STANDARD REGRESSION VERSUS MULTILEVEL MODELING OF MULTISTAGE COMPLEX SURVEY DATA

Complex surveys based on multistage design are commonly used to collect large population data. Stratification, clustering and unequal probability of the selection of individuals are the complexities of complex survey design. Statistical techniques such as the multilevel modeling – scaled weights technique and the standard regression – robust variance estimation technique are used to analyze the complex survey data. Both statistical techniques take into account the complexities of complex survey data but the ways are different. This thesis compares the performance of the multilevel modeling – scaled weights and the standard regression – robust variance estimation technique based on analysis of the cross-sectional and the longitudinal complex survey data. Performance of these two techniques was examined by Monte Carlo simulation based on cross-sectional complex survey design. A stratified, multistage probability sample design was used to select samples for the cross-sectional Canadian Heart Health Surveys (CHHS) conducted in ten Canadian provinces and for the longitudinal National Population Health Survey (NPHS). Both statistical techniques (the multilevel modeling – scaled weights and the standard regression – robust variance estimation technique) were utilized to analyze CHHS and NPHS data sets. The outcome of interest was based on the question “Do you have any of the following long-term conditions that have been diagnosed by a health professional? – Diabetes”. For the cross-sectional CHHS, the results obtained from the proposed two statistical techniques were not consistent. However, the results based on analysis of the longitudinal NPHS data indicated that the performance of the standard regression – robust variance estimation technique might be better than the multilevel modeling – scaled weight technique for analyzing longitudinal complex survey data. Finally, in order to arrive at a definitive conclusion, a Monte Carlo simulation was used to compare the performance of the multilevel modeling – scaled weights and the standard regression – robust variance estimation techniques . In the Monte Carlo simulation study, the data were generated randomly based on the Canadian Heart Health Survey data for Saskatchewan province. The total 100 and 1000 number of simulated data sets were generated and the sample size for each simulated data set was 1,731. The results of this Monte Carlo simulation study indicated that the performance of the multilevel modeling – scaled weights technique and the standard regression – robust variance estimation technique were comparable to analyze the cross-sectional complex survey data. To conclude, both statistical techniques yield similar results when used to analyze the cross-sectional complex survey data, however standard regression-robust variance estimation technique might be preferred because it fully accounts for stratification, clustering and unequal probability of selection

The Wigner function and its relation with the wavelet transform for certain Lie groups

We study Wigner functions on general Lie groups when the group admits square-integrable representations. We develop a relation between Wigner functions and wavelet transforms. In the main part of this thesis, we build Wigner functions and study the connection between Wigner functions and wavelet transforms on the group [Special characters omitted.] . Further we check the covariance property, marginality and overlap conditions for the Wigner functions on G ab

UGROŽENE VRSTE RIBA U SVIJETU: Labeo bata (Hamilton, 1822) (Cypriniformes: Cyprinidae)

Minor carp Labeo bata is an endangered fish species in Bangladesh. This fish is one of the commercially and nutritionally valuable food fish in Asian countries including Bangladesh, India and Pakistan. L. bata is an important target species for small scale fishermen in Bangladesh who use a variety of traditional fishing gears. However, natural populations are seriously declining due to loss of habitat, siltation in the river basin, indiscriminate killing of fry and fingerlings, water pollution by industrial and domestic waste, agrochemicals and overexploitation. This paper recommends the sustainable conservation measures of this endangered fish species in Bangladesh and neighboring countries.Bata, Labeo bata, je ugrožena vrsta ribe u Bangladešu. Ova vrsta je od komercijalne važnosti te nutritivno vrijedna hrana u azijskim zemljama, uključujući Bangladeš, Indiju i Pakistan. L. bata je važna lovna vrsta za male ribare u Bangladešu koji pritom koriste razne tradicionalne ribolovne alate. Međutim, prirodne populacije ozbiljno opadaju zbog gubitka staništa, zamuljenja riječnih korita, neselektivnog ubijanja mlađi i mladunaca, onečišćenja voda industrijskim i kućnim otpadom, agrokemikalijama i prekomjernim iskorištavanjem. U radu se preporučuju održive mjere očuvanja ove ugrožene vrste riba u Bangladešu i susjednim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Eutropiichthys vacha (Hamilton, 1822) (Siluriformes: Schilbeidae)

River catfish Eutropiichthys vacha is one of the foods high in nutritional value in Asian countries. However, natural populations have seriously declined or are on the verge of extinction due to over-exploitation and various ecological changes in its natural habitats, leading to an alarming situation which deserves high conservation attention. This paper suggests conservation measures that should be taken into account towards the preservation of the remnant isolated population of E. vacha in Asian countries.Riječni som, Eutropiichthys vacha, služi kao komercijalno visoka, nutritivno vrijedna hrana u azijskim zemljama. Međutim, prirodne populacije ozbiljno su opale ili su na rubu izumiranja zbog prekomjernog iskorištavanja i raznih ekoloških promjena u svojim prirodnim staništima, što dovodi do alarmantne situacije te je potreban visok stupanj zaštite. U radu se predlažu mjere zaštite koje treba uzeti u obzir kako bi se očuvao ostatak izolirane populacije E. vacha u azijskim zemljama

