Determining the control threshold for a pest is common prior to initiating a pest control program; however, previous studies related to the house fly control threshold for a poultry farm are insufficient for determining such a threshold. This study aimed to predict the population changes of house fly population by comparing the intrinsic rate of increase (rm) for different house fly densities in a simulated system. This study first defined the knee points of a known population growth curve as a control threshold by comparing the rm of five densities of house flies in a simulated condition. Later, to understand the interactions between the larval and adult populations, the correlation between larval and adult capacity rate (rc) was studied. The rm values of 300- and 500-fly densities were significantly higher compared with the rm values at densities of 50 and 100 flies. This result indicated their representative indices as candidates for a control threshold. The rc of larval and adult populations were negatively correlated with densities of fewer than 300 flies; this implicated adult populations with fewer than 300 flies as declining while the larval population was growing; therefore, control approaches should focus on the immature stages. The results in the present study suggest a control threshold for house fly populations. Future works should focus on calibrating the threshold indices in field conditions.
The fertility and parameters of population growth of the Semai Senoi of Malaysia are studied by using a two-census method based on nonstable population theory. Semai fertility is shown to be moderately high; female completed fertility is 7.42 children and the crude birth rate is greater than 0.050. Previous estimates of Semai mortality rates are also moderately high but are insufficient to balance birth; thus, the overall rate of growth is presently nearly 2%. Compared with an earlier description of the pre-1969 Semai population, fertility has increased markedly leading to a nearly threefold increase in the annual growth rate.
The process of somatic embryogenesis and plant regeneration involve changes in gene expression and have been associated with changes in DNA methylation. Here, we report the expression and DNA methylation patterns of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK), BABY BOOM (BBM), LEAFY COTYLEDON 2 (LEC2) and WUSCHEL (WUS) in meristematic block of newly emerged shoots from rhizome, embryogenic and non-embryogenic calli, prolonged cell suspension culture, ex vitro leaf, and in vitro leaf of regenerated plants of Boesenbergia rotunda. Among all seven samples, based on qRT-PCR, the highest level of expression of SERK, BBM and LEC2 was in embryogenic callus, while WUS was most highly expressed in meristematic block tissue followed by embryogenic callus. Relatively lower expression was observed in cell suspension culture and watery callus for SERK, LEC2 and WUS and in in vitro leaf for BBM. For gene specific methylation determined by bisulfite sequencing data, embryogenic callus samples had the lowest levels of DNA methylation at CG, CHG and CHH contexts of SERK, LEC2 and WUS. We observed negative correlation between DNA methylation at the CG and CHG contexts and the expression levels of SERK, BBM, LEC2 and WUS. Based on our results, we suggest that relatively higher expression and lower level of DNA methylation of SERK, BBM, LEC2 and WUS are associated with somatic embryogenesis and plant regeneration in B. rotunda.
The pace of urbanization in Peninsular Malaysia was slower in the most recent intercensal interval, 1957 to 1970, than in the previous period, 1947 to 1957. Most of the small change in the rural-urban balance from 1957 to 1970 appears due to the growth of towns into the urban classification rather than to a redistribution of population into the previous urban settlements. A number of towns in Peninsular Malaysia do show exceptional growth from 1957 to 1970, but there seems to be no clear relationship between a city's size and its subsequent growth. The rural areas on the outskirts of the largest cities do show rapid growth, especially the periphery of the capital city. It appears that neither the classic model of urbanization based upon Western experience nor the over-urbanization thesis explain the urbanization process in Peninsular Malaysia.
Population explosion is one of the global issues of concern. The increasing number of individuals could result in negative impact on social and economy. To overcome this problem, convenient and safe modern contraception was introduced. However, recently many researchers have conducted studies on the effectiveness of medicinal plants as contraceptive agents on human and animal models. Therefore, the studies of herbal and modern contraceptives were summarized in this review article. A total of 66 relevant articles were documented having information regarding the modern and herbal contraceptives. All contraceptives are highly effective provided they are used consistently and in the proper way. Contraception is important as it could prevent diseases and infections caused by sexual intercourse and prevent unintended pregnancy. Therefore, this review is an attempt to summarize the potential of medicinal plants as contraceptive agents and the modern contraceptive methods used as birth control in males and females.
This paper studies the harvesting strategies for tilapia fish farming. Two logistic growth models have been used namely constant harvesting and periodic harvesting. Even though tilapia fish farming has been commercialized, the use of mathematical models in determining harvesting strategies has not been widely applied in Malaysia. Logistic growth model is appropriate for population growth of animal when overcrowding and competition resources are taken into consideration. The objectives of this study were to estimate the highest continuing yield from fish harvesting strategies implemented. Secondly, the study predicted the optimum quantity for harvesting that can ensure the tilapia fish supply is continuous. Finally, to compare the results obtained between the two strategies. The best harvesting strategy for the selected fish farm is periodic harvesting. These findings can assist fish farmers to increase the supply to meet the demand for tilapia fish.
