Modification of the biological intercept model to account for ontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus)*

We investigated age, growth, and ontogenetic effects on the proportionality of otolith size to fish size in laboratory-reared delta smelt (Hypomesus transpacificus) from the San Francisco Bay estuary. Delta smelt larvae were reared from hatching in laboratory mesocosms for 100 days. Otolith increments from known-age fish were enumerated to validate that growth increments were deposited daily and to validate the age of fish at first ring formation. Delta smelt were found to lay down daily ring increments; however, the first increment did not form until six days after hatching. The relationship between otolith size and fish size was not biased by age or growth-rate effects but did exhibit an interruption in linear growth owing to an ontogenetic shift at the postflexon stage. To back-calculate the size-at-age of individual fish, we modified the biological intercept (BI) model to account for ontogenetic changes in the otolith-size−fish-size relationship and compared the results to the time-varying growth model, as well as the modified Fry model. We found the modified BI model estimated more accurately the size-at-age from hatching to 100 days after hatching. Before back-calculating size-at-age with existing models, we recommend a critical evaluation of the effects that age, growth, and ontogeny can have on the otolith-size−fish-size relation

Fish larval nutrition and feed formulation: knowledge gaps and bottlenecks for advances in larval rearing

Despite considerable progress in recent years, many questions regarding fish larval nutrition remain largely unanswered, and several research avenues remain open. A holistic understanding of the supply line of nutrients is important for developing diets for use in larval culture and for the adaptation of rearing conditions that meet the larval requirements for the optimal presentation of food organisms and/or microdiets. The aim of the present review is to revise the state of the art and to pinpoint the gaps in knowledge regarding larval nutritional requirements, the nutritional value of live feeds and challenges and opportunities in the development of formulated larval diets.Norwegian Ministry of Fisheries; Research Council of Norway [CODE-199482, GutFeeling-190019]; Spanish Ministry of Science and Innovation MICINN + FEDER/ERDF [AGL2007-64450-C02-01, CSD2007-0002]; project HYDRAA [PTDC/MAR/71685/2006]; Fundacao para a Ciencia e a Tecnologia (FCT), Portugal; FEDER; EC [LIFECYCLE- 222719]; EU RTD [FA0801]info:eu-repo/semantics/publishedVersio

Proton and deuteron spin-lattice relaxation measurements in the dilute gas for methane and its deuterated modifications.

The spin-lattice relaxation time T₁ has been measured for the proton and the deuteron resonances in methane -and its deuterated modifications as a function of density ƿ , at low densities where T₁ is proportional to ƿ ; and temperature T, between 110°K and 300°K. For the proton relaxation, plots of log T₁/ƿ versus log T for each of the gases CH₄₌ո Dո, n=0, 1, 2, 3 gave the temperature dependence of T₁/ƿ as T₁/ƿ∝T⁻³ʹ² . The value of T₁/ƿ at constant temperature changed very little with n. This implied that the main interaction contributing to proton spin relaxation was the spin-rotational interaction. For the deuteron results it was found that T₁/ƿ was nearly independent of temperature but differed by a factor of approximately four over the range of isotopic compositions n = 1, 2, 3,4. CD₄ gave the shortest value of T₁ while CHD₃ gave the longest. This was attributed to the dominance of the quadrupolar interaction of the deuteron over the dipolar and spin-rotational interactions.Science, Faculty ofPhysics and Astronomy, Department ofGraduat

Computation and predictive modeling to increase efficiency and performance in cell line and bioprocess development

Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, in conjunction with the Leaders for Global Operations Program at MIT, May, 2020Thesis: S.M., Massachusetts Institute of Technology, Department of Chemical Engineering, in conjunction with the Leaders for Global Operations Program at MIT, May, 2020Cataloged from the official PDF of thesis.Includes bibliographical references (pages 57-58).A critical early step in the development of a new biopharmaceutical is the selection of the master cell bank. Per FDA requirements, the same master cell bank must be used for all toxicity and clinical trials, as well as all production of the drug should it be commercialized. Developing a master cell bank is a time and labor-intensive process where thousands of clones are screened through a series of experiments. The Berkeley Lights Beacon® platform can be used as a high-throughput screening tool in cell line development and has been shown to produce clonally-derived cell lines, suitable for the development of a master cell bank. In a typical use case, a Berkeley Lights chip is loaded with 1750 cells, data is collected related to cell growth and on-chip assays, and the top 50-100 are selected for further analysis. The methodology for selecting the top clones, however, is not standardized and individual users may select different top clones based on how they weigh the growth and assay data. As a relatively new tool, there is little literature outlining how to best use data collected on Berkeley Lights to select the "best" clones for further screening. In this project, we use Amgen's database of Berkeley Lights experiments to determine which parameters are most predictive of performance in future fed-batch experiments. Data from 9 chips (N=13,900 pens; N=305 fed-batch experiments) was analyzed using linear and non-linear machine learning models to identify feature importance and improve cell selection methodology. The models generated show an improved ability to rank top clones compared to the currently methodology, a finding that is expected to improve average clone quality in cell line development.by Aaron Baskerville-Bridges.M.B.A.S.M.M.B.A. Massachusetts Institute of Technology, Sloan School of ManagementS.M. Massachusetts Institute of Technology, Department of Chemical Engineerin

