The study of human-environmental relations is complex and by nature draws on theories and practices from multiple disciplines. There is no single research strategy or universal set of methods to which researchers must adhere. Particularly for scholars interested in a political ecology approach to understanding human-environmental relationships, very little has been written examining the details of "how to" design a project, develop appropriate methods, produce data, and, finally, integrate multiple forms of data into an analysis. A great deal of attention has been paid, appropriately, to the theoretical foundations of political ecology, and numerous scholarly articles and books have been published recently. But beyond Andrew Vayda's "progressive contextualization" and Piers Blaikie and Harold Brookfield's "chains of explanation," remarkably little is written that provides a research model to follow, modify, and expand. Perhaps one of the reasons for this gap in scholarship is that, as expected in interdisciplinary research, researchers use a variety of methods that are suitable (and perhaps unique) to the questions they are asking. To start a conversation on the methods available for researchers interested in adopting a political ecology perspective to human-environmental interactions, I use my own research project as a case study. This research is by no means flawless or inclusive of all possible methods, but by using the details of this particular research process as a case study I hope to provide insights into field research that will be valuable for future scholarship.
This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.
We evaluated 38 dura x pisifera (DP) oil palm progenies in four locations in Malaysia for genotype by environment interaction and genotypic stability studies. The DP progenies derived from crosses between pisifera palms of AVROS, Serdang S27B, Serdang 29/36, and Lever Cameroon were chosen to be the males' parent and Deli dura palms designated as females' parent. All the locations differed in terms of soil physical and chemical properties, and the soil types ranged from coastal clay to inland soils. The genotype by environment interaction and stability of the individual genotypes were analyzed for oil yield trait using several stability techniques. A genotype by environment interaction was detected for oil yield and it had a larger variance component than genotypic variance (σ(2)(gl)/σ(2)(g) = 139.7%). Genotype by environment interaction of oil yield was largely explained by a non-linear relationship between genotypic and environmental values. Overall assessment of individual genotypic stability showed that seven genotypes were highly stable and had consistent performance over the environments for the oil yield trait [total individual genotype stability scored more than 10 and mean oil yielded above the average of the environment (genotype means are more than 34.37 kg·palm(-1)·year(-1))]. These genotypes will be useful for oil palm breeding and tissue culture programs for developing high oil yielding planting materials with stable performance.
Sponges are major source of numerous cytotoxic compounds that are used for defence as well as adaptation to the environment. Numerous studies have discovered compounds from sponge extracts that were effective against a wide range of cancer cells. In this study, a total of 23 sponges comprising of 19 species were collected from Northeast Borneo. Sponges were treated and extracted using modified Folch extraction method, followed by cytotoxicity assay to determine their effectiveness against different colorectal cancer cells. Our results demonstrate that Monanchora clathrata, Dysidea sp., and Jaspis sp. possess different degrees of cytotoxicity against a wide range of human colorectal cancer cells. Monanchora clathrata (KDT07), Dysidea sp. (KDT09), and Jaspis sp. (KDT18) are among the demosponges which possess significant cytotoxicity against colorectal cancer cell lines, including HCT116, LoVo, SW480, and SW620. KDT08 and KDT21 which fall under the same genus Dysidea, possess insignificant cytotoxicity against colorectal cancer cells suggested environmental factors (symbiotic organisms) play a role in biosynthesizing bioactive compounds. Presented results suggested the importance of intensifying research on isolating and purifying natural products from marine sponges for useful applications.
The seasonal variation of spider assemblages in botanical garden was investigated. The spiders were manually collected by diurnal and nocturnal session between two seasons. A total of 19 families from 65 genera and 96 species were recorded. Richness-estimator indicates the inventory were 67% complete within the botanical garden. The capture rate for web-weavers were higher compared with non-web weavers. The comparison value showed the species composition and abundance were similar between seasons. Spider abundance was not affected between wet and dry season in tropical countries.
