Sample records for aggregate tests

  1. Platelet aggregation test

    The platelet aggregation blood test checks how well platelets , a part of blood, clump together and cause blood to clot. ... Decreased platelet aggregation may be due to: Autoimmune ... Fibrin degradation products Inherited platelet function defects ...

  2. Testing aggregation consistency across geography and commodities

    Liu, Qinghua; Shumway, C. Richard


    Consistent aggregation of production data across commodities and states was tested using Lewbel's generalized composite commodity theorem (GCCT). This was the first empirical GCCT test for consistent geographic aggregation and was applied to two groups of states. Consistent commodity aggregation was tested in all states for two output groups and three input groups and in one state for a larger number of groups. Using a more powerful test procedure than previously applied to production data, m...

  3. Binodal Colloidal Aggregation Test - 4: Polydispersion

    Chaikin, Paul M.


    Binodal Colloidal Aggregation Test - 4: Polydispersion (BCAT-4-Poly) will use model hard-spheres to explore seeded colloidal crystal nucleation and the effects of polydispersity, providing insight into how nature brings order out of disorder. Crewmembers photograph samples of polymer and colloidal particles (tiny nanoscale spheres suspended in liquid) that model liquid/gas phase changes. Results will help scientists develop fundamental physics concepts previously cloaked by the effects of gravity.

  4. Hydraulic Fracture Test to Determine Aggregate Freeze-Thaw Durability

    Desta, Belayneh; Whiting, Nancy M; Snyder, Mark B


    The freeze-thaw durability of carbonate aggregates can vary greatly from durable to highly susceptible to freeze-thaw distress. Using nondurable aggregate in concrete pavement exposed to freeze-thaw cycles may lead to serious distress and greatly decrease the pavement’s service life. The testing needed to identify freeze-thaw durable aggregates can take several months to complete. The main objective of this study was to develop a reliable, quick test method for determining the freeze-thaw res...

  5. Aggregating IDS Alerts Based on Time Threshold: Testing and Results

    Homam Reda El-Taj


    Full Text Available Every secure system has the possibility to fail. Therefore, extra effort should be taken to protect these systems. Intrusion Detection Systems (IDSs had been proposed with the aim of providing extra protection to security systems. These systems trigger thousands of alerts per day, which prompt security analysts to verify each alert for relevance and severity based on an aggregation criterion. Several aggregation methods have been proposed to collect these alerts. This paper presents our threshold aggregation system (TAS. Results shows that TAS aggregates IDS alerts accurately based on user demands and threshold value.

  6. Lithuanian Quarry Aggregates Concrete Effects of Alkaline Corrosion Tests

    Aurimas Rutkauskas


    Full Text Available Aggregate alkaline corrosion of cement in concrete is going to respond in sodium and potassium hydroxide (lye with active SiO2 found in some aggregates. During this reaction, the concrete has resulted in significant internal stresses which cause deformation of the concrete, cracking and disintegration. The reaction is slow and concrete signs of decomposition appear only after a few months or years. The study used two different aggregates quarries. Studies show that Lithuania gravel contaminated with reactive particles having amorphous silicon dioxide reacting with cement in sodium and potassium hydroxide and the resulting alkaline concrete corrosion. It was found that, according to AAR 2 large aggregates include Group II – potentially reactive because of their expansion after 14 days, higher than 0.1%.


    Davis, George C.


    In the estimation of aggregate meat demand systems, weak separability is often a maintained assumption. However, only a few studies have tested and failed to reject this assumption. Recently, Lewbel (1996) developed a generalized composite commodity theorem (GCCT) that is less restrictive than weak separability. In this study, a data set in which the weak separability conditions for aggregation have been rejected is reconsidered to determine if aggregation can be based on the GCCT. Some subtl...

  8. Quantification of Anti-Aggregation Activity of Chaperones: A Test-System Based on Dithiothreitol-Induced Aggregation of Bovine Serum Albumin

    Vera A Borzova; Markossian, Kira A.; Dmitriy A. Kara; Natalia A Chebotareva; Makeeva, Valentina F.; Poliansky, Nikolay B.; Muranov, Konstantin O.; Kurganov, Boris I.


    The methodology for quantification of the anti-aggregation activity of protein and chemical chaperones has been elaborated. The applicability of this methodology was demonstrated using a test-system based on dithiothreitol-induced aggregation of bovine serum albumin at 45°C as an example. Methods for calculating the initial rate of bovine serum albumin aggregation (v agg) have been discussed. The comparison of the dependences of v agg on concentrations of intact and cross-linked α-crystallin ...

  9. Impact Behavior of Recycled Aggregate Concrete Based on Split Hopkinson Pressure Bar Tests

    Yubin Lu; Xing Chen; Xiao Teng; Shu Zhang


    This paper presents the experimental results of recycled aggregate concrete (RAC) specimens prepared with five different amounts of recycled coarse aggregate (RCA) (i.e., 0, 25%, 50%, 75%, and 100%) subjected to impact loading based on split Hopkinson pressure bar tests. Strain-rate effects on dynamic compressive strength and critical strain of RAC were studied. Results show that the impact properties of RAC exhibit strong strain-rate dependency and increase approximately linearly with strain...

  10. Trends in Aggregate Vehicle Emissions: Do We Need To Emissions Test?

    Matthew Kahn


    Vehicle emissions are falling. As the oldest vehicles in the fleet are scrapped and are replaced by cleaner vehicles, aggregate emissions decline. Given this trend, must costly used car regulation continue? The Clean Air Act of 1990 requires more stringent used car testing without considering the counter-factual of how aggregate emissions would evolve in the absence of more regulation. This paper use data on vehicle scrappage rates, vehicle emissions by model year, and county air quality leve...

  11. Admissible clustering of aggregator components: a necessary and sufficient stochastic semi-nonparametric test for weak separability

    Barnett, William A.; De Peretti, Philippe


    In aggregation theory, the admissibility condition for clustering together components to be aggregated is blockwise weak separability, which also is the condition needed to separate out sectors of the economy. Although weak separability is thereby of central importance in aggregation and index number theory and in econometrics, prior attempts to produce statistical tests of weak separability have performed poorly in Monte Carlo studies. This paper deals with semi-nonparametric tests for weak ...

  12. Accelerated Test Method to Identify Freeze-Thaw Durability of Aggregates

    Desta, Belayneh B.; Whiting, Nancy


    INDOT currently identifies freeze-thaw durable aggregate using ITM210, a 90-day concrete beam freeze-thaw test. To accelerate this procedure, the 8-day Hydraulic Fracture Test (HFT) was investigated and modified. Samples from 18 quarries and six RCA sources were subjected to HFT and ITM210. Statistical analysis demonstrated that HFT can predict the ITM210 results with reasonable accuracy. The modified HFT procedures and equipment are recommended as a quick screening tool for predicting ITM210...

  13. Stationarity Test for Aggregate Outputs in the Presence of Structural Breaks

    Srivastava, D. K.; Shanmugam, K. R.


    This study tests for the stationarity of aggregate output (GDP at factor cost) and its three major components, namely GDP agriculture, GDP industry and GDP services in the presence of structural breaks during 1950-51 to 2011-12. Results indicate that (i) the GDP has three break points; (ii) GDP agriculture contains one while the GDP industry and GDP services contain four breaks each; and (iii) all variables are trends stationary with one or more structural breaks. Our alternative test, which ...

  14. Aggregate demand for electricity in South Africa: An analysis using the bounds testing approach to cointegration

    Electricity demand in South Africa has grown at a very rapid rate over the past decade. As part of reform initiatives to enhance long-term sustainability of the country's electricity industry, South Africa's authorities have in recent years sought to develop an electricity pricing framework that is cost reflective and forms the cornerstone of demand management schemes meant to foster changes in consumption behaviour and enhance efficiency in resource use. The effects of any pricing policy on aggregate electricity consumption will depend on a useful understanding of the factors that influence electricity demand, and the magnitude to which electricity demand responds to changes in such factors. In this context, this paper applies the bounds testing approach to cointegration within an autoregressive distributed lag framework to examine the aggregate demand for electricity in South Africa during the period 1960-2007. The results indicate that in the long run, income is the main determinant of electricity demand. With electricity prices having an insignificant effect on aggregate electricity demand, future pricing policies will need to ensure that electricity prices are cost reflective and enhance efficiency of electricity supply and use.

  15. The Wedge Splitting Test: Influence of Aggregate Size and Water-to-Cement Ratio

    Pease, Bradley Justin; Skocek, Jan; Geiker, Mette Rica;


    Since the development of the wedge splitting test (WST), techniques have been used to extract material properties that can describe the fracture behavior of the tested materials. Inverse analysis approaches are commonly used to estimate the stress-crack width relationship; which is described by the...... elastic modulus, tensile strength, fracture energy, and the assumed softening behavior. The stress-crack width relation can be implemented in finite element models for computing the cracking behavior of cementitious systems. While inverse analysis provides information about the material properties of...... enables the stress-crack width response to be determined simultaneously from multiple experimental tests. The effect of water-to-cement ratio and aggregate size are discussed. A comparison of epoxy-impregnated cracked WST specimen and material properties indicate a relationship between fracture properties...

  16. Field tests for the verification of oil-mineral aggregate (OMA) formation

    Prior studies identified a process where small mineral particles in beach sediments or suspended in nearshore waters interacted with oil in seawater to form oil-mineral aggregates (OMA). This process facilitated the dispersion of oil in the sea, thereby contributing to the removal of oil from marine shorelines. It proved possible to improve this natural occurrence by choosing appropriate shoreline clean up techniques with sediment relocation. The best way to identify OMA in water samples was with ultraviolet (UV) epi-fluorescence microscopy. A new method was developed to determine the potential of beach sediment to form OMA with spilled oil. It involved a simple, rapid and cost-effective test performed on location. This new test, used in conjunction with microscopy techniques or used alone, demonstrated its potential to assist planners in the measures to be implemented to achieve remediation. 11 refs., 1 tab., 5 figs

  17. Testing the Effectiveness of Monetary Policy in Malaysia Using Alternative Monetary Aggregation

    Leong, Choi-Meng; Puah, Chin-Hong; Abu Mansor, Shazali; Evan, Lau


    The capability of monetary aggregates to generate stable link with fundamental economic indicators verifies the effectiveness of monetary targeting. However, traditional monetary aggregates have become flawed when financial reforms take place. As official monetary aggregates fail to maintain stable link with crucial economic indicators in Malaysia, monetary targeting has been substituted by interest rate targeting. Therefore, Divisia monetary aggregates, which are considered more superior tha...

  18. Stress Testing of the Montenegrin Banking System with Aggregated and Bank-Specific Data

    Vuković Sanja


    Full Text Available There are many different approaches to the process of stress testing and two of them will be investigated in this paper. The first one is a stress test performed on aggregated data i.e. the banking system as a whole. The variable of interest in both exercises is the Loan Loss Provision ratio (hereinafter: the LLP. The main goal of the thesis is to find an answer to the following question: what are the macroeconomic variables that influence LLP the most and how will LLP, as a variable of interest, behave in a situation when all these variables were to experience negative performance at the same time? The resilience of the banking system to such scenario will be tested through the capital adequacy ratio. In order to find out more about the management practices of banks, microlevel data on banks were also used in the analysis. The focus was to see which of the variables are able to explain the LLP ratio for each bank individually and how is this information helpful for possible improvements in the banking sector. The relations between these variables will be able to explain some of the banks’ losses and some of the banks’ practices regarding credit activities. The analysis there will provide for some recommendations for the banks but also for the Central Bank and its way to influence the practices in the banking sector.


    Shumway, C. Richard; Davis, George C.


    Consistent aggregation assures that behavioral properties which apply to disaggregate relationships also apply to aggregate relationships. The agricultural economics literature is reviewed which has tested for consistent aggregation or measured statistical bias and/or inferential errors due to aggregation. Tests for aggregation bias and errors of inference are conducted using indices previously tested for consistent aggregation. Failure to reject consistent aggregation in a partition did not ...


    Shumway, C. Richard; Davis, George C.


    Consistent aggregation assures that behavioral properties, which apply to disaggregate relationships also, apply to aggregate relationships. The agricultural economics literature is reviewed which has tested for consistent aggregation or measured statistical bias and/or inferential errors due to aggregation. Tests for aggregation bias and errors of inference are conducted using indices previously tested for consistent aggregation. Failure to reject consistent aggregation in a partition did no...

  1. Mechanical Degradation of Aggregate by the Los Angeles-, the Micro-Deval- and the Nordic Test Methods

    Erichsen, E.; Ulvik, A.; Sævik, K.


    The quality of aggregate used as buildings materials is defined by European Standard test methods. According to the agreement within the European Economic Area, each individual country decides test methods of current interest. Among the Nordic countries, the Los Angeles-, micro-Deval- and the Nordic test are the most common methods used to decide the mechanical properties of the aggregate. The three test methods are all drum test where the degradation of the material occur by rotation between the test material and steel balls together with, or without water. The mechanical test methods are empirical and are believed to express either resistance to fragmentation or wearing. The results of this study show that analysing the particle size distribution of a material after the drum testing give indication of which type and degree of degradation the test material is exposed to. Knowledge of the type of degradation for the test methods is important compared to the understanding of the real breakdown of the aggregate for instance used in road construction.

  2. Aggregation and sedimentation processes during a spring phytoplankton bloom: A field experiment to test coagulation theory

    Kiørboe, Thomas; Lundsgaard, Claus; Olesen, Michael; Hansen, Jørgen L. S.


    intervals and we estimated the turbulent shear rate from observations of wind velocity. By means of coagulation theory these observations were combined into a predictor of aggregation rate. We also quantified the sedimentation of phytoplankton, other suspended particles and of aggregates by means of moored......Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large floes and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles, on the...... turbulent shear that makes particles collide, and on their stickiness (= probability of adhesion upon collision), During a mixed diatom bloom in a shallow Danish fjord, for 3 weeks we monitored the concentration and stickiness of suspended particles and the species composition of the phytoplankton at 2-3 d...

  3. Aggregation and sedimentation processes during a spring phytoplankton bloom: A field experiment to test coagulation theory

    Kiørboe, Thomas; Lundsgaard, Claus; Olesen, Michael;


    Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large floes and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles, on the...... turbulent shear that makes particles collide, and on their stickiness (= probability of adhesion upon collision), During a mixed diatom bloom in a shallow Danish fjord, for 3 weeks we monitored the concentration and stickiness of suspended particles and the species composition of the phytoplankton at 2-3 d...... intervals and we estimated the turbulent shear rate from observations of wind velocity. By means of coagulation theory these observations were combined into a predictor of aggregation rate. We also quantified the sedimentation of phytoplankton, other suspended particles and of aggregates by means of moored...

  4. Information-aggregation bias

    Goodfriend, Marvin


    Aggregation in the presence of data-processing lags distorts the information content of data, violating orthogonality restrictions that hold at the individual level. Though the phenomenon is general, it is illustrated here for the life-cycle-permanent-income model. Cross-section and pooled-panel data induce information-aggregation bias akin to that in aggregate time series. Calculations show that information aggregation can seriously bias tests of the life-cycle model on aggregate time series...

  5. The Testing Strength Curves of Lightweight Aggregate Concrete by Rebound Method and Ultrasonic-rebound Combined Method

    RONG Hui; QIAN Chunxiang; GAO Lixiong; HAN Jiande; WANG Caihui


    The strength curves of lightweight aggregate concrete (LWAC) were tested based on detecting LWAC with density of 1 400-1 900 kg/m3 and LWAC with strength grade of LCI5-LC50 by rebound method and ultrasonic-rebound combined method.The results show that the common measured strength curves tested by above two methods can not satisfy the required accuracy of LWAC strength test.In addition,specified compressive strength curves of testing LWAC by rebound method and ultrasonic-rebound combined method are obtained,respectively.

  6. Whole Blood Platelet Aggregation and Release Reaction Testing in Uremic Patients

    Jay Zeck


    Full Text Available Background. Platelet function analysis utilizing platelet-rich plasma and optical density based aggregometry fails to identify patients at risk for uremia associated complications. Methods. We employed whole blood platelet aggregation analysis based on impedance as well as determination of ATP release from platelet granules detected by a chemiluminescence method. Ten chronic kidney disease (CKD stage 4 or 5 predialysis patients underwent platelet evaluation. Our study aims to evaluate this platform in this patient population to determine if abnormalities could be detected. Results. Analysis revealed normal aggregation and ATP release to collagen, ADP, and high-dose ristocetin. ATP release had a low response to arachidonic acid (0.37 ± 0.26 nmoles, reference range: 0.6–1.4 nmoles. Platelet aggregation to low-dose ristocetin revealed an exaggerated response (20.9 ± 18.7 ohms, reference range: 0–5 ohms. Conclusions. Whole blood platelet analysis detected platelet dysfunction which may be associated with bleeding and thrombotic risks in uremia. Diminished ATP release to arachidonic acid (an aspirin-like defect in uremic patients may result in platelet associated bleeding. An increased aggregation response to low-dose ristocetin (a type IIb von Willebrand disease-like defect is associated with thrombus formation. This platelet hyperreactivity may be associated with a thrombotic diathesis as seen in some uremic patients.

  7. A study of the ASR of an aggregate with high chert content by means of ultra-accelerated mortar bar test and pore fluid analysis

    Larbi, J.A.; Visser, J.H.M.


    Various studies have indicated that the use of some ultra-accelerated mortar bar expansion test methods for assessing the alkali-silica reactivity of concrete aggregates (particularly those using 1 M NaOH solution at 80 oC) can give rise to misleading results causing certain types of aggregates to b

  8. Whole Blood Platelet Aggregation and Release Reaction Testing in Uremic Patients

    Louis DePalma; Lew, Susie Q.; Jason Schallheim; Jay Zeck


    Background. Platelet function analysis utilizing platelet-rich plasma and optical density based aggregometry fails to identify patients at risk for uremia associated complications. Methods. We employed whole blood platelet aggregation analysis based on impedance as well as determination of ATP release from platelet granules detected by a chemiluminescence method. Ten chronic kidney disease (CKD) stage 4 or 5 predialysis patients underwent platelet evaluation. Our study aims to evaluate this p...

  9. Comparison of aggregate stability within six soil profiles under conventional tillage using various laboratory tests

    Kodešová, R.; Rohošková, M.; Žigová, Anna


    Roč. 64, č. 3 (2009), s. 550-554. ISSN 0006-3088 R&D Projects: GA ČR GA526/08/0434 Institutional research plan: CEZ:AV0Z30130516 Keywords : fast wetting test * slow wetting test * shaking after pre-wetting test * wet sewing Subject RIV: DF - Soil Science Impact factor: 0.617, year: 2009

  10. Estimating herd prevalence on the basis of aggregate testing of animals

    Faes, Christel; Aerts, Marc; LITIERE, Saskia; Meroc, Estelle; Van der Stede, Yves; Mintiens, Koen


    It is common practice that some or all animals in a group of animals, e. g. a herd, are tested for their health status by using a diagnostic test to investigate whether the herd is infected by a disease. Several obstacles complicate the estimation of herd prevalence on the basis of test results of the animals. First, diagnostic tests are often imperfect, resulting in a misclassification of the animal's disease status. It is well known how to correct the animal's apparent prevalence by using t...


    Joanna Ochremiak


    In the paper we present an introduction to the theory of judgment aggregation and discuss its relation to the theory of preference aggregation. We compare the formal model of judgment aggregation, based on logic, with the formal model of preference aggregation. Finally, we present a theorem in judgmentaggregation which is an exact analogue of Arrow's theorem for strict preferences.

  12. The Wedge Splitting Test: Influence of Aggregate Size and Water-to-Cement Ratio

    Pease, Bradley Justin; Skocek, Jan; Geiker, Mette Rica; Weiss, Jason; Stang, Henrik


    Since the development of the wedge splitting test (WST), techniques have been used to extract material properties that can describe the fracture behavior of the tested materials. Inverse analysis approaches are commonly used to estimate the stress-crack width relationship; which is described by the elastic modulus, tensile strength, fracture energy, and the assumed softening behavior. The stress-crack width relation can be implemented in finite element models for computing the cracking behavi...

  13. Hybridization-Induced Aggregation Technology for Practical Clinical Testing: KRAS Mutation Detection in Lung and Colorectal Tumors.

    Sloane, Hillary S; Landers, James P; Kelly, Kimberly A


    KRAS mutations have emerged as powerful predictors of response to targeted therapies in the treatment of lung and colorectal cancers; thus, prospective KRAS genotyping is essential for appropriate treatment stratification. Conventional mutation testing technologies are not ideal for routine clinical screening, as they often involve complex, time-consuming processes and/or costly instrumentation. In response, we recently introduced a unique analytical strategy for revealing KRAS mutations, based on the allele-specific hybridization-induced aggregation (HIA) of oligonucleotide probe-conjugated microbeads. Using simple, inexpensive instrumentation, this approach allows for the detection of any common KRAS mutation in platform may involve the detection of mutations in other key oncogenic pathways. PMID:27289420

  14. Dynamic testing of concrete under high confined pressure. Influence of saturation ratio and aggregate size

    Forquin, P.; Piotrowska, E.; Gary, G.


