A scientific forum on the Gulf of Mexico: The Islands in the Stream Concept. Proceedings of the Forum: 23 January 2008, Keating Education Center, Mote Marine Laboratory, Sarasota, Florida

The Scientific Forum on the Gulf of Mexico: The Islands in the Stream Concept took place in January 2008 in Sarasota, Florida. The purpose of the meeting was to bring together scientists and managers from around the Gulf of Mexico to discuss a range of topics on our knowledge of the Gulf of Mexico, from its geology to larger-scale connectivity to the Caribbean region, and their applications to the concept of a more integrated approach to area-based management. The forum included six panels of invited experts who spoke on the oceanographic and biological features in the Gulf of Mexico, including connections with Mexico and the Mesoamerican barrier reef system, and the legal and regulatory structure currently in place. The charge to the group was to share information, identify gaps in our knowledge, identify additional potential areas for protection, and discuss available science about connectivity and the potential value of establishing a marine protected area network in the Gulf of Mexico. (PDF has 108 pages.)

Citation Analysis of Theses/Dissertations for a Marine Biological Laboratory

A basic analysis of sources, dates, authors for an Environmental Science Laboratory based at waters edge. (22 powerpoint slides)

Development of kelp rockfish, Sebastes atrovirens (Jordan and Gilbert 1880), and brown rockfish, S. auriculatus (Girard 1854), from birth to pelagic juvenile stage, with notes on early larval development of black-and-yellow rockfish, S. chrysomelas (Jordan and Gilbert 1880), reared in the laboratory (Pisces: Sebastidae).

Larval kelp (Sebastes atrovirens), brown (S. auriculatus), and blackand-yellow (S. chrysomelas) rockfish were reared from known adults, to preflexion stage, nine days after birth for S. chrysomelas, to late postflexion stage for S. atrovirens, and to pelagic juvenile stage for S. auriculatus. Larval S. atrovirens and S. chrysomelas were about 4.6 mm body length (BL) and S. auriculatus about 5.2 mm BL at birth. Both S. atrovirens and S. auriculatus underwent notochord flexion at about 6–9 mm BL. Sebastes atrovirens transform to the pelagic juvenile stage at about 14–16 mm BL and S. auriculatus transformed at ca. 25 mm BL. Early larvae of all three species were characterized by melanistic pigment dorsally on the head, on the gut, on most of the ventral margin of the tail, and in a long series on the dorsal margin of the tail. Larval S. atrovirens and S. auriculatus developed a posterior bar on the tail during the flexion or postflexion stage. In S. atrovirens xanthic pigment resembled the melanistic pattern throughout larval development. Larval S. auriculatus lacked xanthophores except on the head until late preflexion stage, when a pattern much like the melanophore pattern gradually developed. Larval S. chrysomelas had extensive xanthic pigmentation dorsally, but none ventrally, in preflexion stage. All members of the Sebastes subgenus Pteropodus (S. atrovirens, S. auriculatus, S. carnatus, S. caurinus, S. chrysomelas, S. dalli, S. maliger, S. nebulosus, S. rastrelliger) are morphologically similar and all share the basic melanistic pigment pattern described here. Although the three species reared in this study can be distinguished on the basis of xanthic pigmentation, it seems unlikely that it will be possible to reliably identify field-collected larvae to species using traditional morphological and melanistic pigmentation characters. (PDF file contains 36 pages.)

Laboratory guide to early life history stages of northeast Pacific fishes

This laboratory guide presents taxonomic information on eggs and larvae of fishes of the Northeast Pacific Ocean (north of California) and the eastern Bering Sea. Included are early-life-history series, illustrations, and comparative descriptions of 232 species expected to spawn here, out of a total 627 species known to occur in marine waters of this area. Meristic and general life-history data are included, as well as diagnostic characters to help identify eggs and larvae. Most of this information has been gleaned from literature, with the addition of 200 previously unpublished illustrations. (PDF file contains 654 pages.)

Embryonic development in Clarias gariepinus under laboratory conditions

The embryonic development in Clarias gariepinus was studied under laboratory conditions. The developmental stages of eggs starting from first cleavage were examined microscopically. Photomicroscope was used to take important stages of segmentation, blastulation, differentiation of embryo and hatching. The films of the photograph were developed and printed for each stage produced. The accurate timing and detailed description of each stage was done. The results show that the blastodisc (Polar cap) appeared about 35 minutes after fertilization and the first cleavage dividing the blastodisc into two blastomeres occurs 15 minutes after polar cap formation. Details of the developmental stages of embryos and the timing from one stage to the other were described. The larva shook off the shell and emerged completely from the egg case about 22 hours after fertilization at a water temperature of 25.1 degree C. The accurate determination of the time of initiation of first mitosis is of great importance in fish culture and breeding especially in the production of tetraploids

Investigations of secondary organic aerosol formation in laboratory chambers

Secondary organic aerosol (SOA) is produced in the atmosphere by oxidation of volatile organic compounds. Laboratory chambers are used understand the formation mechanisms and evolution of SOA formed under controlled conditions. This thesis presents studies of SOA formed from anthropogenic and biogenic precursors and discusses the effects of chamber walls on suspended vapors and particles.

During a chamber experiment, suspended vapors and particles can interact with the chamber walls. Particle wall loss is relatively well-understood, but vapor wall losses have received little study. Vapor wall loss of 2,3-epoxy-1,4-butanediol (BEPOX) and glyoxal was identified, quantified, and found to depend on chamber age and relative humidity.

