Estimates of the size of winter flocks of the Pied Currawong, Strepera graculina (Shaw) from mark -recapture data - a new approach

1968 ◽  
Vol 16 (1) ◽  
pp. 27 ◽  
Author(s):  
JL Readshaw

Banding records were used to estimate the size of non-breeding winter flocks of the pied currawong, Strepera graculina, at Albury, N.S.W., during 1964 and 1965. A new method of analysing mark-recapture data is compared with conventional methods, and it is shown that the flocks contained between 500 and 1000 birds in both years. In 1964, the new method provided information on emigration and immigration that was not apparent when the data were treated in the conventional way. The new approach considers the common situation in which a population (flock) is sampled continuously by catching one member (bird) at a time, marking (banding) it, and returning it to the population. For closed populations, the population size was estimated by a method involving cumulative catch and recapture data. Subsequently, this method was successfully tested by simulating the sampling of 20 "populations" of 10,000 random numbers with a computer. The method also provided a simple way of controlling sampling effort based on recapture data to obtain any desired precision in the estimation of population size.

2009 ◽  
Vol 3 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Karol Šotnár ◽  
Ján Topercer

Estimating density, population size and dynamics of Common Buzzard (Buteo buteo) in the West Carpathian region by a new method In the Hornr Ponitrie Region (central Slovakia) during 1991-2001 we conducted a regular survey of Common Buzzard nests. In 2002-2006 our sampling effort increased and within the selected areas we studied buzzard dispersion/distribution, density and population dynamics using a new method of large-scale thorough search for nests with multiple nest check. The method is designed to estimate the dispersion/distribution, density and population size of target species (particularly raptors) at an absolute scale of abundance in large tracts of heterogeneous landscapes for studies of population fluctuations, trophic dynamics, reproductive success, habitat selection and use. It consists of systematic search for nests with extent of several tens of km2 and grain of c. 3000 m2, identifying and positioning the nests, and subsequent 1-3 nest checks during the each of three or more consecutive breeding periods. Further essential features include correct record of nest positions and other variables, combination of nest checks with ringing and marking, proportional sampling in apparently suitable and less suitable areas and proper timing and spacing of nest visits. In 2007 the sampling focused on DSF (Databank of Slovak Fauna) grid square 7377 covering c. 135 km2. We searched 71 km2 in total and estimated the density at 129 pairs/100 km2. Within the district of Prievidza (959 km2) we found 150 active buzzard nests. In 2008 we sampled the grid square 7377 more extensively, including higher altitudes (800-1200 m a. s. l.). Sampling of 82 km2 in total yielded the density estimate of 93 pairs/100 km2. Within the district of Prievidza we found 110 active buzzard nests. The reproductive success over four year period averaged 1.2 fledgling per active nest (n = 310 nests). Our sample enabled us to estimate the minimum population size in the whole grid square 7377 at 130 breeding pairs, i.e. 96 pairs/100 km2. Minimum population size for the whole district of Prievidza can be estimated approximately at 500 breeding pairs (52 pairs/100 km2), c. 350 of which breed in mountain forests, c. 80 in agricultural woodlots, and c. 70 in riparian vegetation. Rough estimate of minimum breeding population in the whole Slovakia is c. 15 000 pairs, i.e. on average 31 pairs/100 km2.


Geophysics ◽  
2018 ◽  
Vol 83 (6) ◽  
pp. D203-D215
Author(s):  
Zhentao Yang ◽  
Xinding Fang ◽  
L. Huang

We have developed a robust and reliable method for determining borehole shape from six-arm caliper logs. Four- and six-arm calipers are the common caliper tools used in open-hole logging. They provide information about wellbore geometry that is important in petrophysical and geomechanical analyses. The analysis procedure for four-arm caliper logs is well-established, but the analysis for six-arm caliper logs can be troublesome in complex hole environments containing breakouts or keyseats when the tool is off center. The challenge with the six-arm caliper is how to remove the effect of tool decentralization, which cannot be handled properly by using conventional correction methods, which are developed based on the assumption of circular or elliptical boreholes. To resolve this issue, we have developed a new approach for tool decentralization correction. The new method is based on an assumption that the true borehole center should be the center of a circle that fits the caliper pad positions in the least-squares sense subjected to the restriction that the circle is confined within the six pads. We first compare the new method with the conventional chord method and ellipse-fitting method through numerical modeling. We numerically investigate the general performance of these three methods by using a Monte Carlo approach to generate a large number of simulations that mimic caliper logging run in boreholes with a variety of different wellbore geometry. We then study the applicability of the new method in field data analysis by applying it to a field logging data set acquired in a well that contains the breakout and the keyseat. The modeling and field-data results indicate that the new method can yield more reliable estimates of the virgin borehole center than the other two methods and thus can give clearer delineation of the borehole shape.