    Concrete structures can be exposed to intense pressure loadings such as projectile-impact or detonation near a concrete structural element. To investigate the mechanical behaviour of concrete under high confining pressure, dynamic quasi-oedometric compression tests have been performed with a large diameter (80 mm) Split Hopkinson Pressure Bar apparatus. The concrete sample is placed within a steel confining ring and compressed along its axial direction. Hydrostatic pressures as high as 800 MPa and axial strain of about - 10% are reached during the tests. In the present work, experiments have been conducted on two types of concrete: MB50 microconcrete with a maximum grain size of 2 mm and R30A7 ordinary concrete of maximum grain size about 8 mm. Both concretes are tested in dry or saturated conditions. According to these dynamic experiments it is noted that grain size has a small influence whereas water content has a strong effect on the confined behaviour of concrete.

  15. Dynamic testing of concrete under high confined pressure. Influence of saturation ratio and aggregate size

    Forquin P.


    Full Text Available Concrete structures can be exposed to intense pressure loadings such as projectile-impact or detonation near a concrete structural element. To investigate the mechanical behaviour of concrete under high confining pressure, dynamic quasi-oedometric compression tests have been performed with a large diameter (80 mm Split Hopkinson Pressure Bar apparatus. The concrete sample is placed within a steel confining ring and compressed along its axial direction. Hydrostatic pressures as high as 800 MPa and axial strain of about − 10% are reached during the tests. In the present work, experiments have been conducted on two types of concrete: MB50 microconcrete with a maximum grain size of 2 mm and R30A7 ordinary concrete of maximum grain size about 8 mm. Both concretes are tested in dry or saturated conditions. According to these dynamic experiments it is noted that grain size has a small influence whereas water content has a strong effect on the confined behaviour of concrete.

  16. Not all calcite ballast is created equal: Differing effects of foraminiferan tests and coccoliths on the aggregation and sinking of diatoms

    De La Rocha, C. L.; Schmidt, K.; Gallinari, M.; Cortese, G.


    There is a strong correlation between sinking fluxes of CaCO3 biominerals and particulate organic carbon (POC), leading to suggestions that sinking fluxes of CaCO3 might control the amount of POC reaching the deep sea. Research has shown that CaCO3 (which is considerably denser than both seawater and particulate organic matter), in the form of coccoliths produced by coccolithophores, can be incorporated into phytoplankton aggregates, reducing their size and POC content but significantly increasing their sinking velocity (W, in m d-1). Coccoliths are, however, not the only form of CaCO3 common in the water column. The tests of foraminiferans represent roughly half of the global flux of CaCO3 to the seafloor and it is unclear what role they play in "carrying" POC to depth. Tests of foraminiferans are commonly large and heavily calcified enough to sink with velocities of 1 km per day. Foraminiferan tests should not accumulate organic matter, as the resulting aggregate should fall apart when subject to the hydrodynamic shear associated with such rapid sinking. To investigate this, thick cultures of the marine diatom Chaetoceros gracilis were placed into 4.5 L cylindrical tanks. Added to the tanks was either no CaCO3, 4.5 mg L-1 of coccoliths, or 4.5 mg L-1 of foraminiferan tests > 250 μm. The tanks were then placed on roller tables to simulate sinking through the water column. Incubation was done in the dark at 16°C for 2 days. Aggregates formed in all treatments. Aggregates in the Chaetoceros-only tanks were the largest and contained the most POC per aggregate. Aggregates in the coccolith tanks were smaller but had higher sinking velocities for their equivalent spherical diameter (ESD, in mm) (W = 678(ESD) + 173; r2 = 0.52) Foraminiferan tests in the foraminiferan tanks absorbed visible but minor amounts of organic matter and sank extremely rapidly (400-700 m d-1). However, most of the POC in the foraminiferan tanks occurred in aggregates that did not contain

  17. Application of an in vitro-amplification assay as a novel pre-screening test for compounds inhibiting the aggregation of prion protein scrapie

    Matthias Schmitz; Maria Cramm; Franc Llorens; Niccolò Candelise; Dominik Müller-Cramm; Daniela Varges; Schulz-Schaeffer, Walter J.; Saima Zafar; Inga Zerr


    In vitro amplification assays, such as real-time quaking-induced conversion (RT-QuIC) are used to detect aggregation activity of misfolded prion protein (PrP) in brain, cerebrospinal fluid (CSF) and urine samples from patients with a prion disease. We believe that the method also has a much broader application spectrum. In the present study, we applied RT-QuIC as a pre-screening test for substances that potentially inhibit the aggregation process of the cellular PrP (PrPC) to proteinase (PK)-...

  18. Rational Aggregation

    Bruce Chapman


    In two recent papers, Christian List and Philip Pettit have argued that there is a problem in the aggregation of reasoned judgements that is akin to the aggregation of the preference problem in social choice theory.1 Indeed, List and Pettit prove a new general impossibility theorem for the aggregation of judgements, and provide a propositional interpretation of the social choice problem that suggests it is a special case of their impossibility result.2 Specifically, they show that no judgemen...

  19. On the dynamics of aggregate output, electricity consumption and exports in Malaysia: Evidence from multivariate Granger causality tests

    This paper employs annual data from 1971 to 2006 to examine the causal relationship between aggregate output, electricity consumption, exports, labor and capital in a multivariate model for Malaysia. We find that there is bidirectional Granger causality running between aggregate output and electricity consumption. The policy implication of this result is that Malaysia should adopt the dual strategy of increasing investment in electricity infrastructure and stepping up electricity conservation policies to reduce unnecessary wastage of electricity, in order to avoid the negative effect of reducing electricity consumption on aggregate output. We also find support for the export-led hypothesis which states Granger causality runs from exports to aggregate output. This result is consistent with Malaysia pursuing a successful export-orientated strategy. (author)

  20. Weighted aggregation

    Feiveson, A. H. (Principal Investigator)


    The use of a weighted aggregation technique to improve the precision of the overall LACIE estimate is considered. The manner in which a weighted aggregation technique is implemented given a set of weights is described. The problem of variance estimation is discussed and the question of how to obtain the weights in an operational environment is addressed.

  1. Reaction of rat subcutaneous tissue to mineral trioxide aggregate and Portland cement: A secondary level biocompatibility test

    P Karanth


    Full Text Available Objectives: This secondary-level animal study was conducted to assess and compare the subcutaneous tissue reaction to implantation of white mineral trioxide aggregate (MTA and white Portland cement. Study Design: Polyethylene tubes filled with either freshly mixed white MTA (Group I or white Portland cement (Group II were implanted subcutaneously into 12 Wistar Albino rats. Each animal also received an empty polyethylene tube as the control (Group III. After 7, 14, 21 and 30 days, the implants, together with surrounding tissues were excised. Two pathologists blinded to the experimental procedure, evaluated sections taken from the biopsy specimens for the severity of the inflammatory response, calcification and the presence and thickness of fibrous capsule surrounding the implant. Statistical analysis was performed using the Cross-tabs procedure, Univariate analysis of the variance two-way and the Pearson product moment correlation to assess inter-rater variability between the two evaluators. Results: At 7 days, there was no significant difference in the severity of inflammation between the control group, white MTA, and white Portland cement groups. In the 14 day, 21 day and 30 day test periods, control group had significantly less inflammation than white MTA and white Portland cement. There was no significant difference in the grading of inflammation between white MTA and white Portland cement. All materials exhibited thick capsule at 7 days and thin capsule by 30 days. Conclusion: Both white MTA and white Portland cement were not completely non-irritating at the end of 30 days as evidenced by the presence of mild inflammation. However, the presence of a thin capsule around the materials, similar to the control group, indicates good tissue tolerance. White MTA and white Portland cement seem to be materials of comparable biocompatibility.

  2. Glycine reduces platelet aggregation

    Schemmer, Peter; Zhong, Zhi; Galli, Uwe; Wheeler, Michael D.; Xiangli, Li; Bradford, Blair U.; Conzelmann, Lars O.; Forman, Dow; Boyer, José; Thurman, Ronald G


    It has been demonstrated that a wide variety of white blood cells and macrophages (i.e. Kupffer cells, alveolar and peritoneal macrophages and neutrophils) contain glycine-gated chloride channels. Binding of glycine on the receptor stimulates Cl− influx causing membrane hyperpolarization that prevents agonist-induced influx of calcium. Since platelet-aggregation is calcium-dependent, this study was designed to test the hypothesis that glycine would inhibit platelet aggregation. Rats were fed ...

  3. A simple slide test to assess erythrocyte aggregation in acute ST-elevated myocardial infarction and acute ischemic stroke: Its prognostic significance

    Atla Bhagya Lakshmi


    Full Text Available A simple slide test and image analysis were used to reveal the presence of an acute-phase response and to determine its intensity in subjects of acute myocardial infarction and acute ischemic stroke. Erythrocytes tend to aggregate during an inflammatory process. Evaluation of erythrocyte adhesiveness/aggregation is currently available to the clinicians indirectly by erythrocyte sedimentation rate (ESR, but ESR correlates poorly with erythrocyte aggregation, hence a simple slide technique using citrated blood was used to evaluate erythrocyte aggregation microscopically and also by using image analysis. Aims: (1 To study erythrocyte aggregation/adhesiveness by a simple slide test in subjects with acute ST-elevated myocardial infarction (STEMI, acute ischemic stroke and healthy controls. (2 To study the prognostic significance of ESR and erythrocyte aggregation/adhesiveness test (EAAT in predicting the outcome after 1 week in subjects of acute myocardial infarction and acute ischemic stroke. Patients and Methods: Three groups of subjects were included in the study; 30 patients of acute STEMI, 30 patients of acute ischemic stroke, and 30 subjects with age- and gender-matched healthy controls. Citrated blood was subjected to simple slide test and ESR estimation by Westergren′s method. Stained smears were examined under 400Χ and graded into four grades. Images were taken from nine fields; three each from head, body, and tail of the smear. The degree of erythrocyte aggregation was quantified using a variable called erythrocyte percentage (EP, by using the software MATLAB Version 7.5. A simple program was used to count the number of black and white pixels in the image by selecting a threshold level. Results: The mean ESR of the subjects with acute myocardial infarction (29 + 17.34 was significantly higher (P = 0.001 than the mean ESR of the control group (15.5 + 12.37. The mean EP of the subjects with acute myocardial infarction (69.91 + 13.25 was

  4. Aggregate productivity and aggregate technology

    Susanto Basu; John G. Fernald


    Aggregate productivity and aggregate technology are meaningful but distinct concepts. We show that a slightly-modified Solow productivity residual measures changes in economic welfare, even when productivity and technology differ because of distortions such as imperfect competition. We then present a general accounting framework that identifies several new non-technological gaps between productivity and technology, gaps reflecting imperfections and frictions in output and factor markets. Empi...

  5. The Method of Evaluation and Implementation of the Non-destructive Test on Aggregate denuded Concrete Structure for Irrigation and Drainage

    Ogata, Hidehiko; Sato, Shushi; Hattori, Kunio

    The surfaces of the servicing concrete structure for irrigation and drainage have the denuding aggregates. Various diagnoses can't be done properly by the test method for ultrasonic pulse velocity, because close adhesion between pulse terminal and aggregate denuded concrete surface is insufficient. In this research, the solution of this problem by coating method that mediated material is applied to the concrete was examined. As a result, the ultrarapid hardening cement and the epoxy clay were suitable as a mediated material, and the method to evaluate ultrasonic pulse velocity of the coated concrete by the mediated material were clarified. Moreover, the method to evaluate rebound number and impact points of the coated concrete by the mediated material was recommended.

  6. Methods for testing familial aggregation of diseases in population-based samples: application to Hodgkin lymphoma in Swedish registry data.

    Pfeiffer, R M; Goldin, L R; Chatterjee, N; Daugherty, S; Hemminki, K; Pee, D; X, L I; Gail, M H


    We use data on lymphoma in families of Hodgkin lymphoma (HL) cases from the Swedish Family Cancer Database (Hemminki et al. 2001) to illustrate survival methods for detecting familial aggregation in first degree relatives of case probands compared to first degree relatives of control probands, from registries that permit sampling of all cases. Because more than one case may occur in a given family, the first degree relatives of case probands are not necessarily independent, and we present procedures that allow for such dependence. A bootstrap procedure also accommodates matching of case and control probands by resampling the matching clusters, defined as the combined set of all first degree relatives of the matched case and control probands. Regarding families as independent sampling units leads to inferences based on "sandwich variance estimators" and accounts for dependencies from having more than one proband in a family, but not for matching. We compare these methods in analysis of familial aggregation of HL and also present simulations to compare survival analyses with analyses of binary outcome data. PMID:15469426

  7. Relationships between high-stakes testing policies and student achievement after controlling for demographic factors in aggregated data.

    Gregory J. Marchant


    Full Text Available With the mandate of No Child Left Behind, high-stakes achievement testing is firmly in place in every state. The few studies that have explored the effectiveness of high-stakes testing using NAEP scores have yielded mixed results. This study considered state demographic characteristics for each NAEP testing period in reading, writing, mathematics, and science from 1992 through 2002, in an effort to examine the relation of high-stakes testing policies to achievement and changes in achievement between testing periods. As expected, demographic characteristics and their changes were related significantly to most achievement outcomes, but high-stakes testing policies demonstrated few relationships with achievement. The few relationships between high-stakes testing and achievement or improvement in reading, writing, or science tended to appear only when demographic data were missing; and the minimal relationships with math achievement were consistent with findings in previous research. Considering the cost and potential unintended negative consequences, high-stakes testing policies seem to provide a questionable means of improving student learning.

  8. Recycled aggregates concrete: aggregate and mix properties

    González-Fonteboa, B.


    Full Text Available This study of structural concrete made with recycled concrete aggregate focuses on two issues: 1. The characterization of such aggregate on the Spanish market. This involved conducting standard tests to determine density, water absorption, grading, shape, flakiness and hardness. The results obtained show that, despite the considerable differences with respect to density and water absorption between these and natural aggregates, on the whole recycled aggregate is apt for use in concrete production. 2. Testing to determine the values of basic concrete properties: mix design parameters were established for structural concrete in non-aggressive environments. These parameters were used to produce conventional concrete, and then adjusted to manufacture recycled concrete aggregate (RCA concrete, in which 50% of the coarse aggregate was replaced by the recycled material. Tests were conducted to determine the physical (density of the fresh and hardened material, water absorption and mechanical (compressive strength, splitting tensile strength and modulus of elasticity properties. The results showed that, from the standpoint of its physical and mechanical properties, concrete in which RCA accounted for 50% of the coarse aggregate compared favourably to conventional concrete.

    Se aborda el estudio de hormigones estructurales fabricados con áridos reciclados procedentes de hormigón, incidiéndose en dos aspectos: 1. Caracterización de tales áridos, procedentes del mercado español. Para ello se llevan a cabo ensayos de densidad, absorción, granulometría, coeficiente de forma, índice de lajas y dureza. Los resultados obtenidos han puesto de manifiesto que, a pesar de que existen diferencias notables (sobre todo en cuanto a densidad y absorción con los áridos naturales, las características de los áridos hacen posible la fabricación de hormigones. 2. Ensayos sobre propiedades básicas de los hormigones: se establecen parámetros de dosificaci

  9. Both compressive test and drying shrinkage test on recycled aggregate concrete with different fine recycled aggregate replacement ratio%不同再生细骨料取代率混凝土的抗压及干燥收缩试验研究

    郝彤; 赵文兰


    对不同再乍细骨料替代率混凝土的抗压性能和干燥收缩性能进行研究.结果表明,随着再生细骨料替代率的提高,再生混凝土呈脆性趋势发展,但当采用基于自由水灰比的配合比设计方法和二次搅拌工艺时,再生细骨料混凝土的强度基本与普通混凝土相近.再生混凝土的收缩机理与普通混凝土基本相同,再生细骨料混凝土的收缩值随龄期增长而逐渐增大;再生混凝土的干燥收缩率大于普通混凝土;随着再生细骨料替代率的增加,再生混凝土收缩率随之增大.%Both compressive test and drying shrinkage test on recycled aggregate concrete with different fine recycled aggregate replacement ratio were studied. The reaults show that with the replacement ratio increase,recycled concreie are becoming more and more brittle:with the mixing proportion design of free W/C and the secondary mixing process,compressive intensity of recycled cancrete iB nearly comparable with those of normal concrete with similar composition.The shrinkage theory of the recycled concrete is the same as natural aggregate concrete,with the increase of the curing ages,the shrinkage of the recycled concrete increases;the shrinkage of the recycled concrete is higher than that of natural aggregate concrete;with the ingrease of the replacement rate,the shrinkage of the recycled concrete increases.

  10. Utilization Possibility of Natural Aggregate Resources in Central Town of Tokat as Concrete Aggregate

    S. I. Tutmaz


    Full Text Available In this study, aggregates of three quarries sampled from Tokat Province were tested to evaluate their suitability for concrete production. The aggregates were supplied from Yesilirmak River, and largely used in agricultural structures constructed in Tokat. Standard aggregate tests approved by Turkish Standards Institute were carried out to analyze the samples. Granulation, unit weight, specific weight, water absorption rate, resistance to frost, resistance against abrasion, ratio of fine materials, organic material contents and, mineralogical analysis of aggregates sampled from aggregate quarries were determined. Pressure resistance tests were conducted on concrete prepared by the aggregates. The results indicated that the aggregate granulation distribution of aggregate quarries evaluated was not suitable however other parameters determined were appropriate for concrete production. The resultant concrete had sufficient pressure resistance. The possible solutions to improve the improper characteristics of aggregates used in concrete were also determined and introduced with this study.

  11. 78 FR 68945 - Aggregation of Positions


    ... (``1979 Aggregation Policy''), 44 FR 33839, 33843 (June 13, 1979). Note, however, that consistent with the... the ownership criteria of aggregation. \\40\\ See, e.g., 53 FR 13290, 13292 (1988) (proposal). The 1988... approach best resolves those issues while maintaining a bright-line aggregation test? \\41\\ See 77 FR...

  12. Aggregation of Scale Efficiency

    Valentin Zelenyuk


    In this article we extend the aggregation theory in efficiency and productivity analysis by deriving solutions to the problem of aggregation of individual scale efficiency measures, primal and dual, into aggregate primal and dual scale efficiency measures of a group. The new aggregation result is coherent with aggregation framework and solutions for the other related efficiency measures that already exist in the literature.

  13. Concrete = aggregate, cement, water?

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  14. A fluorescent chemosensor for Cu2+ detection in solution based on aggregation-induced emission and its application in fabricating Cu2+ test papers

    A fluorescent chemosensor for Cu2+ has been developed based on the aggregation-induced emission (AIE) characteristics of bis(pyridin-2-ylmethylene) terephthalohydrazide (1). The dye molecule 1 exhibits a large Stokes shift of ∼182 nm and shows highly sensitive and selective response to Cu2+ over other metal ions by forming a 1:2 metal-to-ligand complex in aqueous solution. Cu2+-induced fluorescence quenching at 516 nm was proportional to the concentration of Cu2+ in the range of 0.2–8.0 μM, with a detection limit as low as 160 nM. In addition, by taking advantage of its AIE characteristics, compound 1 can also enable the fabrication of test papers for in-field detections, which is challenging for many other fluorescent Cu2+ sensors due to their strong self-quenching effect in solid state. - Highlights: • Compound 1 can effectively detect Cu2+ in aqueous solutions with a negligible amount of organic cosolvents. • Compound 1 exhibits a large Stokes shift of ∼182 nm in aqueous solution. • By taking advantage of its AIE characteristics, compound 1 can function as a Cu2+ sensor in solid state to enable the fabrication of test papers

  15. Recycled aggregate concrete exposed to elevated temperature

    Arundeb Gupta; Saroj Mandal; Somnath Ghosh


    An experimental investigation has been conducted to study the mechanical as well as micro structural properties of Recycled aggregate concrete (RAC) exposed to elevated temperature. Fly ash (as replacement of cement) was added while making concrete. Recycled aggregates are mixed with natural aggregates also to prepare concrete. Cubes and cylinder test specimens were prepared and cured under water for 28 days. Test specimens were exposed to different levels of temperature (200oC, 400oC, 600oC,...

