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  • Author: H. S. Singh x
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Abstract

In surveys covering human populations it is observed that information in most cases are not obtained at the first attempt even after some callbacks. Such problems come under the category of non-response. Surveys suffer with non-response in various ways. It depends on the nature of required information, either surveys is concerned with general or sensitive issues of a society. have considered the problem of non-response while estimating the population mean by taking a subsample from the non-respondent group with the help of extra efforts and an estimator was suggested by combining the information available from the response and nonresponse groups. We also mention that in survey sampling auxiliary information is commonly used to improve the performance of an estimator of a quantity of interest. For estimating the population mean using auxiliary information in presence of non-response has been discussed by various authors. In this paper, we have developed estimators for estimating the population mean of the variable under interest when there is non-response error in the study as well as in the auxiliary variable. We have studied properties of the suggested estimators under large sample approximation. Comparison of the suggested estimators with usual unbiased estimator reported by and the ratio estimator due to have been made. The results obtained are illustrated with aid of an empirical study.

Abstract

This paper addresses the problem of estimating the population mean at the current occasion in two occasion successive sampling when non-response occurs on the current (second) occasions. Using the power transformation we have suggested classes of estimators of current population mean and their properties are studied. Optimum replacement strategies for the proposed estimators have been given and empirical studies are carried out to assess the performance of estimators. We have made suitable recommendation to the practitioners on the basis of the empirical study.

Summary

Three species of digenetic trematodes are redescribed based on specimens collected from the intestine of freshwater fishes of Hastinapur and Meerut (U.P.), India: Allocreadium handiai () (Allocreadioidea: Allocreadiidae) from Mystus tengara (Hamilton, 1822) (Siluri-formes: Bagridae), Genarchopsis goppo (Hemiuroidea: Derogenidae) and Phyllodistomum chauhani (Plagiorchioidea: Gorgoderidae) from Channa punctata (Bloch, 1793) (Perciformes: Channidae). The three species were subjected to morphological, morphometric and molecular analyses. The morphological study revealed that A. handiai, G. goppo and P. chauhani can be distinguished by their congeners on the basis of their morphology. Partial nucleotide sequences of the 28S ribosomal RNA gene were obtained from the three trematode species and deposited in the GenBank. A phylogenetic reconstruction based on the 28S rRNA gene placed the three studied species within their respective families and their validity is discussed. For the first time molecular data of newly collected material of these species from India were used for confirmation of their validity and to assess their phylogenetic relationships.

Abstract

Morphological Redescription and Molecular Characterization of Dactylogyrus labei (Monogenea, Dactylogyridae) from Catla catla: a New Host Record in India. Chiary, H. R., Chaudhary, A., Singh, H. S. - Dactylogyrus labei Musselius et Gusev, 1976 (atypical form) specimens were collected from host Catla catla from the river Brahmaputra, Guwahati, Assam, India. The Dactylogyrus samples were examined by morphological and molecular methods. This parasite was originally described from Labeo rohita from fish farm Kalyani, West Bengal, India, but the morphological study of sclerotized parts showed the existence of D. labei on Catla catla. This is the first record of D. labei from Catla catla in India.

Summary

A new nematode species, Heliconema monopteri n. sp. (Physalopteridae), is described from the stomach and intestine of the freshwater fish Monopterus cuchia (Hamilton) (Synbranchidae) in Bijnor district, Uttar Pradesh, India. It is mainly characterized by the lengths of spicules (468 – 510 µm and 186 – 225 µm), the postequatorial vulva without elevated lips, the presence of pseudolabial lateroterminal depressions and by the number and arrangement of caudal papillae. This is the first representative of the genus reported from a synbranchiform fish. Another new congeneric species, Heliconema pisodonophidis n. sp. is established based on a re-examination of nematodes previously reported as H. longissimum (Ortlepp, 1922) from Pisodonophis boro (Hamilton) (Ophichthidae) in Thailand; ovoviviparity in this species is a unique feature among all physalopterids. Heliconema hamiltonii Bilqees et Khanum, 1970 is designated as a species dubia and the nematodes previously reported as H. longissimum from Mastacembelus armatus (Lacépède) in India are considered to belong to H. kherai Gupta et Duggal, 1989. A key to species of Heliconema Travassos, 1919 is provided.

