Count Aggregation Research Articles

Evaluating aggregate operations over imprecise data

Imprecise data in databases were originally denoted as null values, which represent the meaning of "values unknown at present." More generally, a partial value corresponds to a finite set of possible values for an attribute in which exactly one of the values is the "true" value. We define a set of extended aggregate operations, namely sum, average, count, maximum, and minimum, which can be applied to an attribute containing partial values. Two types of aggregate operators are considered: scalar aggregates and aggregate functions. We study the properties of the aggregate operations and develop efficient algorithms for count, maximum and minimum. However, for sum and average, we point out that in general it takes exponential time complexity to do the computations.

Pathological Flow Properties of Blood in the Fetus and Neonate

Normal Hemorheology: Plasma proteins, plasma viscosity, and red blood cell (RBC) aggregation are very low in the fetus and the preterm infant, but increase with increasing gestational and postnatal age. Moreover, both the viscosity (F~hrffius-Lindqvist effect) and the hematocrit reductions (F~hrffius effect) in narrow tubes are more pronounced in the fetus and neonate than in adults. As a result of these peculiar hemorheological properties, viscosity of blood (measured in 50 ~m diameter tubes) with given hematocrit is markedly lower in the fetus (-50% at 25 wk gestation) and neonate (-25%) than in adults. Blood viscosity in 50-~m tubes is similar in neonates with a hematocrit of 0.70 III as in adults with a hematocrit of 0.50 III. This may explain why polycythemia does not impair systemic, cerebral and intestinal RBC transport in neonates as long as the hematocrit does not exceed 0.70 III and why polycythemic neonates are less susceptible to serious complications than polycythemic children and adults. Pathological Hemorheology: Since high flow conditions in the fetus and neonate are strongly dependent on the favorable rheologic properties of their blood, hemorheolocal abnormalities may contribute to the high risk of the fetus and neonate to ischemic damage of vital organs (e.g. brain) in a variety of disorders: 1) Perinatal asphyxia may be associated with impaired RBC deformability, increased RBC aggregation and leukocyte count, thereby aggravating tissue hypoxia. 2) In growth-retarded fetuses, increased hematocrit, RBC aggregation and leukocyte count may contribute to the high risk of ischemic damage of vital organs (e.g. brain). 3) Fetal and neonatal cells are less protected from radicals than adults, thereby predisposing them to oxidative damage. 4) Neonatal septic shock may be associated with markedly decreased RBC defo rm ability , increase in the count of rigid, immature leukocytes, RBC aggregation and plasma viscosity. 5) Infants of poorly-controlled insulin-dependent diabetic mothers show markedly increased hematocrit and decreased RBC deformability. This may increase their risk of thromboses.

Flow cytometric analysis of punctate and aggregate reticulocyte responses in phlebotomized cats

SUMMARY Five cats were made anemic by one-time phlebotomy, and their reticulocyte responses were monitored daily for 20 days, using manual enumeration and a standardized feline reticulocyte protocol developed and validated in our laboratory. The reticulocyte responses of 38 clinically normal client-owned cats also were analyzed manually and cytometrically to determine clinical reference ranges. Increases in the percentage of aggregate reticulocytes over the reference range were detected in 5 of 5 phlebotomized cats, using the cytometric protocol. Only 4 of the 5 cats had an increase by results of manual enumeration. Manual aggregate counts had considerable daily variation and often fluctuated in and out of reference range, whereas cytometric aggregate counts remained consistently increased for distinct periods. Increased numbers of aggregate cells could also be detected for longer periods when evaluated by flow cytometry. Increased numbers of punctate reticulocytes were detected in 4 of 5 cats, using the cytometric protocol. None of the cats had increased numbers of punctate cells when evaluated by use of the manual technique. Aggregate reticulocytes in the 38 clinically normal cats ranged from 0.1 to 0.5%, which corresponded to 8,487 to 42,120 cells/μl. Punctate reticulocytes ranged from 2 to 17%, which corresponded to 225,400 to 1,268,584 cells/μl. Flow cytometry, using a standardized analysis protocol, was a more reliable and sensitive technique for detection and evaluation of feline reticulocytosis than was manual enumeration. The sensitivity of the flow cytometer to small amounts of intracellular nucleoprotein makes this assay especially valuable for detection of punctate reticulocytosis and low degrees of aggregate reticulocytosis in cats.