  16. Shrinkage of concrete with replacement of aggregate with recycled concrete aggregate

    Gómez Soberón, José Manuel Vicente


    In this paper we present the experimental analysis of samples of concrete where portion of the natural aggregate were replaced with recycled aggregate originating from concrete (RCA). Experimental analysis to obtain the shrinkage properties (basic and dried) of the concrete containing recycled concrete aggregate (CRCA) was performed. The percentages of replacement of natural aggregate with RCA were 0%, 15%, 30%, 60% and 100% with test conditions of 50% RH and 20°C. The results of these ...

  17. Consistent Trade Policy Aggregation

    Anderson, James E.


    Much empirical work requires the aggregation of policies. This paper provides methods of policy aggregation that are consistent with two common objectives of empirical work. One is to preserve real income. The other is to preserve the real volume of activity in one or more parts of the economy. Trade policy aggregation is an acute example of the aggregation problem with thousands of highly dispersed trade barriers to be aggregated. An application to India shows that the standard atheoretic me...

  18. Consistency in Aggregation

    Ludwig Auer


    In empirical economic research, individual prices are often aggregated into average prices of sub-aggregates. Then, these average prices are aggregated to produce the average price of the total aggregate. Often, such two stage procedures help to illuminate the underlying forces driving the overall result. Since price data are usually published as price changes, this two stage aggregation is typically based on some price index formula. In this paper, various screening devices are introduced wh...

  19. Influence of shear stress on erythrocyte aggregation.

    Kim, Jeong-Ho; Lee, Hoyoon; Lee, Byoung-Kwon; Shin, Sehyun


    Shear stress is known to induce platelet activation and aggregation. The red blood cell (RBC) aggregation test requires the application of shear stress for the cells to disaggregate for initialization. We tested the hypothesis that applying shear stress may activate platelets, which can influence RBC aggregation. The present study used a commercial microchip-based aggregometer (RheoSCan-AnD300) with a rotating stirrer for RBC disaggregation. Whole blood samples were exposed to different magnitudes of shear stress with various shearing times. As the rotational speed was increased up to 2800 rpm, the RBC aggregation index (AI) of the whole blood increased by up to 30% (p <  0.05), whereas that of the platelet-excluded blood samples did not show any apparent alteration. The AI also increased in proportion with the stirring time. The data suggest that high shear stress affects RBC aggregation through shear-induced platelet aggregation. PMID:26444600

  20. Secure Data Aggregation Using Reliable Nodes for Wireless Sensor Networks

    M.Y. Mohamed Yacoab; V. Sundaram


    Generally, aggregation techniques in Wireless Sensor Networks (WSNs) are defenseless against various attacks. The aggregator and aggregated data has to be secured to assure integrity and confidentiality. In this study, we propose a secure data aggregation technique with reliable nodes using key predicate test protocol for sensor network. This technique specialize some nodes as Reliable nodes (R-nodes) to monitor the process of aggregation. Initially, for each node, a secret key is shared betw...

  1. 抑郁情绪大鼠模型中糖水偏好实验数据的聚合分析%Depression in Rat Model Sucrose Preference Test Data Analysis of Aggregation

    侯金良; 魏盛; 杜希扬; 张惠云


    Objective To explore the rat model depression sucrose preference test (Sucrose preference test, SPT) in sucrose preference value SP (Sucrose preference) the best aggregation. Methods Chronic mild stress (CMS) rat model of depression was replicated. In the four weeks of modeling process, gathering a sucrose preference test data for every other week, and the sucrose preference test data using twi-two aggregation analysis approach. Aggregation of different means than the preparation of model reliability and correlation effects. Result ① Kappa TM showed only way to get a higher aggregate reliability (Kappa = 0.611), ② ICC results showed that the aggregation of TM's credibility highest (ICC = 0.910)). Conclusion The appropriate data aggregation can significantly improve depression in rats with sucrose preference test data credibility and stability.%目的 探讨抑郁情绪大鼠模型糖水偏好实验(Sucrose preference test,SPT)中糖水偏好SP(Sucrose preference,sp)系数的最佳聚合方式.方法 慢性温和刺激法复制抑郁情绪大鼠模型.4周造模过程中,每隔一周采集一次大鼠的行为学数据,并对糖水偏好实验数据采用两两聚合的分析方法处理.比对不同聚合手段对模型制备信度及相关性的影响.结果 ①一致性系数(Kappa)结果显示,只有第3种聚合方式能得到较高的可信度(Kappa=0.611),②组内相关系数(ICC)结果表明,聚合方式中TM的可信度最高(ICC=0.910).结论 恰当的数据聚合方式可以大幅提升抑郁情绪大鼠糖水偏好实验中数据的可信度与稳定性.

  2. Aggregation in manpower planning

    Wijngaard, J


    In manpower planning, as in all other kinds of planning, an important choice is the level of aggregation. The proper level of aggregation depends on the flexibility (mobility) of the personnel. This dependency is investigated in this paper. The manpower system considered is characterized by two dimensions, level and function group. Conditions are derived for aggregate long-term planning (aggregation over function group) combined with one-period disaggregation being optimal.

  3. Aggregating Reputation Feedback

    Garcin, Florent; Faltings, Boi; Jurca, Radu


    A fundamental task in reputation systems is to aggregate multiple feedback ratings into a single value that can be used to compare the reputation of different entities. Feedback is most commonly aggregated using the arithmetic mean. However, the mean is quite susceptible to outliers and biases, and thus may not be the most informative aggregate of the reports. We consider three criteria to assess the quality of an aggregator: the informativness, the robustness and the strategyproofness, and a...

  4. Protein aggregation and bioprocessing

    Cromwell, Mary E. M.; Hilario, Eric; Jacobson, Fred


    Protein aggregation is a common issue encountered during manufacture of biotherapeutics. It is possible to influence the amount of aggregate produced during the cell culture and purification process by carefully controlling the environment (eg, media components) and implementing appro-priate strategies to minimize the extent of aggregation. Steps to remove aggregates have been successfully used at a manufacturing scale. Care should be taken when developing a process to monitor the compatibili...

  5. Papel da curva de agregação plaquetária no controle da antiagregação na prevenção secundária do acidente vascular cerebral isquêmico Platelet aggregation test: application in the control of antiplatelet aggregation in the secondary prevention of stroke

    Patrícia Regina Piedade


    Full Text Available INTRODUÇÃO: O acidente vascular cerebral (AVC é atualmente a primeira causa de morte no Brasil. O risco de recorrência de AVC é de aproximadamente 30% em cinco anos. Agentes antiagregantes plaquetários são frequentemente prescritos para a prevenção de recorrência do AVC, porém sem um parâmetro laboratorial de ajuste terapêutico. OBJETIVO: Determinar a aplicabilidade da curva de agregação plaquetária, no controle do antiagregante, na prevenção secundária do acidente vascular cerebral isquêmico (AVCi. MÉTODO: Estudo retrospectivo de janeiro de 1990 a janeiro de 2001; foram analisados 189 pacientes com diagnóstico de AVCi acompanhados durante este período com curva de agregação plaquetária. Foram excluídos os portadores de doenças cardioembólicas. Consideraram-se hipoagregados os doentes com agregação plaquetária ativada pelo ADP e/ou pela adrenalina menor ou igual a 50%. Os doentes tiveram acompanhamento por 1 a 6 anos e a taxa de recorrência de AVCi foi comparada entre os normoagregados e os hipoagregados. RESULTADOS: Nove doentes apresentaram novo AVCi no período do seguimento. Entre os hipoagregados ocorreu 2,6% de recidiva e entre os normoagregados, 15,1% (0,03INTRODUCTION: Stroke is the leading cause of death in Brazil. The risk of suffering a recurrent stroke is around 30% in 5 years. Antiplatelet therapy has been frequently used to prevent recurrent strokes without laboratory control. OBJECTIVE: To determine the value of the platelet aggregation test in the control of antiplatelet aggregation in the secondary stroke prevention. METHOD: Retrospective study from January 1990 to January 2001 with 189 patients with stroke that were followed up during this period with platelet aggregation curve. Patients with cardioembolic disease were excluded. Low aggregation rates of platelet aggregation activated by ADP and/or epinephrine lower or equal to 50% were considered. Patients were followed up for a period from one

  6. Resistência inter e intra-agregados em ensaios de cisalhamento direto de um nitossolo vermelho distrófico Inter and intra-aggregate strength in direct shear tests of a typic hapludox

    João Alfredo Braida


    Full Text Available Para solos agregados, a envoltória da resistência ao cisalhamento pode ser dividida em dois segmentos, com declividades e interceptos diferentes. Um primeiro segmento mais inclinado e com intercepto menor representaria a envoltória de ruptura definida pelo atrito e coesão interagregados, enquanto o segundo segmento, menos inclinado e com intercepto maior, seria a envoltória definida pelo atrito e coesão intra-agregados. O presente estudo foi realizado com o objetivo de avaliar se a envoltória de resistência ao cisalhamento de agregados do horizonte superficial de um Nitossolo Vermelho pode ser subdividida em segmentos distintos, com coeficientes angulares diferentes, e se isso está relacionado à existência de agregados nele. Inicialmente, amostras coletadas na superfície de um Nitossolo Vermelho distrófico latossólico de textura argilosa foram submetidas ao ensaio de cisalhamento direto com pressões normais de 24,4; 48,9; 98,2; 196,4; 294,6; 392,8 e 491,8 kPa. Posteriormente, o ensaio foi realizado com amostras de agregados de cinco classes de diâmetro: For aggregated soils the Mohr failure line can be separated into two straight lines, with different slopes and intercepts. In the range of low normal load, when the slope is very steep and the intercept is small, the failure line is defined by the friction and cohesion inter-aggregates, while for the higher load range the slope becomes smaller and intercept is larger, which defines the intra-aggregate friction and cohesion. Therefore, for aggregated soils the normal load range used in the direct shear test affects the final result. The present study was carried out with the objective of evaluating if the Mohr failure line of a Red Latosolic Nitisol can be subdivided in different segments, with different steepness and intercepts, and if this is related to the existence of soil aggregates. Initially, soil surface samples of a Typic Hapludox (Nitossolo Vermelho Distrófico latoss

  7. In vitro biocompatibility tests of two commercial types of mineral trioxide aggregate Testes de biocompatibilidade in vitro de duas formas comerciais do agregado de trióxido mineral

    Daniel Araki Ribeiro


    Full Text Available Recently, regular and white mineral trioxide aggregate (MTA are being used in Dentistry as retrofilling materials. Genotoxicity and cytotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. Thus, the goal of this study was to examine the genotoxicity and cytotoxicity of regular and white MTA in vitro by the single cell gel (comet assay and trypan blue exclusion test, respectively. Mouse lymphoma cells were exposed to two presentation forms of MTA at final concentrations ranging from 1 to 1,000 µg/mL for 3 h at 37°C. The results showed that both compounds tested did not produce genotoxic effects at all concentrations evaluated. Likewise, no statistically significant differences (p > 0.05 were observed in cytotoxicity. Taken together, our results suggest that regular and white MTA are not genotoxins and are not able to interfere in cellular viability as assessed by single cell gel (comet assay and trypan blue assay, respectively.Recentemente, o agregado de trióxido mineral (MTA regular e branco estão sendo utilizados na Odontologia como materiais para obturação retrógrada de canais radiculares. Testes de genotoxicidade e citotoxicidade formam uma importante parte da pesquisa do câncer e da avaliação de risco de carcinógenos potenciais. Assim, o objetivo deste estudo foi examinar a genotoxicidade e citotoxicidade do MTA branco e regular in vitro pelo teste do cometa e teste de exclusão pelo azul de tripan, respectivamente. Células do linfoma murino foram expostas às duas formas de apresentação do MTA nas concentrações finais de 1 a 1.000 µg/mL por 3 horas a 37°C. Os resultados mostraram que ambos os compostos testados não produziram efeito genotóxico em todas as concentrações testadas. Da mesma forma, nenhuma diferença estatisticamente significativa (p > 0,05 foi observada na citotoxicidade. Em suma, nossos resultados sugerem que o MTA regular e branco não são genotoxinas e




    Working performance and mechanical performance of the recycled aggregates of pervious concrete,pervious concrete and ordinary concrete were analyzed by test.On this basis,shrinkage and freeze resistance of the recycled aggregates of pervious concrete, pervious concrete were mainly studied.The test results showed that the recycled aggregates of the pervious concrete contraction deformation was the largest one,the pervious concrete deformation was larger, and normal concrete deformation was minimal.After 25 freeze-thaw cycles of pervious and recycled aggregate pervious concrete,the compressive strength loss was less than 20%,the quality loss was less than 5%,which could meet the requirement for no sand cement pervious concrete frost resistance index.%通过对再生骨料透水混凝土、透水混凝土、普通混凝土的工作性能和力学性能的试验分析,重点研究再生骨料透水混凝土、透水混凝土的收缩性和抗冻性。试验结果表明:再生骨料透水混凝土的收缩变形最大,透水混凝土的收缩变形次之,普通混凝土的收缩变形最小。透水混凝土和再生骨料透水混凝土25次冻融循环后的抗压强度损失不大于20%,质量损失不大于5%,满足无砂水泥透水混凝土的抗冻性指标要求。

  9. Provenance for Aggregate Queries

    Yael Amsterdamer; Daniel Deutch; Val Tannen


    We study in this paper provenance information for queries with aggregation. Provenance information was studied in the context of various query languages that do not allow for aggregation, and recent work has suggested to capture provenance by annotating the different database tuples with elements of a commutative semiring and propagating the annotations through query evaluation. We show that aggregate queries pose novel challenges rendering this approach inapplicable. Consequently, we propose...

  10. Diffusion in aggregated soil.

    Rappoldt, C.


    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consists of spherical, or cylindrical or plane aggregates, which do not represent the individual aggregates of the soil, however. The radii of the spheres, cylinders or plane sheets represent different le...

  11. The Aggregate-Supply/Aggregate-Demand Model

    BARRO, Robert J.


    The aggregate-supply/ aggregate-demand (AS-AD) model is popular in textbooks, but has problems with logical consistency. In one interpretation, the Keynesian underpinnings of the AD curve-derived from the IS/LM model with downward price stickiness-conflict with the determination of the price level at the intersection of the AS and AD curves. In another view, the model corresponds to rational-expectations theories in which Keynesian properties are absent. In a third interpretation, the model i...

  12. An Aggregation Matrix MATLAB Function

    Caleb Stair


    This Technical Document describes the foundations for an aggregation matrix function implemented in MATLAB, including the format and structure of the required aggregation vector used as an argument to the function. The function is passed with the N-dimensional aggregation vector as an argument. The aggregation vector contains N values ranging from 1 to M, each of which is the aggregate index corresponding to the N pre-aggregation indices. The function returns an aggregation matrix with M rows...

  13. Concrete manufacture with un-graded recycled aggregates

    Richardson, Alan; Coventry, Kathryn; Graham, Sue


    Purpose – The purpose of this paper is to investigate whether concrete that includes un-graded recycled aggregates can be manufactured to a comparable strength to concrete manufactured from virgin aggregates. Design/methodology/approach – A paired comparison test was used to evaluate the difference between concrete made with virgin aggregates (plain control) and concrete including recycled waste. Un-graded construction demolition waste and un-graded ground glass were used as aggregate re...

  14. p53 Aggregates penetrate cells and induce the co-aggregation of intracellular p53.

    Karolyn J Forget

    Full Text Available Prion diseases are unique pathologies in which the infectious particles are prions, a protein aggregate. The prion protein has many particular features, such as spontaneous aggregation, conformation transmission to other native PrP proteins and transmission from an individual to another. Protein aggregation is now frequently associated to many human diseases, for example Alzheimer's disease, Parkinson's disease or type 2 diabetes. A few proteins associated to these conformational diseases are part of a new category of proteins, called prionoids: proteins that share some, but not all, of the characteristics associated with prions. The p53 protein, a transcription factor that plays a major role in cancer, has recently been suggested to be a possible prionoid. The protein has been shown to accumulate in multiple cancer cell types, and its aggregation has also been reproduced in vitro by many independent groups. These observations suggest a role for p53 aggregates in cancer development. This study aims to test the «prion-like» features of p53. Our results show in vitro aggregation of the full length and N-terminally truncated protein (p53C, and penetration of these aggregates into cells. According to our findings, the aggregates enter cells using macropinocytosis, a non-specific pathway of entry. Lastly, we also show that once internalized by the cell, p53C aggregates can co-aggregate with endogenous p53 protein. Together, these findings suggest prion-like characteristics for p53 protein, based on the fact that p53 can spontaneously aggregate, these aggregates can penetrate cells and co-aggregate with cellular p53.

  15. A Novel Method to Quantify Soil Aggregate Stability by Measuring Aggregate Bond Energies

    Efrat, Rachel; Rawlins, Barry G.; Quinton, John N.; Watts, Chris W.; Whitmore, Andy P.


    Soil aggregate stability is a key indicator of soil quality because it controls physical, biological and chemical functions important in cultivated soils. Micro-aggregates are responsible for the long term sequestration of carbon in soil, therefore determine soils role in the carbon cycle. It is thus vital that techniques to measure aggregate stability are accurate, consistent and reliable, in order to appropriately manage and monitor soil quality, and to develop our understanding and estimates of soil as a carbon store to appropriately incorporate in carbon cycle models. Practices used to assess the stability of aggregates vary in sample preparation, operational technique and unit of results. They use proxies and lack quantification. Conflicting results are therefore drawn between projects that do not provide methodological or resultant comparability. Typical modern stability tests suspend aggregates in water and monitor fragmentation upon exposure to an un-quantified amount of ultrasonic energy, utilising a laser granulometer to measure the change in mean weight diameter. In this project a novel approach has been developed based on that of Zhu et al., (2009), to accurately quantify the stability of aggregates by specifically measuring their bond energies. The bond energies are measured operating a combination of calorimetry and a high powered ultrasonic probe, with computable output function. Temperature change during sonication is monitored by an array of probes which enables calculation of the energy spent heating the system (Ph). Our novel technique suspends aggregates in heavy liquid lithium heteropolytungstate, as opposed to water, to avoid exposing aggregates to an immeasurable disruptive energy source, due to cavitation, collisions and clay swelling. Mean weight diameter is measured by a laser granulometer to monitor aggregate breakdown after successive periods of calculated ultrasonic energy input (Pi), until complete dispersion is achieved and bond

  16. Antiplatelet aggregation principles from Ephemerantha lonchophylla.

    Chen, C C; Huang, Y L; Teng, C M


    Bioactivity-directed separation led to the identification of four compounds, viz. denbinobin (1), 3,7-dihydroxy-2,4-dimethoxyphenanthrene (2), 3-methylgigantol (3), and erianthridin (4) from the ethanolic extract of Ephemerantha lonchophylla. Antiplatelet tests were carried out using 4 different aggregation inducers, viz. arachidonic acid (AA), thrombin, collagen and platelet activating factor (PAF). The results indicated that only compounds 2, 3, and 4 exhibited generally significant anti-aggregation activities with that against AA-induced aggregation being most effective. Estimated IC50, values in this regard for 2, 3, and 4 were 24 microM, 30 microM and 9 microM, respectively. PMID:10865460

  17. Charged Dust Aggregate Interactions

    Matthews, Lorin; Hyde, Truell


    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  18. Aggregated Computational Toxicology Online Resource

    U.S. Environmental Protection Agency — Aggregated Computational Toxicology Online Resource (AcTOR) is EPA's online aggregator of all the public sources of chemical toxicity data. ACToR aggregates data...

  19. Some Properties of concretes containing recycled aggregates

    DJERBI TEGGUER, Assia; SAILLIO, Mickael; MAIH-NHU, Johnathan; SCHMITT, Lucie; ROUGEAU, Patrick


    This paper presents the results of an experimental campaign which aimed at determining the viability of incorporating recycled aggregates from concrete, in the production of a new concrete, with acceptable performances for its use in new structures. Nine concrete mixtures with different recycled aggregates contents and with different water to binder (w/b) ratio were studied. The mean compressive strength for the reference concretes is comprised between 30 and 60 MPa. Tests were performed to m...

  20. Protein Colloidal Aggregation Project

    Oliva-Buisson, Yvette J. (Compiler)


    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  1. Platelet activation and aggregation

    Jensen, Maria Sander; Larsen, O H; Christiansen, Kirsten; Fenger-Eriksen, C; Ingerslev, J; Sørensen, Benny


    This study introduces a new laboratory model of whole blood platelet aggregation stimulated by endogenously generated thrombin, and explores this aspect in haemophilia A in which impaired thrombin generation is a major hallmark. The method was established to measure platelet aggregation initiated...... by tissue factor evaluated by means of impedance aggregometry. Citrated whole blood from healthy volunteers and haemophilia A patients with the addition of inhibitors of the contact pathway and fibrin polymerization was evaluated. In healthy persons, a second wave of platelet aggregation was found to...... coincide with the thrombin burst and to be abolished by thrombin inhibitors. In this system, platelet aggregation in severe haemophilia A (n = 10) was found to be significantly decreased as compared with healthy individuals (912 ± 294 vs. 1917 ± 793 AU × min, P = 0.003), most probably due to the weak level...

