True Anomalies Research Articles

A formulation to obtain semi-analytical planetary theories using true anomalies as temporal variables

The main methods used to obtain analytical theories of perturbed motion in celestial mechanics are based on the expansion of the disturbing function in trigonometric series of the mean anomalies (or longitudes). In this paper a new method based on the double Fourier series expansion using the true anomalies (or longitudes) is developed. The method involves a semi-analytical technique to allow the expansion of the inverse of the distance with great accuracy, and a new integration technique using a linear combination of the true anomalies based on an iterative method to integrate each term of the expansion of the Lagrange planetary equations.

Modelling the large particle environment of comet 67P/Churyumov–Gerasimenko

A method is presented to simulate images of a cometary dust trail in consistency with observed gas and dust production rates. It is also applicable to dust tails including neckline and antitail phenomena. Our main objective is to analyse the amount of mm-sized and larger particles within a given image. These are interesting to us because their emission by comets may constitute a major source of interplanetary dust. The model is applied to 67P/Churyumov–Gerasimenko, the target of ESA’s Rosetta mission. The employed parameters are consistent with a hydrodynamic coma model. Dust emitted during all apparitions of 67P since the Jupiter encounter in 1959 is taken into account. We compare simulated images with two images taken in May 2003 and April 2004. Both of these show a bright feature close to the projected orbit of the comet. We analyse the simulated images with respect to the age of the dust in this feature. We find that, within our model, the feature in 2003 is dominated by particles emitted during the same apparition. For 2004 we estimate that 25% of the intensity in the bright feature can be attributed to dust emitted during previous apparitions and 29% to particles emitted at true anomalies of (180 ± 5)° before observation. Concerning the sizes of dust grains in the bright feature, we find that in 2003, particles with radii between about 10 μm and 1 cm contribute nearly equally to the total intensity. In 2004 however, the structure is dominated by particles having sizes of 100 μm to 1 mm.

Detailed FISH analysis of day 5 human embryos reveals the mechanisms leading to mosaic aneuploidy

Fluorescence in situ hybridization (FISH) analysis has shown that human embryos display a high level of chromosomal mosaicism at all preimplantation stages. The aim of this study was to investigate the mechanisms involved by the use of two probes for each of three autosomes at different loci and to determine the true level of aneuploid mosaicism by excluding FISH artefacts. Embryos were cultured in two different types of medium: group I were cultured in standard cleavage medium for up to day 5 and group II were cultured from day 3 to day 5 in blastocyst medium. Three rounds of FISH were performed. In round 1, the probes used were 1pTel, 11qTel and 18CEP; in round 2, the probes used were 1satII/III, 11CEP and 18qTel; in round 3, the probes used were 18CEP, XCEP and YCEP. A total of 21 embryos were analysed in each group. The FISH results revealed one uniformly diploid and 20 mosaic embryos for group I, and two uniformly diploid and 19 mosaic embryos for group II. The predominant type of mosaicism was diploid/aneuploid. The use of two different probes per autosome was able to distinguish FISH artefacts affecting 5% of nuclei from true single cell anomalies. Post-zygotic chromosome loss was the most common mechanism leading to aneuploidy mosaicism for both groups, followed by chromosome gain, with fewer examples of mitotic non-disjunction.

An Addendum to the Damour and Deruelle's Solution of the Post-Newtonian Two-Body Problem

A complement to the the analytical solution given by Damour and Deruelle (D&D) in order to solve the differential equations that describe the conic-like and rectilinear post-Newtonian two-body problem is presented. We show the geometric relation between the eccentric and true anomalies for the elliptic-like and hyperbolic-like cases and expressions for their velocities are obtained. A post-Newtonian version of the Lambert's theorem is shown.

