scholarly journals Precession Theory Using the Invariable Plane of the Solar System

1991 ◽  
Vol 127 ◽  
pp. 323-326 ◽  
Author(s):  
W.M. Owen
Keyword(s):  
Solar System ◽  
Numerical Integration ◽  
Chebyshev Polynomials ◽  
Alternative Formulation ◽  
Euler Angles ◽  
Short Term ◽  
Polynomial Coefficients ◽  
The Mean ◽  
Invariable Plane

AbstractStandard precession theory builds up the precession matrix P, which rotates coordinates from the mean equator and equinox of epoch to the mean equator and equinox of date, by a sequence of three elementary rotations by the accumulated Euler angles ϚA, θA and zA: P = R3(−zA)R2(θA)R3(−ϚA). This scheme works well provided both the epoch and the date are within a few centuries of J2000. For long-term applications, the alternative formulation using the accumulated luni-solar and planetary precession, P = R3(ᵡA)R1(−ѡA)R3(−ψA)R1(ɛ), is more stable.Yet another formulation for P is possible, using the invariable plane of the Solar System as an intermediate plane: P = R3(−L) R1(−I) R3(−Δ) R1(I0) R3(L0). The angles I0 and L0 are the inclination and ascending node of the invariable plane at epoch; I and L are the same quantities at the date. Only the angle Δ is a function of both times. This scheme works for both short-term and long-term applications.For the short term, polynomial coefficients for I, L, and Δ are derived from the currently-accepted coefficients of the angles ϚA, θA and zA. For the long term, these angles are expressed as sums of Chebyshev polynomials obtained from analysis of a million-year numerical integration.If the intersection of the mean equator and the invariable plane were adopted as the origin of right ascensions, the theory would be simplified further: since L0 and L would no longer be required, P would again consist of the minimum three rotations.

Elevations in Thyroid-Stimulating Hormone in Normal Subjects after Receiving Short-Term Lithium Carbonate

1988 ◽  
Vol 22 (3) ◽  
pp. 202-204 ◽  
Author(s):  
Merlin V. Nelson ◽  
Vickie Tutag-Lehr ◽  
R. Lee Evans
Keyword(s):  
Lithium Carbonate ◽  
Normal Subjects ◽  
Thyroid Stimulating Hormone ◽  
Short Term ◽  
The Mean ◽  
Early Rise ◽  
State Concentration ◽  
Male Subjects ◽  
Stimulating Hormone

Nine normal, healthy male subjects had significantly elevated thyroid-stimulating hormone (TSH) concentrations while receiving oral lithium carbonate for two weeks. The mean minimum lithium serum concentration was 0.765 mEq/L. The TSH concentrations after 15 days on lithium were significantly correlated to the TSH concentration at baseline. No correlation was found between mean minimum lithium steady-state concentration and TSH concentration after 15 days on lithium. Further research is necessary to determine if a high baseline TSH concentration or an early rise in TSH will predict those patients who will eventually develop hypothyroidism after long-term lithium therapy.

scholarly journals A SLR Pre-Processing Algorithm Based on Satellite Signature Effect

2021 ◽  
Vol 11 (19) ◽  
pp. 8880
Author(s):  
Bowen Guan ◽  
Cunbo Fan ◽  
Ning An ◽  
Ricardo Cesar Podesta ◽  
Dra Ana Pacheco ◽  
...  
Keyword(s):  
Mean Value ◽  
Observation Data ◽  
Short Term ◽  
Error Sources ◽  
Effect Model ◽  
The Mean ◽  
The Stability ◽  
First Time ◽  
Satellite Signature Effect

As one of the major error sources, satellite signature effect should be reduced or even erased from the distribution of the post-fit residuals to improve the ranging precision. A simulation of satellite signature effect removal process for normal point algorithm is conducted based on a revised model of satellite response, which fully considers the structural and distribution characteristics of retroreflectors. In order to eliminate both long-term and short-term satellite signature effect, a clipping method for SLR data processing is proposed by defining the clipping location as 5.6 mm away from the mean value of the long-term fit residuals to select effective returns for normal points. The results indicate that, compared to normal points algorithm, the RMS per NP of LAGEOS-1 observation data processed by the clipping method is reduced from 62.90 ± 9.9 mm to 56.07 ± 4.69 mm, and the stability of RMS is improved 53%. This study improves the satellite signature effect model and simulates the fluctuation of normal points caused by satellite signature effect for the first time. The new method based on the simulation of satellite signature effect has stronger robustness and applicability, which can further minimize the influence of satellite signature effect on the SLR production and significantly improve the data property.