Using the cow-baited trap (CBT) method, 1,845 Anopheles mosquitos, comprising 14 species, were caught in malaria-endemic area of Hulu Perak district, Peninsular Malaysia. The two dominant species were An. barbirostris (18.59%) and An. aconitus (18.86%). Anopheles maculatus, the main malaria vector, constituted 9.11% of the total number of mosquitos sampled. Three hundred and seventy-seven Anopheles larvae, comprising 8 species, were sampled using the North Carolina Biological Station dipper. Anopheles barbirostris larvae amounted to 64.69% of the total number of larvae; An. aconitus accounted for 10.65% of larvae. Seven habitats were identified as breeding places of Anopheles. Most species were found to breed in paddies, fishponds, and rivers. Other less popular habitats were temporary pools, mountain streams, and spring wells.
Spatio-temporal land-use change modeling, simulation, and prediction have become one of the critical issues in the last three decades due to uncertainty, structure, flexibility, accuracy, the ability for improvement, and the capability for integration of available models. Therefore, many types of models such as dynamic, statistical, and machine learning (ML) models have been used in the geographic information system (GIS) environment to fulfill the high-performance requirements of land-use modeling. This paper provides a literature review on models for modeling, simulating, and predicting land-use change to determine the best approach that can realistically simulate land-use changes. Therefore, the general characteristics of conventional and ML models for land-use change are described, and the different techniques used in the design of these models are classified. The strengths and weaknesses of the various dynamic, statistical, and ML models are determined according to the analysis and discussion of the characteristics of these models. The results of the review confirm that ML models are the most powerful models for simulating land-use change because they can include all driving forces of land-use change in the simulation process and simulate linear and non-linear phenomena, which dynamic models and statistical models are unable to do. However, ML models also have limitations. For instance, some ML models are complex, the simulation rules cannot be changed, and it is difficult to understand how ML models work in a system. However, this can be solved via the use of programming languages such as Python, which in turn improve the simulation capabilities of the ML models.
The abundance of marine benthic organisms often exhibits distinct distributional patterns, which is generally governed by many physical and biological factors specific to the habitat. In this study, the spatial and temporal variations in abundance of the dog conch, Strombus canarium Linnaeus 1758, a commercially important marine gastropod, was investigated. Assessment of conch abundance at Merambong seagrass bed, Malaysia, was conducted using a transect belt method. Sampling stations were randomly selected and environmental parameters associated with the habitat were recorded. The species showed distinct spatial distributional pattern. Conch densities were significantly higher in sheltered areas, mainly in mixed seagrass bed dominated by Halophila spp. and with high sediment organic content. The densities were relatively very low in areas dominated by the tape seagrass, Enhalus acoroides. The species studied also showed distinct temporal variation in abundance. The abundance value was seasonally varied with highest density recorded during the wet monsoon season (p<0.05). The densities were otherwise very low during the dry season, except for a slight peak in July. Since the conch is a very important fishery species within the Johor Straits and regulations on their harvesting is still lacking, this information would be very important for their sustainable management.
An analysis is presented of psychiatric research interviews conducted among the Iban, a longhouse dwelling people of Sarawak, Malaysia. It draws on transcripts of interviews recorded in the course of carrying out research into schizophrenia in this group. The article examines three different interview spaces within the longhouse--public, family, and private--in order to explore the interplay between ethnographic context and interview conversation. The public setting is notable for the number of relatives who join in and transform the communication from dyadic to collective interlocution; the role of repetition in recruiting them into the conversation is explored. Indirect contrast is the private space, which allows for a level of confidentiality commensurate with Western psychiatric research practice. Intermediate between the two is the family space. The communicative forms that correspond to these settings influence the way symptoms of schizophrenia are experienced and expressed in the Iban. Implications for the practice of psychiatry cross-culturally are examined.
