Population dynamics,delta vulnerability and environmental change: comparison of the Mekong,Ganges–Brahmaputra and Amazon delta regions

Tropical delta regions are at risk of multiple threats including relative sea level rise and human alterations, making them more and more vulnerable to extreme floods, storms, surges, salinity intrusion, and other hazards which could also increase in magnitude and frequency with a changing climate. Given the environmental vulnerability of tropical deltas, understanding the interlinkages between population dynamics and environmental change in these regions is crucial for ensuring efficient policy planning and progress toward social and ecological sustainability. Here, we provide an overview of population trends and dynamics in the Ganges–Brahmaputra, Mekong and Amazon deltas. Using multiple data sources, including census data and Demographic and Health Surveys, a discussion regarding the components of population change is undertaken in the context of environmental factors affecting the demographic landscape of the three delta regions. We find that the demographic trends in all cases are broadly reflective of national trends, although important differences exist within and across the study areas. Moreover, all three delta regions have been experiencing shifts in population structures resulting in aging populations, the latter being most rapid in the Mekong delta. The environmental impacts on the different components of population change are important, and more extensive research is required to effectively quantify the underlying relationships. The paper concludes by discussing selected policy implications in the context of sustainable development of delta regions and beyond.     

The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera

During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances. Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight. The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous groups of workers during nestsite selection and colony relocation. Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000     

Issues in monitoring hazardous chemicals in stormwater runoff/discharges from superfund and other hazardous chemical sites

Deficiencies in design and execution render stormwater‐runoff monitoring programs for many hazardous chemical sites inadequate for assessing the potential environmental quality and public health impacts of chemicals in the runoff. Two pervasive problems are the use of analytical methods that are inadequate for measuring certain hazardous chemicals at potentially hazardous concentrations, and the application of “criteria/standards” that are inappropriate for evaluating the environmental/public health impacts of chemicals. These concerns are most notable for carcinogens and chemicals that bioaccumulate in edible aquatic organisms, including arsenic, chromium, beryllium, mercury, dioxins, organochlorine pesticides (such as DDT), and polychlorinated biphenyls; unrecognized pollutants; and nanomaterials. In order to appropriately evaluate whether the runoff/discharge from a hazardous chemical site is a threat to human health, the analytical methods must be sufficiently sensitive in critical concentration ranges; sampling regimens need to be sufficiently rigorous to provide reliable characterization of the content of the runoff, receiving water, and, for bioaccumulatable chemicals, levels in edible organisms in receiving water. Proper sampling and analysis will then provide data to enable the appropriate criteria/standards to be applied. © 2010 Wiley Periodicals, Inc.     

Thermal Strain in Fire Fighters While Wearing Task-Fitted Versus EN 469:2005 Protective Clothing During a Prolonged Rescue Drill

Fire fighters are normally overprotected during their working hours because of the tendency to keep the personal protection level sufficiently high in case of the worst possible scenarios. This study investigated the effects of task-fitted protective clothing on thermal strain in fire fighters as compared to EN 469:2005 protective clothing during a prolonged (2 1/2 hrs) job-related rescue drill under neutral and hot climates. The subjects were 23 healthy, physically fit professional male fire fighters aged 26–44 years. Measurements included cardiovascular and thermal responses and subjective assessments. Wearing task-fitted clothing during rescue tasks in a neutral climate considerably reduced total thermal and cardiovascular strain in prolonged rescue work. The fire fighters also perceived physical work as significantly harder on average, and reported more intense subjective discomfort while wearing EN 469:2005 as compared to task-fitted clothing.     

Differential effects of strain on two forms of work performance: individual employee sales and creativity

In this research, we develop and test a model of the links between psychological strain (subjective experiences of feeling conflict and tension) and work performance. Our model includes two types of strain (work strain and home strain) and two forms of work performance (quantity of individual sales performance and creativity). Thus we acknowledge the importance of work and non‐work sources of strain as well as the multidimensional nature of work performance. We test the proposed relationships with data collected over six months from a field sample of 195 hair salon stylists (personal service workers who interact directly with customers and provide services directly to individuals and not to other firms). Results demonstrate a positive relation between work strain and individual employee sales performance and a negative relation between home strain and employee creativity at work. Leader–member exchange moderated the effects of work strain and home strain on creativity. We discuss findings and implications, emphasizing multiple roles, the importance of differentiating types of strain, and the multidimensionality of work performance. We conclude by suggesting that strain may be particularly relevant to work performance of employees in jobs like those in our sample which are characterized by high social interdependence and low task interdependence. Copyright © 2001 John Wiley & Sons, Ltd.     

“Buckle Up NOW!” An Enforcement Program to Achieve High Belt Use

In the mid-1980s, the first formal seat-belt enforcement program in the United States was conducted in Elmira, NY. Front seat-belt use increased from 49% to 80%, and the Elmira program became a model for other such programs. In the spring of 1999, the New York State Police launched a statewide seat-belt enforcement campaign, and the Elmira program was revived as part of this effort. This 3-week program was coordinated by the Chemung County Sheriff's Office, and carried out in cooperation with local police departments as well as the state police. The earlier Elmira program emphasized the health and safety benefits of seat belts and warning periods prior to tickets being issued. The 1999 program featured a strong no-excuses, no-warning enforcement message, 32 belt-use checkpoints, and publicity about the enforcement through a variety of mechanisms, including feedback signs that informed motorists of current belt use rates. Front seat-belt use increased from 69% to 90%. Public opinion surveys indicated the program was well known to Elmira residents, and had the support of 79% of those polled. The 1999 Elmira program demonstrates that high-intensity enforcement programs can increase seat-belt use to very high levels with strong community support.     

Exposure to airborne allergens: a review of sampling methods

A number of methods are used to assess exposure to high-molecular weight allergens. In the occupational setting, airborne dust is often collected on filters using pumps, the filters are eluted and allergen content in the eluate analysed using immunoassays. Collecting inhalable dust using person-carried pumps may be considered the gold standard. Other allergen sampling methods are available. Recently, a method that collects nasally inhaled dust on adhesive surfaces within nasal samplers has been developed. Allergen content can be analysed in eluates using sensitive enzyme immunoassays, or allergen-bearing particles can be immunostained using antibodies, and studied under the microscope. Settling airborne dust can be collected in petri dishes, a cheap and simple method that has been utilised in large-scale exposure studies. Collection of reservoir dust from surfaces using vacuum cleaners with a dust collector is commonly used to measure pet or mite allergens in homes. The sampling methods differ in properties and relevance to personal allergen exposure. Since methods for all steps from sampling to analysis differ between laboratories, determining occupational exposure limits for protein allergens is today unfeasible. A general standardisation of methods is needed.