Particles reside in the atmosphere for a week or more and can evolve chemically during that time period, a process termed aging. Simulating aging in laboratory chambers has proven to be challenging. A protocol was developed to extend the duration of a chamber experiment to 36 h of oxidation and was used to evaluate aging of SOA produced from m-xylene. Total SOA mass concentration increased and then decreased with increasing photooxidation suggesting a transition from functionalization to fragmentation chemistry driven by photochemical processes. SOA oxidation, measured as the bulk particle elemental oxygen-to-carbon ratio and fraction of organic mass at m/z 44, increased continuously starting after 5 h of photooxidation.

The physical state and chemical composition of an organic aerosol affect the mixing of aerosol components and its interactions with condensing species. A laboratory chamber protocol was developed to evaluate the mixing of SOA produced sequentially from two different sources by heating the chamber to induce particle evaporation. Using this protocol, SOA produced from toluene was found to be less volatile than that produced from a-pinene. When the two types of SOA were formed sequentially, the evaporation behavior most closely represented that of SOA from the second parent hydrocarbon, suggesting that the structure of the mixed SOA particles resembles a core of SOA from the first precursor coated by a layer of SOA from the second precursor, indicative of limiting mixing.

Efficient methods for empirical tests of behavioral economics theories in laboratory and field experiments

In the quest for a descriptive theory of decision-making, the rational actor model in economics imposes rather unrealistic expectations and abilities on human decision makers. The further we move from idealized scenarios, such as perfectly competitive markets, and ambitiously extend the reach of the theory to describe everyday decision making situations, the less sense these assumptions make. Behavioural economics has instead proposed models based on assumptions that are more psychologically realistic, with the aim of gaining more precision and descriptive power. Increased psychological realism, however, comes at the cost of a greater number of parameters and model complexity. Now there are a plethora of models, based on different assumptions, applicable in differing contextual settings, and selecting the right model to use tends to be an ad-hoc process. In this thesis, we develop optimal experimental design methods and evaluate different behavioral theories against evidence from lab and field experiments.

We look at evidence from controlled laboratory experiments. Subjects are presented with choices between monetary gambles or lotteries. Different decision-making theories evaluate the choices differently and would make distinct predictions about the subjects' choices. Theories whose predictions are inconsistent with the actual choices can be systematically eliminated. Behavioural theories can have multiple parameters requiring complex experimental designs with a very large number of possible choice tests. This imposes computational and economic constraints on using classical experimental design methods. We develop a methodology of adaptive tests: Bayesian Rapid Optimal Adaptive Designs (BROAD) that sequentially chooses the "most informative" test at each stage, and based on the response updates its posterior beliefs over the theories, which informs the next most informative test to run. BROAD utilizes the Equivalent Class Edge Cutting (EC²) criteria to select tests. We prove that the EC² criteria is adaptively submodular, which allows us to prove theoretical guarantees against the Bayes-optimal testing sequence even in the presence of noisy responses. In simulated ground-truth experiments, we find that the EC² criteria recovers the true hypotheses with significantly fewer tests than more widely used criteria such as Information Gain and Generalized Binary Search. We show, theoretically as well as experimentally, that surprisingly these popular criteria can perform poorly in the presence of noise, or subject errors. Furthermore, we use the adaptive submodular property of EC² to implement an accelerated greedy version of BROAD which leads to orders of magnitude speedup over other methods.

We use BROAD to perform two experiments. First, we compare the main classes of theories for decision-making under risk, namely: expected value, prospect theory, constant relative risk aversion (CRRA) and moments models. Subjects are given an initial endowment, and sequentially presented choices between two lotteries, with the possibility of losses. The lotteries are selected using BROAD, and 57 subjects from Caltech and UCLA are incentivized by randomly realizing one of the lotteries chosen. Aggregate posterior probabilities over the theories show limited evidence in favour of CRRA and moments' models. Classifying the subjects into types showed that most subjects are described by prospect theory, followed by expected value. Adaptive experimental design raises the possibility that subjects could engage in strategic manipulation, i.e. subjects could mask their true preferences and choose differently in order to obtain more favourable tests in later rounds thereby increasing their payoffs. We pay close attention to this problem; strategic manipulation is ruled out since it is infeasible in practice, and also since we do not find any signatures of it in our data.

In the second experiment, we compare the main theories of time preference: exponential discounting, hyperbolic discounting, "present bias" models: quasi-hyperbolic (α, β) discounting and fixed cost discounting, and generalized-hyperbolic discounting. 40 subjects from UCLA were given choices between 2 options: a smaller but more immediate payoff versus a larger but later payoff. We found very limited evidence for present bias models and hyperbolic discounting, and most subjects were classified as generalized hyperbolic discounting types, followed by exponential discounting.

In these models the passage of time is linear. We instead consider a psychological model where the perception of time is subjective. We prove that when the biological (subjective) time is positively dependent, it gives rise to hyperbolic discounting and temporal choice inconsistency.

We also test the predictions of behavioral theories in the "wild". We pay attention to prospect theory, which emerged as the dominant theory in our lab experiments of risky choice. Loss aversion and reference dependence predicts that consumers will behave in a uniquely distinct way than the standard rational model predicts. Specifically, loss aversion predicts that when an item is being offered at a discount, the demand for it will be greater than that explained by its price elasticity. Even more importantly, when the item is no longer discounted, demand for its close substitute would increase excessively. We tested this prediction using a discrete choice model with loss-averse utility function on data from a large eCommerce retailer. Not only did we identify loss aversion, but we also found that the effect decreased with consumers' experience. We outline the policy implications that consumer loss aversion entails, and strategies for competitive pricing.

In future work, BROAD can be widely applicable for testing different behavioural models, e.g. in social preference and game theory, and in different contextual settings. Additional measurements beyond choice data, including biological measurements such as skin conductance, can be used to more rapidly eliminate hypothesis and speed up model comparison. Discrete choice models also provide a framework for testing behavioural models with field data, and encourage combined lab-field experiments.