  2. Coagulation with limited aggregations

    Bertoin, Jean


    Smoluchowski's coagulation equations can be used as elementary mathematical models for the formation of polymers. We review here some recent contributions on a variation of this model in which the number of aggregations for each atom is a priori limited. Macroscopic results in the deterministic setting can be explained at the microscopic level by considering a version of stochastic coalescence with limited aggregations, which can be related to the so-called random configuration model of random graph theory.

  3. The Aggregation Dilemma

    Ingmar Schumacher


    The results in this paper show that the level of aggregation used in a social welfare func- tion matters significantly for policy analysis. Using climate change as an example, it is shown that, under the mild and widely-accepted assumptions of asymmetric climate change impacts and declining marginal utility, an aggregation dilemma may arise that dwarfs most other policy-relevant aspects in the climate change cost-benefit analysis. Estimates based on the RICE-99 model (Nordhaus and Boyer 2000)...

  4. Recycled Concrete as Aggregate for Structural Concrete Production

    Mirjana Malešev; Vlastimir Radonjanin; Snežana Marinković


    A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC) as a control concrete and two types of concrete made with natural fine and recycle...

  5. Evaluation of Colemanite Waste as Aggregate Hot Mix Asphalt Concrete

    Nihat MOROVA


    Full Text Available In this study usability of waste colemanite which is obtained after cutting block colemanite for giving proper shape to blocks as an aggregate in hot mix asphalt. For this aim asphalt concrete samples were prepared with four different aggregate groups and optimum bitumen content was determined. First of all only limestone was used as an aggregate. After that, only colemanite aggregate was used with same aggregate gradation. Then, the next step of the study, Marshall samples were produced by changing coarse and fine aggregate gradation as limestone and colemanite and Marshall test were conducted. When evaluated the results samples which produced with only limestone aggregate gave the maximum Marshall Stability value. When handled other mixture groups (Only colemanite, colemanite as coarse aggregate-limestone as fine aggregate, colemanite as fine aggregate-limestone as coarse aggregate all groups were verified specification limits. As a result, especially in areas where there is widespread colemanite waste, if transportation costs did not exceed the cost of limestone, colemanite stone waste could be used instead of limestone in asphalt concrete mixtures as fine aggregate

  6. Sustainable Concrete with Recycled Aggregate

    Kara, P


    Concretes produced with recycled aggregates are the subject of several papers recently published in the technical literature. Substitution of natural aggregates can be one of possibilities to take care of landfills and increase of CO2 emissions into the atmosphere in Latvia. Recycled aggregate is a valuable resource; value-added consumption of recycled aggregate, as replacement for virgin aggregate in concrete, can yield significant energy and environmental benefits. In present study recycled...

  7. Arrow's Theorem in Judgement Aggregation

    Franz Dietrich; Christian List


    In response to recent work on the aggregation of individual judgements on logically connected propositions into collective judgements, it is often asked whether judgement aggregation is a special case of Arrowian preference aggregation. We argue the opposite. After proving a general impossibility theorem, we construct an embedding of preference aggregation into judgement aggregation and prove Arrow's theorem as a corollary of our result. Although we provide a new proof of Arrow's theorem, our...

  8. Absorption Spectra of Astaxanthin Aggregates

    Olsina, Jan; Durchan, Milan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas


    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption...

  9. Aggregate Oligopoly Games with Entry

    Anderson, Simon P.; Erkal, Nisvan; Piccinin, Daniel


    We use cumulative reaction functions to compare long-run market structures in aggregative oligopoly games. We first compile an IO toolkit for aggregative games. We show strong neutrality properties across market structures. The aggregator stays the same, despite changes in the number of firms and their actions. The IIA property of demands (CES and logit) implies that consumer surplus depends on the aggregator alone, and that the Bertrand pricing game is aggregative. We link together the follo...

  10. Aggregation on heterogeneous surface

    Lu Hang-Jun; Wu Feng-Min; Fang Yun-Zhang


    Chessboard-like substrates are introduced in this paper, in order to study the diffusion-limited aggregation (DLA)and the motion of poly-atoms on heterogeneous surfaces. The effect of morphology of such substrates upon the cluster aggregation is investigated using the Monte Carlo simulation. It is found that the growth process and the cluster morphology are governed by the energetic topography of the substrates. Our simulation also indicate that the island density and the fractal dimension of the clusters depend strongly on the substrate topography and the activation energy.


    杜园芳; 王社良; 赵勤; 樊禹江


    The test is mainly focused on enhanced recycled aggregate concrete .There are two main factors which enhance the performance of recycled aggregate concrete: silica fume and hybrid fiber .The research on the seismic behavior of frame could be done in such way that according to different replacement rate of recycled aggregate the reinforcing materials with different ratio were added to the main parts of frame .The natural frequency , equivalent stiffness,the damping ratio,the vibration mode, the acceleration response and the displacement response etc were analyzed and discussed .The inter-storey deformation was adopted as the index to evaluate the seismic performance of the RAC frame model .The experimental results show that the following points:reinforced materials can significantly inhibit the damage of the RAC frame structure model , reduce earthquake damage of the frame key parts and make up for the deficiency of the ductility of the recycled aggregate concrete .According to research , reinforced materials have good effect on enhancing the aseismic capacity of recycled aggregate concrete frame structures .%试验主要以性能增强再生混凝土为切入点,以构成性能增强再生混凝土的两个主要因素:硅灰及混杂纤维,将框架主要受力部位按照不同再生骨料取代率及掺入不同比率的性能增强材料,着手进行框架抗震性能的研究。对框架模型的自振频率、结构等效刚度、结构阻尼比、结构振型、加速度反应、位移反应进行分析。采用层间变形作为评估指标,对性能增强再生混凝土框架的抗震能力进行评估。试验结果表明:随着地震强度的增加,性能增强材料对再生混凝土框架的破坏有明显的抑制作用,减轻了关键部位的震害,弥补了再生混凝土延性不足,易开裂的缺点。研究表明,性能增强材料对再生混凝土框架结构的抗震能力具有良好的加强作用。

  12. Secure Data Aggregation Using Reliable Nodes for Wireless Sensor Networks

    M.Y. Mohamed Yacoab


    Full Text Available Generally, aggregation techniques in Wireless Sensor Networks (WSNs are defenseless against various attacks. The aggregator and aggregated data has to be secured to assure integrity and confidentiality. In this study, we propose a secure data aggregation technique with reliable nodes using key predicate test protocol for sensor network. This technique specialize some nodes as Reliable nodes (R-nodes to monitor the process of aggregation. Initially, for each node, a secret key is shared between base station and neighboring nodes. Then, an aggregation tree is constructed for transmitting data to the base station in a hierarchical fashion. The aggregator encrypts the data using secret key and forwards to a level up aggregator in aggregation tree. By enhancing broadcasting feature of R-nodes, the aggregated value is verified for ensuring integrity. As keys are shared between neighboring nodes, the nodes are validated using self-key predicate test. The proposed technique is proved through simulation results. It increases the throughput by reducing the packet drops significantly.

  13. A Study of Concrete Made with Fine and Coarse Aggregates Recycled from Fresh Concrete Waste

    Mamery Sérifou; Sbartaï, Z. M.; S. Yotte; Boffoué, M. O.; Emeruwa, E.; Bos, F


    This paper deals with the possibility of using fresh concrete waste as recycled aggregates in concrete. An experimental program based on two variables (proportion of fine aggregates replacement and proportion of coarse aggregates replacement) was implemented. The proportions of replacement were 0%, 50%, and 100% by mass of aggregates. Several mechanical properties were tested as compressive and tensile strengths. The results show a good correlation between aggregates replacement percentage an...

  14. The Effects of Different Fine Recycled Concrete Aggregates on the Properties of Mortar

    Cheng-Chih Fan; Ran Huang; Howard Hwang; Sao-Jeng Chao


    The practical use of recycled concrete aggregate produced by crushing concrete waste reduces the consumption of natural aggregate and the amount of concrete waste that ends up in landfills. This study investigated two methods used in the production of fine recycled concrete aggregate: (1) a method that produces fine as well as coarse aggregate, and (2) a method that produces only fine aggregate. Mortar specimens were tested using a variety of mix proportions to determine how the characteristi...

  15. Modeling the Aggregation Propensity and Toxicity of Amyloid-β Variants

    Tiwari, Manish Kumar; Kepp, Kasper Planeta


    contributes to our understanding of amyloid aggregation and suggests a method to predict aggregation propensity and toxicity of Aβ variants, and potentially to reduce aggregation propensities of amyloids by molecular intervention directed toward specific conformations of the peptides........ The present paper reports modeling of the aggregation propensities and cell toxicities of genetic variants of Aβ known to increase disease risk. From correlation to experimental data, and using four distinct experimental structures to test structural sensitivity, we find that the Spatial Aggregation...

  16. Quality characteristics of fine aggregates and controlling their effects on concrete

    Järvenpää, Hanna


    For the aggregate producer, the concrete aggregates are end products, while, for the concrete manufacturer, the aggregates are raw materials to be used for mix designs and successful concrete production. The aim of this study was to identify which fine aggregate characteristics are important, and additionally to relate the extent of the effect that the aggregate has on the concrete as compared against the effect of the changes in mix design. The testing programme contained six different m...

  17. Aggregates, broccoli and cauliflower

    Grey, Francois; Kjems, Jørgen K.


    Naturally grown structures with fractal characters like broccoli and cauliflower are discussed and compared with DLA-type aggregates. It is suggested that the branching density can be used to characterize the growth process and an experimental method to determine this parameter is proposed.

  18. Diffusion in aggregated soil.

    Rappoldt, C.


    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consist

  19. Repercussions on concrete permeability due to recycled concrete aggregate

    Gómez Soberón, José Manuel Vicente; Agulló Fité, Luís; Vázquez Ramonich, Enric


    This paper presents an experimental analysis of recycled concrete (RC) in which the natural aggregates are replaced by recycled concrete aggregates (RCA). This experimental program covers the specifications of the aggregates employed, together with that of the concrete that is manufactured with them. The considerable effect on the permeability of RC that is produced by the use of RCA is described and discussed. Tests reveal considerable increase in permeability of RC in compari...

  20. Aggregation Algorithms in Heterogeneous Tables

    Titus Felix FURTUNA; Ivan, Ion; Marian DARDALA


    The heterogeneous tables are most used in the problem of aggregation. A solution for this problem is to standardize these tables of figures. In this paper, we proposed some methods of aggregation based on the hierarchical algorithms.

  1. The Effects of Different Fine Recycled Concrete Aggregates on the Properties of Mortar

    Cheng-Chih Fan


    Full Text Available The practical use of recycled concrete aggregate produced by crushing concrete waste reduces the consumption of natural aggregate and the amount of concrete waste that ends up in landfills. This study investigated two methods used in the production of fine recycled concrete aggregate: (1 a method that produces fine as well as coarse aggregate, and (2 a method that produces only fine aggregate. Mortar specimens were tested using a variety of mix proportions to determine how the characteristics of fine recycled concrete aggregate affect the physical and mechanical properties of the resulting mortars. Our results demonstrate the superiority of mortar produced using aggregate produced using the second of the two methods. Nonetheless, far more energy is required to render concrete into fine aggregate than is required to produce coarse as well as fine aggregate simultaneously. Thus, the performance benefits of using only fine recycled concrete aggregate must be balanced against the increased impact on the environment.


    Ahmad Mujahid Ahmad Zaidi


    Used of recycled aggregate (RA) in concrete can be described in environmental protection and economical terms. The application of recycled aggregate to use in construction activities have been practice by developed European countries and also of some Asian countries. This paper reports the results of an experimental study on the mechanical properties of recycled aggregate concrete (RAC) as compared to natural aggregate concrete (NAC). The effects of size of RA on compressive strength were dis...

  3. Judgement aggregation and distributed thinking

    Spiekermann, Kai


    In recent years, judgement aggregation has emerged as an important area of social choice theory. Judgement aggregation is concerned with aggregating sets of individual judgements over logically connected propositions into a set of collective judgements. It has been shown that even seemingly weak conditions on the aggregation function make it impossible to find functions that produce rational collective judgements from all possible rational individual judgements. This implies...

  4. Optimal policies for aggregate recycling from decommissioned forest roads.

    Thompson, Matthew; Sessions, John


    To mitigate the adverse environmental impact of forest roads, especially degradation of endangered salmonid habitat, many public and private land managers in the western United States are actively decommissioning roads where practical and affordable. Road decommissioning is associated with reduced long-term environmental impact. When decommissioning a road, it may be possible to recover some aggregate (crushed rock) from the road surface. Aggregate is used on many low volume forest roads to reduce wheel stresses transferred to the subgrade, reduce erosion, reduce maintenance costs, and improve driver comfort. Previous studies have demonstrated the potential for aggregate to be recovered and used elsewhere on the road network, at a reduced cost compared to purchasing aggregate from a quarry. This article investigates the potential for aggregate recycling to provide an economic incentive to decommission additional roads by reducing transport distance and aggregate procurement costs for other actively used roads. Decommissioning additional roads may, in turn, result in improved aquatic habitat. We present real-world examples of aggregate recycling and discuss the advantages of doing so. Further, we present mixed integer formulations to determine optimal levels of aggregate recycling under economic and environmental objectives. Tested on an example road network, incorporation of aggregate recycling demonstrates substantial cost-savings relative to a baseline scenario without recycling, increasing the likelihood of road decommissioning and reduced habitat degradation. We find that aggregate recycling can result in up to 24% in cost savings (economic objective) and up to 890% in additional length of roads decommissioned (environmental objective). PMID:18481140


    ESEN, Yüksel; ÖZKAYA, Harun


    ABSTRACT The aim of the present study was to investigate the usability of Pyrophyllite rock, which was provided from Poturge district of Malatya province in eastern Turkey, as concrete aggregate. For this purpose some of the aggregate and hardened concrete tests were carried out. In the evaluation of the aggregate trial results; the aggregate loss of 28%, specific gravity of 2.67, saturated surface dry weight of 2.70, absorption percentage of 0.9 and the average loss percentage of 22% accord...

  6. Aggregating governance indicators

    Kaufmann, Daniel; Kraay, Aart; Zoido-Lobaton, Pablo


    In recent years the growing interest of academics and policymakers in governance has been reflected in the proliferation of cross-country indices measuring various aspects of governance. The authors explain how a simple variant of an unobserved components model can be used to combine the information from these different sources into aggregate governance indicators. The main advantage of this method us that it allows quantification of the precision of both individual sources of governance data...

  7. Study of Recycled Concrete Aggregates

    Jitender Sharma; Sandeep Singla


    This paper describes the introduction and production of recycled concrete aggregates and its various applications in the construction industry. In this paper, properties of recycled aggregates and its comparison with the natural aggregates are also mentioned. Future recommendations about RCA are also included.

  8. Proteins aggregation and human diseases

    Hu, Chin-Kun


    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  9. Influence of granitic aggregates from Northeast Brazil on the alkali-aggregate reaction

    Gomes Neto, David de Paiva; Santana, Rodrigo Soares de; Barreto, Ledjane Silva, E-mail: [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Ciencias dos Materiais e Engenharia; Conceicao, Herbert; Lisboa, Vinicios Anselmo Carvalho [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Geologia


    The alkali-aggregate reaction (AAR) in concrete structures is a problem that has concerned engineers and researchers for decades. This reaction occurs when silicates in the aggregates react with the alkalis, forming an expanded gel that can cause cracks in the concrete and reduce its lifespan. The aim of this study was to characterize three coarse granitic aggregates employed in concrete production in northeastern Brazil, correlating petrographic analysis with the kinetics of silica dissolution and the evolution of expansions in mortar bars, assisted by SEM/EDS, XRD, and EDX. The presence of grains showing recrystallization into individual microcrystalline quartz subgrains was associated with faster dissolution of silica and greater expansion in mortar bars. Aggregates showing substantial deformation, such as stretched grains of quartz with strong undulatory extinction, experienced slower dissolution, with reaction and expansion occurring over longer periods that could not be detected using accelerated tests with mortar bars. (author)

  10. Gender differences in platelet aggregation in healthy individuals.

    Otahbachi, Mohammad; Simoni, Jan; Simoni, Grace; Moeller, John F; Cevik, Cihan; Meyerrose, Gary E; Roongsritong, Chanwit


    This study evaluated gender variability in platelet aggregation in response to common agonists. Platelet aggregation was measured in 36 healthy men and women free of any antiplatelet medication, aged 22-36 years, of Caucasian (White not of Hispanic origin), Hispanic, and African-American not of Hispanic origin. In this ex-vivo study, we investigated platelet aggregation in response to adenosine-5'-diphosphate (ADP), epinephrine (EPI), arachidonic acid (AA) and collagen (COL), using a platelet ionized calcium aggregometer (Chrono-Log Co.). Platelet aggregation response to all tested agonists was higher in females than in males regardless of ethnicity. The most significant differences were observed with collagen (P < 0.01). Among the ethnic groups, Caucasian women were most prone to platelet aggregation. Gender is a determinant of agonist effects on platelet aggregability in healthy subjects. PMID:20039102

  11. Assays for alpha-synuclein aggregation

    Giehm, Lise; Lorenzen, Nikolai; Otzen, Daniel


    aggregates 1. The ability to form amyloid structures has also been exploited by living systems, where proteins forming fibrils during the normal life-cycle have functional rather than disease associated properties 2; 3; 4; 5. Thus, understanding the structural features of fibrils, as well as the processes......Over the last few decades, protein aggregation gone from being an irritating side product in the test tube to becoming a subject of great interest. This has been stimulated by the realization that a large and growing number of diseases is associated with the formation and accumulation of proteins...

  12. Concrete Waste Recycling Process for High Quality Aggregate

    . Various tests and evaluation confirmed that the high quality recycled aggregate concrete is almost equal strength and durability to ordinary aggregate concrete. The developed techniques of high quality recycled aggregate production have been applied to several new reinforced concrete buildings in industry since 2002. A practical recycling process for slightly contaminated concrete that consists of high quality recycled aggregate production and radiological survey was proposed

  13. Identifying Fine Aggregates Prone to Polishing in PCC Pavements

    Fowler, David W; Rached, Marc M.


    Surface polishing in portland cement concrete (PCC) pavements leads to higher incidences of skid-related accidents on highways. This type of failure is often associated with the usage of softer fine aggregate such as limestone sands. To identify polish resistance aggregates, state agencies like TxDOT have adopted tests such as the acid insoluble residue test (AIR). Since calcium carbonate is soluble in acid, no carbonate sand passes the AIR test which has a minimum limit of 60% in Texas. This...

  14. Absorption Spectra of Astaxanthin Aggregates

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas


    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  15. Aggregate Demand and Supply

    Farmer, Roger E.A.


    This paper is part of a broader project that provides a microfoundation to the General Theory of J.M. Keynes. I call this project 'old Keynesian economics' to distinguish it from new-Keynesian economics, a theory that is based on the idea that to make sense of Keynes we must assume that prices are sticky. I describe a multi-good model in which I interpret the definitions of aggregate demand and supply found in the General Theory through the lens of a search theory of the labor market. I argue...

  16. Aggregation of smooth preferences

    Norman Schofield


    Suppose p is a smooth preference profile (for a society, N) belonging to a domain PN. Let be a voting rule, and (p)(x) be the set of alternatives in the space, W, which is preferred to x. The equilibrium E((p)) is the set {x∈W:(p)(x) is empty}. A sufficient condition for existence of E((p)) when p is convex is that a "dual", or generalized gradient, d(p)(x), is non-empty at all x. Under certain conditions the dual "field", d(p), admits a "social gradient field" (p). is called an "aggregator" ...

  17. Charge-based fractionation of oxyanion-forming metals and metalloids leached from recycled concrete aggregates of different degrees of carbonation: a comparison of laboratory and field leaching tests.