Population growth and rise in per capital income have influenced the demand for convenience foods and a meat protein-rich diet. The per capital consumption of beef which had increased from 3.89 kg in 1980 to 5.49 kg in 2006 (DVS, 2006/2007) had resulted in an increased in demand for beef at the rate of 6.2% annually. The local beef production although recorded a 2.5% increased over the last 10 years, is still unable to meat the increasing national demand for beef. In 2008, local production of beef is about 38,250 mt. could only meet about 26.7% of the national demand (DVS, 2008). The gap between supply and demand for beef is expected to widen in the next decades unless efforts is been made to accelerate local production. The lack of number of quality breeding stocks and unorganized breeding system had been the major factors that contribute to the slow growth of the local beef industry.
Which factors have the greater influence on family planning performance: fixed background variables such as racial composition, urbanization, and mortality, which are affected by level of development, or program inputs such as assignment of personnel and location of clinics, which are subject to manipulation by administrators? An analysis of differences in family planning acceptance among 70 districts of Malaysia shows that two main program-manipulable variables--level of personnel deployment and accessibility of clinics--have the largest direct effect upon acceptance levels. Variations in background factors explain a smaller proportion.
PIP: The application to the Malaysian family planning program of a conceptual model in which background factors, affected by the level of development, are distinguished from program input variables, subject to program manipulation, is considered in an effort to examine reasons for variations in program performance. Focus is particularly on the inputs of workers, who provide services and distribute supplies, and clinic facilities, through which services and supplies are made available. The questions asked concerned how their availability and use are affected by background factors, which themselves reflect to some extent the population's readiness to accept family planning. Distinguishing the program-manipulable factors from the background factors involved determination of the impact of both groups of variables, separately and together on levels of program acceptance, using appropriate bivariate and multivariate techniques. The evidence shows that in addition to background factors, over which program administrators can exercise no direct influence, there is a major contribution made to program acceptance through program factors over which the planner and administrator do have control. The 2 program variables contributed more in explaining performance levels than all 5 selected background variables combined, and the relative contribution of these program factors has increased over time. The key finding emerging from the different analyses is that program manipulable inputs are the dominant direct determinants of subsequent levels of family planning acceptance in Malayasia. Clearly, higher levels of development, as reflected in the measures of background variables, have facilitated acceptance, and background variables contributed significantly. Yet, whatever the level of development, the extent of deployment of program resources does significantly influence the level of program performance.
Kuala Lumpur is the capital city of Malaysia with an estimated population of 1.55 million. Approximately 12% of the population live in squatter settlements occupying about 7% of the city total area. The squatter settlements generally are provided with basic amenities such as piped water, toilet facilities and electricity. Health indicators for the overall population of Kuala Lumpur are better off than for the rest of the country; however, intra-city differentials prevail along ethnic and socio-economic lines. Malays and Indians have higher rates for stillbirths, and neonatal, infant and toddler mortality than the Chinese. The wide disparity in the socio-economic status between the advantaged and the poor groups in the city is reflected in the dietary practices and nutritional status of young children from these communities. The percentage of preschool children from urban poor households with inadequate intakes of calories and nutrients is two to three times higher than those from the advantaged group. Compared to rural infants, a lower percentage of urban infants are breastfed. A lower percentage of Malays from the urban advantaged group breastfed, compared with the urban poor group. The reversed trend is found for the Chinese community. Growth attainment of young children from the urban poor is worse than the urban advantaged, though better than the rural poor. Health and nutritional practices implications related to both undernutrition and overnutrition are discussed, to illustrate the twin challenges of malnutrition in the city.
PIP: At the Population and Natural Resources Workshop of the World Conservation Union (IUCN) General Assembly in Perth, Australia, December 1990, population and quality of life issues were stressed as one of the central items to be placed on the 1992 Agenda of the UN Conference on Environment. The pace of environmental degradation is quickening, the causes are becoming more entrenched, and indecision will narrow our options. Poverty and population growth are making development unsustainable. Technological miracles will not appear to restore balance. Deforestation, soil erosion, decertification and loss of water resources are fueling urbanization. Therefore the World Commission on Environment and Development, known as the Brundtland Commission, ranks human resources development as a top priority in sustainable development and quality of life. Human resources can be improved by providing maternal and child care, family planning and improving the status of women. Successful family planning programs as seen in Thailand and Malaysia can show results very quickly once national population policies, institutions and capacity are in place.
