Comparison of maturation of female Clethrionomys glareolus from cyclic and noncyclic populations

1986 ◽  
Vol 64 (10) ◽  
pp. 2099-2102 ◽  
Author(s):  
Søren Bondrup-Nielsen ◽  
Rolf Anker Ims
Keyword(s):  
Population Density ◽  
Clethrionomys Glareolus ◽  
Previous Knowledge ◽  
Factors Affecting ◽  
Laboratory Colonies ◽  
Density Dynamics ◽  
Cyclic Populations

We examined the effect of mothers with and without new litters on maturation and growth of their daughters in laboratory colonies derived from cyclic and noncyclic populations of Clethrionomys glareolus. Mature individuals from cyclic populations are heavier than those from noncyclic populations, however, this difference was lost in our colonies. The presence of a mother had a significant effect in delaying vaginal perforation in cyclic females but not in noncyclic females. If a mother in the cyclic colony had a new litter and was lactating she appeared to be more effective in delaying vaginal perforation of her daughter than if she did not have a litter. The results are discussed in light of previous knowledge of factors affecting maturation in males and theory on population density dynamics.

scholarly journals Size-at-maturity shift in a male-only fishery: factors affecting molt-type outcomes in Newfoundland and Labrador snow crab (Chionoecetes opilio)

2020 ◽  
Author(s):  
Darrell R J Mullowney ◽  
Krista D Baker
Keyword(s):  
Population Density ◽  
Newfoundland And Labrador ◽  
Cold Water ◽  
Large Male ◽  
Snow Crab ◽  
Size At Maturity ◽  
Chionoecetes Opilio ◽  
Factors Affecting ◽  
Male Density ◽  
Process Factors

Abstract A sex-asymmetric downward shift in size-at-terminal-molt has recently occurred in males in some portions of the Newfoundland and Labrador (NL) snow crab stock range, a first known occurrence for such processes in snow crab (Chionoecetes opilio) stocks. This study examines plausible factors promoting the shift in size-at-terminal-molt [synonymous with size-at-maturity (SaM)] including individual size, temperature, population density, and sex ratio. Analyses highlight expanse of cold water and large male density as being significant predictors of molt-type outcomes. A confluence of cold conditions and low density of large males promoted the SaM shift. In turn, the low male density was associated with recently elevated fishery exploitation rates under quota-controlled management. It remains unknown the extent to which the reduction in terminal size reflects a phenotypic vs. genotypic process. Factors affecting skip-molting in male snow crab are investigated, and we find that skip-molting occurs most frequently under extreme cold and high population density conditions. Potential complications arising from altered growth dynamics are discussed. Overall, the results advance knowledge on intraspecific competition processes within snow crab populations and inform fisheries management systems that male-only harvest strategies do not provide full protection from biological harm to aquatic resources through fishing.

Pemanfaatan Peta Tematik dalam Perencanaan Pembangunan Sarana dan Prasarana Pendukung Pariwisata Daerah di Kabupaten Pangandaran

Tunas Agraria ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 1-19
Author(s):  
Rizka Fakhrizatullah ◽  
Rochmat Martanto ◽  
Yendi Sufyandi
Keyword(s):  
Land Use ◽  
Data Collection ◽  
Population Density ◽  
Literature Review ◽  
Qualitative Method ◽  
Thematic Maps ◽  
Coastal Tourism ◽  
Factors Affecting ◽  
Regional Autonomy