scholarly journals Visions of Human Futures in Space and SETI

2017 ◽  
Author(s):  
Jason T. Wright ◽  
Michael P. Oman-Reagan
Keyword(s):  
Solar System ◽  
Science Fiction ◽  
Dark Matter Particle ◽  
Short Term ◽  
National Science ◽  
The Galaxy ◽  
Near Future ◽  
Far Future ◽  
Made In

We discuss how visions for the futures of humanity in space and SETI are intertwined, and are shaped by prior work in the fields and by science fiction. This appears in the language used in the fields, and in the sometimes implicit assumptions made in discussions of them. We give examples from articulations of the so-called Fermi Paradox, discussions of the settlement of the Solar System (in the near future) and the Galaxy (in the far future), and METI. We argue that science fiction, especially the campy variety, is a significant contributor to the ‘giggle factor’ that hinders serious discussion and funding for SETI and Solar System settlement projects. We argue that humanity's long-term future in space will be shaped by our short-term visions for who goes there and how. Because of the way they entered the fields, we recommend avoiding the term ‘colony’ and its cognates when discussing the settlement of space, as well as other terms with similar pedigrees. We offer examples of science fiction and other writing that broaden and challenge our visions of human futures in space and SETI. In an appendix, we use an analogy with the well-funded and relatively uncontroversial searches for the dark matter particle to argue that SETI's lack of funding in the national science portfolio is primarily a problem of perception, not inherent merit.Also on arXiv: https://arxiv.org/abs/1708.05318Please cite this version:Wright, Jason T., and Michael P. Oman-Reagan. “Visions of Human Futures in Space and SETI.” International Journal of Astrobiology, 2017, 1–12. doi:10.1017/S1473550417000222.

scholarly journals Early and long-term complications following transanal pull through Soave technique in infants with Hirschsprung's diseaseric infants with Hirschsprung's disease

2019 ◽  
Author(s):  
Manoochehr Ghorbanpour ◽  
Mohammad Ali Seyfrabie ◽  
Babak Yousefi
Keyword(s):  
Intestinal Obstruction ◽  
Hirschsprung's Disease ◽  
Hirschsprung’S Disease ◽  
Statistical Tests ◽  
Case Series ◽  
P Value ◽  
Short Term ◽  
Case Series Study ◽  
The Mean

Objective. Patients undergoing Soave surgery for Hirschsprung's disease are at risk for some complications. The aim of this study was to investigate such short-term and long-term complications and evaluate the outcome of the operation in these patients. Methods. A case series study was carried out during the last 12 years, during 2007 to 2018 in Besat hospital of Hamadan. Data collection conducted using a checklist includes questions about demographic information, clinical features, and short-term and long-term complications, and consequences of post-operative surgery. The findings of the study were analyzed using SPSS software version 20 and appropriate statistical tests. P-value less than 0.05 was considered statistically significant. Results. A total of 55 children underwent Soave surgery during the last 12 years in Besat Hospital Hamadan, Iran. The mean age of the patients was 38±10 days during surgery, of which 56.4% were female. The mean hospital stay was 7.3 days. Also, the mean weight of children at birth was 2970±447 gr. Most of the patients were born as NVD (52.7%) and term (74.5%). The most common comorbidity was congenital heart disease. The most common short-term complication was intestinal obstruction in 14 patients (25.5%) and the most frequent long-term complication was intestinal obstruction and constipation (27.3% each cases). The mortality rate of patients in this study was 14.5% in total. Conclusions. One stage surgical procedure in Hirschsprung's disease is a safe and effective method, but care should be taken in choosing patients and patients should be monitored for possible complications, so that they can be considered and implemented for proper treatment.