Fehlbildungen des äusseren und inneren Genitales

Die gynäkologische Untersuchung von Kindern und Jugendlichen gehört in spezialisierte Hände und sollte in kindgerechter Umgebung erfolgen. Eine ihrer wichtigsten Aufgaben ist die Trennung von vermeintlichen und echten Fehlbildungen. Die Chance hierzu kann bereits beim neugeborenen Mädchen ohne grösseren Aufwand genutzt werden. Meist reicht bereits die Inspektion, später werden Vaginoskopie und gynäkologische Spiegeluntersuchung erforderlich. Weiterführende Massnahmen sind die Abdominalsonographie und die Kernspintomographie. Zu den vermeintlichen Fehlbildungen gehört die Synechie der kleinen Labien, die Pseudohymenalatresie, die Pseudoklitorishypertrophie und die Pseudotumore des äusseren Genitales (z.B. die Harnröhrenkarunkel). Die wichtigste asymptomatische Anlagestörung von Vagina und Uterus ist das Mayer-Rokitansky-Küster-Hauser-Syndrom (Uterus- und Vaginalaplasie). Zu den symptomatischen Verschlussfehlbildungen zählen die Hymenalatresie, das Vaginalseptum und die Doppelanlagen von Uterus und Vagina, bei denen eine Seite verschlossen sein kann. Letztere können zu einem Aufstau von Menstrualblut und damit zu einem Hemihämatokolpos und einer Hämatometra führen. Die Behandlung der genannten Fehlbildungen ist oft einfach, erfordert dennoch viel Erfahrung.

Testing the Significance of Calendar Effects

Working Paper 2005-2 January 2005 Abstract: This paper studies tests of calendar effects in equity returns. It is necessary to control for all possible calendar effects to avoid spurious results. The authors contribute to the calendar effects literature and its significance with a test for calendar-specific anomalies that conditions on the nuisance of possible calendar effects. Thus, their approach to test for calendar effects produces robust data-mining results. Unfortunately, attempts to control for a large number of possible calendar effects have the downside of diminishing the power of the test, making it more difficult to detect actual anomalies. The authors show that our test achieves good power properties because it exploits the correlation structure of (excess) returns specific to the calendar effect being studied. We implement the test with bootstrap methods and apply it to stock indices from Denmark, France, Germany, Hong Kong, Italy, Japan, Norway, Sweden, the United Kingdom, and the United States. Bootstrap p- values reveal that calendar effects are significant for returns in most of these equity markets, but end-of-the-year effects are predominant. It also appears that, beginning in the late 1980s, calendar effects have diminished except in small-cap stock indices. JEL classification: C12, C22, G14 Key words: calendar effects, data mining, significance test 1. Introduction Calendar effects are anomalies in stock returns that relate to the calendar, such as the day-of-the-week, the month-of-the-year, or holidays. Two leading examples are the Monday effect and the January effect. Economically small calendar specific anomalies need not violate no-arbitrage conditions, but the reason for their existence, if they are indeed real, is intriguing. Much effort continues to be devoted to research on calendar effects. Yet, the literature remains open about the significance of these effects for asset markets. One reason is that the of specific calendar effects could be a result of data mining. Even if there are no calendar anomalies, an extensive search - or data mining - exercise across a large number of possible calendar effects can yield significant results of an by pure chance. (1) Another reason data mining is a plausible explanation is that theoretical explanations have been suggested only subsequent to the empirical discovery of the anomalies. The universe of possible calendar effects is not given ex ante from economic theory. Rather, the number of different calendar effects that potentially could be analyzed is only bounded by the creativity of interested researchers. Since an extensive empirical analysis of calendar effects is likely to suffer from data mining problems, it is therefore surprising that there is little work that aims to limit the problem. The reason might be that an explicit control for data mining is costly because it is less likely that a true anomaly will be found to be significant. The best remedy for preserving the ability to detect true anomalies, is to employ a test for calendar effects that is as powerful as possible. A robust test for a specific calendar effect needs to condition on the nuisance of all conceivable effects, unless one is willing to violate basic principles for inference. We construct a powerful test to evaluate the significance of calendar effects in this paper. This test combines and incorporates the information from all calendar anomalies to achieve good power properties without compromising test size by exploiting the correlation structure that is specific to this testing problem. The new test is asymptotically F-distributed. However, we implement a bootstrap version of the test that diminishes possible small sample problems. Our new test of calendar effects can be interpreted as a generalized-F test. It is related to some recent methods for comparing forecasting models that have been proposed byWhite (2000) and Hansen (2001), who builds on results of Diebold & Mariano (1995) and West (1996). …