Two juvenile hormone analogs (JHAs), pyriproxyfen and S-methoprene, were impregnated into dried tuna fish and fed to colonies of Monomorium pharaonis (L.) at very low concentrations (1.0, 2.0, 3.0, 4.0, and 5.0 microg/ml). Its effects on the production of sexuals and colonial growth were observed. Colonies treated with pyriproxyfen yielded sexuals with physical abnormalities. Both female and male sexuals developed bulbous wings, decreased melanization, and died shortly after emergence. Sexuals emerged from colonies treated with S-methoprene did not possess anomalous characteristics. Both pyriproxyfen and S-methoprene did not have significant effects on colonial growth because of the low concentrations of the baits. A commercial bait containing 0.3% S-methoprene (Bioprene-BM) also was evaluated for its efficacy on Pharaoh's ant colonies. Results showed that Pharaoh's ant colonies succumbed to the lethal effects of S-methoprene. Colony members were reduced significantly. Production of queens also decreased significantly in treated colonies and treated queens were unable to lay eggs. JHAs are slow acting and eliminate ant colonies at a relatively slow rate. At low concentrations, pyriproxyfen recorded baffling results, i.e., bulbous wings and demelanized exoskeleton, and it is vital that further studies are initiated to solidify these findings.
The effects of eight diets (atta flour, wheat flour, self-rising flour, rice flour, custard powder, corn flour, tapioca starch, and potato starch) on the development of the red flour beetle, Tribolium castaneum (Herbst), reared at 29-31 degrees C and 66-70% RH were assessed. Five pairs of male and female T. castaneum were reared on the respective diets for 28 d before the experimental setup was dismantled and adult counts were recorded. In another experiment, the insects were allowed to mate and oviposit in each flour or starch type over a period of 7 d before being removed. The counting of pupae and adult emergence began on the day of emergence and was continued on a daily basis until day 140. Proximate analysis was performed for chemical composition of each diet, and the numbers of new adults that developed were found to be positively correlated (r2 = 0.97; P < 0.05) with the protein content and negatively correlated (r2 = 0.93; P < 0.05) with the carbohydrate content. For T. castaneum, the suitable diets were ranked as follows: atta flour > wheat flour > self-rising flour > rice flour > custard powder > corn flour > tapioca starch > potato starch. T. castaneum larval development to the pupal and adult stages developed significantly faster in atta flour (P < 0.05) than in the other diets, and the greatest number of progeny was produced from beetles reared on atta flour. Fewer adults emerged from wheat flour, self-rising flour, and rice flour, and no new emergences were recorded for the remaining diets. Developmental rate was much slower in beetles reared on diets in which a low number in progeny was produced. These data illustrate that different diets can influence the sustainability of these insects and affect their development and growth.
Several studies on birds have proposed that a lack of invertebrate prey in urbanized areas could be the main cause for generally lower levels of breeding success compared to rural habitats. Previous work on house sparrows Passer domesticus found that supplemental feeding in urbanized areas increased breeding success but did not contribute to population growth. Here, we hypothesize that supplementary feeding allows house sparrows to achieve higher breeding success but at the cost of lower nestling quality. As abundant food supplies may permit both high- and low-quality nestlings to survive, we also predict that within-brood variation in proxies of nestling quality would be larger for supplemental food broods than for unfed broods. As proxies of nestling quality, we considered feather corticosterone (CORT f), body condition (scaled mass index, SMI), and tarsus-based fluctuating asymmetry (FA). Our hypothesis was only partially supported as we did not find an overall effect of food supplementation on FA or SMI. Rather, food supplementation affected nestling phenotype only early in the breeding season in terms of elevated CORT f levels and a tendency for more variable within-brood CORT f and FA. Early food supplemented nests therefore seemed to include at least some nestlings that faced increased stressors during development, possibly due to harsher environmental (e.g., related to food and temperature) conditions early in the breeding season that would increase sibling competition, especially in larger broods. The fact that CORT f was positively, rather than inversely, related to nestling SMI further suggests that factors influencing CORT f and SMI are likely operating over different periods or, alternatively, that nestlings in good nutritional condition also invest in high-quality feathers.
Two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) were selected to study the population dynamics of Aedes aegypti and Aedes albopictus mosquitoes, vectors of dengue and chikungunya infections. Ovitrap surveillance was conducted between October 2007 and October 2008. There was an inverse negative association between ovitrap index and rainfall at the time of collection, probably because rainfall increased the number of available oviposition sites. Rainfall and ovitrap index were positively associates the 25th day after rainfall occurred. A minor, second peak was observed from the 38th to the 42nd day. The first peak was consistent with the minimum 18-day period between the hatching of eggs to the first oviposition. The second minor peak could be due to the second gonotrophic cycle of the female mosquitoes. Rainfall is an important environmental factor associated with Aedes breeding at the study sites.