Effects of kelp canopy removal on young-of-the-year rockfish abundance, using two census methods

In 1976 an experimental research project was initiated to examine the possible effects of the removal of a giant kelp, Macrocystis pyrifera, canopy in a central California kelp bed on Young-of-the-Year (YOY) fish populations. A total of 7823 fishes was captured and marked using freeze branding. Pre-canopy removal population estimates were made using the Schnabel method and post-canopy removal population estimates were made using the Petersen method (Lincoln Index). A significant (p < .0004) reduction of fish occurred immediately after the canopy was removed and the population remained at a reduced level for at least 60 days. This information warranted the creation of a second expanded project. In 1977 we established three study areas consisting of a kelp bed to be harvested (C), a kelp bed not to be harvested (NC) and a control kelp bed. We captured and marked over 82,000 YOY fish in Areas C and NC. Using the same statistical methods from the 1976 study, a significant reduction was found to occur in fish populations within harvested Area C and unharvested area NC: however, the reductions were not significantly different between the two areas. The large reduction in the fish population in the harvested area occurred when fish moved into the unharvested area. The large, unexpected reduction in fish numbers in the unharvested area (NC) occurred when larger predatory YOY bocaccio moved into the control area (X) as the experimental area (C) was being harvested. The bocaccio removed in excess of 20% of the biomass of YOY blue rockfish, which was composed of resident fish and recently migrated fish from the harvested kelp bed. Predation on YOY blue rockfish was also evident in the harvested area. Population estimates using visible fish transects by divers correlated well with population estimates from the capture/recapture studies in 1976, but correlation was poorer the following year when many more fish were present. (32pp.

Characteristics of Waterfowl Harvest at Horseshoe Lake, Madison County, Illinois

Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 13Report issued on: April 21, 197

Modeling Signal Transduction in Classical Conditioning with Network Motifs

Biological networks are constructed of repeated simplified patterns, or modules, called network motifs. Network motifs can be found in a variety of organisms including bacteria, plants, and animals, as well as intracellular transcription networks for gene expression and signal transduction processes in neuronal circuits. Standard models of signal transduction events for synaptic plasticity and learning often fail to capture the complexity and cooperativity of the molecular interactions underlying these processes. Here, we apply network motifs to a model for signal transduction during an in vitro form of eyeblink classical conditioning that reveals an underlying organization of these molecular pathways. Experimental evidence suggests there are two stages of synaptic AMPA receptor (AMPAR) trafficking during conditioning. Synaptic incorporation of GluR1-containing AMPARs occurs early to activate silent synapses conveying the auditory conditioned stimulus and this initial step is followed by delivery of GluR4 subunits that supports acquisition of learned conditioned responses (CRs). Overall, the network design of the two stages of synaptic AMPAR delivery during conditioning describes a coherent feed-forward loop (C1-FFL) with AND logic. The combined inputs of GluR1 synaptic delivery AND the sustained activation of 3-phosphoinositide-dependent protein-kinase-1 (PDK-1) results in synaptic incorporation of GluR4-containing AMPARs and the gradual acquisition of CRs. The network architecture described here for conditioning is postulated to act generally as a sign-sensitive delay element that is consistent with the non-linearity of the conditioning process. Interestingly, this FFL structure also performs coincidence detection. A motif-based approach to modeling signal transduction can be used as a new tool for understanding molecular mechanisms underlying synaptic plasticity and learning and for comparing findings across forms of learning and model systems

Early life-history studies of nearshore rockfishes and lingcod off Central California, 1987-92

This study focused on the physical and biological processes that influence the distribution, abundance, growth, and survival of young-of-the-year (YOY) rockfishes and lingcod along the central California coast. The annual somatic and reproductive condition of adult female blue rockfish corresponded to annual upwelling. Resulting larval production may correspond to the reproductive potential of adults; however, ultimate recruitment success of YOY is also effected by oceanographic conditions during their planktonic stage. Within a year, each species of settled YOY was observed concurrently and in relatively similar abundances at all study dive sites along the central coast. Most species of YOY exhibited similar growth patterns among stations and years. We found a high degree of interannual variability in the condition of adults and relative abundances of YOY. We believe a large part of this variability is due to annual oceanographic conditions, specifically upwelling. Marine reserves, which would protect populations of reproductively mature rockfishes and lingcod and insure 1arval production, have been suggested as an alternative to present management strategies for these species. However, a crucial question is whether or not larvae from adult fish in reserves would significantly contribute to replenishing stocks in other areas. This study was undertaken to assist in determining the feasibility of reserves to enhance nearshore rockfish and lingcod populations. (78pp.

