough curves, cutting-off frequency, noises.Analiza sledilnih krivulj z Gaussovimi filtriSledilne krivulje (krivulja časovne odvisnosti koncentracije povrnjenega sledila) v hidrogeologiji so podobno kot seizmogrami v geofiziki obremenjene z nezaželenimi visokofrekvenčnimi šumi in interferencami. V tem članku uporabimo Gaussov filter, primarno namenjen obdelavi seizmičnih podatkov, za odstanitev visokofrekvenčnih šumov iz sledilnih krivulj. Najprej predstavimo matematične osnove filtriranja, potem Gaussov filter z parametrom 0,2 in 0,5 uporabimo na štirih sledilnih krivuljah, dobljenih v laboratorijskih pogojih. Na koncu z različnimi Gaussovimi parametri obravnavamo sledilno krivuljo, dobljeno pri sledenju v naravi. Z rezultati prikažemo vpliv izbranih parametrov na mejno frekvenco ter prilagodljivost , učinkovitost in uporabnost filtra za izluščenje primarnih značilnosti sledilnih krivulj.Ključne besede: Gaussov filter, konvolucija, sledilne krivulje, mejne frekvence, šum

    The resilience of interdependent transportation networks under targeted attack

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    Modern world builds on the resilience of interdependent infrastructures characterized as complex networks. Recently, a framework for analysis of interdependent networks has been developed to explain the mechanism of resilience in interdependent networks. Here we extend this interdependent network model by considering flows in the networks and study the system's resilience under different attack strategies. In our model, nodes may fail due to either overload or loss of interdependency. Under the interaction between these two failure mechanisms, it is shown that interdependent scale-free networks show extreme vulnerability. The resilience of interdependent SF networks is found in our simulation much smaller than single SF network or interdependent SF networks without flows.Comment: 5 pages, 4 figure

    Formal Analysis of Fairness for Optimistic Multiparty Contract Signing Protocol

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    Optimistic multiparty contract signing (OMPCS) protocols are proposed for exchanging multiparty digital signatures in a contract. Compared with general two-party exchanging protocols, such protocols are more complicated, because the number of protocol messages and states increases considerably when signatories increase. Moreover, fairness property in such protocols requires protection from each signatory rather than from an external hostile agent. It thus presents a challenge for formal verification. In our analysis, we employ and combine the strength of extended modeling language CSP# and linear temporal logic (LTL) to verify the fairness of OMPCS protocols. Furthermore, for solving or mitigating the state space explosion problem, we set a state reduction algorithm which can decrease the redundant states properly and reduce the time and space complexity greatly. Finally, this paper illustrates the feasibility of our approach by analyzing the GM and CKS protocols, and several fairness flaws have been found in certain computation times

    Parameter Identifiability and Redundancy in a General Class of Stochastic Carcinogenesis Models

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    Background Heidenreich et al. (Risk Anal 1997 17 391–399) considered parameter identifiability in the context of the two-mutation cancer model and demonstrated that combinations of all but two of the model parameters are identifiable. We consider the problem of identifiability in the recently developed carcinogenesis models of Little and Wright (Math Biosci 2003 183 111–134) and Little et al. (J Theoret Biol 2008 254 229–238). These models, which incorporate genomic instability, generalize a large number of other quasi-biological cancer models, in particular those of Armitage and Doll (Br J Cancer 1954 8 1–12), the two-mutation model (Moolgavkar et al. Math Biosci 1979 47 55–77), the generalized multistage model of Little (Biometrics 1995 51 1278–1291), and a recently developed cancer model of Nowak et al. (PNAS 2002 99 16226–16231). Methodology/Principal Findings We show that in the simpler model proposed by Little and Wright (Math Biosci 2003 183 111–134) the number of identifiable combinations of parameters is at most two less than the number of biological parameters, thereby generalizing previous results of Heidenreich et al. (Risk Anal 1997 17 391–399) for the two-mutation model. For the more general model of Little et al. (J Theoret Biol 2008 254 229–238) the number of identifiable combinations of parameters is at most less than the number of biological parameters, where is the number of destabilization types, thereby also generalizing all these results. Numerical evaluations suggest that these bounds are sharp. We also identify particular combinations of identifiable parameters. Conclusions/Significance We have shown that the previous results on parameter identifiability can be generalized to much larger classes of quasi-biological carcinogenesis model, and also identify particular combinations of identifiable parameters. These results are of theoretical interest, but also of practical significance to anyone attempting to estimate parameters for this large class of cancer models