The influence of mixtures of Stylosanthes spp. accessions on the occurrence of anthracnose caused by Colletotrichum gloeosporioides

1994 ◽  
Vol 45 (1) ◽  
pp. 203 ◽  
Author(s):  
RD Davis ◽  
S Chakraborty ◽  
DF Cameron ◽  
JAG Irwin ◽  
RM Boland
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Resistant Cultivar ◽  
Pure Stand ◽  
Northern Australia ◽  
Short Term ◽  
Mixed Stands ◽  
The Mean ◽  
Moderately Resistant ◽  
Long Term Studies

The effectiveness of using accession mixtures of Stylosanthes spp. to manage anthracnose (Colletotrichum gloeosporioides) in pastures in northern Australia was examined during three consecutive years. Two mixtures containing six accessions were compared with the components grown as pure stands. No significant differences in anthracnose incidence (proportion of infected plants/plot) were indicated between the two mixtures and the mean incidence of their respective components grown in pure swards. Areas under the disease progress curves for the accessions were not significantly different between pure and mixed stands of the cultivars other than Seca and Verano. Resistant cultivar Seca developed more disease in a mixture than in a pure stand, and moderately resistant Verano had less disease in a mixture than in a pure stand. In the short term, no apparent anthracnose control advantage is achieved in highly susceptible accessions of Stylosanthes spp. when they are included in mixtures with less susceptible accessions. Long term studies involving grazing animals are necessary to adequately evaluate control of this disease through the use of mixtures.

scholarly journals Mid-infrared evolution of η Carinae from 1968 to 2018

2019 ◽  
Vol 630 ◽  
pp. L6 ◽  
Author(s):  
A. Mehner ◽  
W.-J. de Wit ◽  
D. Asmus ◽  
P. W. Morris ◽  
C. Agliozzo ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Circumstellar Dust ◽  
Spectral Energy ◽  
Short Term ◽  
Dust Extinction ◽  
Bolometric Luminosity ◽  
Very Large Telescope ◽  
Optical Wavelengths ◽  
The Mean

η Car is one of the most luminous and massive stars in our Galaxy and is the brightest mid-IR source in the sky outside our solar system. Since the late 1990s, the central source has dramatically brightened at UV and optical wavelengths. This might be explained by a decrease in circumstellar dust extinction. We aim to establish the mid-IR flux evolution and further our understanding of the star’s UV and optical brightening. Mid-IR images from 8−20 μm were obtained in 2018 with VISIR at the Very Large Telescope. Archival data from 2003 and 2005 were retrieved from the ESO Science Archive Facility, and historical records were collected from publications. We present mid-IR images of η Car with the highest angular resolution to date at the corresponding wavelengths (≥0.22″). We reconstruct the mid-IR evolution of the spectral energy distribution of the spatially integrated Homunculus nebula from 1968 to 2018 and find no long-term changes. The bolometric luminosity of η Car has been stable over the past five decades. We do not observe a long-term decrease in the mid-IR flux densities that could be associated with the brightening at UV and optical wavelengths, but circumstellar dust must be declining in our line of sight alone. Short-term flux variations within about 25% of the mean levels could be present.

scholarly journals Supratentorial cavernous malformations adjacent to the corticospinal tract: surgical outcomes and predictive value of diffusion tensor imaging findings

2018 ◽  
Vol 128 (2) ◽  
pp. 541-552 ◽  
Author(s):  
Yuanxiang Lin ◽  
Fuxin Lin ◽  
Dezhi Kang ◽  
Yuming Jiao ◽  
Yong Cao ◽  
...  
Keyword(s):  
Surgical Outcomes ◽  
Predictive Value ◽  
Diffusion Tensor ◽  
Motor Deficits ◽  
Short Term ◽  
Cavernous Malformations ◽  
Scale Scores ◽  
The Mean ◽  
Deep Location