A laser light scattering in situ system for counting aggregates in blood platelet aggregation

A novel system has been developed to evaluate biochemically induced blood platelet aggregation by means of a particle counting technique that uses light scattering. Variations in the particle size and concentration were measured by detecting the scattered light intensity and the number of particles, respectively, passing through a laser beam. The system is capable of performing sensitive, in situ continuous measurements of platelet aggregation by counting and sizing of aggregates.

A multielement Ge detector with complete spectrum readout for x‐ray fluorescence microprobe and microspectroscopy (abstract)

Multielement Ge and Si(Li) detectors have been used in recent years to improve the increase count rate capability and to improve the solid‐angle efficiency in fluorescence x‐ray absorption spectroscopy (XAS). Such systems have typically been equipped with one or more single‐channel analyzers (SCAs) for each detector element. Such SCA‐based electronics are sufficient when only the counts in one or two well‐resolved peaks are of interest. For the fluorescence (XRF) microprobe at beamline X‐26A at the NSLS, SCA‐based electronics were not a satisfactory solution for two reasons: (1) for XRF experiments, the entire fluorescence spectrum is required; (2) for micro‐XAS studies of trace elements in complex systems, the fluorescence peak often sits on a significant background or partially overlaps another fluorescence peak, requiring software background subtraction or peak deconvolution. An electronics system which permits collection of the entire fluorescence spectrum from each detector element has been designed. The system is made cost‐effective by the use of analog multiplexors, reducing the number of analog‐to‐digital converters (ADCs) and multichannel analyzers (MCAs) required. The system was manufactured by Canberra Industries and consists of: (1) a 13 element Ge detector (11 mm diameter detector elements), (2) 13 NIM spectroscopy amplifiers with programmable gains, (3) four analog multiplexors with maximum of eight inputs each, (4) four ADCs with programmable offsets and gains and 800 ns conversion time, and (5) two MCAs with Ethernet communications ports and two ADC inputs each.The amplifiers have shaping times which are adjustable from 0.5 to 12 μs. The analog multiplexors were modified to perform pileup rejection. The analog multiplexing does not significantly reduce the count rate capability of the system, even at the shortest amplifier shaping times. The average detector resolution is 170 eV at 12 μs shaping time and 200 eV at 4 μs shaping time. The maximum aggregate count rate is 400 kHz with 0.5 μs shaping time. The system is controlled by software based upon a package from Canberra and another commercial package (IDL), both running on a VAXstation 4000/90. The software automatically adjusts the gains of the amplifiers and offsets of the ADCs so that the spectra from each detector have identical calibrations and can be added channel for channel. The overhead to read a 1024 channel spectrum from each of the 13 elements and sum them is about 2 s. The software allows a range of options for data storage, from saving the complete spectrum for each of the 13 detectors elements (≳50 000 bytes/point) to saving only the net counts under a single fluorescence peak summed over all the detector elements (4 bytes/point). These data can be stored at each pixel in an elemental map or at each point in a monochromator scan. The system has been commissioned and is being used for XRF and micro‐XAS studies.

Errored block detection with bit interleaved parity failures in SDH network

As indicated in ITU-T SG XVIII Rec. G.826 (July 1993 version) an important study is the relationship between the synchronous digital hierarchy (SDH) path level performance monitoring and the block based parameters. The measure of errored blocks using one second aggregated counts of bit interleaved parity (BIP) failures, as proposed in the Annex 3 of Rec. G.826, is reported and analyzed with Poisson error distribution and error burst distribution.

Aggregate operations in the information source tracking method

The Information Source Tracking method, IST, is an approach to the management of uncertain and imprecise data in database systems. In this paper we study the processing of queries involving aggregate operations min, max, sum, count, and average in the IST method. The problems discussed include producing all possible outcomes of an aggregate query and their probabilities; determining the probability of a specific outcome; finding the largest (or smallest) possible outcome; determining whether the outcome could be greater than or equal to (or less than or equal to) a given value; and finding the expected-value of the outcome of an aggregate query. We present algorithms for the evaluation of aggregate queries, and show that some of these problems are NP-complete, and hence highly unlikely to have efficient algorithms.

