scholarly journals Using Gaia DR2 to solve differential colour refraction and charge transfer efficiency issues

2020 ◽  
Vol 498 (1) ◽  
pp. 258-264
Author(s):  
F R Lin ◽  
Q Y Peng ◽  
Z J Zheng
Keyword(s):  
Charge Transfer ◽  
Systematic Error ◽  
Convenient Method ◽  
Transfer Efficiency ◽  
Sigmoidal Function ◽  
The Poor ◽  
The Mean ◽  
Gaia Dr2

ABSTRACT The Gaia DR2 catalogue released in 2018 gives information about more than one billion stars, including their extremely precise positions that are not affected by the atmosphere, as well as the magnitudes in the G, RP, and BP passbands. This information provides great potential for the improvement of the ground-based astrometry. Based on Gaia DR2, we present a convenient method to calibrate the differential colour refraction (DCR). This method only requires observations with dozens of stars taken through a selected filter. Applying this method to the reduction of observations captured through different filters by the 1- and 2.4-m telescopes at Yunnan Observatory, the results show that the mean of the residuals between observed and computed positions (O − C) after DCR correction is significantly reduced. For our observations taken through an N (null) filter, the median of the mean (O − C) for well-exposed stars (about 15 G-mag) decreases from 19 to 3 mas, thus achieving better accuracy, i.e. mean (O − C). Another issue correlated is a systematic error caused by the poor charge transfer efficiency (CTE) when a CCD frame is read out. This systematic error is significant for some of the observations captured by the 1-m telescope at Yunnan Observatory. Using a sigmoidal function to fit and correct the mean (O − C), a systematic error up to 30 mas can be eliminated.

Charge transfer efficiency in proton damaged CCD's

1998 ◽  
Vol 45 (2) ◽  
pp. 154-163 ◽  
Author(s):  
T. Hardy ◽  
R. Murowinski ◽  
M.J. Deen
Keyword(s):  
Charge Transfer ◽  
Transfer Efficiency

scholarly journals Length-weight relationships and condition factor of Hyperopisus bebe (Lacepede, 1803) (Actinopterygii: Osteoglossiformes) in River Galma, Zaria, Kaduna State, Nigeria

2017 ◽  
Vol 4 (8) ◽  
pp. 301-305
Author(s):  
Matouke M. Moise
Keyword(s):  
Water Quality ◽  
Water Body ◽  
Growth Pattern ◽  
Condition Factor ◽  
Allometric Growth ◽  
Male And Female ◽  
B Values ◽  
The Poor ◽  
Poor Water Quality ◽  
The Mean

The investigation of length-weight relationship and condition factor are very relevant indices to ascertain the health of fish in the water body. Length-weigh relationship and condition factor of Hyperopisus bebe (Lacepede, 1803) (Actinopterygii: Osteoglossiformes: Mormyridae) in River Galma, Zaria, Kaduna State, Nigeria, were assessed. The mean length and mean weigh in male and female were 26.703 cm +/- 0.51 cm and 25.32 cm +/- 0.898 cm; 158.2 g +/- 10.1 g and 95.91 g +/- 9.26 g, respectively. The exponent or growth pattern 'b' values for male and female were 2.009 and 2.176. The condition factor for male and female were 0.59 and 0.83, respectively. The negative allometric growth pattern and poor condition factor might be due to the poor water quality in the fish ecosystem and should be regarded with concern.

scholarly journals STUDY OF AN INTERMEDIATE AGE OPEN CLUSTER IC 1434 USING GROUND-BASED IMAGING AND GAIA DR2 ASTROMETRY

2021 ◽  
Vol 57 (2) ◽  
pp. 381-389
Author(s):  
Y. H. M. Hendy ◽  
D. Bisht
Keyword(s):  
Radial Distribution ◽  
Proper Motion ◽  
Open Cluster ◽  
Membership Probability ◽  
Kinematical Analysis ◽  
The Mean ◽  
First Time ◽  
Right Ascension ◽  
Cluster Age ◽  
Gaia Dr2