Consistency conditions and trace anomalies in sixdimensions

Conformally invariant quantum field theories develop trace anomalieswhen defined on curved backgrounds. We study again the problem ofidentifying all possible trace anomalies in d = 6 by studying theconsistency conditions to derive their ten independent solutions. It isknown that only four of these solutions represent true anomalies, classifiedas one type A anomaly, given by the topological Euler density, and threetype B anomalies, made up by three independent Weyl invariants. However,we also present the explicit expressions of the remaining six trivialanomalies, namely those that can be obtained by the Weyl variation oflocal functionals. The knowledge of the latter is in general necessary todisentangle the universal coefficients of the type A and B anomalies fromcalculations performed on concrete models.

Sequential integrated inversion of refraction and wide-angle reflection traveltimes and gravity data for two-dimensional velocity structures

SUMMARY A new algorithm is presented for the integrated 2-D inversion of seismic traveltime and gravity data. The algorithm adopts the ‘maximum likelihood’ regularization scheme. We construct a ‘probability density function’ which includes three kinds of information: information derived from gravity measurements; information derived from the seismic traveltime inversion procedure applied to the model; and information on the physical correlation among the density and the velocity parameters. We assume a linear relation between density and velocity, which can be node-dependent; that is, we can choose diVerent relationships for diVerent parts of the velocity‐density grid. In addition, our procedure allows us to consider a covariance matrix related to the error propagation in linking density to velocity. We use seismic data to estimate starting velocity values and the position of boundary nodes. Subsequently, the sequential integrated inversion (SII) optimizes the layer velocities and densities for our models. The procedure is applicable, as an additional step, to any type of seismic tomographic inversion. We illustrate the method by comparing the velocity models recovered from a standard seismic traveltime inversion with those retrieved using our algorithm. The inversion of synthetic data calculated for a 2-D isotropic, laterally inhomogeneous model shows the stability and accuracy of this procedure, demonstrates the improvements to the recovery of true velocity anomalies, and proves that this technique can eYciently overcome some of the limitations of both gravity and seismic traveltime inversions, when they are used independently. An interpretation of field data from the 1994 Vesuvius test experiment is also presented. At depths down to 4.5 km, the model retrieved after a SII shows a more detailed structure than the model obtained from an interpretation of seismic traveltime only, and yields additional information for a further study of the area.

Sperm morphology and chromatin condensation before and after semen processing.

Semen analysis constitutes the most important investigation of male infertility. However, the true anomalies present in defective sperm cells have been only partially characterized. The integrity of the sperm chromatin may play the most important role, particularly in ICSI, where most of the natural selection mechanisms are bypassed. This study was carried out to characterize sperm morphology (strict criteria), to evaluate chromatin condensation and sperm count in native semen as well as after semen preparation by the swim-up technique, and to eventually evaluate any correlation between these parameters. Semen from 90 men was analyzed for the above parameters in both the fresh and processed semen. Whereas the sperm count decreased after sperm preparation by the swim-up technique in comparison to the value in the fresh semen (p < .001), there was an increase in the percentage of morphologically normal (p < .001) and chromatin-condensed sperm (p = .99). However, there was no correlation between sperm morphology, chromatin condensation, and sperm count either in the fresh or in the processed semen samples. These results suggest that sperm morphology, sperm count, and chromatin condensation are independent parameters that should be evaluated separately in the assessment of male fertility in an assisted reproduction program.