Efficiently counting program events with support for on-line queries

The ability to count events in a program's execution is required by many program analysis applications. We represent an instrumentation method for efficiently counting events in a program's execution, with support for on-line queries of the event count. Event counting differs from basic block profiling in that an aggregate count of events is kept rather than a set of counters. Due to this difference, solutions to basic block profiling are not well suited to event counting. Our algorithm finds a subset of points in a program to instrument, while guaranteeing that accurate event counts can be obtained efficiently at every point in the execution.

Platelet activation in normotensive and hypertensive pregnancies complicated by intrauterine growth retardation.

To study platelet function in normotensive and hypertensive intrauterine growth retardation (IUGR). ADP and collagen induced whole blood platelet aggregation, beta-thromboglobulin release and platelet count were measured in the IUGR groups at a mean gestational age of 36 weeks (28-40), and at 1, 24, 48 h and six weeks post delivery. The normal pregnancy group were studied serially at 12, 20, 28, 32 and 36 weeks of gestation and at 1, 24, 48 h and six weeks post delivery. Trinity College Medical School, St. James's Hospital, Dublin. Twenty-nine women with a fetus with diagnosed IUGR were recruited for the study. Of these, 15 were normotensive throughout their pregnancy and the remaining 14 pregnancies were complicated by both hypertension and proteinuria. Twenty healthy primigravida acted as controls. In the hypertensive IUGR group, levels of collagen and ADP induced aggregation were almost 50% lower before delivery than in normal pregnancy. Platelet count in the hypertensive group was decreased by 30% compared with normal pregnancy. Levels of beta-thromboglobulin were 40 to 50% higher in both the normotensive and hypertensive IUGR groups compared with normal pregnancy. Unlike the hypertensive IUGR group, the normotensive IUGR group showed similar levels of platelet count and ADP and collagen induced aggregation to those found at 36 weeks of normal pregnancy. In the early puerperium of hypertensive pregnancies, the platelet parameters measured returned gradually to normal. The normotensive IUGR group had increased levels of ADP induced aggregation in the first 24 to 48 h post delivery. The platelet count in the normotensive but not the hypertensive group correlated with birthweight. Normotensive and hypertensive IUGR are accompanied by platelet activation. In normotensive IUGR, this activation appears to be confined to the uteroplacental circulation. In hypertensive IUGR, the results suggest that platelet activation also extends into the peripheral circulation resulting in a reduced platelet responsiveness and a lower platelet count. Release of vasoactive amines from activated platelets in the peripheral circulation may be responsible for the clinical syndrome of hypertension and proteinuria present in pregnancies complicated by pre-eclampsia and IUGR but absent in normotensive IUGR.

Mouse antithrombotic assay. Inhibition of platelet thromboembolism by disintegrins

The mouse antithrombotic assay represents a model of fatal pulmonary thromboembolism induced by intravenous injection of collagen and epinephrine. Mice were protected by low doses of two disintegrins, albolabrin (10 μg/mouse) and eristostatin (0.6 μg/mouse), whereas high doses of a thrombin inhibitor and an inhibitor of von Willebrand Factor binding to glycoprotein Ib were not effective. Injection of collagen and epinephrine resulted in the drop of platelet count and accumulation of platelet aggregates in the lung that appears to be the immediate cause of death. Albolabrin or eristostatin administration did not prevent the decrease of platelet count. Injection of albolabrin resulted in the formation of smaller and reversible platelet aggregates in the lungs and decreased accumulation of 51Cr-labeled platelets in the lung suggesting that this disintegrin decreases formation of platelet aggregates in vivo . We compared the effects of albolabrin and eristostatin on platelet aggregation, tail bleeding time, and survival of challenged animals. Eristostatin was about 5 times more potent in inhibiting platelet aggregation in vitro than albolabrin and 38 times more potent than albolabrin in protecting animals from sudden death. Both disintegrins, at the same doses (0.6-5 μg/mouse), caused similar dose-dependent prolongation of the bleeding time; however, only eristostatin exerted a protective effect. In conclusion, a) the mouse antithrombotic assay is a suitable model to screen and to evaluate the potency of platelet fibrinogen receptor antagonists in vivo ; b) the results of the antithrombotic assay correlate better with the inhibition of platelet aggregation in vitro than with the prolongation of bleeding time.