Development of hot spring touristic projects receives more interest in Malaysia in recent years since the country has a high potential of hot springs that are vital to the economy. However, such developmental activities could produce negative impacts if not accompanied with adequate knowledge of the subsurface conditions. Active multichannel analysis of surface waves (MASW) was applied to determine the subsurface shear wave velocities and Vs30. The inverted shear waves velocity models have then presented in both vertical cross-sectional plots and depth slices maps. Depth slices were chosen at about 5, 18.5 m and 32 m depths. Model obtained showed that the soil is stiffer near the highway side and turns to be softer as we go away in the scrub direction. Vs30 is also estimated and mapped to show the quality of the soil. Inverted parameters showed that the soil at the site ranges from soft soil to stiff one. Also, the result obtained proposed that the surface occurrence of the hot spring might be a result of intersection of faulted segments, where hot spring is located near the intersection points. Furthermore, the model helped in proposing a suitable for complex extension. The proposed is chosen such that it minimize any possible effects on the geothermal resources at the site.
Children aged 2 to 6 years are in a crucial period of growth development, during which it is important for them to attain specific cognition related to concentration and attention so that they can perform well in school later in life. Various factors influence children's cognition during this crucial period. However, to date, only a limited number of studies have examined the cognitive performance of underprivileged children living in poverty, particularly indigenous children (also known as Orang Asli children in Malaysia). Therefore, this cross-sectional study aimed to determine the associations between sociodemographic factors, nutritional factors (body composition and hemoglobin), and environmental factors (home environment and parasitic infections) with cognitive performance among Orang Asli children in Negeri Sembilan, Malaysia. The participants were 269 children (51% boys, 49% girls) aged 2 to 6 years (M = 4.0, SD = 1.2 years) and their mothers, from 14 Orang Asli villages. Face-to-face interviews were conducted with the mothers, and the children's cognitive performance, operationalized as working memory index (WMI), processing speed index (PSI), and cognitive proficiency index (CPI), was assessed using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV). The children's weight and height were measured, and their blood and stool samples were collected to assess hemoglobin level and parasitic infections, respectively. Multiple linear regression analysis showed that the father's years of education (β = 0.262-0.342, p < 0.05), availability of learning materials at home (β = 0.263-0.425, p < 0.05), and responsiveness of the parent to the child (β = 0.192-0.331, p < 0.05) were consistently associated with all three cognitive indices (WMI, PSI, and CPI). A holistic approach involving parents, communities, and government agencies should be established to improve the cognitive performance of these underprivileged children.
Little research on body dissatisfaction and body change behaviors, and the sociocultural influences on them, has been undertaken in non-Western contexts. The current study investigated these variables and the relationships between them among a sample of 529 Malaysian high school students (103 Malays, 344 Chinese and 82 Indians), who completed a set of measures in classroom settings. Chinese girls were more dissatisfied with their bodies than Chinese boys, but no gender difference was found for Malay and Indian participants. Girls were more likely to engage in behaviors to lose weight, and boys were more likely to engage in behaviors to increase muscle. The influence of sociocultural factors on body dissatisfaction and body change behaviors was limited and varied across both sex and ethnicity. Findings are discussed in relation to Western research, and it is concluded that cultural nuances need to be considered when investigating these phenomena.
Soil-transmitted helminthiasis is a common problem in communities with poor socio-environmental conditions. This study was undertaken to identify important socio-environmental predictors of soil-transmitted helminthiasis in Bachok, a rural community in Kelantan for the development and implementation of an effective prevention and control program. Of 363 children randomly sampled, 38.8% were infected with soil-transmitted helminthiasis. Risk predictors of soil-transmitted helminthiasis found to be significant after adjustment included poor household hygiene score and large household size. The probability of being infected was 0.58 amongst children with both of these risk factors.
PIP: Morality in Peninsular Malaysia has reached a level that is quite similar to that prevailing in the low mortality countries. This article systematically documents changes in mortality levels and differentials in Malaysia over time and relates these to changes in development indicators and health-related policies. Remedial measures undertaken by the authorities including the expansion of hospital and health services into the estates, together with a comprehensive malaria-eradication program, improvements in sanitation laws, and increased provision of public utilities and education, resulted in beriberi being eliminated and the incidence of malaria, typhus, and smallpox being greatly reduced by the time of World War II. The gain in life expectancy over the period of 1957-1979 was greatest for the Malay, the most significant period being 1957-1967, which saw the introduction of rural health programs. The infant mortality rate and the neonatal and post-neonatal rates declined substantially for all ethnic groups in Peninsular Malaysia for the same time period. Although the lower infant mortality of the Chinese can be explained by their advantageous socioeconomic position the same reason cannot explain the lower decline in infant mortality levels of the Indians. Much still needs to be done to narrow, if not to eliminate, the existing mortality differentials of different groups in the country. Overall, the quality of life of the general population can be further enhanced by reducing the high mortality level of disadvantaged groups.