Cytogenetic and Molecular Biology for Acute Leukemias at Diagnosis: A Cost/Effectiveness Comparison

This article presents a cost-effectiveness study comparing cytogenetic and molecular analyses for detection of chromosomal abnormalities which are prognostic factors in acute leukemia. The aim of the study was to determine how these two techniques could substitute or complement one another. The study sample consisted of 107 adult patients with de novo myeloid or lymphoid acute leukemias, tested by both techniques in 1994 and 1995, for identification of translocations t(9;22), t(8;21), t(15;17), t(4;11), t(1;19), the inversion of chromosome 16 and for monosomy 5 or 7 (or deletion of their long arms) and trisomy 8. The criterion for diagnostic effectiveness of these strategies was the rate of detection of true positive anomalies which are clinically relevant, according to the current state of knowledge. On the basis of these observations six alternative strategies at diagnosis were compared (each technique alone or different combinations of the two techniques). The study shows that:-for ALL, PCR alone appears the most cost-effective strategy;-for AML, cytogenetic analysis alone is the best strategy;-sequential strategies are more cost effective than simultaneous use of both techniques for minimising risk of false negatives.

Numerical Computation of Hansen-like Expansions

Fourier expansions of elliptic motion functions in multiples of the true, eccentric, elliptic and mean anomalies are computed numerically by means of the fast Fourier transform. Both Hansen-like coefficients and their derivatives with respect to eccentricity of the orbit are considered. General behavior of the coefficients and the efficiency (compactness) of the expansions are investigated for various values of eccentricity of the orbit.

Potential coordinate mislocations in crosshole tomography: Results from the Grimsel test site, Switzerland

Tomographic techniques based on borehole‐to‐borehole and tunnel‐to‐borehole traveltime data are now being employed in a wide range of studies associated with the exploration and exploitation of hydrocarbons and metallic minerals, the disposal of chemical and radioactive waste, diverse civil engineering projects, and archaeology. A fundamental assumption of currently employed tomographic inversion strategies is that the coordinates of the boreholes and tunnels containing the seismic sources and receivers are accurately known. By inverting both synthetic and observed traveltime data, we demonstrate that relatively minor coordinate errors (1–2%) in the deeper parts of long boreholes (&gt;100 m) may produce artifacts in the tomographic images that are comparable in extent and amplitude to true velocity anomalies. To address this problem, we introduce the coupled inverse method, commonly used in earthquake studies, as a means to determine simultaneously borehole coordinate adjustments and an estimate of the tomographic image. This method has been applied to traveltime data generated and collected along a tunnel and in three boreholes within a granitic body situated in the central Swiss Alps (Grimsel test site operated by NAGRA, the Swiss National Cooperative for the Disposal of Radioactive Waste). Coupled inversions of two independent subsets of traveltime data that involve a common central borehole, together with a coupled inversion of the entire data set, yield consistent coordinate adjustments for all boreholes and tomographic images that are compatible with the known geology and a sonic log from the central borehole. Further tests with synthetic data demonstrate that certain types of weak anisotropy could influence the coupled inversions. Regardless of whether minor coordinate mislocations or weak anisotropy is the dominant effect at the Grimsel test site, distinct low‐velocity zones appear to delineate fractures zones that are conduits for groundwater flow.

Comparison of Tropospheric Temperatures Derived from the NCEP/NCAR Reanalysis, NCEP Operational Analysis, and the Microwave Sounding Unit

Abstract The Climate Prediction Center has used atmospheric temperatures for data analysis from the National Centers for Environmental Prediction (NCEP) model since 1979. Unfortunately, model changes have adversely affected the stability of the climatologic fields, introducing time-varying biases in the anomaly patterns of the Climate Diagnostic Data Base (CDDB). Fortunately, NCEP has addressed this issue by rerunning a state-of-the-art model using fixed assimilation, parameterization, and physics in order to derive a true climatology and anomalies. The authors compare the previous CDDB temperatures with those derived from the stable reanalysis. Results show major improvements for climate diagnostics and monitoring. Also compared are the reanalysis temperatures with brightness temperature Tb observed by the Microwave Sounding Units (MSU), flown aboard the National Oceanic and Atmospheric Administration (NOAA) series of polar-orbiting satellites (TIROS-N to NOAA-14). This MSU dataset has a precision of abo...

Why are perfect animals, hybrids, and monsters food for symbolic thought?

