Extrinsic factors affecting population density

1995 ◽  
pp. 169-216 ◽  
Author(s):  
Darrell R J Mullowney ◽  
Krista D Baker

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.


Tunas Agraria ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 1-19
Author(s):  
Rizka Fakhrizatullah ◽  
Rochmat Martanto ◽  
Yendi Sufyandi

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.


2019 ◽  
Vol 8 (2) ◽  
pp. 101
Author(s):  
Annisa Dwinda Shafira

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.


2018 ◽  
Vol 3 (4) ◽  
pp. 525-533
Author(s):  
Raudhatul Husna ◽  
Azhar Azhar ◽  
Edy Marsudi

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).


2018 ◽  
Vol 89 (4) ◽  
pp. 580-589 ◽  
Author(s):  
NWM Edwards ◽  
EL Best ◽  
P Goswami ◽  
MH Wilcox ◽  
SJ Russell

Wiping of surfaces contaminated with pathogenic bacteria is a key strategy for combating the transmission of healthcare associated infections. It is essential to understand the extent to which removal of bacteria is modulated by fiber properties, biocidal liquid impregnation and applied hand pressure. The influence of intrinsic and extrinsic factors on the removal efficiencies of pathogenic bacteria was studied. Nonwoven wipes made of either hydrophobic (polypropylene) or hygroscopic (lyocell) fibers were manufactured and dynamic removal efficiency of bacteria studied. The single most important parameter affecting bacterial removal efficiency was impregnation with biocidal liquid ( p < 0.05). For inherently hygroscopic 100% regenerated cellulose (lyocell) wipes impregnated with biocidal liquid, removal of E. coli, S. aureus and E. faecalis improved by increasing the fabric surface density and wiping pressure to their maximal values – 150 g.m–2 and 13.80 kN.m–2, respectively. For inherently hydrophobic 100% polypropylene nonwoven wipes, the same conditions maximized the removal efficiency of S. aureus, but for E. coli and E. faecalis a reduction in the wiping pressure to 4.68 kN.m–2 was required. Best practice involves the use of higher surface density wipes (150 g.m–2) containing regenerated cellulose fibers loaded with liquid biocide, and applied with the greatest possible wiping pressure.


1982 ◽  
Vol 152 (2) ◽  
pp. 803-808
Author(s):  
T W Woodworth ◽  
D T John ◽  
S G Bradley

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.


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