Image processing: a non-destructive method for measuring growth in cell and tissue culture

The use of machine vision in evaluating callus growth directly in Petri dishes is reported for carrot cell suspension growing in the presence of increasing concentrations of various herbicides. Machine vision was much more accurate and sensitive than visual counting of the cell aggregates. Image processing also gives more detailed information than does counting because of its ability to distinguish between intermediate levels of callus growth.

Proposal of a new method to avoid misinterpretations in the evaluation of the leukergy test.

The leukergy test has been widely used in recent years to detect the phenomenon of leucocyte aggregation in various clinical conditions. It is performed by processing some drops of blood on a slide. According to the authors proposing this test, the leucocyte aggregation is expressed as the mean of the number of aggregates detected among 300 cells of a randomly chosen tract of two slides. We noted, however, that significant differences in the percentage of leucocyte aggregates were sometimes detected between two different slides prepared from the same patient, and hypothesized that an unequal distribution of aggregates along the slide could explain this finding. To test this hypothesis we analysed separately the leucocyte aggregates of three tracts of equal size of blood smears taken from 20 patients. Three slides, numbered 1, 2 and 3, were prepared from each patient. The first tract run by the drops when placing them in the slide showed a significantly lower percentage of aggregates than the remaining tracts (p less than 0.01 post hoc Tukey test). We conclude that the distribution of aggregated leucocytes is unequal along the slide and that the evaluation of the phenomenon of leukergy should always include the count of aggregates of the proximal, intermediate and distal tract of each slide.

Associations of daily mortality and air pollution in Los Angeles County

We report results of a multiple regression analysis examining associations between aggregate daily mortality counts and environmental variables in Los Angeles County, California for the period 1970 to 1979. Mortality variable included total deaths not due to accidents and violence (M), deaths due to cardiovascular causes (CV), and deaths due to respiratory causes (Resp). The environmental variables included five pollutants averaged over Los Angeles County--total oxidants (Ox), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and KM (a measure of particulate optical reflectance). Also included were three metereological variables measured at the Los Angeles International Airport--temperature (Temp), relative humidity (RH), and extinction coefficient (Bext), the latter estimated from noontime visual range. To reduce the possibility of spurious correlations arising from the shared seasonal cycles of mortality and environmental variables, seasonal cycles were removed from the data by applying a high-pass filter. Cross-correlation functions were examined to determine the lag structure of the data prior to specifying and fitting the multiple regression models relating mortality and the environmental variables. The results demonstrated significant associations of M (or CV) with Ox at lag 1, temperature, and NO2, CO, or KM. Each of the latter three variables were strongly associated with daily mortality but also were highly correlated with one another in the high-frequency band, making it impossible to uniquely estimate their separate relationships to mortality. The results of this study show that small but significant associations exist in Los Angeles County between daily mortality and three separate environmental factors: temperature, primary motor vehicle-related pollutants (e.g., CO, KM, NO2), and photochemical oxidants.

Rheological studies on patients with posterior subretinal neovascularization and exudative age-related macular degeneration

To investigate the potential influence of a decreased perfusion rate of the choriocapillaris on the development of age-related macular degeneration (ARMD) with subretinal neovascularization (SRNV) apparently caused by disturbed flow properties of blood, we compared the hemorheological parameters of blood from 35 patients suffering from ARMD with SRNV with those from the 35 healthy patients of the same age. In both groups hematocrit, plasma viscosity, erythrocyte filtrability, aggregation, aggregating proteins, leukocyte and thrombocyte count, differentiation of leukocytes, thrombelastography, PTT, Quick test, and rheological profiles were comparable. The differences were not significant (P greater than 0.05). These results refute the hypothesis that changed flow properties of blood are the primary cause of the pathogenesis of ARMD with SRNV.