    Mulugeta, Mesay; Engelsen, Christian J; Wibetoe, Grethe; Lund, Walter


    The release and charge-based fractionation of As, Cr, Mo, Sb, Se and V were evaluated in leachates generated from recycled concrete aggregates (RCA) in a laboratory and at a field site. The leachates, covering the pH range 8.4-12.6, were generated from non-carbonated, and artificially and naturally carbonated crushed concrete samples. Comparison between the release of the elements from the non-carbonated and carbonated samples indicated higher solubility of the elements from the latter. The laboratory leaching tests also revealed that the solubility of the elements is low at the "natural pH" of the non-carbonated materials and show enhancement when the pH is decreased. The charge-based fractionation of the elements was determined by ion-exchange solid phase extraction (SPE); it was found that all the target elements predominantly existed as anions in both the laboratory and field leachates. The high fraction of the anionic species of the elements in the leachates from the carbonated RCA materials verified the enhanced solubility of the oxyanionic species of the elements as a result of carbonation. The concentrations of the elements in the leachates and SPE effluents were determined by inductively coupled plasma mass spectrometry (ICP-MS). PMID:20542679

  18. Asphaltene Aggregation and Fouling Behavior

    Derakhshesh, Marzie

    . Analysis of the spectra of the whole asphaltene samples in toluene indicates that the absorbance of visible light with wavelengths > 600 nm follows a lambda--4 dependence. This functional dependence is consistent with Rayleigh scattering. Rayleigh scattering provides strong evidence that the apparent absorption of visible light by asphaltenes from 600-800 nm is not a molecular absorption phenomenon but rather a scattering mechanism. Rayleigh scattering equations were combined with experimental visible spectra to estimate the average nanoaggregate sizes, which were in a very good agreement with the sizes reported in the literature. The occlusion of two polynuclear aromatic hydrocarbons (PAHs) (pyrene and phenanthrene) in asphaltene precipitates was tested by adding PAHs to the asphaltene in toluene solutions, precipitating by n-pentane and determining the amount of PAHs in precipitates using simulated distillation instrument. Pyrene and phenanthrene, which are normally soluble in the toluene-n-pentane solutions, were detected in the asphaltene precipitates at up to 6 wt% concentration. Trapping of PAHs outside of the nanoaggregates during precipitation gave 7-14 times less of the PAHs in the solid precipitate. This study shows that asphaltene aggregates can interact significantly with PAHs. The results are consistent with the presence open porous asphaltene nanoaggregates in solutions such as toluene.

  19. Taurine and platelet aggregation

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 μM/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na+ and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with 14C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 μM, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet

  20. A Study of Concrete Made with Fine and Coarse Aggregates Recycled from Fresh Concrete Waste

    Mamery Sérifou


    Full Text Available This paper deals with the possibility of using fresh concrete waste as recycled aggregates in concrete. An experimental program based on two variables (proportion of fine aggregates replacement and proportion of coarse aggregates replacement was implemented. The proportions of replacement were 0%, 50%, and 100% by mass of aggregates. Several mechanical properties were tested as compressive and tensile strengths. The results show a good correlation between aggregates replacement percentage and concrete properties. Concerning mechanical properties, a gradual decrease in compressive, splitting, and flexural strengthn with the increase in recycled aggregate percentage is shown.

  1. Laboratory evaluation of cement treated aggregate containing crushed clay brick

    Liqun Hu


    Full Text Available The waste clay bricks from debris of buildings were evaluated through lab tests as environmental friendly materials for pavement sub-base in the research. Five sets of coarse aggregates which contained 0, 25%, 50%, 75% and 100% crushed bricks, respectively, were blended with sand and treated by 5% cement. The test results indicated that cement treated aggregate which contains crushed clay brick aggregate had a lower maximum dry density (MDD and a higher optimum moisture content (OMC. Moreover, the unconfined compressive strength (UCS, resilience modulus, splitting strength, and frost resistance performance of the specimens decreased with increase of the amount of crushed clay brick aggregate. On the other hand, it can be observed that the use of crushed clay brick in the mixture decreased the dry shrinkage strain of the specimens. Compared with the asphalt pavement design specifications of China, the results imply that the substitution rate of natural aggregate with crushed clay brick aggregate in the cement treated aggregate sub-base material should be less than 50% (5% cement content in the mixture. Furthermore, it needs to be noted that the cement treated aggregate which contains crushed clay bricks should be cautiously used in the cold region due to its insufficient frost resistance performance.

  2. Recycled Concrete as Aggregate for Structural Concrete Production

    Mirjana Malešev


    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  3. Holographic characterization of protein aggregates

    Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David

    Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.

  4. Biomimetic Dye Aggregate Solar Cells

    Marek, Peter L.


    A biomimetic self-assembling dye, which forms aggregates that mimic the natural light-harvesting system of special photosynthetic active bacteria, has been investigated towards its applicability to solar cells. This fully synthetic dye, self-assembles to orderly structured nano- to micrometer sized rod-shaped aggregates, which might improve solar cells based on conventional organic dyes. In order to use the full potential of the dye aggregates, the self-assembly needed to be controlled and a ...

  5. Aggregation in Large Dynamic Panels

    Pesaran, Mohammad Hashem; Chudik, Alexander


    This paper considers the problem of aggregation in the case of large linear dynamic panels, where each micro unit is potentially related to all other micro units, and where micro innovations are allowed to be cross sectionally dependent. Following Pesaran (2003), an optimal aggregate function is derived, and the limiting behavior of the aggregation error is investigated as N (the number of cross section units) increases. Certain distributional features of micro parameters are also identi...

  6. Effects of maximum aggregate size on UPV of brick aggregate concrete.

    Mohammed, Tarek Uddin; Mahmood, Aziz Hasan


    Investigation was carried out to study the effects of maximum aggregate size (MAS) (12.5mm, 19.0mm, 25.0mm, 37.5mm, and 50.0mm) on ultrasonic pulse velocity (UPV) of concrete. For investigation, first class bricks were collected and broken to make coarse aggregate. The aggregates were tested for specific gravity, absorption capacity, unit weight, and abrasion resistance. Cylindrical concrete specimens were made with different sand to aggregate volume ratio (s/a) (0.40 and 0.45), W/C ratio (0.45, 0.50, and 0.55), and cement content (375kg/m(3) and 400kg/m(3)). The specimens were tested for compressive strength and Young's modulus. UPV through wet specimen was measured using Portable Ultrasonic Non-destructive Digital Indicating Tester (PUNDIT). Results indicate that the pulse velocity through concrete increases with an increase in MAS. Relationships between UPV and compressive strength; and UPV and Young's modulus of concrete are proposed for different maximum sizes of brick aggregate. PMID:27085110

  7. Some mechanical properties of normal and recycled aggregate concretes

    Kazemi, K Akhavan; EREN, Özgür; Rezaei, Alireza


    This paper describes an experimental study conducted to investigate the properties of concretes produced with recycled aggregates and normal aggregates for two different concrete classes (C20/25, C30/37). Tests of compressive strength, splitting tensile strength, ultrasonic pulse velocity, rebound hammer, wet and dry density, and freeze-thaw resistance were conducted on specimens of the concretes. Moreover, slump test was conducted on fresh concrete. The results showed that the slump of Recyc...

  8. Modifiers of mutant huntingtin aggregation

    Teuling, Eva; Bourgonje, Annika; Veenje, Sven; Thijssen, Karen; Boer, Jelle de; van der Velde, Joeri; Swertz, Morris; Nollen, Ellen


    Protein aggregation is a common hallmark of a number of age-related neurodegenerative diseases, including Alzheimer’s, Parkinson’s, and polyglutamine-expansion disorders such as Huntington’s disease, but how aggregation-prone proteins lead to pathology is not known. Using a genome-wide RNAi screen in a C. elegans-model for polyglutamine aggregation, we previously identified 186 genes that suppress aggregation. Using an RNAi screen for human orthologs of these genes, we here present 26 human g...

  9. Aggregation dynamics of rigid polyelectrolytes

    Tom, Anvy Moly; Rajesh, R.; Vemparala, Satyavani


    Similarly charged polyelectrolytes are known to attract each other and aggregate into bundles when the charge density of the polymers exceeds a critical value that depends on the valency of the counterions. The dynamics of aggregation of such rigid polyelectrolytes are studied using large scale molecular dynamics simulations. We find that the morphology of the aggregates depends on the value of the charge density of the polymers. For values close to the critical value, the shape of the aggregates is cylindrical with height equal to the length of a single polyelectrolyte chain. However, for larger values of charge, the linear extent of the aggregates increases as more and more polymers aggregate. In both the cases, we show that the number of aggregates decrease with time as power laws with exponents that are not numerically distinguishable from each other and are independent of charge density of the polymers, valency of the counterions, density, and length of the polyelectrolyte chain. We model the aggregation dynamics using the Smoluchowski coagulation equation with kernels determined from the molecular dynamics simulations and justify the numerically obtained value of the exponent. Our results suggest that once counterions condense, effective interactions between polyelectrolyte chains short-ranged and the aggregation of polyelectrolytes are diffusion-limited.

  10. Novel aspects of platelet aggregation

    Roka-Moya Y. M.


    Full Text Available The platelet aggregation is an important process, which is critical for the hemostatic plug formation and thrombosis. Recent studies have shown that the platelet aggregation is more complex and dynamic than it was previously thought. There are several mechanisms that can initiate the platelet aggregation and each of them operates under specific conditions in vivo. At the same time, the influence of certain plasma proteins on this process should be considered. This review intends to summarize the recent data concerning the adhesive molecules and their receptors, which provide the platelet aggregation under different conditions.

  11. Platelet aggregation following trauma

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders;


    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED......). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...

  12. Fractal Aggregation Under Rotation

    WUFeng-Min; WULi-Li; LUHang-Jun; LIQiao-Wen; YEGao-Xiang


    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω; thefractal dimension decreases with increasing ω;, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  13. Fractal Aggregation Under Rotation

    WU Feng-Min; WU Li-Li; LU Hang-Jun; LI Qiao-Wen; YE Gao-Xiang


    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω the fractal dimension decreases with increasing ω, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  14. Acoustic emission monitoring of recycled aggregate concrete under bending

    Tsoumani, A. A.; Barkoula, N.-M.; Matikas, T. E.


    The amount of construction and demolition waste has increased considerably over the last few years, making desirable the reuse of this waste in the concrete industry. In the present study concrete specimens are subjected at the age of 28 days to four-point bending with concurrent monitoring of their acoustic emission (AE) activity. Several concrete mixtures prepared using recycled aggregates at various percentages of the total coarse aggregate and also a reference mix using natural aggregates, were included to investigate their influence of the recycled aggregates on the load bearing capacity, as well as on the fracture mechanisms. The results reveal that for low levels of substitution the influence of using recycled aggregates on the flexural strength is negligible while higher levels of substitution lead into its deterioration. The total AE activity, as well as the AE signals emitted during failure, was related to flexural strength. The results obtained during test processing were found to be in agreement with visual observation.

  15. Research on Judgment Aggregation Based on Logic

    Li Dai; Jihua Zhang


    Preference aggregation and judgment aggregation are two basic research models of group decision making. And preference aggregation has been deeply studied in social choice theory. However, researches of social choice theory gradually focus on judgment aggregation which appears recently. Judgment aggregation focuses on how to aggregate many consistent logical formulas into one, from the perspective of logic. We try to start with judgment aggregation model based on logic and then explore differ...

  16. Effect of Chipped Rubber Aggregates on Performance of Concrete

    Sunil N. Shah


    Full Text Available Due to rapid growth in automobile industry, use of tyre increases day to day and there is no reuse of the same to decrease the environmental pollution. The decomposition and disposing of waste tyre rubber is harmful to environment. This research reflects the reuse of waste tyre rubber into concrete after observing their properties. In that experimental work chipped rubber aggregates replaced to the natural coarse aggregates by varying percentage of 3, 6, 9 and 12 with comparison of 0% replacement. Silica fume is replaced in 10% with cement for improving the bond properties between cement paste and rubber. In evaluation, test has been carried out to determine the properties of concrete such as workability, unit weight, flexural strength and split tensile strength. The workability of fresh concrete is observed with the help of compaction factor test. From the test of compaction factor, workability is decrease with increasing percentage of chipped rubber. The specific gravity of chipped rubber aggregates is lower as compared to natural aggregates therefore decrease the unit weight of rubber mix concrete. Increasing chipped rubber aggregates as partial replacement into concrete reduces compressive strength. So these can use in non-primary structural applications of medium to low strength requirements. The overall results of study show that it is possible to use recycled rubber tyre aggregates in concrete construction as partial replacement to natural coarse aggregates.

  17. A study of concrete properties using phyllite as coarse aggregates

    Nowadays, industrial activities generate a huge amount of waste. One such activity is underground mining which generates phyllite wastes that are recycled as coarse aggregates for use in concrete production. Aggregate use in concrete is dependent on availability. This paper reports of an experimental study on some of the physical and mechanical properties of phyllite aggregate concrete as compared to granite (conventional) aggregate concrete. The obtained physical and mechanical properties of both aggregates for specific gravity, water absorption (%), dry density, aggregate impact value (%), aggregate crushing value (%), 10% fines, elongation index (%), flakiness index (%) and Los Angeles abrasion values satisfied minimum requirements for aggregates suitable for concrete production. Five mixes of concrete mix proportions designated M1, M2, M3, M4 and M5 were cast using phyllite and granite aggregates. A total of 400 concrete cubes and 210 modulus of rupture beams were cast and cured by total submerging in water for ages 3, 7, 14, 28, 56, 90, 180 and 360 days before compression and bending tests were performed. The results show that the trends in the development of compressive and bending strengths of plain phyllite concrete were similar to those in granite (conventional) aggregate concrete. However the compressive and bending strengths of phyllite concrete mixes were on the average 15-20% lower than those of the corresponding granite concrete mixes at all ages. The same concrete mix proportions gave lower concrete classes for phyllite compared to granite with the exception of the lowest grade. This was probably because the flakiness and elongation properties coupled with reactive materials in phyllite aggregates affect the absorption and bond characteristics of its concrete.

  18. Material properties of frc with recycled aggregate

    Trčková, Jiřina; Procházka, P.


    Roč. 8, č. 2 (2011), s. 105-113. ISSN 1214-9705 R&D Projects: GA ČR GA103/08/1197 Institutional research plan: CEZ:AV0Z30460519 Keywords : recycled aggregate * concrete composite * pullout test Subject RIV: JM - Building Engineering Impact factor: 0.530, year: 2011

  19. Topics in Probabilistic Judgment Aggregation

    Wang, Guanchun


    This dissertation is a compilation of several studies that are united by their relevance to probabilistic judgment aggregation. In the face of complex and uncertain events, panels of judges are frequently consulted to provide probabilistic forecasts, and aggregation of such estimates in groups often yield better results than could have been made…

  20. J-aggregates, v.2

    Kobayashi, Takayoshi


    This work deals with J-aggregates, which have a long history of research. The volume covers electronic states, linear and nonlinear optical properties. Various properties and processes of J-aggregates, such as super-radiance, excitons, photon echo, geometrical structure, electron transfer and femtosecond spectroscopy, are discussed.

  1. Molecular aggregation of humic substances

    Wershaw, R. L.


    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  2. Immunogenicity of Therapeutic Protein Aggregates.

    Moussa, Ehab M; Panchal, Jainik P; Moorthy, Balakrishnan S; Blum, Janice S; Joubert, Marisa K; Narhi, Linda O; Topp, Elizabeth M


    Therapeutic proteins have a propensity for aggregation during manufacturing, shipping, and storage. The presence of aggregates in protein drug products can induce adverse immune responses in patients that may affect safety and efficacy, and so it is of concern to both manufacturers and regulatory agencies. In this vein, there is a lack of understanding of the physicochemical determinants of immunological responses and a lack of standardized analytical methods to survey the molecular properties of aggregates associated with immune activation. In this review, we provide an overview of the basic immune mechanisms in the context of interactions with protein aggregates. We then critically examine the literature with emphasis on the underlying immune mechanisms as they relate to aggregate properties. Finally, we highlight the gaps in our current understanding of this issue and offer recommendations for future research. PMID:26869409


    F.; Einar; Kruis


    A new procedure was developed for estimating the effective collision diameter of an aggregate composed of primary particles of any size. The coagulation coefficient of two oppositely charged particles was measured experimentally and compared with classic Fuchs theory, including a new method to account for particle non-sphericity. A second set of experiments were performed on well-defined nanoparticle aggregates at different stages of sintering, i.e. from the aggregate to the fully sintered stage. Here, electrical mobility was used to characterize the particle drag. The aggregates are being built from two different size-fractionated nanoparticle aerosols, the non-aggregated particles are discarded by an electrofilter and then they are passed through a furnace at concentrations low enough not to induce coagulation.

  4. Mechanics of fire ant aggregations

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto


    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks.

  5. Erythrocyte aggregation in flowing blood

    This paper addresses the issue of whether nonionic contrast media (CM) promote thrombosis by the formation of large, irregular red blood cell aggregates with videomicroscopy and a flow chamber, red blood cell aggregates adjacent to an endothelial cell monolayer were imaged at 17 sec-1 in dilute suspensions (hematocrit, --8) at 370C in plasma with 20% CM by non-red blood cell volume. All aggregates were rouleaux (<100 μm) readily dispersed at higher shear rates. Aggregate length in eight experiments was increased 11% by ioxaglate (320 mg of iodine per milliliter), decreased 58% by diatrizoate (370 mg of iodine per milliliter) but reduced similarly (16%) by iohexol (350 mg of iodine per milliliter) and saline. Iohexol did not enhance platelet aggregation on injured monolayers

  6. RankAggreg, an R package for weighted rank aggregation

    Datta Susmita


    Full Text Available Abstract Background Researchers in the field of bioinformatics often face a challenge of combining several ordered lists in a proper and efficient manner. Rank aggregation techniques offer a general and flexible framework that allows one to objectively perform the necessary aggregation. With the rapid growth of high-throughput genomic and proteomic studies, the potential utility of rank aggregation in the context of meta-analysis becomes even more apparent. One of the major strengths of rank-based aggregation is the ability to combine lists coming from different sources and platforms, for example different microarray chips, which may or may not be directly comparable otherwise. Results The RankAggreg package provides two methods for combining the ordered lists: the Cross-Entropy method and the Genetic Algorithm. Two examples of rank aggregation using the package are given in the manuscript: one in the context of clustering based on gene expression, and the other one in the context of meta-analysis of prostate cancer microarray experiments. Conclusion The two examples described in the manuscript clearly show the utility of the RankAggreg package in the current bioinformatics context where ordered lists are routinely produced as a result of modern high-throughput technologies.

  7. Platelet aggregation and quality control of platelet concentrates produced in the Amazon Blood Bank

    Maria José Dantas Coêlho; Taysa de Castro Monteiro; Felicien Gonçalves Vasquez; Kátia Luz Torres Silva; Kleber Sandro Brasil dos Santos; Viviana Maria Araújo de Oliveira; Francimary de Oliveira Cavalcante


    BACKGROUND: The study of platelet aggregation is essential to assess in vitro platelet function by different platelet activation pathways. OBJECTIVE: To assess aggregation and biochemical parameters of random platelet concentrates produced at the Fundação HEMOAM using the quality control tests defined by law. METHODS: Whole blood samples from 80 donors and the respective platelet concentrate units were tested. Platelet concentrates were tested (platelet count, aggregation and pH) on days 1, 3...

  8. Perspectives on Preference Aggregation.

    Regenwetter, Michel


    For centuries, the mathematical aggregation of preferences by groups, organizations, or society itself has received keen interdisciplinary attention. Extensive theoretical work in economics and political science throughout the second half of the 20th century has highlighted the idea that competing notions of rational social choice intrinsically contradict each other. This has led some researchers to consider coherent democratic decision making to be a mathematical impossibility. Recent empirical work in psychology qualifies that view. This nontechnical review sketches a quantitative research paradigm for the behavioral investigation of mathematical social choice rules on real ballots, experimental choices, or attitudinal survey data. The article poses a series of open questions. Some classical work sometimes makes assumptions about voter preferences that are descriptively invalid. Do such technical assumptions lead the theory astray? How can empirical work inform the formulation of meaningful theoretical primitives? Classical "impossibility results" leverage the fact that certain desirable mathematical properties logically cannot hold in all conceivable electorates. Do these properties nonetheless hold true in empirical distributions of preferences? Will future behavioral analyses continue to contradict the expectations of established theory? Under what conditions do competing consensus methods yield identical outcomes and why do they do so? PMID:26158988

  9. Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete

    Fidelis O. OKAFOR


    Full Text Available Recycled asphalt pavement (RAP is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely differing water/cement ratios and mix proportions were made using RAP as coarse aggregate. The properties tested include the physical properties of the RAP aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar concretes made with natural gravel aggregate. Results of the tests suggest that the strength of concrete made from RAP is dependent on the bond strength of the “asphalt-mortar” (asphalt binder-sand-filler matrix coatings on the aggregates and may not produce concrete with compressive strength above 25 MPa. However, for middle and low strength concrete, the material was found to compare favorably with natural gravel aggregate.

  10. Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

    al-Swaidani Aref M.