Summary

The phylogenetic relationships of the nematode species Thelandros scleratus (Oxyurida: Pharyn-godonidae) and Physalopteroides dactyluris (Spirurida: Physalopteridae) were analyzed using the ribosomal 18S rRNAand the mitochondrial cytochrome C oxidase subunit genes. The nematodes were recovered from Brook's house gecko, Hemidactylus brooki (Reptilia: Gekkonidae) from Hast-inapur, Meerut (U.P.), India. The results demonstrated that T. scleratus shows 100% similarity with another sequence available from the same species and a close relationship (98-99%) with species of Parapharyngodon in both 18S rRNAand cox 1 regions. Regarding the nematode Physalopteroides. analysis showed a close phylogenetic relationship between P. dactyluris and several species of Phy-saloptera. This is the first sequence of 18S available for any species of the genus Physalopteroides

Summary

Two species of digenetic trematodes of the genus Pleurogenoides viz., P. cyanophlycti and P. euphlycti have been described from India. Information regarding the molecular data of various species of the genus Pleurogenoides Travassos, 1921 is virtually lacking. This study addresses the application of molecular markers to validate the phylogenetic position of P. cyanophlycti and P. euphlycti. In the present study, two species P. cyanophlycti and P. euphlycti were collected between January 2016 to October 2017, infecting the freshwater frogs inhabiting the Western Ghats, India. In the present study, the two species were identifi ed morphologically and by PCR amplification of the 28S ribosomal RNA gene. Phylogenetic tree results clearly demonstrate that both P. cyanophlycti and P. euphlycti belongs to the family Pleurogenidae . Based on these results, we presented and discussed the phylogenetic relationships of P. cyanophlycti and P. euphlycti within family Pleurogenidae from India. Phylogenetic analyses showed that P. cyanophlycti and P. euphlycti cluster according to their vertebrate host and revealed an important congruence between the phylogenetic trees of Pleurogenoides and of their vertebrate hosts. P. cyanophlycti and P. euphlycti clearly constitute a separate, sister branch with other species of the genera, Pleurogenoides, Pleurogenes (=Candidotrema), Prosotocus and Brandesia. The present study firstly provides important information about the molecular study and phylogenetic analysis of P. cyanophlycti and P. euphlycti. This study will also serve as a baseline for Pleurogenoides species identifi cation for further studies.

Summary

Two species of Thaparocleidus Jain (1952a) were found harboring W. attu from the Ganga River at two localities, Meerut and Farrukhabad, Uttar Pradesh, India, during the period of 2013-2015. Morphology and morphometric study of specimens identified as Thaparocleidus gomtius (Jain, 1952a) Lim, 1996 and T. sudhakari (Gusev, 1976) Lim, 1996. Molecular analyses using the 18S rRNA gene confirmed the validity of T. gomtius and T. sudhakari and demonstrated that both the species clustered with other Thaparocleidus species from different geographical regions. We aim at reassessing the taxonomy and establishing the phylogenetic relationships among these two redescribed species with other representatives of the genus Thaparocleidus.

Summary

The nematode, Procamallanus spiculogubernaculus Agarwal, 1958 was found from the Stinging catfish, Heteropneustes fossilis (Bloch, 1794) from Ghazipur, Delhi, India. Morphological characterization, including scanning electron microscope observation supplemented with DNA sequences is provided. Specimens recently found are characterized by the presence of an unlined buccal capsule having a small basal ring, esophagus muscular and glandular, vulva position is slightly post-equatorial, tail conical, long, and ending in three digit-like processes, phasmids present at about mid-length and cloaca located at the posterior end. In this study the species P. spiculogubernaculus is validated on the basis of molecular data after 47 years from its original description. In the scanning electron microscope examination, the topology of mouth and sensory pits in anterior portion, while the phasmids and digit like processes in posterior portion is clearly observed. Molecular data of the 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were analyzed. Molecular phylogenetic analyses supported the validity of Procamallanus spiculogubernaculus and confirmed the paraphyletic status of the members of Procamallanus, Spirocamallanus, Camallanus and Paracamallanus. Taxonomic status of members of the family Camallanidae are briefly discussed along with the results of the systematic evaluation of P. spiculogubernaculus based on molecular data.

Abstract

Gupta et al (2002) suggested an optional randomized response model under the assumption that the mean of the scrambling variable S is ‘unity’ [i.e. µs = 1]. This assumption limits the use of Gupta et al’s (2002) randomized response model. Keeping this in view we have suggested a modified optional randomized response model which can be used in practice without any supposition and restriction over the mean (µs) of the scrambling variables S. It has been shown that the estimator of the mean of the stigmatized variable based on the proposed optional randomized response sampling is more efficient than the Eicchorn and Hayre (1983) procedure and Gupta et al’s (2002) optional randomized technique when the mean of the scrambling S is larger than unity [i.e. µs > 1]. A numerical illustration is given in support of the present study.