Abstract: Pangandaran is a district with a coastline of 91 Km, so this district has the potential for coastal tourism that needs to be developed. As a new regency of regional autonomy, demands to carry out construction of facilities and infrastructure to support tourism need to be increased. This study aims to determine the distribution of facilities and infrastructure that need to be developed and to know the factors that influence the determination of the construction of facilities and infrastructure. This research uses qualitative method, data collection is done through literature review and interviews. The results of the study indicate that the factors affecting the distribution of infrastructure include land use, population density, tourism objects, land slope and disaster vulnerability. The analysis shows that the distribution of villages suitable for the development of infrastructure includes the villages of Wonoharjo, Babadan, Pananjang and Pangandaran Village.Keyword: tourism, facilities and infrastructure, thematic maps. Intisari: Pangandaran merupakan kabupaten dengan garis pantai sepanjang 91 Km, sehingga kabupaten ini memiliki potensi pariwisata pantai yang perlu dikembangkan. Sebagai Kabupaten yang baru melakukan otonomi daerah, tuntutan untuk melaksanakan pembangunan sarana dan prasarana guna mendukung pariwisata perlu ditingkatkan. Kajian ini bertujuan untuk untuk mengetahui sebaran sarana dan prasarana yang perlu dikembangkan serta mengetahui faktor-faktor yang mempengaruhi penentuan pembangunan sarana dan prasarana. Penelitian ini menggunakan metode kualitatif, pengumpulan data dilakukan melalui kajian pustaka dan wawancara. Hasil kajian menunjukkan bahwa faktor-faktor yang mempengaruhi sebaran sarana prasarana meliputi penggunaan lahan, kepadatan penduduk, obyek wisata, kemiringan lahan dan kerawanan bencana. Dari hasil analisis menunjukkan bahwa sebaran desa yang sesuai untuk pengembangan sarana prasarana meliputi Desa Wonoharjo, Babadan, Pananjang dan Desa Pangandaran.Kata kunci: pariwisata, sarana dan prasarana, peta tematik.

scholarly journals Estimating population and livestock density of mobile pastoralists and sedentary settlements in the south-eastern Lake Chad area

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Vreni Jean-Richard ◽  
Lisa Crump ◽  
Abbani Alhadj Abicho ◽  
Ali Abba Abakar ◽  
Abdraman Mahamat II ◽  
...  
Keyword(s):  
Land Use ◽  
Population Density ◽  
Small Ruminants ◽  
Dry Season ◽  
Land Use Management ◽  
Lake Chad ◽  
Mobile Pastoralists ◽  
Livestock Density ◽  
Density Dynamics ◽  
First Time

Mobile pastoralists provide major contributions to the gross domestic product in Chad, but little information is available regarding their demography. The Lake Chad area population is increasing, resulting in competition for scarce land and water resources. For the first time, the density of people and animals from mobile and sedentary populations was assessed using randomly defined sampling areas. Four sampling rounds were conducted over two years in the same areas to show population density dynamics. We identified 42 villages of sedentary communities in the sampling zones; 11 (in 2010) and 16 (in 2011) mobile pastoralist camps at the beginning of the dry season and 34 (in 2011) and 30 (in 2012) camps at the end of the dry season. A mean of 64.0 people per km2 (95% confidence interval, 20.3-107.8) were estimated to live in sedentary villages. In the mobile communities, we found 5.9 people per km2 at the beginning and 17.5 people per km2 at the end of the dry season. We recorded per km2 on average 21.0 cattle and 31.6 small ruminants in the sedentary villages and 66.1 cattle and 102.5 small ruminants in the mobile communities, which amounts to a mean of 86.6 tropical livestock units during the dry season. These numbers exceed, by up to five times, the published carrying capacities for similar Sahelian zones. Our results underline the need for a new institutional framework. Improved land use management must equally consider the needs of mobile communities and sedentary populations.

scholarly journals Pemodelan Kasus DBD di Provinsi Jawa Timur dengan Metode Data Panel

2019 ◽  
Vol 8 (2) ◽  
pp. 101
Author(s):  
Annisa Dwinda Shafira
Keyword(s):  
Panel Data ◽  
Population Density ◽  
Time Series Data ◽  
Secondary Data ◽  
Series Data ◽  
Panel Regression ◽  
Affecting Factors ◽  
Factors Affecting ◽  
Panel Data Regression ◽  
Data Regression

The combination of panel data regression consist of time series data, it was collected based on a characteristic at a certain time (cross section). This research aimed to analyze the affecting factors and dominant factors of Dengue Hemoragic Fever (DHF) cases in East Java using panel data regression. This research uses secondary data published by the East Java Provincial Health Office, namely the Health Profile and the East Java Provincial Statistics Agency such as documents of each Districts/City in Numbers of East Java on 2014––2017 using total research population that were collected in all districts/cities in East Java Province. The data of new cases of DHF and factors affecting the incidence of DHF including clean and healthy living behavior in the household, poverty, population density, rainfall in East Java on 2014––2017. Panel regression analysis is used to determine the best model of the CEM, FEM and REM using Chow test, Hausman test and Langrange Multiplier test. Based on the results, the best model of panel regression is FEM with affecting variables such as poverty, population density, and rainfall.

