UV Photodissociation Dynamics of CHI2Cl and its Role as a Photolytic Precursor for a Chlorinated Criegee Intermediate

Photolysis of geminal diiodoalkanes in the presence of molecular oxygen has become an established route to the laboratory production of several Criegee intermediates, and such compounds also have marine sources. Here, we explore the role that the trihaloalkane, chlorodiiodomethane (CHI2Cl), may play as a photolytic precursor for the chlorinated Criegee intermediate ClCHOO. CHI2Cl has been synthesized and its UV absorption spectrum measured; relative to that of CH2I2 the spectrum is shifted to longer wavelength and the photolysis lifetime is calculated to be less than two minutes. The photodissociation dynamics have been investigated using DC slice imaging, probing ground state I and spin-orbit excited I* atoms with 2+1 REMPI and single-photon VUV ionization. Total translational energy distributions are bimodal for I atoms and unimodal for I*, with around 72% of the available energy partitioned in to the internal degrees of freedom of the CHICl radical product, independent of photolysis wavelength. A bond dissociation energy of D0 = 1.73±0.11 eV is inferred from the wavelength dependence of the translational energy release, which is slightly weaker than typical C–I bonds. Analysis of the photofragment angular distributions indicate dissociation is prompt and occurs primarily via transitions to states of A″ symmetry. Complementary high-level MRCI calculations, including spin-orbit coupling, have been performed to characterize the excited states and confirm that states of A″ symmetry with highly mixed singlet and triplet character are predominantly responsible for the absorption spectrum. Transient absorption spectroscopy has been used to measure the absorption spectrum of ClCHOO produced from the reaction of CHICl with O2 over the range 345–440 nm. The absorption spectrum, tentatively assigned to the syn conformer, is at shorter wavelengths relative to that of CH2OO and shows far weaker vibrational structure

Biology, Fishery, Conservation and Management of Indian Ocean Tuna Fisheries

The focus of the study is to explore the recent trend of the world tuna fishery with special reference to the Indian Ocean tuna fisheries and its conservation and sustainable management. In the Indian Ocean, tuna catches have increased rapidly from about 179959 t in 1980 to about 832246 t in 1995. They have continued to increase up to 2005; the catch that year was 1201465 t, forming about 26% of the world catch. Since 2006 onwards there has been a decline in the volume of catches and in 2008 the catch was only 913625 t. The Principal species caught in the Indian Ocean are skipjack and yellowfin. Western Indian Ocean contributed 78.2% and eastern Indian Ocean 21.8% of the total tuna production from the Indian Ocean. The Indian Ocean stock is currently overfished and IOTC has made some recommendations for management regulations aimed at sustaining the tuna stock. Fishing operations can cause ecological impacts of different types: by catches, damage of the habitat, mortalities caused by lost or discarded gear, pollution, generation of marine debris, etc. Periodic reassessment of the tuna potential is also required with adequate inputs from exploratory surveys as well as commercial landings and this may prevent any unsustainable trends in the development of the tuna fishing industry in the Indian Ocean

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Animal-borne telemetry: An integral component of the ocean observing toolkit

Animal telemetry is a powerful tool for observing marine animals and the physical environments that they inhabit, from coastal and continental shelf ecosystems to polar seas and open oceans. Satellite-linked biologgers and networks of acoustic receivers allow animals to be reliably monitored over scales of tens of meters to thousands of kilometers, giving insight into their habitat use, home range size, the phenology of migratory patterns and the biotic and abiotic factors that drive their distributions. Furthermore, physical environmental variables can be collected using animals as autonomous sampling platforms, increasing spatial and temporal coverage of global oceanographic observation systems. The use of animal telemetry, therefore, has the capacity to provide measures from a suite of essential ocean variables (EOVs) for improved monitoring of Earth's oceans. Here we outline the design features of animal telemetry systems, describe current applications and their benefits and challenges, and discuss future directions. We describe new analytical techniques that improve our ability to not only quantify animal movements but to also provide a powerful framework for comparative studies across taxa. We discuss the application of animal telemetry and its capacity to collect biotic and abiotic data, how the data collected can be incorporated into ocean observing systems, and the role these data can play in improved ocean management

Development of a core descriptor set for Crohn's anal fistula

AIM: Crohn's anal fistula (CAF) is a complex condition, with no agreement on which patient characteristics should be routinely reported in studies. The aim of this study was to develop a core descriptor set of key patient characteristics for reporting in all CAF research. METHOD: Candidate descriptors were generated from published literature and stakeholder suggestions. Colorectal surgeons, gastroenterologists and specialist nurses in inflammatory bowel disease took part in three rounds of an international modified Delphi process using nine-point Likert scales to rank the importance of descriptors. Feedback was provided between rounds to allow refinement of the next ratings. Patterns in descriptor voting were assessed using principal component analysis (PCA). Resulting PCA groups were used to organize items in rounds two and three. Consensus descriptors were submitted to a patient panel for feedback. Items meeting predetermined thresholds were included in the final set and ratified at the consensus meeting. RESULTS: One hundred and thirty three respondents from 22 countries completed round one, of whom 67.0% completed round three. Ninety seven descriptors were rated across three rounds in 11 PCA-based groups. Forty descriptors were shortlisted. The consensus meeting ratified a core descriptor set of 37 descriptors within six domains: fistula anatomy, current disease activity and phenotype, risk factors, medical interventions for CAF, surgical interventions for CAF, and patient symptoms and impact on quality of life. CONCLUSION: The core descriptor set proposed for all future CAF research reflects characteristics important to gastroenterologists and surgeons. This might aid transparent reporting in future studies

Example-based knowledge acquisition for automated interpretation of group-average lactation curves

Dairy producers enrolled in a Dairy Herd Improvement Association (DHI) receive a large amount of milkrecording data following each test day. These data can be a useful source of information to support dairy farm management and control activities. For example, the analysis of group-average lactation curves can be a valuable tool in detecting tactical level management problems. However, proper interpretation of group-average lactation curves and additional milk-recording data tends to be time-consuming and complex. Use of a knowledge-based system (KBS) to partially automate this process would thus be advantageous, providing dairy producers and their advisors with expert interpretation of the available data.[...