OBJECTIVEDiffusion tensor imaging (DTI) findings may facilitate clinical decision making in patients with supratentorial cavernous malformations adjacent to the corticospinal tract (CST-CMs). The objective of this study was to determine the predictive value of preoperative DTI findings for surgical outcomes in patients with CST-CMs.METHODSA prospectively maintained database of patients with CM referred to the authors' hospital between September 2012 and October 2015 was reviewed to identify all consecutive surgically treated patients with CST-CM. All patients had undergone sagittal T1-weighted anatomical imaging and DTI before surgery. Both DTI findings and clinical characteristics of the patients and lesions were analyzed with respect to surgery-related motor deficits. DTI findings included lesion-to-CST distance (LCD) and the alteration (i.e., deviation, interruption, or degeneration due to the CM) of CST on preoperative DTI images. Surgery-related motor deficits at 1 week and the last clinic visit (≥ 3 months) after surgery were defined as short-term and long-term deficits, respectively. Preoperative and final modified Rankin Scale scores were also analyzed to identify the surgical outcomes in these patients.RESULTSA total of 56 patients with 56 CST-CMs were included in this study. The mean LCD was 3.9 ± 3.2 mm, and alterations of the CST were detected in 20 (36.7%) patients. One week after surgery, 21 (37.5%) patients had short-term surgery-related motor deficits, but only 14 (25.0%) patients had long term deficits at the last clinical visit. The mean patient follow-up was 14.7 ± 10.1 months. The difference between preoperative and final modified Rankin Scale scores was not statistically significant (p = 0.490). Multivariate analysis showed that both short-term (p < 0.001) and long-term (p = 0.002) surgery-related motor deficits were significantly associated with LCD. Receiver operating characteristic (ROC) curve results were as follows: for short-term surgery-related motor deficits, the area under the ROC curve (AUC) was 0.860, and the cutoff point was LCD = 2.55 mm; for long-term deficits, the AUC was 0.894, and the cutoff point was LCD = 2.30 mm. Both univariate (p = 0.012) and multivariate (p = 0.049) analyses revealed that CST alteration on preoperative DTI was significantly correlated with short-term surgery-related motor deficits. On univariate analysis, deep location of the CST-CMs was significantly correlated with long-term motor deficits (p = 0.016). Deep location of the CST-CMs had a trend toward significance with long-term motor deficits on the multivariate analysis (p = 0.060).CONCLUSIONSTo facilitate clinical practice, the authors propose that 3.00 mm (2.55 to ∼3.00 mm) may be the safe LCD for surgery in patients with CST-CMs. A CST alteration on preoperative DTI and a deep location of the CST-CM may be risk factors for short- and long-term surgery-related motor deficits, respectively. A randomized controlled trial is needed to demonstrate the predictive value of preoperative DTI findings on surgical outcomes in patients with CST-CMs in future studies.

Long- and short-term in vitro D-dimer stability measured with INNOVANCE D-Dimer

2010 ◽  
Vol 103 (02) ◽  
pp. 461-465 ◽  
Author(s):  
Martina Böhm-Weigert ◽  
Thomas Wissel ◽  
Heidrun Muth ◽  
Bettina Kemkes-Matthes ◽  
Dirk Peetz
Keyword(s):  
Frozen Storage ◽  
Percentage Change ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Repeated Freezing ◽  
The Mean ◽  
D Dimer

Summary In vitro D-dimer stability in plasma is widely assumed, but has not yet been documented by systematic studies using samples covering a wide range of D-dimer. We investigated the short- and long-term stability of D-dimer in clinical citrated plasma samples with normal and pathological levels. The short-term stability was analysed by measuring D-dimer fresh, after storage of plasma for 4 hours at room temperature (RT) and after an additional 24 h storage at +2 to +8°C (n=40). Long-term stability samples (n=40) were measured fresh and after storage for 19, 25 and 36 months at ≤-60°C. The effect of repeated freezing was analysed by measuring samples (n=50) fresh and after four consecutive freeze-thaw cycles. D-dimer was measured on the BCS System using the INNOVANCE D-Dimer assay (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). D-dimer values at baseline ranged from 0.23–22.2 mg/l FEU. The mean percentage change after storage for 4 hours at RT and additional 24 hours at +2 to +8°C was +3.8% and +2.7%, respectively. The mean percentage change after frozen storage for 19, 25 and 36 months at ≤-60°C was –11.7%, –4.8% and –9.3%, respectively. The small decrease of D-dimer values after frozen storage was not time-dependent. Repeated freezing did not significantly alter D-dimer values (mean change ≤5%). The data demonstrate stability of D-dimer in plasma prior to freezing for up to 4 hours at RT and for up to 24 hours at +2 to +8°C as well as in plasma stored for up to three years at ≤-60°C.