    Full Text Available The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction. Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289 and accelerated mortar bar test (ASTM C1260 have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida’a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

  11. Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

    al-Swaidani, Aref M.; Baddoura, Mohammad K.; Aliyan, Samira D.; Choeb, Walid


    The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction). Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289) and accelerated mortar bar test (ASTM C1260) have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida'a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

  12. Relationship between soil aggregate strength, shape and porosity for soils under different long-term management

    Munkholm, Lars Juhl; Heck, Richard J; Deen, Bill;


    Soil aggregate properties, such as strength, shape and porosity, influence a range of essential soil functions and there is a need for more detailed understanding of the effect of soil management on these aggregate properties. There is also a need for improved knowledge on the link between...... aggregate and bulk soil properties. The objectives of this study were to quantify the long-term effect of rotation and tillage on aggregate shape, strength and pore characteristics, to evaluate the influence of aggregate shape and pore characteristics on aggregate strength and soil friability and to...... the aggregateswere determined using image analysis with 40 μm voxel size. Subsequently, aggregate tensile strength was determined in an indirect tension test. Rotation had a more pronounced effect than tillage treatment on the different aggregate properties. The diverse rotation resulted in higher...

  13. Using new aggregation operators in rule-based intelligent control

    Berenji, Hamid R.; Chen, Yung-Yaw; Yager, Ronald R.


    A new aggregation operator is applied in the design of an approximate reasoning-based controller. The ordered weighted averaging (OWA) operator has the property of lying between the And function and the Or function used in previous fuzzy set reasoning systems. It is shown here that, by applying OWA operators, more generalized types of control rules, which may include linguistic quantifiers such as Many and Most, can be developed. The new aggregation operators, as tested in a cart-pole balancing control problem, illustrate improved performance when compared with existing fuzzy control aggregation schemes.

  14. Comparative environmental assessment of natural and recycled aggregate concrete.

    Marinković, S; Radonjanin, V; Malešev, M; Ignjatović, I


    Constant and rapid increase in construction and demolition (C&D) waste generation and consumption of natural aggregate for concrete production became one of the biggest environmental problems in the construction industry. Recycling of C&D waste represents one way to convert a waste product into a resource but the environment benefits through energy consumption, emissions and fallouts reductions are not certain. The main purpose of this study is to determine the potentials of recycled aggregate concrete (concrete made with recycled concrete aggregate) for structural applications and to compare the environmental impact of the production of two types of ready-mixed concrete: natural aggregate concrete (NAC) made entirely with river aggregate and recycled aggregate concrete (RAC) made with natural fine and recycled coarse aggregate. Based on the analysis of up-to-date experimental evidence, including own tests results, it is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible. The Life Cycle Assessment (LCA) is performed for raw material extraction and material production part of the concrete life cycle including transport. Assessment is based on local LCI data and on typical conditions in Serbia. Results of this specific case study show that impacts of aggregate and cement production phases are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types. Limit natural aggregate transport distances above which the environmental impacts of RAC can be equal or even lower than the impacts of NAC are calculated for the specific case study. PMID:20434898

  15. Asbestos Tailings as Aggregates for Asphalt Mixture

    LIU Xinoming; XU Linrong


    To use many asbestos tailings collected in Ya-Lu highway, and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures, and properties of some asphalt mixtures were evaluated as well. X-ray diffraction (XRD), X-ray fluorescent (XRF), and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper, zinc, lead, and cadmium. Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated compared with those with basalt as aggregates.XRD and XRF measurement results infer that asbestos tailing is an excellent road material. Volume properties of AC-25 asphalt mixture with asbestos tailings satisfied the related specifications. No heavy metals and toxic pollution were detected in AAS test and the value of pH test is 8.23, which is help to the adhesion with asphalt in the asphalt concrete. When compared with basalt, high temperature property and the resistance to low temperature cracking of AC-25 asphalt mixture was improved by using asbestos tailings as aggregates. In-service AC-25 asphalt pavement with asbestos tailings also presented excellent performance and British Pendulum Number (BPN) coefficient of surface.

  16. Anonymous aggregator election and data aggregation in wireless sensor networks

    Tamás Holczer; Levente Buttyán


    In mission critical cyber-physical systems, dependability is an important requirement at all layers of the system architecture. In this paper, we propose protocols that increase the dependability of wireless sensor networks, which are potentially useful building blocks in cyber-physical systems. More specifically, we propose two private aggregator node election protocols, a private data aggregation protocol, and a corresponding private query protocol for sensor networks that allow for secure ...

  17. Mapuche Herbal Medicine Inhibits Blood Platelet Aggregation

    Susan Skanderup Falkenberg


    Full Text Available 12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM and collagen- (2.0 μg/mL induced aggregations in human blood. These four species in respective extracts (in brackets were Blechnum chilense (MeOH, Luma apiculata (H2O, Amomyrtus luma (DCM : MeOH 1 : 1 and Cestrum parqui (DCM : MeOH 1 : 1. The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1, and L. apiculata (H2O were substantial and confirmed by inhibition of platelet surface activation markers.

  18. Fault tolerant aggregation for power system services

    Kosek, Anna Magdalena; Gehrke, Oliver; Kullmann, Daniel


    Exploiting the flexibility in distributed energy resources (DER) is seen as an important contribution to allow high penetrations of renewable generation in electrical power systems. However, the present control infrastructure in power systems is not well suited for the integration of a very large...... number of small units. A common approach is to aggregate a portfolio of such units together and expose them to the power system as a single large virtual unit. In order to realize the vision of a Smart Grid, concepts for flexible, resilient and reliable aggregation infrastructures are required. This...... paper presents such a concept while focusing on the aspect of resilience and fault tolerance. The proposed concept makes use of a multi-level election algorithm to transparently manage the addition, removal, failure and reorganization of units. It has been implemented and tested as a proof-of-concept on...

  19. Performance of Recycled Aggregate Concrete Containing Micronised Biomass Silica

    Suraya Hani Adnan; Ismail Abdul Rahman; Lee Yee Loon


    This paper presents a study on Micronised Biomass Silica (MBS) that was produced from the controlled burning of waste Rice Husk. The MBS was used as pozzolan material to enhance the performance of Recycled Aggregate Concrete (RAC). Various percentages by mass of Micronised Biomass Silica were applied in the normal and recycled aggregate concrete cube samples. Compressive strength and water permeability tested on the samples at the age of 7, 14, 28 and 90 days showed that concrete containing M...

  20. Intraspecific Aggregation Alters Competitive Interactions in Experimental Plant Communities

    Stoll, Peter; Prati, Daniel


    We tested the prediction from spatial competition models that intraspecific aggregation may promote coexistence and thus maintain biodiversity with experimental communities of four annual species. Monocultures, three-species mixtures, and the four-species mixture were sown at two densities and with either random or intraspecifically aggregated distributions. There was a hierarchy of competitive abilities among the four species. The weaker competitors showed higher aboveground biomass in the a...

  1. Arrow’s theorem in judgment aggregation

    Dietrich, Franz; List, Christian


    In response to recent work on the aggregation of individual judgments on logically connected propositions into collective judgments, it is often asked whether judgment aggregation is a special case of Arrowian preference aggregation. We argue for the converse claim. After proving two impossibility theorems on judgment aggregation (using “systematicity” and “independence” conditions, respectively), we construct an embedding of preference aggregation into judgment aggregation and prove Arrow’s ...

  2. Aggregated Computational Toxicology Resource (ACTOR)

    U.S. Environmental Protection Agency — The Aggregated Computational Toxicology Resource (ACTOR) is a database on environmental chemicals that is searchable by chemical name and other identifiers, and by...

  3. Isolation and Aggregation in Economics

    Schlicht, Ekkehart


    In explaining economic phenomena, economic analysis concentrates on selected influences and fixes the host of other factors under a ceteris paribus clause. This view, which goes back to Alfred Marshall (1842-1924), is developed in the first part of the book. Aggregation is viewed as a particular application of ceteris paribus analysis - isolation from "structural effects". This leads to an approach, called "closed aggregation", which was introduced by Kenneth May and is also implicit in Keyne...

  4. Judgment aggregation with consistency alone

    Dietrich, Franz; List, Christian


    All existing impossibility theorems on judgment aggregation require individ- ual and collective judgment sets to be consistent and complete (in some recent results with completeness relaxed to deductive closure), arguably a demand- ing rationality requirement. They do not carry over to aggregation functions mapping pro…les of (merely) consistent individual judgment sets to (merely) consistent collective ones. We prove that, whenever the agenda of propositions under consideration exhibits mild...

  5. Judgment aggregation without full rationality

    Dietrich, Franz; List, Christian


    Several recent results on the aggregation of judgments over logically connected propositions show that, under certain conditions, dictatorships are the only independent (i.e., propositionwise) aggregation rules generating fully rational (i.e., complete and consistent) collective judgments. A frequently mentioned route to avoid dictatorships is to allow incomplete collective judgments. We show that this route does not lead very far: we obtain (strong) oligarchies rather than dictatorships if i...

  6. Familial aggregation of cluster headache

    Cruz, S; Lemos, C; Monteiro, JM


    Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders. OBJECTIVE: To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects. METHOD: Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonom...

  7. Familial aggregation of cluster headache

    Simao Cruz; Carolina Lemos; Jose Maria Pereira Monteiro


    Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders. Objective To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects. Method Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonomic headache...

  8. Comparative study of heavy and deuterium-depleted water on platelet aggregation

    The effects of timed incubation of PRP (Platelet-Rich Plasma) with various concentrations of deuterium-depleted or deuterated water were tested. Aggregation curves were obtained under constant stirring at 20 deg.C and at 37 deg.C, using 5 - 10 μM ADP as aggregation trigger, using a Specord photo colorimeter. Incubation with 10 % deuterated water showed a significant decrease in the aggregation curves, an effect consistent with the data in the literature. Incubation with deuterium depleted water in the same conditions showed a marked increase in the aggregation curves, which suggests a powerful pro-aggregating effect of deuterium depleted water. (authors)

  9. [Isosorbide dinitrate inhibits in vitro platelet aggregation at submicromolar concentrations].

    Gachet, C; Guillou, J; Moog, S; Cazenave, J P


    Nitrate derivatives have in vivo and in vitro platelet anti-aggregant properties in addition to their vasodilatory effects. The mode of action is related to increased intracytoplasmic cyclic GMP concentrations. It has been shown that isosorbide dinitrate (ISDN) has this type of platelet anti-aggregant activity but the reported results about the active concentrations and the inhibited pathways of activation are contradictory. This study was designed to determine whether ISDN has in vitro platelet anti-aggregant activity at low doses and to verify if this effect is selective by aggregation induced by ADP. Finally, a possible potentialisation of the inhibitors due to ISDN was looked for with cyclic nucleotide phosphodiesterase inhibitors and with agents simulating the effect of adenylate cyclase. The results showed that: 1) ISDN had platelet anti-aggregant activity in vitro at concentrations of about 10-7 M, 2) that this effect was not limited to the aggregation induced by ADP as the aggregation induced by PAF-acether was also inhibited by low dose ISDN, 3) of the cyclic nucleotide modulators tested, only quercetine (flavonoide) potentialised the effects of ISDN. PMID:1326933

  10. Tillage system effects on stability and sorptivity of soil aggregates

    M. Turski


    Full Text Available Stability and sorptivity of soil aggregates play an important role in numerous soil processes and functions. They are largely influenced by tillage methods. We have compared the effects of long-term application of various tillage systems on aggregate bulk density, rate of wetting, sorptivity, water stability, tensile strength and bulk density of silt loam Eutric Fluvisol. Tillage treatments were: 1 ploughing to the depth of 20 cm (CT, 2 ploughing to 20 cm every 6 years and harrowing to 5 cm in the remaining years (S/CT, 3 harrowing to 5 cm each year (S, 4 sowing to uncultivated soil (NT, all in a micro-plot experiment. Bulk density of soil aggregates was determined by wax method, sorptivity – by a steady state flow, water stability – by drop impact method, and tensile strength – by crushing test. Tillage had a significant effect on the aggregate characteristics. Soil aggregate bulk density and water stability were greater and rate of wetting and sorptivity were smaller in reduced and no-tillage treatments compared with CT. Greater soil organic matter and bulk density accompanied greater water stability. Smaller rate of wetting and sorptivity can be associated with lower aggregate porosity. The differences in the rate of wetting, sorptivity, and water stability of the initially air-dry soil aggregates and bulk density between the tillage treatments were relatively greater than those in the tensile strength.

  11. Ceramic ware waste as coarse aggregate for structural concrete production.

    García-González, Julia; Rodríguez-Robles, Desirée; Juan-Valdés, Andrés; Morán-Del Pozo, Julia M; Guerra-Romero, M Ignacio


    The manufacture of any kind of product inevitably entails the production of waste. The quantity of waste generated by the ceramic industry, a very important sector in Spain, is between 5% and 8% of the final output and it is therefore necessary to find an effective waste recovery method. The aim of the study reported in the present article was to seek a sustainable means of managing waste from the ceramic industry through the incorporation of this type of waste in the total replacement of conventional aggregate (gravel) used in structural concrete. Having verified that the recycled ceramic aggregates met all the technical requirements imposed by current Spanish legislation, established in the Code on Structural Concrete (EHE-08), then it is prepared a control concrete mix and the recycled concrete mix using 100% recycled ceramic aggregate instead of coarse natural aggregate. The concretes obtained were subjected to the appropriate tests in order to conduct a comparison of their mechanical properties. The results show that the concretes made using ceramic sanitary ware aggregate possessed the same mechanical properties as those made with conventional aggregate. It is therefore possible to conclude that the reuse of recycled ceramic aggregate to produce recycled concrete is a feasible alternative for the sustainable management of this waste. PMID:25188783

  12. Glycation precedes lens crystallin aggregation

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [3H]NaBH4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  13. Kinetic model for erythrocyte aggregation.

    Bertoluzzo, S M; Bollini, A; Rasia, M; Raynal, A


    It is well known that light transmission through blood is the most widely utilized method for the study of erythrocyte aggregation. The curves obtained had been considered empirically as exponential functions. In consequence, the process becomes characterized by an only parameter that varies with all the process factors without discrimination. In the present paper a mathematical model for RBC aggregation process is deduced in accordance with von Smoluchowski's theory about the kinetics of colloidal particles agglomeration. The equation fitted the experimental pattern of the RBC suspension optical transmittance closely and contained two parameters that estimate the most important characteristics of the aggregation process separately, i.e., (1) average size of rouleaux at equilibrium and (2) aggregation rate. The evaluation of the method was assessed by some factors affecting erythrocyte aggregation, such as temperature, plasma dilutions, Dextran 500, Dextran 70 and PVP 360, at different media concentrations, cellular membrane alteration by the alkylating agent TCEA, and decrease of medium osmolarity. Results were interpreted considering the process characteristics estimated by the parameters, and there were also compared with similar studies carried out by other authors with other methods. This analysis allowed us to conclude that the equation proposed is reliable and useful to study erythrocyte aggregation. PMID:10660481

  14. Application of Analytic Hierarchy Process to Prioritize Urban Transport Options - Comparative Analysis of Group Aggregation Methods

    Sudhakar Yedla; Ram M. Shrestha


    The present study presents a comparative analysis of different group aggregation methods adopted in AHP by testing them against social choice axioms with a case study of Delhi transport system. The group aggregation (GA) methods and their correctness were tested while prioritizing the alternative options to achieve energy efficient and less polluting transport system in Delhi. It was observed that among all group aggregation methods, geometric mean method (GMM) - the most widely adopted GA me...




    Full Text Available Continuous aggregation queries are used to monitor the changes in data with time varying for online decision making. For continuous queries low cost and scalable techniques used a network of aggregators. Individual node cannot by itself determine its inclusion in the query result for this a different algorithmic challenges from aggregate and selection queries are presented. At specific coherencies each data item can serve for a set of data aggregators. Technique involves disseminating query into sub query and sub queries are executed on the chosen data aggregators. We build a query cost model which can be used to estimate the number of refresh messages which is required to satisfy the client specified incoherency bound. Performance results shows that by our method the query can be executed using less than one third the messages required for existing schemes. Our adaptive strategy employs distributed decisions made by the distributed servers independently based on localized statistics collected by each server at runtime. When comparatively static environment, propose two motionless tree construction algorithms relying on apriori system statistics. These static trees can also be used as early trees in a dynamic environment and apply our schemes to both single- and multi object distribution. Our extensive performance study illustrate that the adaptive mechanisms.

  16. Utilization of sewage sludge in the manufacture of lightweight aggregate.

    Franus, Małgorzata; Barnat-Hunek, Danuta; Wdowin, Magdalena


    This paper presents a comprehensive study on the possibility of sewage sludge management in a sintered ceramic material such as a lightweight aggregate. Made from clay and sludge lightweight aggregates were sintered at two temperatures: 1100 °C (name of sample LWA1) and 1150 °C (name of sample LWA2). Physical and mechanical properties indicate that the resulting expanded clay aggregate containing sludge meets the basic requirements for lightweight aggregates. The presence of sludge supports the swelling of the raw material, thereby causing an increase in the porosity of aggregates. The LWA2 has a lower value of bulk particle density (0.414 g/cm(3)), apparent particle density (0.87 g/cm(3)), and dry particle density (2.59 g/cm(3)) than it is in the case of LWA1 where these parameters were as follows: bulk particle density 0.685 g/cm(3), apparent particle density 1.05 g/cm(3), and dry particle density 2.69 g/cm(3). Water absorption and porosity of LWA1 (WA = 14.4 %, P = 60 %) are lower than the LWA2 (WA = 16.2 % and P = 66 %). This is due to the higher heating temperature of granules which make the waste gases, liberating them from the decomposition of organic sewage sludge. The compressive strength of LWA2 aggregate is 4.64 MPa and for LWA1 is 0.79 MPa. Results of leaching tests of heavy metals from examined aggregates have shown that insoluble metal compounds are placed in silicate and aluminosilicate structure of the starting materials (clays and sludges), whereas soluble substances formed crystalline skeleton of the aggregates. The thermal synthesis of lightweight aggregates from clay and sludge mixture is a waste-free method of their development. PMID:26635022

  17. Soil aggregation and aggregate associated organic carbon and total nitrogen under long-term contrasting soil management regimes in loess soil

    XIE Jun-yu; XU Ming-gang; Qiangjiu Ciren; YANG Yang; ZHANG Shu-lan; SUN Ben-hua; YANG Xue-yun


    This study investigated the effects of three contrasting soil management regimes and different nutrient treatments on the distribution of water-stable aggregates (>2, 1–2, 0.5–1, 0.25–0.5, and 0.25 mm) and mean weight diameter (MWD) at 0–10 and 10–20 cm soil horizons compared with Cropping, whereas Falow yielded lower values of above two parameters. Abandonment increased SOC and TN contents in al aggregate sizes by 17–62%and 6–60%, respectively, at 0–10 cm soil layer compared with Cropping. Conversely, Falow decreased SOC and TN contents in al aggregates by 7–27% and 7–25%, respectively. Nevertheless, the three soil management regimes presented similar SOC contents in al aggregates at 10–20 cm soil horizon. Only Cropping showed higher TN content in >0.5 mm aggregates than the two other regimes. Consequently, Abandonment enhanced the partitioning proportions of SOC and TN in >1 mm macro-aggregates, and Falow promoted these proportions in micro-aggregates compared with Cropping. Under Cropping, long-term fertilization did not affect the distribution of aggregates and MWD values compared with those under CK, except for NPK treatment. Fertilizer treatments enhanced SOC and TN contents in aggregates at al tested soil depths. However, fertilization did not affect the partitioning proportions of SOC and TN contents in al aggregates compared with CK. Comprehensive results showed that different soil management regimes generated varied patterns of SOC and TN sequestration in loess soil. Abandonment enhanced soil aggregation and sequestered high amounts of SOC and TN in macro-aggregates. Long-term amendment of organic manure integrated with NPK maintained soil aggregate stability and improved SOC and TN sequestration in al aggregates in loess soil subjected to dryland farming.

  18. Aggregation patterns of fetal rat brain cells following exposure to X-irradiation

    Shoji, R.; Suzuki, K.; Lee, I.P.


    In our search for a simplified in vitro test system to assess the teratogenic effects of physical factors, we studied the effects of total maternal body X-irradiation on aggregation patterns of enzymatically isolated fetal rat brain cells and on ultrastructural aggregate changes. The fetal brain cells were derived from day 14 gestation fetuses of pregnant Sprague-Dawley (CD strain) rats exposed to X-irradiation (25 - 200 R) one hour prior to sacrifice. Notable changes in the cell aggregates following X-irradiation included a reduction in cell aggregate size and an increase in number. The frequency of cell aggregates was higher in the treated than in the control group, and the mean diameter of cell aggregates was inversely related to increasing X-irradiation doses. Transmission electron microscopy revealed in isolated cells features of degenerative process which were similar to those found in intact fetal brain lesions caused by maternal X-irradiation. Furthermore, scanning electron microscopy revealed that inhibition of cell aggregation following X-irradiation could probably be attributed to inhibition of membrane filopodia development and a consequent failure of cell aggregates to fuse into a greater cell aggregate mass. These results suggest that the membrane factors which influence cell aggregation may be a useful parameter to assess early effects of X-irradiation-induced brain deformity. Presently, the cell aggregation culture system is being further evaluated as a short term test system for environmental teratogens.