AbstractWork on animal symbolism, in particular that of Mary Douglas, suggests that the symbolic value of some animals is grounded in taxonomic anomaly. Yet the work of ethnozoologists tends to show that folk taxonomies are consistent and devoid of true anomalies. This raises a first problem. Moreover, not only anomalous animals, but also exemplary animals often take on a symbolic value, thus raising a second problem. A solution to both problems is suggested, based on an examination of the cognitive organization of folk taxonomies, and with illustrations drawn from Ethiopian, Biblical, and Western culture.

Magnetic precession and product-of-inertia nutation damping of bias momentum satellites

This paper is concerned with large angle precession of earth-pointing bias momentum satellites in circular orbits and small angle precession in eccentric orbits. In the first part, ideal torque requirements are determined for precessing a wheel momentum vector by a large yaw angle, maintaining the earth pointing. It is then shown that a quasi-quarter-orbit magnetic precession is more easily feasible if once-per-orbit rotation of the spacecraft for earth-pointing is halted before commencing the precession. General relationships are developed to size the pitch dipole for a specified precession angle in a given number of orbits, using a tilted dipole model of the rotating geomagnetic field. The formulae involve true anomalies, not necessarily quarter orbit apart, at which the pitch dipole reverses its signs. The second part of the paper considers elliptic orbits. A pitch dipole sizing equation is developed first for a small angle open-loop rolllyaw magnetic precession. A closed-loop bang-bang precession scheme is presented next, working in concert with nutation damping via a rolllpitch product-of-inertia. The sizing equations and the quasi-quarter-orbit apart true anomalies for sign reversals of the pitch dipole apply to spin-stabilized satellites as well, for they are generalization of the related existing results. The literal relationship between the desired nutation damping coefficient (or time constant), rolllpitch product-of-inertia, and rate gain of the proportional-plus-integralplus-derivative pitch wheel controller is helpful in determining the required mass distribution of the spacecraft and the pitch controller bandwidth.

Increased incidence of cytogenetic abnormalities in chorionic villus samples from pregnancies established by in vitro fertilization and embryo transfer (IVF–ET)

We studied 201 pregnancies that were established by in vitro fertilization and embryo transfer (IVF-ET) and compared the frequency of cytogenetic abnormalities with that found in a large control population matched for indication group (advanced maternal age) and time of sampling. A total of 252 IVF-ET fetuses were cytogenetically analysed by either chorionic villus sampling (CVS; n = 80) or amniocentesis (n = 172). Eleven chromosome abnormalities were found in the CVS group (13.8 per cent); among them, a 45,X/46,X,dic(Y)(q11)/46,X,del(Y)(q11) mosaic that was found in an IVF pregnancy established by intracytoplasmic sperm injection (ICSI), four cases of trisomy 21, and three cases of trisomy 7 confined to the placenta. The results indicate a statistically significant three- to five-fold increase in both confined placental abnormalities (P < 0.008) and true fetal chromosome anomalies (P < 0.04). In the amniocentesis group, identical rates (1.7 per cent) of chromosome abnormalities were found in the IVF-ET and control groups. It is concluded that late first trimester, but not early second trimester, IVF-ET pregnancies are characterized by an increased frequency of cytogenetic abnormalities found at prenatal diagnosis.

Sagebrush as a sampling medium for gold exploration in the Great Basin — evaluation from a greenhouse study

Seedlings of hasin big sagebrush ( Artemisia tridentata subsp. tridentata) germinated from seed collected near Preble, Nevada were grown in soils containing Carlin-type disseminated gold ore from Pinson and Getchell, Nevada. After 4 months growth in a greenhouse, leaves, twigs and stems for each plant were combined and analyzed by instrumental neutron activation analysis (INAA) for the Carlin suite of elements which includes gold, arsenic, antimony and tungsten. Plants grown in soils containing Carlin ore did not accumulate significantly more gold than those growing in control soil ( p < 0.05). Gold measured in experimental plants averaged 0.9–2.6 ng/g (ppb) compared to 1.6 ng/g in controls. On the other hand, sagebrush grown in soils containing Carlin ores accumulated significantly more arsenic and antimony compared to those grown in control soils ( p > 0.95). Mean arsenic in experimental plants varied from 4.4 to 6.4 μg/g (ppm) compared to 0.4 μg/g in control plants. Experimental plants contained 0.2 μg/g (ppm) antimony compared to 0.03 μg/g in control plants. Results suggest that sagebrush would be a good prospecting medium for detecting concealed Carlin-type deposits in the Great Basin if arsenic and antimony are used as the pathfinder elements. Results also suggest that true gold anomalies in sagebrush will be more difficult to separate from aeolian contamination than those for arsenic and antimony in arid environments. Based on this greenhouse study, optimum anomaly-to-background contrast would be obtained from combined arsenic and antimony content of stems or twigs stripped of bark. Leaves would be less likely to show anomalies because surface tissue cannot be adequately cleaned or stripped.