Evaluation of Current and Historical 10-inute-count screens at the Tracy Fish Collection Facility, Tracy, California

The U.S. Department of the Interior, Bureau of Reclamation\u27s Tracy Fish Collection Facilities (TFCF) 10-minute-count screen is a critical tool used to acquire sub-samples and provide an estimate of fish entering the facility. The introduction of a new screen in 1999, prior to fish screen retention comparisons, could possibly have altered TFCF salvage estimates. Three experiments were conducted during 2003 and 2004 to evaluate the retention efficiencies of the current and historical screens for juvenile delta smelt (Hypomesus transpacificus): (1) Wild Juvenile Delta Smelt Retention Comparison, (2) Evaluation of Bead Loss, and (3) Cultured Juvenile Delta Smelt Retention Comparison. In experiment No. 1 there was no significant difference between the mean number of juvenile delta smelt (20 to 30.5 mm in fork length [FL]) retained using the current (40.1 percent +/- 7.4; mean +/- standard error [SE], n = 6) and historical (34.5 percent +/- 7.9; n = 8) screens (p = 0.70). However, delta smelt with a greater maximum body depth than the maximum hole width were recovered outside of both screens. Experiment No. 2 was conducted to determine where, aside from screen holes, these fish may have been lost. The lowest success rate for retention of beads was achieved when no seal was used (8.6 percent for 4 mm, 41 percent for 10 mm). Retention of particles was highest (100 percent for beads \u3e 5 mm) when seals were used on the top and bottom of the screen, demonstrating that loss was occurring at both locations. In experiment No. 3 eight conditions were tested, using the two screen types. Retention was evaluated with and without seals with two class sizes of delta smelt (small, 20 to 25 mm in FL and large, 25 to 30 mm in FL). Retention of the small class size was significantly lower using the current screen with seals, compared to all three other treatment types (current + seal, 3 percent; current, 18 percent; historical + seal, 13 percent; historical, 15 percent, P = 0.002). However, no significant differences were detected among treatments of the large class size (current + seal, 23 percent; current, 33 percent; historical + seal, 59 percent; historical, 44 percent, P = 0.06). Experiments Nos. 1 and 3 support the hypothesis that there is no difference in retention between current and historical screens when seals are not used. SInce seals were not used historically, we conclude that the current and historical salvage data sets are comparable

109-117 BaskerÕille-Bridges

Abstract Ž . Ž A microparticulate diet was introduced on 8, 15, 22, 29 and 29 days post-hatch dph with . Artemia . Larvae were weaned from rotifers directly onto the diet in the first four treatments. Artemia were used in the fifth treatment and were fed for a period of 10 days. The microparticulate diet was able to completely replace live prey long before metamorphosis and larvae were weaned by 8.5 mm standard length. With the earliest introduction of the microparticulate diet on 8 Ž . dph, we observed 35% survival through 71 dph 21 mm . The survival of larvae from the other treatments was not significantly different and ranged from 32.7% to 39.4%. Weaning time did not have a significant affect on growth of cod larvae, as there were no differences when introducing Ž . the microparticulate diet on 8 or 29 without Artemia dph. However, supplementation of Artemia for 10 days had a growth-promoting effect. Larvae were larger than individuals from the other four treatments beginning on 29 dph and continued throughout the experiment. By 71 dph, Ž . they were 24 mm and weighed 20 mg dry weight . Successful culture of many finfish species is dependent on the use of live prey during the larval period. Early introduction of a microparticulate diet reduces the quantity of rotifers required and makes Artemia nonessential. This lowers production costs considerably by reducing the number of live animal cultures that must be maintained. However, until better diets are produced, careful consideration should be given to how early weaning affects production cost vs. growth rate of the larvae. q 2000 Elsevier Science B.V. All rights reserved