  19. Recycling of PET bottles as fine aggregate in concrete.

    Frigione, Mariaenrica


    An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility. PMID:20176466

  20. Thiazine dyes: Evaluation of monomeric and aggregate forms.

    Vara, Jimena; Ortiz, Cristina S


    The aggregation phenomenon of Azure B, monobrominated Azure B, Thionine and Methylene Blue was studied by UV-Visible spectrophotometry in different media as a function of dye concentration and temperature variations. The tests carried out in organic solvents allowed the identification of monomeric species of these compounds, which have not been reported in literature and have been wrongly assigned for years. The results obtained in water allowed demonstrating that different kinds of aggregates are present in this medium. In addition, the aggregation tendency of these dyes in organic solvent and aqueous media was established. Several parameters such as lipophilicity, effect of bulky substituents and interactions with media were considered to interpret the aggregation behavior of thiazine dyes. PMID:27219075

  1. Collisional evolution of dust aggregates. From compaction to catastrophic destruction

    Paszun, D


    The coagulation of dust aggregates occurs in various astrophysical environments. Each one is characterized by different conditions that influence the growth, e.g. relative velocities, composition, and size of the smallest constituents (monomers). Here we study the microphysics of collisions of dust aggregates in a four-dimensional parameter space. The parameters are the collision energy, the initial compactness of agglomerates, the mass ratio of collision partners, and the impact parameter. For this purpose we employ a state of the art molecular dynamics type of model that has been extensively and successfully tested against laboratory experiments. It simulates the motion of individual monomers interacting dynamically via van der Waals surface forces. The structure of aggregates is quantified by the filling factor that provides information about the internal structure, the packing density of monomers, and the projected surface area of aggregates. Our results show the importance of the impact parameter that ca...

  2. Aggregated wind power generation probabilistic forecasting based on particle filter

    Highlights: • A new method for probabilistic forecasting of aggregated wind power generation. • A dynamic system is established based on a numerical weather prediction model. • The new method handles the non-Gaussian and time-varying wind power uncertainties. • Particle filter is applied to forecast predictive densities of wind generation. - Abstract: Probability distribution of aggregated wind power generation in a region is one of important issues for power system daily operation. This paper presents a novel method to forecast the predictive densities of the aggregated wind power generation from several geographically distributed wind farms, considering the non-Gaussian and non-stationary characteristics in wind power uncertainties. Based on a mesoscale numerical weather prediction model, a dynamic system is established to formulate the relationship between the atmospheric and near-surface wind fields of geographically distributed wind farms. A recursively backtracking framework based on the particle filter is applied to estimate the atmospheric state with the near-surface wind power generation measurements, and to forecast the possible samples of the aggregated wind power generation. The predictive densities of the aggregated wind power generation are then estimated based on these predicted samples by a kernel density estimator. In case studies, the new method presented is tested on a 9 wind farms system in Midwestern United States. The testing results that the new method can provide competitive interval forecasts for the aggregated wind power generation with conventional statistical based models, which validates the effectiveness of the new method

  3. Fire Resistance of Concrete Constructions with Expanded Clay Aggregate

    Hertz, Kristian Dahl

    The paper describes briefly a series of full-scale tests made as documentation for extending the field of application of the reduced cross section method from the structural codes to constructions based on expanded clay aggregate. As a special result the tests verify that slabs with a short...

  4. Fractal Aggregates in Tennis Ball Systems

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.


    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  5. Lithological influence of aggregate in the alkali-carbonate reaction

    The reactivity of carbonate rock with the alkali content of cement, commonly called alkali-carbonate reaction (ACR), has been investigated. Alkali-silica reaction (ASR) can also contribute in the alkali-aggregate reaction (AAR) in carbonate rock, mainly due to micro- and crypto-crystalline quartz or clay content in carbonate aggregate. Both ACR and ASR can occur in the same system, as has been also evidenced on this paper. Carbonate aggregate samples were selected using lithological reactivity criteria, taking into account the presence of dedolomitization, partial dolomitization, micro- and crypto-crystalline quartz. Selected rocks include calcitic dolostone with chert (CDX), calcitic dolostone with dedolomitization (CDD), limestone with chert (LX), marly calcitic dolostone with partial dolomitization (CD), high-porosity ferric dolostone with clays (FD). To evaluate the reactivity, aggregates were studied using expansion tests following RILEM AAR-2, AAR-5, a modification using LiOH AAR-5Li was also tested. A complementary study was done using petrographic monitoring with polarised light microscopy on aggregates immersed in NaOH and LiOH solutions after different ages. SEM-EDAX has been used to identify the presence of brucite as a product of dedolomitization. An ACR reaction showed shrinkage of the mortar bars in alkaline solutions explained by induced dedolomitization, while an ASR process typically displayed expansion. Neither shrinkage nor expansion was observed when mortar bars were immersed in solutions of lithium hydroxide. Carbonate aggregate classification with AAR pathology risk has been elaborated based on mechanical behaviours by expansion and shrinkage. It is proposed to be used as a petrographic method for AAR diagnosis to complement the RILEM AAR1 specifically for carbonate aggregate. Aggregate materials can be classified as I (non-reactive), II (potentially reactive), and III (probably reactive), considering induced dedolomitization ACR

  6. An exact approach for aggregated formulations

    Gamst, Mette; Spoorendonk, Simon; Røpke, Stefan

    Aggregating formulations is a powerful approach for problems to take on tractable forms. Aggregation may lead to loss of information, i.e. the aggregated formulation may be an approximation of the original problem. In branch-and-bound context, aggregation can also complicate branching, e.g. when...... optimality cannot be guaranteed by branching on aggregated variables. We present a generic exact solution method to remedy the drawbacks of aggregation. It combines the original and aggregated formulations and applies Benders' decomposition. We apply the method to the Split Delivery Vehicle Routing Problem....

  7. Flexural fatigue characteristics of steel fiber reinforced recycled aggregate concrete (SFRRAC

    Heeralal M.


    Full Text Available This research work is aimed at investigating the flexural fatigue behavior of Steel Fiber Reinforced Recycled Aggregate Concrete (SFRRAC. This study gains importance in view of the wide potential for demolished concrete to serve as a source of quality aggregate feed stock in a variety of structural and non-structural applications. This is a continuation of a series of investigations being conducted aimed at optimizing the utilization of recycled aggregate concrete in rigid pavements. A total of 72 standard flexure specimens of 100mm x 100mm x 450mm were cast and tested for flexure under both static and fatigue loading. The parameters of the investigation included the different replacements of recycled aggregate in natural aggregate, presence of steel fiber and different stress levels. The study showed that the recycled aggregates can be used in rigid pavements also and the inclusion of fibers can benefit the fatigue performance of recycled aggregate concrete.

  8. Benchmarking in healthcare using aggregated indicators

    Traberg, Andreas; Jacobsen, Peter


    databases, the model is constructed as a comprehensive hierarchy of indicators. By aggregating the outcome of each indicator, the model is able to benchmark healthcare providing units. By assessing performance deeper in the hierarchy, a more detailed view of performance is obtained. The validity test of the...... model is performed at a Danish non-profit hospital, where four radiological sites are benchmarked against each other. Because of the multifaceted perspective on performance, the model proved valuable both as a benchmarking tool and as an internal decision support system....

  9. Mapuche Herbal Medicine Inhibits Blood Platelet Aggregation

    Susan Skanderup Falkenberg; Inge Tarnow; Alfonso Guzman; Per Mølgaard; Henrik Toft Simonsen


    12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM) and collagen- (2.0 μg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H2O), Amomyrtus l...

  10. Destructive Strength Properties of Recycled Coarse Aggregate

    Chetna M Vyas,; Darshana R Bhatt,


    Due to a critical shortage of natural aggregate, the availability of demolished concrete for use as recycled coarse aggregate (RCA) is increasing. Use of waste concrete as RCA conserves natural aggregate, reduces the impact on landfills, save energy and can provide cost benefit. Recycled aggregates are the materials for the future. The application of recycled aggregate has been started in many Asian & Western countries for construction projects. Research Paper reports the basic strength prope...

  11. Erythrocyte aggregation: Basic aspects and clinical importance

    Başkurt, Oğuz K.; Meiselman, Herbert J.


    Red blood cells (RBC) aggregate to form two- and three-dimensional structures when suspended in aqueous solutions containing large plasma proteins or polymers; this aggregation is reversible and shear dependent (i.e., dispersed at high shear and reformed at low or stasis). The extent of aggregation is the main determinant of low shear blood viscosity, thus predicting an inverse relationship between aggregation and in vivo blood flow. However, the effects of aggregation on hemodynamic mechanis...

  12. Individual income, incomplete information, and aggregate consumption

    Pischke, J.


    In this paper I study a model of life-cycle consumption in which individuals react optimally to their own income process but ignore economy wide information. Since individual income is less persistent than aggregate income consumers will react too little to aggregate income variation. Aggregate consumption will be excessively smooth. Since aggregate information is slowly incorporated into consumption, aggregate consumption will be autocorrelated and correlated with lagged income. The second p...

  13. Turbulent breakage of ductile aggregates

    Marchioli, Cristian


    In this paper we study breakage rate statistics of small colloidal aggregates in non-homogeneous anisotropic turbulence. We use pseudo-spectral direct numerical simulation of turbulent channel flow and Lagrangian tracking to follow the motion of the aggregates, modelled as sub-Kolmogorov massless particles. We focus specifically on the effects produced by ductile rupture: This rupture is initially activated when fluctuating hydrodynamic stresses exceed a critical value, $\\sigma>\\sigma_{cr}$, and is brought to completion when the energy absorbed by the aggregate meets the critical breakage value. We show that ductile rupture breakage rates are significantly reduced with respect to the case of instantaneous brittle rupture (i.e. breakage occurs as soon as $\\sigma>\\sigma_{cr}$). These discrepancies are due to the different energy values at play as well as to the statistical features of energy distribution in the anisotropic turbulence case examined.

  14. Equilibrium structure of ferrofluid aggregates

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  15. Molecular Aggregation in Disodium Cromoglycate

    Singh, Gautam; Agra-Kooijman, D.; Collings, P. J.; Kumar, Satyendra


    Details of molecular aggregation in the mesophases of the anti-asthmatic drug disodium cromoglycate (DSCG) have been studied using x-ray synchrotron scattering. The results show two reflections, one at wide angles corresponding to π-π stacking (3.32 å) of molecules, and the other at small angles which is perpendicular to the direction of molecular stacking and corresponds to the distance between the molecular aggregates. The latter varies from 35 - 41 å in the nematic (N) phase and 27 -- 32 å in the columnar (M) phase. The temperature evolution of the stack height, positional order correlations in the lateral direction, and orientation order parameter were determined in the N, M, and biphasic regions. The structure of the N and M phases and the nature of the molecular aggregation, together with their dependence on temperature and concentration, will be presented.

  16. Photostimulated Aggregation of Metal Aerosols

    Karpov, Sergei V


    The effect of optical radiation on the rate of aggregation of nanoscopic particles is studied in metal aerosols. It has been shown that under light exposure, polydisperse metal aerosols can aggregate up to two orders faster due to the size dependent photoelectron effect from nanoparticles. Different size nanoparticles undergo mutual heteropolar charging when exchanging photoelectrons through the interparticle medium to result in an increased rate of aggregation. It is shown that long-range electrostatic attractive forces drive the particles into closer distances where the short-range Van-der-Waals forces become dominating. Attention is drawn to the fact that this effect may occur in various types of dispersed systems as well as in natural heteroaerosols.

  17. Quantum Diffusion-Limited Aggregation

    Johnson, David B


    Though classical random walks have been studied for many years, research concerning their quantum analogues, quantum random walks, has only come about recently. Numerous simulations of both types of walks have been run and analyzed, and are generally well-understood. Research pertaining to one of the more important properties of classical random walks, namely, their ability to build fractal structures in diffusion-limited aggregation, has been particularly noteworthy. However, only now has research begun in this area in regards to quantum random motion. The study of random walks and the structures they build has various applications in materials science. Since all processes are quantum in nature, it is important to consider the quantum variant of diffusion-limited aggregation. Recognizing that Schr\\"odinger equation and a classical random walk are both diffusion equations, it is possible to connect and compare them. Using similar parameters for both equations, we ran various simulations aggregating particles....

  18. Balancing energy flexibilities through aggregation

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach


    in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already......One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... during aggregation aim at balancing flexibilities in production and consumption to reduce the probability of congestions and reduce the complexity of scheduling. We present results of our extensive experiments....

  19. Characterization of the effects of isoprostanes on platelet aggregation in human whole blood

    Cranshaw, Julius H; Evans, Timothy W.; Mitchell, Jane A.


    We tested the effects of 11 commercially-available isoprostanes on platelet aggregation directly or when triggered by the thromboxane receptor agonist U46619 or collagen in healthy human citrated blood using a whole blood aggregometer.None of the isoprostanes tested triggered aggregation alone, nor facilitated aggregation by a sub-threshold dose of U46619 or collagen. Five isoprostanes inhibited aggregation (rank order of potency 8-iso PGE1>8-iso PGE2>8-iso PGF2α>8-iso PGF3α>8-iso-13,14-dihyd...

  20. Aggregation models on hypergraphs

    Alberici, Diego; Mingione, Emanuele; Molari, Marco


    Following a newly introduced approach by Rasetti and Merelli we investigate the possibility to extract topological information about the space where interacting systems are modelled. From the statistical datum of their observable quantities, like the correlation functions, we show how to reconstruct the activities of their constitutive parts which embed the topological information. The procedure is implemented on a class of polymer models with hard-core interactions. We show that the model fulfils a set of iterative relations for the partition function that generalise those introduced by Heilmann and Lieb for the monomer-dimer case. After translating those relations into structural identities for the correlation functions we use them to test the precision and the robustness of the inverse problem. Finally the possible presence of a further interaction of peer-to-peer type is considered and a criterion to discover it is identified.

  1. Testing Study on the Strength and Permeable Performance of Recycled Aggregate Pervious Concrete%再生骨料透水混凝土的强度和透水性能试验研究



    Recycled aggregate pervious concrete integrates the function of the recycled concrete and permeable concrete advantages,which have important application prospect in the road and landscape architecture engineering.With the double index of strength and permeable coefficient,factors that have influence on the permeable concrete intensity recycled aggregates, including the particle size, size distribution and composition,and water-binder ratio (0.25,0.30,0.35),the adding of mineral admixture proportion (10%, 20%,30%),target porosity (15%,20%,25%),and permeable coefficient,were experimentally studied. The configuration method of recycled aggregate pervious concrete was proposed.Results are useful for permeable concrete proportion design and construction technology of recycled aggregates.%再生骨料透水混凝土集成了再生混凝土和透水混凝土的功能优点,在小区道路和景观工程中有重要应用前景。采用强度和透水系数双指标控制,试验研究了再生骨料的粒径、级配和组成、水胶比(0.25、0.30、0.35)、矿物掺和料及掺加比例(10%、20%、30%)、目标孔隙率(15%、20%、25%)等因素对再生骨料透水混凝土强度和透水系数的影响,给出了再生骨料透水混凝土的配制方法,研究成果对于再生骨料透水混凝土的配比设计及施工技术应用具有工程应用价值。

  2. Utilisation of iron ore tailings as aggregates in concrete

    Francis Atta Kuranchie


    Full Text Available Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did not improve against the control mix due high content of fines in the tailings aggregates but showed 4.8% improvement compared with the previous study where the conventional fine aggregates was partially replaced by 20% with iron ore tailings.


    Yamada, Hiroshi; Katahira, Hiroshi; Watanabe, Hiroshi

    Drying shrinkage of coarse aggregate is one of principal indexes to evaluate drying shrinkage of concrete. However, testing of drying shrinkage of a coarse aggregate particle has not been commonly conducted. We carried out measurement of drying shrinkage of a coarse aggregate particle using wire strain gauges and discussed the variation in the measurement. We found that variation among particles in drying shrinkage strain of coarse aggregate is intrinsic and much bigger than test result due to the simplified unidirectional strain measurement under the assumption of ignoring multi-axial strain field. Strong relationship between the mean value of drying shrinkage strain of coarse aggregate and drying shrinkage strain of concrete prism specimens was observed, which indicates that measured drying shrinkage strain of aggregate particles intrinsically contains large variation, however the mean value is an effective index to estimate drying shrinkage of concrete.

  4. Studies on recycled aggregates-based concrete.

    Rakshvir, Major; Barai, Sudhirkumar V


    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design. PMID:16784165

  5. Diversity, intent, and aggregated search

    M. de Rijke


    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous que

  6. Child Labor and Aggregate Fluctuations

    Stéphane Pallage; Alice Fabre


    In this paper, we build a dynamic general equilibrium model with heterogeneous agents to measure the welfare effect of banning child labor in an economy with aggregate fluctuations and idiosyncratic shocks to employment. We then design an unemployment insurance system that generates the endogenous elimination of child labor.

  7. Test

    Bendixen, Carsten


    Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers.......Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers....

  8. High Modulus Asphalt Concrete with Dolomite Aggregates

    Haritonovs, V.; Tihonovs, J.; Smirnovs, J.


    Dolomite is one of the most widely available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1,000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality, mainly, its LA index (The Los Angeles abrasion test). Therefore, mostly the imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used, which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue, and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance with EN 13108-1 standard.

  9. Porous Pavers: Effects of the Recycled Aggregate Size on Drainage Properties

    Abdul Ghani A.N.; Cheong P.C.


    Pervious pavers allow water to percolate through the pavement surface. One of its functions is to reduce runoff. This research studies the possible usage of recycled aggregates as the main base material for pervious pavers. Recycled aggregates are produced by crushing waste concrete and mixing with a non-cement, epoxy binder to produce a pervious pavement. The samples were tested for permeability, porosity and compressive strength. The effects of using recycled aggregates and epoxy binders on...

  10. Effect of Thai medicinal plant extracts on cell aggregation of Escherichia coli O157: H7.

    Limsuwan, S.; Vanmanee, S.; Voravuthikunchai, S.


    Medicinal plants have been used for treating diarrhoea but the interference mechanisms are not clearly understood. One possible hypothesis is that of an effect on cell surface hydrophobicity of microbial cells. In this study, we examined cell aggregation affected by crude extracts of Thai medicinal plants on cell surface hydrophobicity of Escherichia coli strains by salt aggregation test. Correlation between minimal inhibitory concentration and cell aggregation was performed. Aqueous and etha...

  11. Keishibukuryogan, a Traditional Japanese Medicine, Inhibits Platelet Aggregation in Guinea Pig Whole Blood

    Kiyoshi Terawaki; Masamichi Noguchi; Mitsutoshi Yuzurihara; Yuji Omiya; Yasushi Ikarashi; Yoshio Kase


    Effects of keishibukuryogan (KBG) on platelet aggregation were investigated. To ensure the specificity of KBG, tokishakuyakusan (TSS) and kamisyoyosan (KSS), which are known to have platelet aggregation-inhibiting effects, and rikkunshito (RKT) and shakuyakukanzoto (SKT), which are considered to be devoid of such effects, were used for comparison. The platelet aggregation of each test drug was measured by the screen filtration pressure method using whole blood of guinea pigs and expressed as ...

  12. Effect of Fractal Dimension of Fine Aggregates on the Concrete Chloride Resistance

    Xue, Wen; J. Chen


    The relationship between fractal dimension of fine aggregates and the chloride resistance of concrete was investigated in this study. Both concrete and mortar specimens were cast. Concrete specimens were in the same mix design as the mortar specimens except for the coarse aggregates. The specimens were divided into different groups based on the gradation of the fine aggregates. The chloride resistances of concrete specimens were tested by using the rapid chloride migration method. The results...

  13. Using Information Aggregation Markets for Decision Support

    Patrick Buckley


    Full Text Available Information Aggregation Markets, often referred to as prediction markets, are markets that are designed to aggregate information from a disparate pool of human individuals to make predictions about the likely outcome of future uncertain events. This paper looks at how Information Aggregation Markets can be incorporated into the standard body of decision making theory. It examines how Information Aggregation Markets can be used as decision support systems, and provides empirical evidence from a wide variety of sources as to the effectiveness and practicality of Information Aggregation Markets. Finally, this paper details some future research questions to be addressed in the area of Information Aggregation Markets.

