Carbon dioxide use by chemoautotrophic endosymbionts of hydrothermal vent vestimentiferans: affinities for carbon dioxide, absence of carboxysomes, and δ13C values

The hydrothermal vent vestimentiferans Riftia pachyptila Jones, 1981 and Ridgeia piscesae Jones, 1985 live in habitats with different abundances of external CO₂. R. pachyptila is found in areas with a high input of hydrothermal fluid, and therefore with a high [CO₂]. R. piscesae is found in a range of habitats with low to high levels of hydrothermal fluid input, with a correspondingly broad range of CO₂ concentrations. We examined the strategies for dissolved inorganic carbon (DIC) use by the symbionts from these two species. R. pachyptila were collected from the East Pacific Rise (9°50′N; 104°20′W) in March 1996, and R. piscesae were collected from the Juan de Fuca Ridge (47°57′N; 129°07′W) during September of 1996 and 1997. The differences in the hosts' habitats were reflected by the internal pools of DIC in these organisms. The concentrations of DIC in coelomic fluid from R. piscesae were 3.1 to 10.5 mM, lower than those previously reported for R. pachyptila, which often exceed 30 mM. When symbionts from both hosts were incubated at in situ pressures, their carbon fixation rates increased with the extracellular concentration of CO₂, and not HCO₃ ⁻, and symbionts from R. piscesae had a higher affinity for CO₂ than those from R. pachyptila (K _1/2 of 7.6 μM versus 49 μM). Transmission electron micrographs showed that symbionts from R. piscesae lack carboxysomes, irrespective of the coelomic fluid [DIC] of their host. This suggests that the higher affinity for CO₂ of R. piscesae symbionts may be their sole means of compensating for lower DIC concentrations. The δ¹³C values of tissues from R. piscesae with higher [DIC] in the coelomic fluid were more positive, opposite to the trend previously described for other autotrophs. Factors which may contribute to this trend are discussed. Received: 24 September 1998 / Accepted: 12 May 1999     

Modeling mammal response to fire based on species’ traits

Fire has shaped ecological communities worldwide for millennia, but impacts of fire on individual species are often poorly understood. We performed a meta-analysis to predict which traits, habitat, or study variables and fire characteristics affect how mammal species respond to fire. We modeled effect sizes of measures of population abundance or occupancy as a function of various combinations of these traits and variables with phylogenetic least squares regression. Nine of 115 modeled species (7.83%) returned statistically significant effect sizes, suggesting most mammals are resilient to fire. The top-ranked model predicted a negative impact of fire on species with lower reproductive rates, regardless of fire type (estimate = –0.68), a positive impact of burrowing in prescribed fires (estimate = 1.46) but not wildfires, and a positive impact of average fire return interval for wildfires (estimate = 0.93) but not prescribed fires. If a species’ International Union for Conservation of Nature Red List assessment includes fire as a known or possible threat, the species was predicted to respond negatively to wildfire relative to prescribed fire (estimate = –2.84). These findings provide evidence of experts’ abilities to predict whether fire is a threat to a mammal species and the ability of managers to meet the needs of fire-threatened species through prescribed fire. Where empirical data are lacking, our methods provide a basis for predicting mammal responses to fire and thus can guide conservation actions or interventions in species or communities.     

Effects of external and internal interruptions on boredom at work: two studies

It is proposed that attentional difficulties are central to the experience of boredom. Events which disrupt attention during task performance may contribute to feelings of boredom with the task. Two sources of disruption are explored: external interruptions from the physical environment, and internal interruptions in the form of non-task-related thoughts about current concerns. Study 1 found that external interruptions reduced boredom on a simple task which required little attention, but contrary to expectations, had no impact on reactions to a simple task that did require attention or on reactions to a complex task. Study 2 manipulated internal interruptions via a role-playing methodology, and found that observers attributed greater boredom and less satisfaction to performers who were more frequently interrupted by non-task-related thoughts while at work, especially when these thoughts were about non-urgent concerns. The concepts of internal and external interruptions may be quite useful in understanding variations in the day-to-day experience of work, and in the relationship of non-work to work spheres of life. © 1998 John Wiley & Sons, Ltd.     

Higher education institutions,SDG2 and agri-food sustainability: lessons from Chulalongkorn University and Thailand

Environment, Development and Sustainability - This paper examines higher education efforts linking United Nations Sustainable Development Goals (UNSDGs) and agri-food system sustainability given...     

The need for formal reflexivity in conservation science

Conservation issues are often complicated by sociopolitical controversies that reflect competing philosophies and values regarding natural systems, animals, and people. Effective conservation outcomes require managers to engage myriad influences (social, cultural, political, and economic, as well as ecological). The contribution of conservation scientists who generate the information on which solutions rely is constrained if they are unable to acknowledge how personal values and disciplinary paradigms influence their research and conclusions. Conservation challenges involving controversial species provide an opportunity to reflect on the paradigms and value systems that underpin the discipline and practice of conservation science. Recent analyses highlight the ongoing reliance on normative values in conservation. We frame our discussion around controversies over feral horses (Equus ferus caballus) in the Canadian West and New Zealand and suggest that a lack of transparency and reflexivity regarding normative values continues to prevent conservation practitioners from finding resilient conservation solutions. We suggest that growing scrutiny and backlash to many normative conservation objectives necessitates formal reflexivity methods in conservation biology research, similar to those required of researchers in social science disciplines. Moreover, given that much conservation research and action continues to prioritize Western normative values regarding nature and conservation, we suggest that adopting reflexive methods more broadly is an important step toward more socially just research and practice. Formalizing such methods and requiring reflexivity in research will not only encourage reflection on how personal and disciplinary value systems influence conservation work but could more effectively engage people with diverse perspectives and values in conservation and encourage more novel and resilient conservation outcomes, particularly when dealing with controversial species.     

Larvicidal and repellent activity of N-methyl-1-adamantylamine and oleic acid a major derivative of bael tree ethanol leaf extracts against dengue mosquito vector and their biosafety on natural predator

Environmental Science and Pollution Research - Aegle marmelos (L.) Correa belongs to the family Rutaceae is generally known as “bael fruit tree” occuring across the south Asian...