2020 ◽  
Vol 9 (1) ◽  
pp. 97-115
Author(s):  
Syed Mahmudul Hasan

The Narration of Aisyah (May Allah be pleased with her), is the main focus of the controversy among Bangladeshi scholars on the issue of women's prayer in the mosque. The reason for the dispute is that a group of them issued the ruling based on the phenomenon of the text, and the others explained the ruling of Hadith according to the common situation in the society. If the circumstances change, the ruling will change along with it, because the originality of the issue is permissible, that is proven from other texts. This research adopts an inductive method to survey the Prophetic hadiths that talk about the prayer of women in the Mosque in terms of permissibility and prohibition and analytical method to analyze the difference in opinion of Bangladeshi scholars related to this issue. The research finds that the ruling of Shari’ah is a process that is continuous and permanent. But in necessity and emergency, it has the notion of flexibility and explanation. In the issue of women’s presence in the mosque, they should be allowed if they abide by the suggestions of Prophet (s) and should not if they don’t. So, Prohibition is not from the prophet (s), but it is from their obedience to the ruling.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 2345-2348 ◽  
Author(s):  
C. N. Haas

A new method for the quantitative analysis of multiple toxicity data is described and illustrated using a data set on metal exposure to copepods. Positive interactions are observed for Ni-Pb and Pb-Cr, with weak negative interactions observed for Ni-Cr.


Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 726
Author(s):  
Lamya A. Baharith ◽  
Wedad H. Aljuhani

This article presents a new method for generating distributions. This method combines two techniques—the transformed—transformer and alpha power transformation approaches—allowing for tremendous flexibility in the resulting distributions. The new approach is applied to introduce the alpha power Weibull—exponential distribution. The density of this distribution can take asymmetric and near-symmetric shapes. Various asymmetric shapes, such as decreasing, increasing, L-shaped, near-symmetrical, and right-skewed shapes, are observed for the related failure rate function, making it more tractable for many modeling applications. Some significant mathematical features of the suggested distribution are determined. Estimates of the unknown parameters of the proposed distribution are obtained using the maximum likelihood method. Furthermore, some numerical studies were carried out, in order to evaluate the estimation performance. Three practical datasets are considered to analyze the usefulness and flexibility of the introduced distribution. The proposed alpha power Weibull–exponential distribution can outperform other well-known distributions, showing its great adaptability in the context of real data analysis.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 466
Author(s):  
Pawel Szczepankowski ◽  
Natalia Strzelecka ◽  
Enrique Romero-Cadaval

This article presents three variants of the Pulse Width Modulation (PWM) for the Double Square Multiphase type Conventional Matrix Converters (DSM-CMC) supplying loads with the open-end winding. The first variant of PWM offers the ability to obtain zero value of the common-mode voltage at the load’s terminals and applies only six switches within the modulation period. The second proposal archives for less Total Harmonic Distortion (THD) of the generated load voltage. The third variant of modulation concerns maximizing the voltage transfer ratio, minimizing the number of switching, and the common-mode voltage cancellation. The discussed modulations are based on the concept of sinusoidal voltage quadrature signals, which can be an effective alternative to the classic space-vector approach. In the proposed approach, the geometrical arrangement of basic vectors needed to synthesize output voltages is built from the less number of vectors, which is equal to the number of the matrix converter’s terminals. The PWM duty cycle computation is performed using only a second-order determinant of the voltages coordinate matrix without using trigonometric functions. A new approach to the PWM duty cycles computing and the load voltage synthesis by 5 × 5 and 12 × 12 topologies has been verified using the PSIM simulation software.