We present a detailed photometric and kinematical analysis of the poorly studied open cluster IC 1434 using CCD VRI, APASS, and Gaia DR2 database for the first time. By determining the membership probability of stars we identify the 238 most probable members with a probability higher than 60%; by using proper motion and parallax data as taken from the Gaia DR2 catalog. The mean proper motion of the cluster is obtained as μx=−3.89±0.19 and μy=−3.34±0.19 mas yr−1 in both the directions of right ascension and declination. The radial distribution of member stars provides the cluster extent as 7.6 arcmin. We estimate the interstellar reddening E(B−V) as 0.34 mag using the transformation equations from the literature. We obtain the values of cluster age and distance as 631±73 Myr and 3.2±0.1 kpc.

scholarly journals Monitoring inner London mental illness services

1995 ◽  
Vol 19 (5) ◽  
pp. 276-280 ◽  
Author(s):  
◽  
Bernard Audini ◽  
Michael Crowe ◽  
Joan Feldman ◽  
Anna Higgitt ◽  
...  
Keyword(s):  
Mental Illness ◽  
Psychiatric Care ◽  
Bed Occupancy ◽  
Local Data ◽  
Catchment Population ◽  
The Poor ◽  
Number Of Patients ◽  
The Mean ◽  
Acute Psychiatric Care ◽  
The Impact

Our objective was to establish a mechanism for monitoring indicators of the state of health of inner London's mental illness services. Data were collected for a census week around 15 June 1994. Local data collection was coordinated by consultant pyschiatrists working in inner London services. Twelve services participated with a combined catchment population of 2.6 m. They included ten London services which were among the 17 most socially deprived areas of England. Main indicators were admission bed occupancy levels (including an estimate of the total requirement), proportion of patients detained under the Mental Health Act, number of assaults committed by inpatients, number of emergency assessments and CPN caseloads. The mean true bed occupancy (which reflects the number of patients who were receiving, or required, in-patient care on census day) was 130%. To meet all need for acute psychiatric care, including for patients who should have been admitted and those discharged prematurely because beds were full, a further 426 beds would have been required. Fifty per cent of patients were legally detained. Physical assaults were virtually a daily occurrence on the admission units. Average community pyschiatric nurse caseloads were 37, suggesting that the majority were not working intensively with limited caseloads of patients with severe mental illness. These indicators, although imperfect, will allow for some measurement of the impact of local and central initiatives on the poor state of London's mental illness services.

scholarly journals The reproductive success of black rhinoceroses in the Hluhluwe–iMfolozi Park, KwaZulu-Natal, South Africa

Koedoe ◽  
2017 ◽  
Vol 59 (1) ◽  
Author(s):  
Zoliswa N. Nhleko ◽  
Dan M. Parker ◽  
Dave J. Druce
Keyword(s):  
South Africa ◽  
Carrying Capacity ◽  
Black Rhinoceros ◽  
Ecological Carrying Capacity ◽  
Diceros Bicornis ◽  
The Poor ◽  
Kwazulu Natal ◽  
Southern Central ◽  
Target Period ◽  
The Mean

Black rhinoceroses (Diceros bicornis) are endangered and the southern-central sub-species (Diceros bicornis minor) is considered critically endangered. We assessed the reproductive lifehistories of black rhinoceroses in Hluhluwe–iMfolozi Park (HiP), KwaZulu-Natal, South Africa, to determine whether this historically important donor sub-population was meeting regional reproductive targets. Detailed life-history information for known individuals (n = 79–120) was used to investigate reproductive parameters between 1998 and 2013. Mean age at sexual maturity was 12 years, which exceeded a target period of 7 years and 5 months. The mean inter-calving interval was 3 years and 8 months – 8 months longer than the recommended 3 years. The poor population performance of the HiP black rhinoceroses could be a result of poor habitat quality, poor animal condition, females losing their first calves, predation of calves or a negative social effect of annual live-harvesting of the population. However, we believe that the estimated ecological carrying capacity of black rhinoceroses at HiP (a figure used to ascertain whether the population can be harvested at all) may be incorrect, leading to the poor reproductive performance. We recommend that the accuracy of the ecological carrying capacity estimate be assessed as a matter of urgency and that a moratorium be placed on the live-harvesting of individuals until the estimate has been refined.Conservation implications: Our results provide key data which can be used to refine black rhinoceros breeding targets in South Africa and the region more broadly

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