scholarly journals Faktor-Faktor yang Mempengaruhi Alih Fungsi Lahan Sawah di Kabupaten Aceh Besar

2018 ◽  
Vol 3 (4) ◽  
pp. 525-533
Author(s):  
Raudhatul Husna ◽  
Azhar Azhar ◽  
Edy Marsudi
Keyword(s):  
Time Series ◽  
Population Density ◽  
Rice Field ◽  
Time Series Data ◽  
Statistical Tests ◽  
Secondary Data ◽  
Series Data ◽  
Factors Affecting ◽  
Rice Productivity ◽  
Negative Impacts

Abstrak. Alih fungsi lahan atau lazimnya disebut sebagai konversi lahan adalah  perubahan fungsi sebagian atau seluruh kawasan lahan dari fungsinya semula (seperti yang direncanakan) menjadi fungsi lain yang membawa dampak negatif terhadap lingkungan dan potensi lahan itu sendiri. Penelitian ini bertujuan untuk mengetahui apakah harga lahan, kepadatan penduduk, produktivitas padi dan jumlah PDRB dapat mempengaruhi alih fungsi lahan sawah di Kabupaten Aceh Besar. Data yang digunakan dalam penelitian ini adalah data sekunder. Data yang dikumpulkan adalah data time series dengan range tahun 2002 sampai 2016. Penelitian ini menggunakan metode analisis  regresi linier berganda. hasil penelitian dan pembahasan serta pengujian SPSS menunjukkan bahwa harga lahan, kepadatan penduduk, dan produktivitas padi berpengaruh nyata terhadap alih fungsi lahan sawah di Kabupaten Aceh Besar. sedangkan jumlah PDRB tidak berpengaruh terhadap alih fungsi lahan sawah. Hal ini ditunjukkan oleh koefisien regresi untuk variabel jumlah PDRB sebesar 0,00015. Hasil pengujian statistik menunjukkan nilai t hitung untuk jumlah PDRB sebesar 1,315 dengan nilai signifikan sebesar 0,218. Sedangkan nilai t tabel sebesar 1,782 yang berarti nilai t hitung t tabel (1,315 1,782).  Factors Affecting The Conversion Of Paddy Fields In Kabupaten Aceh Besar Abstract. Land use change or commonly referred to as land conversion is a change in the function of part or all of the land area from its original function (as planned) into other functions that bring negative impacts to the environment and the potential of the land itself. This study aims to find out whether the price of land, population density, rice productivity and the amount of GRDP can affect the conversion of rice field functions in Aceh Besar District. The data used in this research is secondary data. The data collected is time series data with range of year 2002 until 2016. This research use multiple linier regression analysis method. the results of research and discussion and testing of SPSS showed that land price, population density, and rice productivity significantly affected the conversion of wetland in Aceh Besar district. while the number of GDP does not affect the conversion of wetland. This is indicated by the regression coefficient for the GRDP variable of 0.00015. The results of statistical tests show the value of t arithmetic for the amount of GRDP by 1.315 with a significant value of 0.218. While the value of t table of 1.782 which means the value of t arithmetic t table (1,315 1.782).

Biological factors affecting enflagellation of Naegleria fowleri

1982 ◽  
Vol 152 (2) ◽  
pp. 803-808
Author(s):  
T W Woodworth ◽  
D T John ◽  
S G Bradley
Keyword(s):  
Population Density ◽  
Stationary Phase ◽  
Culture Medium ◽  
Actinomycin D ◽  
Suitable Model ◽  
Naegleria Fowleri ◽  
Biological Factors ◽  
Factors Affecting ◽  
Nægleria Fowleri ◽  
Amoeboid Cells