填料とパルプの相互作用 ＩＩＩ ウエットプレスおよびセルロース性微細物添加の影響

(A) The influence of wet pressing on the structure and properties of paper was studied for filler loaded papers. Handsheet prepared from hardwood kraft pulp and precipitated calcium carbonate as filler is subjected for the study. The results are as follows : (1) At the wet pressed sheets, the number of fibrous layers (Nf) at a given basis weight (excluding filler) increases with increasing filler content and approaches that of none pressed sheet.(2) In the wet pressed sheets, z-directional count and width, and area and area fraction of filler aggregates are smaller than those of none pressed sheets.(3) Although the area fraction of filler aggregates decreases with wet pressing, the result of pore size distribution from mercury intrusion technique show fine pore of filler aggregates remain constant.(4) The contribution due to fiber debonding (Sd) and the filler itself (Sp) to the total light scattering coefficient were caluculated, assuming that these contribution were independent and addible. The caluculation was bases on the light scattering coefficient measured before and after the removal of filler. It is apparent that Sd and Sp are larger for wet pressed sheets.(B) The influence of cellulosic fines on structure and properties of paper was studied for the sheets with varied filler loading level. Same pulp and filler as (A) were used. As cellulosic fines a micro-fibrillated cellulose (MFC) and a crystalline cellulose (Avicel) were used. The results are as follows : (1) In three sheets (sheets without cellulosic fines, with MFC, and with Avicel) Nf increase with increasing filler content. The incremental increase in Nf is largest for the sheets with MFC.(2) z-Directional count of filler aggregates is largest for sheets with MFC. However area fraction measured for three sheets is independent of z-directional count of filler aggregates.(3) Sheets with MFC show remarkably high Sd than others.(4) On the sheets with MFC, results indicate the contribution of the fibril detachment to the increase of optical efficiency of filler.

How Filler Distribution Affects Paper Properties (4)

The influence of a retention aid (cationic polyacrylamide) on structure and properties of filler loaded papers was investigated. Handsheets were prepared under the following conditions:(A) without retention aid, (B) with the addition of 0.02% retention aid to the furnish, (C) preflocculated filler (containing retention aid). Geometrical parameters of filler aggregates were evaluated by image analysis of cross and parallel sections of handsheets. The results are summarized as follows:(1) The deterioration of the light scattering coefficient of handsheets containing retention aid is closely related to the decrease of z-directional count of filler aggregates.(2) A comparison between x-y directional and z-directional geometrical parameters showed that the shape of filler aggregates differs according to the condition of retention aid addition.(3) The count of filler aggregates decreases but the area of filler aggregates increases with retention aid addition. At the same time the filler aggregates tend to be located near the fiber surface.A similar study using machine-made papers was also carried out. The effects of retention aid were clearly observed in the x-y directional width and area of filler aggregates and in the degree of two-sidedness. However no influence on z-derectional count or width was observed.

填料とパルプの相互作用 Ｉ 微細繊維の影響

The influence of fines-filler interaction on the structure and properties of paper was investigated. The fines used in this investigation were collected between 100 mesh and 300 mesh screens from hardwood kraft pulp (450ml c. s. f.). The filler used was a precipitated calcium carbonate. The results are summerized as follows:(1) Raycells, fragments of both fibers and vessel elements, and fibrils separated from the fiber wall are contained in the fines fraction.(2) The z-directional width and area of filler aggregates for sheets with fines added are lager than those for sheets containing only fibers. However, the z-directional count and area fraction of filler aggregates are not affected by fines addition. The rate of increase in the light scattering coefficient is not affected by the presence of fines.(3) The z-directional count and area fraction of filler aggregates in sheets are lager when the fines and filler are coflocculated than when the fines and preflocculated filler are added sequentially. Higher light scattering coefficients are also obtained for sheets with fines and filler coflocculated. The results of sheet surface inspection with SEM show that in a coflocculated sheet the filler tends to form aggregates around fibrils and that fibrils are detached from fiber walls. This fibril detachent is thought to contribute to the higher light scattering coefficient of these sheets.