2000 ◽  
Vol 78 (2) ◽  
pp. 320-326 ◽  
Author(s):  
Frank AM Tuyttens

The algebraic relationships, underlying assumptions, and performance of the recently proposed closed-subpopulation method are compared with those of other commonly used methods for estimating the size of animal populations from mark-recapture records. In its basic format the closed-subpopulation method is similar to the Manly-Parr method and less restrictive than the Jolly-Seber method. Computer simulations indicate that the accuracy and precision of the population estimators generated by the basic closed-subpopulation method are almost comparable to those generated by the Jolly-Seber method, and generally better than those of the minimum-number-alive method. The performance of all these methods depends on the capture probability, the number of previous and subsequent trapping occasions, and whether the population is demographically closed or open. Violation of the assumption of equal catchability causes a negative bias that is more pronounced for the closed-subpopulation and Jolly-Seber estimators than for the minimum-number-alive. The closed-subpopulation method provides a simple and flexible framework for illustrating that the precision and accuracy of population-size estimates can be improved by incorporating evidence, other than mark-recapture data, of the presence of recognisable individuals in the population (from radiotelemetry, mortality records, or sightings, for example) and by exploiting specific characteristics of the population concerned.


Oryx ◽  
2011 ◽  
Vol 45 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Özgün Emre Can ◽  
İrfan Kandemi̇r ◽  
İnci̇ Togan

AbstractThe wildcat Felis silvestris is a protected species in Turkey but the lack of information on its status is an obstacle to conservation initiatives. To assess the status of the species we interviewed local forestry and wildlife personnel and conducted field surveys in selected sites in northern, eastern and western Turkey during 2000–2007. In January–May 2006 we surveyed for the wildcat using 16 passive infrared-trigged camera traps in Yaylacı k Research Forest, a 50-km2 forest patch in Yenice Forest in northern Turkey. A total sampling effort of 1,200 camera trap days over 40 km2 yielded photo-captures of eight individual wildcats over five sampling occasions. Using the software MARK to estimate population size the closed capture–recapture model M0, which assumes a constant capture probability among all occasions and individuals, best fitted the capture history data. The wildcat population size in Yaylacı k Research Forest was estimated to be 11 (confidence interval 9–23). Yenice Forest is probably one of the most important areas for the long-term conservation of the wildcat as it is the largest intact forest habitat in Turkey with little human presence, and without human settlements, and with a high diversity of prey species. However, it has been a major logging area and is not protected. The future of Yenice Forest and its wildcat population could be secured by granting this region a protection status and enforcing environmental legislation.


1963 ◽  
Vol 20 (1) ◽  
pp. 59-88 ◽  
Author(s):  
J. E. Paloheimo

Techniques of estimating population size, level of fishing, and the degree of dependence of fishing success on environmental factors are examined on the basis of tagging, catch and effort data. A new method is developed to estimate population size from catch, effort, and temperature data when the catchability varies with temperature.The methods of estimation discussed are applied to data collected from a number of lobster fisheries on Canada's Atlantic coast. Analysis confirms a relationship between the catchability of lobsters and bottom temperature. Differences in this relationship are found between areas and between tagged and untagged lobsters within areas. It is suggested that these differences are attributable to the differences in densities as well as to aggregations of lobsters and fishing. The effect of these aggregations on population size estimates is considered.Calculated average catchabilities at comparable temperatures are different for different areas. These differences are correlated with the numbers of trap hauls per day per square miles fished. It is suggested that the differences in the catchabilities might be due to interactions between units of gear not predicted by the customary relationship between catch and effort.


1992 ◽  
Vol 101 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Eiji Yanagisawa ◽  
Ken Yanagisawa ◽  
Jay B. Horowitz ◽  
Lawrence J. Mambrino

A new approach to microlaryngeal surgery using a specially designed video microlaryngoscope with a rigid endoscopic telescope and an attached video camera was introduced by Kantor et al in 1990. The ability to video document and perform surgery of the larynx by viewing a high-resolution television image was demonstrated. This method was recommended over the standard microscopic technique for increased visibility with greater depth of field, unimpeded instrument access, instant documentation, and superior teaching value. The authors tried this new method and the standard microscopic technique at the same sitting on a series of patients. This paper will compare these two different techniques and discuss their advantages and disadvantages. Although the new method has many advantages, the standard microscopic technique remains as a valuable method in laryngeal surgery.


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