Naegleria fowleri is a pathogenic amoeboflagellate that can be evoked to transform from amoebae to flagellates by subculture to nonnutrient buffer. More than half of the amoebae of strains KUL, nN68, and Lovell became enflagellated 300 min after subculture to amoeba-saline, whereas no amoebae of strains NF66, NF69, and HB4 did. N. fowleri nN68 enflagellated best when grown at 32 or 37 degrees C and subcultured to amoeba-saline at 37 or 42 degrees C. Amoebae from the stationary phase of growth enflagellated more readily than did actively growing amoebae. Incubation in expended culture medium from stationary-phase cultures enhanced the capability of growing amoebae to enflagellate after subculture to amoebasaline. Enflagellation was more extensive when the population density in amoebasaline did not exceed 2 x 10(5) amoebae per ml. Cycloheximide at 1 microgram/ml and actinomycin D at 25 micrograms/ml inhibited growth of N. fowleri nN68. Cycloheximide at 0.5 microgram/ml and actinomycin D at 25 micrograms/ml completely prevented enflagellation when added at time zero. Cycloheximide at 0.5 microgram/ml, added 120 to 300 min after initiation of enflagellation, prevented further differentiation and caused existing flagellates to revert to amoeboid cells. Similarly, actinomycin D at 25 micrograms/ml, added 90 to 300 min after initiation of enflagellation, retarded differentiation and caused flagellates to revert. Radiolabeled precursors were incorporated into macromolecules during differentiation in nonnutrient buffer. Enflagellation of N. fowleri is a suitable model for studying regulation of a eucaryotic protist.

Demography of Clethrionomys gapperi in different habitats

1987 ◽  
Vol 65 (2) ◽  
pp. 277-283 ◽  
Author(s):  
Søren Bondrup-Nielsen
Keyword(s):  
Habitat Heterogeneity ◽  
Habitat Type ◽  
Late Summer ◽  
Home Range Size ◽  
Clethrionomys Gapperi ◽  
Vole Population ◽  
Habitat Types ◽  
Density Dynamics ◽  
Cyclic Populations ◽  
Sexually Mature

Theoretical considerations indicate that habitat heterogeneity may affect vole population density dynamics. The greater the degree of habitat heterogeneity, the greater the likelihood that a vole population will show stable rather than cyclic density dynamics. A livetrapping study of Clethrionomys gapperi was conducted near Lesser Slave Lake, Alberta, Canada, to examine the effect of habitat on demography and behaviour on this species. Voles in different habitat types differed in spring and late summer density, persistence, ratio of immature to total recruits, transiency, and home range size. There was no difference in litter size of voles among habitat types. Clethrionomys gapperi is not a cyclic species and sexually mature females are territorial. In this study demography of vole populations differed greatly among habitat type and only on one grid in 1 year did the density of sexually mature females reach saturation. Therefore, in each year there was always rooom for territorial establishment of females born in that year. This is unlike the situation for cyclic populations of Clethrionomys spp. in which there is no room for territorial establishment of such females during the peak population phase.

Initiation of breeding after winter in bank voles: effects of food and population density

2001 ◽  
Vol 79 (10) ◽  
pp. 1743-1753 ◽  
Author(s):  
Jana A Eccard ◽  
Hannu Ylönen
Keyword(s):  
Population Density ◽  
Bank Vole ◽  
Local Density ◽  
Local Population ◽  
Food Supplements ◽  
Clethrionomys Glareolus ◽  
Environmental Stability ◽  
Food Treatment ◽  
Bank Voles ◽  
Winter Food

We studied factors causing variation in the initiation of reproduction after winter in the bank vole (Clethrionomys glareolus), an iteroparous seasonal breeder, by offering different winter food supplements and monitoring local density variation. We used either sunflower seeds or barley to supplement the diet of populations of bank voles in grassland enclosures. In a parallel experiment we used spruce seeds, a natural winter food, to supplement the diet of bank vole populations in unfenced spruce forest. Survival, maturation, and breeding were monitored by livetrapping. Population density decreased during winter in grassland enclosures and remained constant in the forest, with no difference between food treatments. Breeding was initiated earlier in the grassland enclosures than in the forest, probably because of the supplemental food supply in both seed treatments and social and environmental stability in enclosures. Within both experiments, we found no differences in timing of parturition between food treatments. Inter actions of food treatment with density of females influenced the time of initiation of breeding in both experiments. At low densities, breeding started up to 1 month earlier than the population average. At high densities, a proportion of females did not breed during spring. Massive food supplements advanced the initiation of breeding, but among animals with similar food supplies, local population density seemed to have stronger regulatory effects. Local density variations may therefore create asynchronous breeding patterns within populations under similar wintering conditions.

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