OPTIMAL MANAGEMENT OF GIANT-CLAM FARMING IN SOLOMON ISLANDS

Giant-clam farming is undertaken by coastal villagers in Solomon Islands as part of a research and development project of the International Center for Living Aquatic Resources Management (ICLARM). The production technology is simple and does not require a large capital investment. The main inputs are clam seed, labour and time. Labour is used for activities such as seeding, cleaning, thinning and harvesting. In this paper, a bioeconomic model is used to explore optimal farm management. The theoretical basis for this analysis is found in the economic theory of optimal forestry exploitation. The management variables considered are husbandry applied to cleaning and the frequency with which thinning is undertaken. The optimal cycle-length is determined for both a single clam harvest and multiple harvests. The labour requirements of various management scenarios are identified for the multiple-cycle case.bioeconomics, giant clams, subsistence mariculture, Farm Management,

A Convenient Synthetic Route to Partial-Cone p-Carboxylatocalix[4]arenes.

p-Carboxylatocalix[n]arenes have emerged as useful building blocks for the construction of a diverse range of supramolecular assemblies. A convenient route to a p-carboxylatocalix[4]arene that is locked in a partial-cone conformation is presented. The conformation gives the molecule markedly different topological directionality relative to those previously used in self- and metal-directed assembly studies

Penetrating the air-liquid interface is the key to colonization and wrinkly spreader fitness

In radiating populations of Pseudomonas fluorescens SBW25, adaptive wrinkly spreader (WS) mutants are able to gain access to the air–liquid (A–L) interface of static liquid microcosms and achieve a significant competitive fitness advantage over other non-biofilm-forming competitors. Aerotaxis and flagella-based swimming allows SBW25 cells to move into the high-O2 region located at the top of the liquid column and maintain their position by countering the effects of random cell diffusion, convection and disturbance (i.e. physical displacement). However, wild-type cells showed significantly lower levels of enrichment in this region compared to the archetypal WS, indicating that WS cells employ an additional mechanism to transfer to the A–L interface where displacement is no longer an issue and a biofilm can develop at the top of the liquid column. Preliminary experiments suggest that this might be achieved through the expression of an as yet unidentified surface active agent that is weakly associated with WS cells and alters liquid surface tension, as determined by quantitative tensiometry. The effect of physical displacement on the colonization of the high-O2 region and A–L interface was reduced through the addition of agar or polyethylene glycol to increase liquid viscosity, and under these conditions the competitive fitness of the WS was significantly reduced. These observations suggest that the ability to transfer to the A–L interface from the high-O2 region and remain there without further expenditure of energy (through, for example, the deployment of flagella) is a key evolutionary innovation of the WS, as it allows subsequent biofilm development and significant population increase, thereby affording these adaptive mutants a competitive fitness advantage over non-biofilm-forming competitors located within the liquid column

Examining the Relationship between Drought and Mental Health Outcomes of Depression and Anxiety in the U.S.

Abstract Examining the relationship between drought and mental health outcomes of depression and anxiety in the U.S. By Robyn J. Cathey December 4, 2017 BACKGROUND: Drought is likely linked to depression and anxiety through environmental and economic factors. Having a better understanding of this relationship would assist public health officials and policy-makers in future drought preparedness and mitigation strategies. METHODS: Depression and anxiety data were collected for 36 states from HCUPnet, an online system of hospital inpatient and emergency department information. Drought data were collected from the U.S. Drought Monitor, a weekly monitor integrating multiple drought indices to produce a single index, for 2011-2014. Proportions were calculated for state hospital mental health discharges from total state hospital discharges. Annual state drought data was dichotomized based on a 30% areal drought threshold for drought exposure conditions. Repeated measures ANOVA was used for analysis of the relationship between states’ depression and anxiety discharges and states’ drought exposure. RESULTS: The effect of time on depression was significantly different for states in the exposed and unexposed condition, F (3, 32) = 4.22, p = 0.01. The effect of time on anxiety was not different for states in the exposed and unexposed drought conditions, F (3, 32) = 1.92, p = 0.15. Post-hoc comparisons using four paired samples t-tests indicated a significant effect of drought exposure on depression comparing exposed drought condition with unexposed drought condition during 2011, 2012, 2013 and 2014. A significant effect of drought exposure condition on anxiety comparing exposed drought condition with unexposed drought condition during 2011, 2012, 2013 and 2014. CONCLUSION: Depression and anxiety discharges differed over time and between states in the exposed and unexposed drought conditions from 2011-2014. Depression and anxiety discharges were higher for states in the unexposed drought condition. Further research would refine the examination of this relationship