Temporal variations of sex ratio and growth pattern of critically endangered catfish Clupisoma garua from the Ganges river of north-western Bangladesh

647-653This research work states the temporal variations of sex ratio (SR), length-frequency distributions (LFDs), growth type based on length-weight relations (LWRs) and length-length relations (LLRs) of Clupisoma garua from the Ganges river of north-western Bangladesh. A total of 1200 specimens (male=630, female=570) were sampled using traditional fishing gears during May 2014 to April 2015. Then, total length (TL), standard length (SL) and fork length (FL) were taken to about 0.1 cm, and body weight (W) was taken to 0.1 g accuracy. The overall SR (male: female=1.0:0.90) did not vary statistically from the expected ratio of 1:1 (df =1, χ2 = 3.00, p>0.05). However, monthly variations of SR indicate males were higher in each month except June-August when females were greater in percentage. The LFDs showed that in males C. garua, ranged from 3.8-25.9 cm TL and females 3.9-26.3 cm TL. The LFDs for both sexes did not pass the normality; and Mann-Whitney U-test showed significant differences between sexes (pbvs. FL and TL vs. SL) of C. garua were highly significant (pr2 values >0.975. Finally, the findings of this study will be helpful for fishery biologists and conservationists to recommend adequate policy for the sustainable fishery of C. garua in the Ganges river and surrounding ecosystem

UGROŽENE VRSTE RIBA U SVIJETU: Botia dario (Hamilton, 1822) (Cypriniformes: Cobitidae)

Bengal loach Botia dario is a valuable food fish in South Asian countries including Bangladesh, Bhutan, India and Nepal. However, the wild population is declining due to heavy harvest, habitat loss and its ecological changes. This paper suggests actions for the conservation of the lasting isolated populations of B. dario in Asian countries.Benegalski vijun, Botia dario, u južnim azijskim zemljama, uključujući Bangladeš, Butan, Indiju i Nepal, ima visoku važnost u prehrani. Međutim, divlje populacije su u opadanju zbog teškog iskorištavanja, gubitka staništa i ekoloških promjena. U ovom članku se predlažu akcije za očuvanje posljednjih izoliranih populacija B. dario u azijskim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Pethia ticto (Hamilton, 1822) (Cypriniformes: Cyprinidae)

The threatened Ticto barb Pethia ticto is a small indigenous fish species widely distributed in the natural waters of Asian countries. Previously it was known as Puntius ticto. Natural populations have been reduced seriously to the verge of extinction due to excess exploitation and ecological changes in their natural habitats. This paper suggests the actions for the conservation of the remaining isolated population of P. ticto in Asian countries.Ugrožena indijska autohtona vrsta, Pethia ticto, široko je rasprostranjena u prirodnim vodama azijskih zemalja. Ranije je bila poznata kao Puntius ticto. Prirodne su populacije ozbiljno smanjene te na rubu izumiranja zbog viška eksploatacije i ekoloških promjena u njihovim prirodnim staništima. U radu se predlažu mjere za očuvanje preostalih izoliranih populacija P. ticto u azijskim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Rhinomugil corsula (Hamilton, 1822) (Mugiliformes: Mugilidae)

Mullet Rhinomugil corsula is a threatened fish of the family Mugilidae and used as food fish in Asian countries but its natural populations have declined due to over-exploitation and various ecological changes in its natural habitats leading to an alarming condition and deserving high conservation importance. This paper recommends measures for the conservation of the remnant isolated wild populations of R. corsula in Asian countries.Cipal, Rhinomugil corsula, je ugrožena vrsta iz porodice Mugilidae i koristi se kao hrana u azijskim zemljama. Prirodne populacije opadaju zbog pretjeranog iskorištavanja i raznih ekoloških promjena u njihovim prirodnim staništima što dovodi do zabrinjavajućeg stanja i zaslužuje veliku važnost u svrhu njihovog očuvanja. U radu se preporučuju mjere zaštite ostatka izoliranih divljih populacija R. corsula u azijskim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Heteropneustes fossilis (Bloch, 1794) (Siluriformes: Heteropneustidae)

The threatened stinging catfish Heteropneustes fossilis is a nutritionally valuable food in Asian countries but its natural populations have declined due to over-exploitation, habitat loss and pollution, thus deserving high conservation importance for the remaining isolated, wild populations of H. fossilis in Asian countries. The results would be useful for the protection of the presence of endemic species and sustainable fisheries in the lake.Ugroženi bodljasti som, Heteropneustes fossilis, je nutritivno vrijedna namirnica u azijskim zemljama, ali njegove prirodne populacije opadaju zbog pretjeranog iskorištavanja, gubitka staništa i zagađenja zbog kojih zaslužuje visoku važnost za zaštitu preostalih izoliranih, divljih populacija H. fossilis u azijskim zemljama