    The Role of Paragus quadri-fasciatus Meigen on Aphid Control and the Observations of its Biological Characteristics

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    Four-strip small syrphid fly, Paragus quadri-fasciatus Meigen is the important natural enemy of aphids in our region. A fly can eat about 800 aphids during its whole life. There are more than 10 kinds of aphids can be food of this fly, such as soybean aphid, Chinese sorghum aphid and radish aphid etc. The fly has 3~4 generations each year in Tonghua county, Jilin province. The adult of the first generation appears after the last ten-day period of April each year. It takes 30~35 days to complete one generation. The fly can oviposit 84~124 eggs in its whole life. Major natural enemies of the fly are ichneumon wasps, spiders, lacewings and etc.Originating text in Chinese.Citation: Gao, Junfeng, Jiang, Lianfeng, Zhang, Guangxin, Li, Chunshan, Zhao, Guangquan. (1996). The Role of Paragus quadri-fasciatus Meigen on Aphid Control and the Observations of its Biological Characteristics. Journal of Jilin Agricultural Sciences, 5(2), 60-61

    Liminality and festivals - Insights from the East

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    This research extends our knowledge of liminality through investigating how the liminal experiences of festival-goers are constructed in a Chinese music festival context. The research employs a multi-site data collection approach undertaking field observations and 68 in-depth semi-structured interviews at seven music festivals across three years. The study contributes to the theoretical development of a liminality framework by providing empirical evidence of the nature of liminality. It extends our understanding of event tourist experiences by highlighting the development and role of three types of communitas and identifying six stages within a rite of passage. The resulting multifaceted coexistence of liminal behaviours and identity with everyday routine life provides a new approach to the critical understanding of the role of liminality

    Dihydropyrano[2,3-c]pyrazole-induced apoptosis in lung cancer cells is associated with ROS generation and activation of p38/JNK pathway

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    Purpose: To investigate the effect of 2,4-dihydropyrano[2,3-c]pyrazole (DHPP) on lung cancer cells, and the associated mechanism.Methods: The effect of DHPP on cell proliferation was measured using sulphorhodamine B (SRB) assay. Apoptosis of cells was determined using Olympus IX71 inverted microscope connected to FITC and rhodamine filters.Results: DHPP significantly suppressed the proliferation of A549 and H1299 cells at doses of 0.5-8.0 μM, but did not affect normal cells (MRC5 and BEAS-2B). In DHPP-treated A549 and H1299 cells, caspase-3 activity was markedly enhanced. At 24 h of treatment with 8.0 μM DUPP, apoptosis in A549 and H1299 cells was increased to 67.89 and 61.35 %, respectively. Phosphorylation levels of JNK-1/2 and p38 in DHPP-treated A549 and H1299 cells were markedly enhanced. The p-ERK-1/2 expressions in DHPP-treated A549 and H1299 cells were suppressed significantly at 24 h. In DHPP-treated A549 and H1299 cells, DCF-fluorescence was increased 10 folds and 8.5 folds, respectively. Pretreatment with FeTMPyP, an antioxidant, effectively alleviated DHPP-induced increase in expressions of p-p38 and p-JNK, and suppression of expression of p-ERK-1/2. In FeTMPyP-pre-treated cells, the DHPPinduced increase in caspase-3 activity was markedly reduced.Conclusion: DHPP selectively inhibits lung cancer cell growth via oxidative stress which subsequently causes cell apoptosis. Moreover, it activates caspase-3 protein and p38/JNK signaling, with simultaneous inactivation of ERK-1/2. Therefore, DHPP has a potential to be developed for the treatment of lung cancer. However; more studies are required to confirm these findings. Keywords: Lung cancer, Anti-oxidant, Apoptosis, Caspase-3, Chemotherap
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