Drowning contributes to incapacity and early death in many countries. In low- and middle-income countries, children are the most susceptible to fatalities. Over 50 % of the global drowning deaths occur among children aged under 15 years old with children aged between 1 and 4 years of age being most at risk. In Bangladesh, drowning rates are 10 to 20 times more than those in other developing countries. The object of this study is to determine the socio-demographic, environmental and caring hazard issues for child drowning in Bangladesh.
The microbes that cause infectious diseases are complex, dynamic, and constantly evolving. They reproduce rapidly, mutate frequently, breach species barriers, adapt with relative ease to new hosts and new environments, and develop resistance to the drugs used to treat them. In their article "Meeting the challenge of epidemic infectious diseases outbreaks: an agenda for research", Kai-Lit Phua and Lai Kah Lee clearly demonstrate how social, behavioural and environmental factors, linked to a host of human activities, have accelerated and amplified these natural phenomena. By reviewing published and non-published information about outbreaks of Nipah virus in Malaysia, severe acute respiratory syndrome (SARS) and avian influenza in Asia, and the HIV pandemic, they provide a series of examples that demonstrate the various social, behavioural and environmental factors of these recent infectious disease outbreaks. They then analyse some of these same determinants in important historical epidemics and pandemics such as plague in medieval Europe, and conclude that it is important to better understand the social conditions that facilitate the appearance of diseases outbreaks in order to determine why and how societies react to outbreaks and their impact on different population groups.
Those Malaysian secondary schoolchildren who have ever used an illicit drug do not differ significantly in terms of social class background, ethnicity or rural/urban location, from the majority of their contemporaries who have not used drugs. The cross-sectional data show a rapid secular trend towards the sexes being equally involved in drug use. Significant differences between ever and never users are, however, found in their attitudes towards drug taking and their beliefs about the properties of drugs, although both groups share the same rather negative image of the typical drug user. Thus, drug users have accepted some of the attitudes towards drug issues which are normative in the non-user group, whilst developing other attitudes which are consistent with their continuing use. It is argued that adolescent drug abuse in Malaysia is not to be linked specifically with social deprivation, but should be seen as being part of the life style of particular groups in all strata of society.
The present paper is the third and concluding part of a study of the secondary school population of two of Malaysia's thirteen states, Penang and Selangor. Since completion of the two earlier papers, the research team has investigated the pattern and nature of drug use among the equivalent population in a third state, Kelantan, and has again found essentially the same pattern of results: youthful drug use is most clearly related to precocious self-assertion, and a set of beliefs and attitudes about drugs and drug taking, and is largely unrelated to indicators of social deprivation or personal problems. The significance of this repeated finding in Kelantan is that, in this much more rural and traditional state, adult and established patterns of drug use had historically differed considerably from those found in the two more urban and cosmopolitan states of Penang and Selangor. Our findings indicate that the new pattern of drug use by youth has transcended the older cultural differences between the states, and is in turn explained by a more universally familiar set of characteristics in adolescent development.
A questionnaire on smoking habits was administered to 4106 Form IV school children in Kuala Lumpur. The period of survey was from 9 to 20 April 1984. 2099 boys and 2007 girls were studied and their mean age was 16.1 years. 32.8% of the students had been initiated to smoking and the mean age of initiation was 13.3 years. The prevalence of smoking was found to be 9.8% and the mean duration of smoking was 2.5 years. Most of the smokers and occasional smokers were boys. About 42% of the smokers wished to stop smoking and only 1% of the non-smokers intended to smoke in the future. The study recommended that health education programmes should be started earlier in school.