A review of pulmonary arterial hypertension: role of ambrisentan

Pulmonary arterial hypertension (PAH) is a rare fatal disease. Current disease-specific therapeutic interventions in PAH target 1 of 3 established pathways in disease pathobiology: prostacyclin, nitric oxide, and endothelin-1. Endothelin receptor antagonists (ERAs) act on the endothelin pathway by blocking binding of endothelin-1 to its receptors (endothelin type-A [ETA] and/or type-B [ETB]) on the surface of endothelial and smooth muscle cells. Ambrisentan is an oral, once-daily, ETA-selective ERA in development for the treatment of PAH. In Phase 3 clinical trials in patients with PAH, ambrisentan (2.5–10 mg orally once-daily) improved exercise capacity, Borg dyspnea index, time to clinical worsening, WHO functional class, and quality of life compared with placebo. Ambrisentan provided durable (at least 2 years) improvement in exercise capacity in a Phase 2 long-term extension study. Ambrisentan was well tolerated with a lower incidence and severity of liver function test abnormalities compared with the ETA/ETB ERA, bosentan, and the ETA-selective ERA, sitaxsentan. Ambrisentan does not induce or inhibit P450 enzymes; therefore, ambrisentan is unlikely to affect the pharmacokinetics of P450-metabolized drugs. The demonstration of clinical efficacy, low incidence of acute hepatic toxicity, and low risk of drug–drug interactions support the role of ambrisentan for the treatment of PAH

A new species of winged fruit from the Miocene of Ecuador: Tipuana ecuatoriana (Leguminosae)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141584/1/ajb213863.pd

Temporary carbon storage and discount rates

Several approaches have been proposed for accounting for temporary carbon sequestration in land-use change and forestry projects that are implemented to offset permanent emissions of carbon dioxide from the energy sector. In a previous paper, we evaluated the incentives provided by some of these approaches. In this paper, we investigate further what we call the “ideal” accounting system, where the forest owner would be paid for carbon sequestration as the service is provided and redeem payments when the forest is harvested and carbon is released back into the atmosphere. We demonstrate how discounting affects the net present value of the forest when carbon sequestration is taken into account under this ideal system. Not all carbon is released back into the atmosphere at harvest, however, since a large proportion may remain fixed in forest products for many years. Here, we compare the profitability of the forest under full redemption of credits at harvest, with partial redemption of credits at harvest followed by annual redemption post-harvest as the carbon decays in a durable forest product. The analysis is based on simulation of farm-forestry systems in south-eastern Australia.carbon accounting, reforestation, discounting, bioeconomics, Environmental Economics and Policy, Land Economics/Use,

Carbon-accounting methods and reforestation incentives

The emission of greenhouse gases, particularly carbon dioxide, and the consequent potential for climate change are the focus of increasing international concern. Temporary land-use change and forestry projects (LUCF) can be implemented to offset permanent emissions of carbon dioxide from the energy sector. Several approaches to accounting for carbon sequestration in LUCF projects have been proposed. In the present paper, the economic implications of adopting four of these approaches are evaluated in a normative context. The analysis is based on simulation of Australian farm–forestry systems. Results are interpreted from the standpoint of both investors and landholders. The role of baselines and transaction costs are discussed.Resource /Energy Economics and Policy,

Plasticizer degradation by marine bacterial isolates : a proteogenomic and metabolomic characterization

Many commercial plasticizers are toxic endocrine-disrupting chemicals that are added to plastics during manufacturing and may leach out once they reach the environment. Traditional phthalic acid ester plasticizers (PAEs), such as dibutyl phthalate (DBP) and bis(2-ethyl hexyl) phthalate (DEHP), are now increasingly being replaced with more environmentally friendly alternatives, such as acetyl tributyl citrate (ATBC). While the metabolic pathways for PAE degradation have been established in the terrestrial environment, to our knowledge, the mechanisms for ATBC biodegradation have not been identified previously and plasticizer degradation in the marine environment remains underexplored. From marine plastic debris, we enriched and isolated microbes able to grow using a range of plasticizers and, for the first time, identified the pathways used by two phylogenetically distinct bacteria to degrade three different plasticizers (i.e., DBP, DEHP, and ATBC) via a comprehensive proteogenomic and metabolomic approach. This integrated multi-OMIC study also revealed the different mechanisms used for ester side-chain removal from the different plasticizers (esterases and enzymes involved in the β-oxidation pathway) as well as the molecular response to deal with toxic intermediates, that is, phthalate, and the lower biodegrading potential detected for ATBC than for PAE plasticizers. This study highlights the metabolic potential that exists in the biofilms that colonize plastics-the Plastisphere-to effectively biodegrade plastic additives and flags the inherent importance of microbes in reducing plastic toxicity in the environment