Tethered cord syndrome in adults

2011 ◽  
Vol 15 (3) ◽  
pp. 258-270 ◽  
Author(s):  
Jörg Klekamp
Keyword(s):  
Spinal Cord ◽  
Tethered Cord ◽  
Tethered Cord Syndrome ◽  
Neurological Deficits ◽  
Short Term ◽  
Group A ◽  
The Mean ◽  
Group B

Object The treatment of tethered cord syndromes in adults is discussed regarding the natural history and surgical indications. The author analyzes data obtained in patients who were diagnosed with a tethered cord in adulthood and either underwent surgical or conservative therapy between 1991 and 2009. Methods Since 1991, data obtained in 2515 patients with spinal cord pathologies were entered into the spinal cord database, and prospective follow-up was performed through outpatient visits and questionnaires. Of the 2515 patients, 85 adults with a tethered cord syndrome formed the basis of this study. The tethering effect was caused either by a split cord malformation, a thick filum terminale, a conus medullaris lipoma with extradural extension, or various combinations of these mechanisms. The mean age of the patients was 46 ± 13 years (range 23–74 years) and the mean follow-up duration was 61 ± 62 months. Two groups were distinguished based on the absence (Group A, 43 patients) or presence (Group B, 42 patients) of an associated lipoma or dysraphic cyst (that is, dermoid, epidermoid, or neurenteric cyst). Surgery was recommended for patients with symptoms only. Short-term results were determined within 3 months of surgery, whereas long-term outcomes (clinical recurrences) were evaluated using Kaplan-Meier statistics. Results For all patients, pain was the most common major complaint. Severe neurological deficits were rare. In Group A, 20 of 43 patients underwent surgery, whereas in Group B 23 of 42 patients underwent surgery. Among individuals who did not undergo surgery, 17 patients refused surgery and 25 patients underwent recommended conservative treatment. Short-term postoperative results indicated a significant improvement of pain and a stabilization of neurological symptoms. Long-term results showed a good prognosis in patients in whom first-time (that is, nonrevision) surgery achieved successful untethering, with a 10-year rate of neurological stabilization in 89% of Group A and a 10-year rate of neurological stabilization in 81% of Group B patients. The benefit of secondary operations in Group B was limited, with eventual clinical deterioration occurring in all patients within 10 years. For patients treated conservatively, follow-up information could be obtained in 33 of 42 patients. Twenty-eight patients remained in stable clinical condition. Only 5 of the conservatively treated patients experienced clinical deterioration over time; in 4 of these individuals with deterioration, surgery had been recommended but was refused by the patient. The clinical recurrence rate in all conservatively treated patients was 21% after 10 years. With a recommendation for surgery this figure rose to 47% within 5 years. Conclusions Surgery in adult patients with a tethered cord syndrome should be reserved for those with symptoms. In surgically treated patients, pain relief can often be achieved, and long-term neurological stabilization tends to persist more often than it does in conservatively treated patients. A conservative approach is warranted, however, in adult patients without neurological deficits. Revision surgery in patients with complex dysraphic lesions should be performed in exceptional cases only.

scholarly journals Institutional Shareholdings and Financial Characteristics of Malaysian Listed Companies

2020 ◽  
Author(s):  
Shamsul Naharabdullah ◽  
Mohd Azlan Yahya ◽  
Faisol Elham
Keyword(s):  
Institutional Investors ◽  
Listed Companies ◽  
Financial Ratios ◽  
Short Term ◽  
Growth Ratio ◽  
Primary Motivation ◽  
The Mean ◽  
Financial Characteristics ◽  
Institutional Shareholders

This study attempts to investigate the extent to which the financial characteristics of firms are related to institutional shareholdings. The primary motivation to carry out the study comes from an earlier paper by Hessel and Norman (1992), which showed that seven financial ratios discriminated between strongly-held and institutionally-neglected firms. As an extension of the study, the present study seeks to investigate the seven financial ratios among Malaysian companies by identifying differences in the means of the seven ratios between a group of companies with substantial institutional shareholdings against another group of companies with negligible institutional shareholdings. The findings, from a sample of KLSE listed companies, broadly support the findings by Hessel and Norman (1992), in which firms with significant institutional shareholdings exhibited a significantly higher profitability ratio against firms that were neglected by institutional investors.. This suggested that institutional investors placed greater emphasis on a firm's short-term results. Our evidence also did not indicate institutional shareholders' direct involvement in ensuring a firm's long-term growth and competitiveness, as shown by the insignificant differences in the mean of growth ratio between firms that had significant institutional shareholdings and those that were neglected by institutional investors.  

Sign in / Sign up

Export Citation Format

Share Document