Inversion of Two-Dimensional Magnetic Data Using Correlation Factors between High-Pass Filtered Anomalies

The magnetic anomaly expression produced by most geo ogic structures can be represented by a continuous function in depth and i dex parameter (magnetic inclination) with an amplitude coefficient (mag etic moment). Correlation factors between high-pass filtered anomalies 0 different or successive graticule spacings are used to determine the dept and the index parameter. The computed depths are determined automati ally from each correlation value for each index parameter value. The comp ted depths are plotted against the index parameter representing a contin ous correlation curve. The solution for the depth and the index parameter fthe buried structure is read at the common intersection of correlation cu ves. The method can be applied not only to true residual anomalies of short profile length but also to magnetic anomalies consisting of the combined ect of the residual component due to purely local structure and a regional omponent represented by a linear trend. Procedures are also formulated 0 estimate the amplitude coefficient. The method is independent of the filt ring process. The method is illustrated by a theoretical example and tested on a field example from Arizona.

Expansions of elliptic motion based on elliptic function theory

New expansions of elliptic motion based on considering the eccentricitye as the modulusk of elliptic functions and introducing the new anomalyw (a sort of elliptic anomaly) defined byw=πu/2K−π/2,g=amu−π/2 (g being the eccentric anomaly) are compared with the classic (e, M), (e, v) and (e, g) expansions in multiples of mean, true and eccentric anomalies, respectively. These (q,w) expansions turn out to be in general more compact than the classical ones. The coefficients of the (e,v) and (e,g) expansions are expressed as the hypergeometric series, which may be reduced to the hypergeometric polynomials. The coefficients of the (q,w) expansions may be presented in closed (rational function) form with respect toq, k, k′=(1−k2)1/2,K andE, q being the Jacobi nome relatedk whileK andE are the complete elliptic integrals of the first and second kind respectively. Recurrence relations to compute these coefficients have been derived.

Oesophageal atresia and associated anomalies: a plea for uniform documentation

Although associated congenital anomalies are the most significant factor affecting prognosis in babies with oesophageal atresia (OA), there is considerable variation in the methods by which they have been documented. To facilitate a uniform approach to the reporting of associated anomalies, we have analysed the data from our own experience and studied the methods used by other workers. During the period 1948–1991, 618 patients with OA and/or tracheo-oesophageal fistula were admitted to the Royal Children's Hospital, Melbourne. Concurrent congenital abnormalities were present in 344 (56%), the most frequent being cardiovascular (20.7%); urinary (21.6%); gastrointestinal (22.7%); and orthopaedic (15.7%). Not only have reports of the incidence of associated anomalies in OA involved a wide variety of classifications, but also they have varied in the extent to which co-existent lesions were sought by investigation. These factors, in addition to the criteria used for inclusion and the method of their documentation, have resulted in marked discrepancies in the apparent incidence of specific anomalies, and made valid comparisons between series difficult or impossible. We advocate a simple approach whereby: (1) data should be collected prospectively; (2) routine investigation should include renal ultrasound and echocardiography (as a minimum requirement); (3) the number of associated anomalies should be reported as a percentage of the total cohort of patients, rather than as a percentage of the anomalies themselves; (4) true congenital anomalies should be recorded separately from acquired conditions; and (5) the wide variation in the impact of associated abnormalities on the management and long-term outlook in OA should be recognized.