  14. Properties of concrete blocks prepared with low grade recycled aggregates.

    Poon, Chi-Sun; Kou, Shi-cong; Wan, Hui-wen; Etxeberria, Miren


    Low grade recycled aggregates obtained from a construction waste sorting facility were tested to assess the feasibility of using these in the production of concrete blocks. The characteristics of the sorted construction waste are significantly different from that of crushed concrete rubbles that are mostly derived from demolition waste streams. This is due to the presence of higher percentages of non-concrete components (e.g. >10% soil, brick, tiles etc.) in the sorted construction waste. In the study reported in this paper, three series of concrete block mixtures were prepared by using the low grade recycled aggregates to replace (i) natural coarse granite (10mm), and (ii) 0, 25, 50, 75 and 100% replacement levels of crushed stone fine (crushed natural granite concrete blocks. Test results on properties such as density, compressive strength, transverse strength and drying shrinkage as well as strength reduction after exposure to 800 degrees C are presented below. The results show that the soil content in the recycled fine aggregate was an important factor in affecting the properties of the blocks produced and the mechanical strength deceased with increasing low grade recycled fine aggregate content. But the higher soil content in the recycled aggregates reduced the reduction of compressive strength of the blocks after exposure to high temperature due probably to the formation of a new crystalline phase. The results show that the low grade recycled aggregates obtained from the construction waste sorting facility has potential to be used as aggregates for making non-structural pre-cast concrete blocks. PMID:19398196

  15. Comparison of different forms of gravel as aggregate in concrete

    Sikiru ORITOLA


    Full Text Available Gradation plays an important role in the workability, segregation, and pump ability of concrete. Uniformly distributed aggregates require less paste which will also decrease bleeding, creep and shrinkage while producing better workability, more durable concrete and higher packing. This attempt looks at the effect of particle size distribution pattern for five types of gravel aggregate forms, angular, elongated, smooth rounded, irregular and flaky as related to the strength of concrete produced. Different forms of naturally existing gravel aggregate were collected from a particular location and tests were carried out on them to determine their gradation. Based on the gradation the aggregates were used to prepare different samples of grade 20 concrete with water-cement ratio of 0.5. The particle size distribution resulted in coefficients of uniformity ranging from 1.24 to 1.44. The granite aggregate, which serves as a reference, had a coefficient of uniformity of 1.47. Tests were conducted on fresh and hardened concrete cube samples. The concrete sample CT5 recorded a slump of 32mm and highest compressive strength value of 21.7 N/mm2, among the concrete produced from different forms of gravel.

  16. Estimation of line efficiency by aggregation

    Koster, de, MBM René


    textabstractPresents a multi-stage flow lines with intermediate buffers approximated by two-stage lines using repeated aggregation. Characteristics of the aggregation method; Problems associated with the analysis and design of production lines.

  17. Aggregation of metallochlorophylls - Examination by spectroscopy

    Boucher, L. J.; Katz, J. J.


    Nuclear magnetic resonance measurements determine which metallochlorophylls, besides magnesium-containing chlorophylls, possess coordination aggregation properties. Infrared spectroscopy reveals that only zinc pheophytin and zinc methyl pheophorbide showed significant coordination aggregation, whereas divalent nickel and copper did not.

  18. Yeast prions: protein aggregation is not enough.

    Sherman, Michael Y


    Although many proteins -- both damaged and normal -- have a tendency to aggregate, only some are capable of dividing and propagating. What does it take to turn a protein aggregate into an infectious prion?

  19. Estimation of Line Efficiency by Aggregation

    M.B.M. de Koster (René)


    textabstractPresents a multi-stage flow lines with intermediate buffers approximated by two-stage lines using repeated aggregation. Characteristics of the aggregation method; Problems associated with the analysis and design of production lines.

  20. Elections, information aggregation, and strategic voting

    Feddersen, Timothy; Pesendorfer, Wolfgang


    A central role of elections is the aggregation of information dispersed within a population. This article surveys recent work on elections as mechanisms for aggregating information and on the incentives for voters to vote strategically in such elections.

  1. Bacterial Association with Particles: Aggregation to Dissolution

    DeSouza, M.J.B.D.

    stick to phytoplankton cells to form larger particles called marine snow that enhance the sinking flux of organic carbon. However, Smith et al. (1992) and Ploug et al. (1999) found that once the bacteria colonize the aggregate they solubilize... trophic levels of the aquatic food web (Kiorboe et al., 2002). Caron et al. (1982) thought that aggregates are important loci of microbial activity in the water column, similar to the much larger oceanic ?marine snow? aggregates. Marine snow aggregates...


    Feys, Charles; Joseph, Miquel; Boehme, Luc; Zhang, Yunlian


    In this study, the influence of fine recycled concrete aggregates as replacement for sand in mortar and the use as cement replacement and filler is investigated. Mortar with fine recycled aggregates is examined on its mechanical and physical properties. The samples are also examined on a microscopic scale. The fine recycled concrete aggregates are made with one-year old concrete made in the laboratory. Fine recycled aggregates (FRCA) are added as a cement replacement (0 %, 10 %...

  3. Revisiting Aggregation Techniques for Data Intensive Applications

    Wen, Jian


    Aggregation has been an important operation since the early days of relational databases. Today's Big Data applications bring further challenges when processing aggregation queries, demanding robust aggregation algorithms that can process large volumes of data efficiently in a distributed, share-nothing architecture. Moreover, aggregation on each node runs under a potentially limited memory budget (especially in multiuser settings). Despite its importance, the design and evaluation of aggrega...

  4. Computers and Productivity: Are Aggregation Effects Important?

    Robert H. McGuckin; Kevin Stiroh


    This paper examines the empirical implications of aggregation bias when measuring the productive impact of computers. To isolate two specific aggregation problems relating to "aggregation in variables" and "aggregation in relations," we compare various production function estimates across a range of specifications, econometric estimators, and data levels. The results show that both sources of bias are important, especially as one moves from the sector to the economy level, and when the elasti...

  5. Internal water curing with Liapor aggregates

    Lura, Pietro


    Internal water curing is a very efficient way to counteract self-desiccation and autogenous shrinkage in high performance concrete, thereby reducing the likelihood of early-age cracking. This paper deals with early-age volume changes and moisture transport in lightweight aggregate concrete realized...... with wet lightweight aggregates. Lightweight aggregate concrete mixtures with different degree of saturation and different particle size of the lightweight aggregates were studied and compared to normal weight concrete. Autogenous deformations, selfinduced stresses in fully restrained conditions...

  6. Erythrocyte Aggregation due to Surface Nanobubble Interactions During the Onset of Thermal Burn Injury

    Seidner, Harrison S.

    Red Blood Cell (RBC) aggregation is an important hemorheological phenomenon especially in microcirculation. In healthy individuals, RBCs are known to aggregate and gravitate toward the faster flow in the center of vessels to increase their throughput for more efficient oxygen delivery. Their aggregation is known to occur during a variety of environmental, pathological, and physiological conditions and is reversible when aggregates are subject to the relatively high shear forces in the circulation. The likelihood that aggregates will monodisperse in flow is dependent on the conditions during which they form. In situations where such aggregates are not sheared to monodispersion their presence can impact the perfusion of microvascular networks. More specifically, aggregates subject to the low shear rates in the zone of stasis near regions of thermal burn injury are capable of occluding vessels in the microcirculation and inhibiting the delivery of oxygen and nutrients to tissue downstream. The basic mechanism leading to erythrocyte aggregation at the onset of thermal injury is unknown. This dissertation investigates parameters involved in erythrocyte aggregation, methods of measuring and testing erythrocyte aggregation, and incorporates modeling based on first principles ultimately to propose a mechanism of this phenomenon.

  7. Aggregation resistant zwitterated superparamagnetic nanoparticles

    Superparamagnetic nanoparticles (NPs) are promising for biomedical applications since they can be directed toward the organ of interest using an external magnetic field. They are also good contrast agents for magnetic resonance imaging and have potential for the treatment of malignant tumors (i.e., hyperthermia). Therefore, there is a need to produce stable, non-aggregating superparamagnetic nanomaterials that can withstand the in vivo environment. In this work, the colloidal stability of a dispersion of iron oxide NPs was enhanced by functionalizing them with a short zwitterionic siloxane shell in aqueous media. The stabilization procedure yields superparamagnetic nanomaterials, ca. 10 nm in diameter, with saturation magnetization of about 54 emu/g that resist aggregation at physiological salt concentration, temperature, and pH. The loading of the zwitterionic shell was established with diffuse reflectance infrared spectroscopy and thermal gravimetric analysis. X-ray and electron diffraction verified the starting magnetite phase, and that no change in phase occurred on surface functionalization.

  8. Aggregating and Disaggregating Flexibility Objects

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja;


    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... of such objects while preserving flexibility. Hence, this paper formally defines the concept of flexibility objects (flex-objects) and provides a novel and efficient solution for aggregating and disaggregating flex-objects. Out of the broad range of possible applications, this paper will focus on smart grid...... energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production...

  9. Containing Internal Diffusion Limited Aggregation

    Duminil-Copin, Hugo; Yadin, Ariel; Yehudayoff, Amir


    Internal Diffusion Limited Aggregation (IDLA) is a model that describes the growth of a random aggregate of particles from the inside out. Shellef proved that IDLA processes on supercritical percolation clusters of integer-lattices fill Euclidean balls, with high probability. In this article, we complete the picture and prove a limit-shape theorem for IDLA on such percolation clusters, by providing the corresponding upper bound. The technique to prove upper bounds is new and robust: it only requires the existence of a "good" lower bound. Specifically, this way of proving upper bounds on IDLA clusters is more suitable for random environments than previous ways, since it does not harness harmonic measure estimates.

  10. Recycled aggregate concrete; an overview

    Sorato, Renan


    The aim of this Bachelor’s thesis was to investigate whether recycled materials can be incorporated into the production of concrete without compromising the compressive strength of the concrete produced. In order to shed light on the compressive strength of concrete made from recycled materials, the thesis reviewed studies in which waste materials are utilised as recycled aggregates in the composition of concrete and presented the results of this synthesis and analysis. It was found that som...

  11. Judgment aggregation functions and ultraproducts

    Herzberg, Frederik


    The relationship between propositional model theory and social decision making via premise-based procedures is explored. A one-to-one correspondence between ultrafilters on the population set and weakly universal, unanimity-respecting, systematic judgment aggregation functions is established. The proof constructs an ultraproduct of profiles, viewed as propositional structures, with respect to the ultrafilter of decisive coalitions. This representation theorem can be used to prove other proper...

  12. Underground economy and aggregate fluctuations

    Juan Carlos Conesa Roca; Carlos Díaz Moreno; José Enrique Galdón Sánchez


    This paper explores the role of underground economic activities as an explanation of differences in registered aggregate fluctuations. In order to do so, we introduce an underground economy sector in an otherwise standard Real Business Cycle model and calibrate it to the USA economy. We find that, at low frequencies, Europe fluctuates more than the USA, while its participation rate is smaller. The existence of underground activities rationalizes the negative relationship between participation...

  13. Credit contagion and aggregate losses

    Giesecke, Kay; Weber, Stefan


    Credit contagion refers to the propagation of economic distress from one firm or sovereign government to another. In this paper we model credit contagion phenomena and study the fluctuation of aggregate credit losses on large portfolios of financial positions. The joint dynamics of firms’ credit ratings is modeled by a voter process, which is well-known in the theory of interacting particle systems. We clarify the structure of the equilibrium joint rating distribution using ergodic decomposit...

  14. Aggregating Labels in Crowdsourcing Data

    Priisalu, Maria; Grey, Francois; Segal, Ben


    Project Specification Crowdsourcing is gaining popularity in academia with the launch of crowdsourcing platforms such as Crowdcrafting [Lombraña, 2015] and GeoTagX [UNOSAT, 2015]. There have been a number of proposed algorithms for the aggregation of true labels and a confusion matrix from crowdsourced labels for ordinal, nominal and binary labels. The work here consists of an implementation of the Dawid Skene [Dawid 1979] adaptation of the Expectation Maximization algorithm [D...

  15. Protein aggregates in Huntington's disease

    Arrasate, M.; Finkbeiner, S


    Huntington's disease (HD) is an incurable neurodegenerative disease characterized by abnormal motor movements, personality changes, and early death. HD is caused by a mutation in the IT-15 gene that expands abnormally the number of CAG nucleotide repeats. As a result, the translated protein huntingtin contains disease-causing expansions of glutamines (polyQ) that make it prone to misfold and aggregate. While the gene and mutations that cause HD are known, the mechanisms underlying HD pathogen...

  16. Intuitionistic fuzzy aggregation and clustering

    Xu, Zeshui


    This book offers a systematic introduction to the clustering algorithms for intuitionistic fuzzy values, the latest research results in intuitionistic fuzzy aggregation techniques, the extended results in interval-valued intuitionistic fuzzy environments, and their applications in multi-attribute decision making, such as supply chain management, military system performance evaluation, project management, venture capital, information system selection, building materials classification, and operational plan assessment, etc.

  17. Belt conveyor for recycle aggregate

    Bezrodný, Roman


    This bachelor thesis deals with the belt conveyor for the transport of recycled aggregate in an oblique direction. The aim is to find constructional solutions to the belt conveyor for the assigned transport capacity of 95 000 kg per hour, and the assigned axial distance of 49 m and different height of 12 m. The thesis contains a brief description of the belt conveyor and a description of basic constructional components. It also contains a functional calculation of the capacity and forces acco...

  18. Aggregate Uncertainty, Money and Banking

    Hongfei Sun


    This paper studies the problem of monitoring the monitor in a model of money and banking with aggregate uncertainty. It shows that when inside money is required as a means of bank loan repayment, a market of inside money is entailed at the repayment stage and generates information-revealing prices that perfectly discipline the bank. The incentive problem of a bank is costlessly overcome simply by involving inside money in repayment. Inside money distinguishes itself from outside money by its ...

  19. Economic Instability and Aggregate Investment

    Robert S. Pindyck; Solimano, Andres


    Recent literature suggests that because investment expenditures are irreversible and can be delayed, they may be highly sensitive to uncertainty. The authors briefly summarize the theory, stressing its empirical implications. Then, using cross-section and time-series data for a set of developing and industrial countries, they explore the empirical relevance of irreversibility and uncertainty to aggregate investment. They find that: (a) the volatility of the marginal profitability of capital (...

  20. Parametric characterization of aggregation functions

    Mesiar, Radko; Kolesárová, A.


    Roč. 160, č. 6 (2009), s. 816-831. ISSN 0165-0114 R&D Projects: GA ČR GA402/08/0618 Institutional research plan: CEZ:AV0Z10750506 Keywords : Aggregation function * Conjunction measure * Disjunction measure * Global/local parametric characterization * Idempotency measure Subject RIV: BA - General Mathematics Impact factor: 2.138, year: 2009


    Cahit GÜRER


    Full Text Available For a safe driving, pavement surface aggregates must have superior physical and mechanical properties. Although high rate of accidents is mainly due to drivers errors, pavement surface properties affect significantly occurance of traffic accidents. The most important factor in the highways leading to traffic accidents are the skid resistance. In this study, adherence test with Vialit plate, Nicholson stripping test, accelerated polishing test (PSV were carried out on four aggregate samples which were used in seal coats and hot mix asphalt in Afyonkarahisar City. Results were compared with values of specification limits. The results showed that particularly limestone aggregates polishing stone values are poorer than volcanic aggregates sample. Especially, use of aggregates having a good polishing resistance, will be an important factor increasing driving safety.

  2. Aggregation functions: an approach using copulae

    Marta Cardin; Maddalena Manzi


    In this paper we present the extension of the copula approach to aggregation functions. In fact we want to focus on a class of aggregation functions and present them in the multilinear form with marginal copulae. Moreover, we define the joint aggregation density function.

  3. 28 CFR 2.5 - Sentence aggregation.


    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... aggregation. When multiple sentences are aggregated by the Bureau of Prisons pursuant to 18 U.S.C. 4161...

  4. Aggregated Authentication (AMAC) Using Universal Hash Functions

    Znaidi, Wassim; Minier, Marine; Lauradoux, Cédric

    Aggregation is a very important issue to reduce the energy consumption in Wireless Sensors Networks (WSNs). There is currently a lack of cryptographic primitives for authentication of aggregated data. The theoretical background for Aggregated Message Authentication Codes (AMACs) has been proposed by Chan and Castelluccia at ISIT 08.

  5. Aggregation of erythrocytes in burn disease

    Levin, Grigory Y; Egorihina, Marpha N


    The manuscript describes experiments designed to examine factors that influence erythrocytes aggregation within the blood of burn patients. Results showed that the rate and degree of erythrocytes aggregation increased significantly in burn patients, and what is especially unfavorable for microcirculation, erythrocytes disaggregation decreased. We show that normalization of blood plasma contents completely restores erythrocytes aggregation and disaggregation of burn patients. The rate and degr...

  6. Usability of Limestone Aggregate Extracted in Göller Region as Highway Materials

    Altan Yılmaz


    Full Text Available In this research some aggregate samples obtaining from Göller region was examined to investigate the usability of limestone as highway materials. For this reason, three quarries including Gümüşgün quarry at the north part of Isparta, Çine at the south part of Burdur and Dağbeli at the north part of Antalya city are visited and the relevant samples are collected. Sieve test, lose density test, specific gravity and water absorption test, freezethaw test, micro-Deval test and aggregate impact value test conducted on the collected samples in the laboratory. Further, Proktor compaction and CBR test applied on the mixtures accrued with dense graded aggregates. As a result of study, it is concluded aggregate samples collected from there different quarries having reliable physical and mechanical properties to be used as highway base and sub-base material. However, aggregate extracted from Dağbeli quarry would be better to use in the mild climate regions instead of cold and severe weather regions. On the other hand, Gümüşgün aggregate that is abrasion resistant and strength properties indicates higher values than others so it may also be used as a hot mix asphalt aggregate.

  7. Network Provisioning Using Multimedia Aggregates

    Joan Vila-Carbó


    Full Text Available Multimedia traffic makes network provisioning a key issue. Optimal provisioning of network resources is crucial for reducing the service cost of multimedia transmission. Multimedia traffic requires not only provisioning bandwidth and buffer resources in the network but also guaranteeing a given maximum end-to-end delay. In this paper we present methods and tools for the optimal dimensioning of networks based on multimedia aggregates. The proposed method minimises the network resources reservations of traffic aggregates providing a bounded delay. The paper also introduces several methods to generate multimedia traffic aggregation using real video traces. The method is evaluated using a network topology based on the European GÉANT network. The results of these simulations allow us to discover the relationship between a required delay and the necessary bandwidth reservation (or the achievable utilisation limit. An interesting conclusion of these scenarios is that, following several recommendations, the network utilisation can reach values of around 80% or higher.

  8. Influence of Polyethylene Glycol on Asphaltic Concrete for Cubical and Rod shaped Aggregates

    U. Arun Kumar


    Full Text Available Aggregates are the principle material in pavement construction. Conventional road aggregates in India are natural aggregates obtained by crushing rocks. Aggregate characteristics such as particle size, shape, and texture etc.., influence the performance and serviceability of pavement. Pavements laid with polymer modified asphalt exhibits greater resistance to rutting, thermal cracking and fatigue damages and hence these were used at locations of higher stress. The present work concentrates on aggregate characteristics which include the shape indices. The particle shapes namely Cubical and Rod are being used in the study. The study shows the behavior of the two shapes of aggregate in terms of Penetration, Ductility, Softening Point and Marshall Stability tests with varying percentages of asphalt and also with varying the percentages of PEG. The results of unmodified asphalt mix are compared with the modified asphalt mix against some critical Marshall Mix parameters.

  9. Social aggregation as a cooperative game

    Vilone, Daniele; Guazzini, Andrea


    A new approach for the description of phenomena of social aggregation is suggested. On the basis of psychological concepts (as for instance social norms and cultural coordinates), we deduce a general mechanism for social aggregation in which different clusters of individuals can merge according to cooperation among the agents. In their turn, the agents can cooperate or defect according to the clusters' distribution inside the system. The fitness of an individual increases with the size of its cluster, but decreases with the work the individual had to do in order to join it. In order to test the reliability of such a new approach, we introduce a couple of simple toy models with the features illustrated above. We see, from this preliminary study, how cooperation is the most convenient strategy only in the presence of very large clusters, while on the other hand it is not necessary to have one hundred percent of cooperators for reaching a totally ordered configuration with only one megacluster filling the whole system.

  10. Floc strength characterization technique. An insight into silica aggregation.

    Hermawan, Mandalena; Bushell, Graeme C; Craig, Vincent S J; Teoh, Wey Yang; Amal, Rose


    This paper tests an approach to the estimation of relative particle bond strength based on the nondimensional floc and aggregation factors. The strength of flocs formed by aggregating nanosized silica particles with the addition of potassium chloride (KCl) or cationic surfactants, alkyltrimethylammonium bromide (mixture of CTAB, DTAB, and MTAB) was analyzed. The bonding force of the flocs formed in surfactant compared to that formed in the KCl system was estimated using the new dimensional analysis approach. This force ratio was then compared to that obtained by atomic force microscopy. PMID:15248736