填料とパルプの相互作用 ＩＩ 叩解の影響

The influence of beating level of fibers on the structure and properties of paper was investigated. For this experiment, handsheets were prepared from either softwood kraft pulp or hardwood kraft pulp beaten to two level of freeness. The filler used was a precipitated calcium carbonate. The results may be summarized as follows:(1) The number of fibrous layers (Nf) at a given basis weight (excluding filler) increases with increasing filler content. The incremental increase in Nf is larger for sheets with a higher level of beating.(2) The geometrical parameters of filler aggregates differ depending on the fiber type, but are not affected by beating level of fibers. Both z-directional count and area fraction of filler aggregates for softwood sheets are lager than those for hardwood sheets.(3) The contributions due to fiber debonding (Sd) and the filler itself (Sr) to the total light scattering coefficient were calculated, assuming that these contributions were independent and additive. The calculation was bases on the light scattering coefficients of filled sheets and sheets with filler removed. It is apparent that the contribution due to fiber debonding is larger in highly beaten sheets, but that of the fiber itself does not change.The results obtained from both structural and optical property analysis show that the increase in optical efficiency of the filler with beating is due to the increased debonding of the fibers.

てん料の分布状態とシートの性質 ＩＩ シート断面構造に及ぼすてん料の影響

Filler distribution was evaluated for cross sections of different filler loaded papers. The fillers used in this investigation were talc, clay, ground calcium carbonate andtwo types of precipitated calcium carbonate (calcite and alagonite). The results are summarized as follows.(1) The specific gravity and refractive index of the fillers used in this study are similar to each other, so the major differences among these fillers seem to be only in their size, shape and zeta potential.(2) For all filler loaded papers except those loaded with clay, it is clear that the z-directional count and width of filler aggregates increases as the filler particle size dicreases. A good correlation between z-directional count and width was obtained, regardless of filler type, but the correlation for clay loaded papers differs from that obtained for the other fillers.(3) The area fraction of filler aggregates tends to increase as filler particle size decreases. Inspection of different filler loaded papers by a scanning electron microscope or mercury intrusion technique showed that the change in area fraction with filler type may be attributed to a change in void volume of filler aggregates.

Issues in medication adherence assessment in clinical trials of the National Heart, Lung, and Blood Institute

The mission of the National Heart, Lung, and Blood Institute is to sponsor research in the prevention, diagnosis, and treatment of heart, lung, and blood diseases. As a part of its activities toward this end, the Institute plans and conducts clinical trials that test the safety and efficacy of a broad range of preventive and treatment regimens. Many of these trials involve thousands of patients and require the cooperation of many research clinics under a common protocol, often for many years. An essential component in these efforts is a standardized methodology to allow accurate tracking of adherence patterns so that problem adherence situations can be identified and rectified. This article reviews the methods that have been used to assess adherence patterns in selected clinical trials supported by the NHLBI. The most frequently used methods have been pill count and direct measurement of the drug, its metabolites, or physiological effects in some bodily fluid. Supplementary information is frequently obtained by self-report. Experience with markers has been very limited and no systematic data are available. The Aspirin Myocardial Infarction Study is used as a case study to illustrate specific strengths and weaknesses of three types of adherence assessment methods, namely, assay of salicylates in the urine, platelet aggregation, and pill count. Generalizations to other clinical trials are discussed. Based on experience to date with traditional methods of compliance assessment, several conclusions are drawn. Combinations of measures, in general, provide the most useful profiles of adherence patterns in clinical trials. The development of an ideal marker compound with appropriate safety for long-term administration would be of use to overcome a number of assessment problems, including (1) inability of current methods to determine temporal patterns of drug consumption, (2) need for more precise quantification of consumption levels beyond a simple “drug present or drug absent” result, (3) providing cheaper or more convenient alternatives to direct analyses of the drug or its metabolites, (4) reducing assessment errors due to non-specificity of analytic methods and individual metabolic variations, and (5) as a supplement to pill counts to assess placebo tablet consumption.