The use of the anesthetic metomidate hydrochloride as an aid in open water capture of young-of-the-year rockfish

Many species of young-of-the-year (YOY) rockfish, Sebastes sp. move inshore into shallow reef areas in central California each year. We monitored the dates of arrival, relative abundance, species composition, lengths, and growth rates of these arrivals to help assess recruitment variability and stock success. We tested the usefulness of the anesthetic metomidate hydrochloride as a non-lethal method to collect YOY rockfish to assess growth, abundance, and species composition. Earlier experiments by other researchers illustrated the usefulness of metomidate to collect benthic-oriented adult rockfish. Our research tested the possibility of using metomidate hydrochloride to collect open-water and benthic-oriented YOY rockfish. The anesthetic was applied and the fish captured by divers. Several concentrations of metomidate were tested, premixed both in fresh and salt water. The anesthetic was not very useful in collecting open water YOY rockfish as the fish rapidly left the area of application and avoided being anesthetized. Increasing the concentration of metomidate did not increase success of capture of open-water YOY rockfish. However, the anesthetic metomidate worked very well in capturing benthic-oriented YOY rockfishes. (22pp.

Presynaptic Inhibition in the Striatum of the Basal Ganglia Improves Pattern Classification and Thus Promotes Superior Goal Selection

This review article takes a multidisciplinary approach to understand how presynaptic inhibition in the striatum of the basal ganglia (BG) contributes to pattern classification and the selection of goals that control behavior. It is a difficult problem both because it is multidimensional and because it is has complex system dynamics. We focus on the striatum because, as the main site for input to the BG, it gets to decide what goals are important to consider

Remembering Forward: Neural Correlates of Memory and Prediction in Human Motor Adaptation

We used functional MR imaging (FMRI), a robotic manipulandum and systems identification techniques to examine neural correlates of predictive compensation for spring-like loads during goal-directed wrist movements in neurologically-intact humans. Although load changed unpredictably from one trial to the next, subjects nevertheless used sensorimotor memories from recent movements to predict and compensate upcoming loads. Prediction enabled subjects to adapt performance so that the task was accomplished with minimum effort. Population analyses of functional images revealed a distributed, bilateral network of cortical and subcortical activity supporting predictive load compensation during visual target capture. Cortical regions – including prefrontal, parietal and hippocampal cortices – exhibited trial-by-trial fluctuations in BOLD signal consistent with the storage and recall of sensorimotor memories or “states” important for spatial working memory. Bilateral activations in associative regions of the striatum demonstrated temporal correlation with the magnitude of kinematic performance error (a signal that could drive reward-optimizing reinforcement learning and the prospective scaling of previously learned motor programs). BOLD signal correlations with load prediction were observed in the cerebellar cortex and red nuclei (consistent with the idea that these structures generate adaptive fusimotor signals facilitating cancelation of expected proprioceptive feedback, as required for conditional feedback adjustments to ongoing motor commands and feedback error learning). Analysis of single subject images revealed that predictive activity was at least as likely to be observed in more than one of these neural systems as in just one. We conclude therefore that motor adaptation is mediated by predictive compensations supported by multiple, distributed, cortical and subcortical structures

Tides and Overtides in Long Island Sound

Using observations obtained by acoustic Doppler profilers and coastal water level recorders, we describe the vertical and horizontal structure of the currents and sea level due to the principal tidal constituents in Long Island Sound, a shallow estuary in southern New England. As expected, the observations reveal that M2 is the dominant constituent in both sea surface and velocity at all depths and sites. We also find evidence that the vertical structure of the M2 tidal current ellipse parameters vary with the seasonal evolution of vertical stratification at some sites. By comparing our estimates of the vertical structure of the M2 amplitudes to model predictions, we demonstrate that both uniform and vertically variable, time invariant eddy viscosities are not consistent with our measurements in the Sound. The current records from the western Sound contain significant overtides at the M4 and M6 frequencies with amplitudes and phases that are independent of depth. Though the M4 amplitude decreases to the west in proportion to M2, the M6 amplifies. Since the dynamics that generate overtides also produce tidal residuals, this provides a sensitive diagnostic of the performances of numerical circulation models. We demonstrate that the observed along-Sound structure of the amplitude of the M4 and M6 overtides is only qualitatively consistent with the predictions of a nonlinear, laterally averaged layer model forced by a mean flow and sea level at the boundaries. Since neither the vertical structure of the principal tidal constituent nor the pattern of horizontal variation of the largest overtides can be explained using well established models, we conclude that they are fundamentally inadequate and should no longer be used for more than a basic qualitative understanding, and even then should be used with caution. We provide comprehensive tables of the tidal current parameters to facilitate the critical evaluation of future models of the circulation in the Sound

The Mind Agents in Netlogo 3.1

In [Houk, 2005], the “Agents of the mind” idea is proposed as a suitable framework for studying the dynamics and complexities of mind. “Agents of the mind” is inspired by the society of mind idea of Marvin Minsky [Minsky, 1988]. According to the society of mind, the mind is a complex system. The mind agents are elusive to identify. The mind is proposed as a hierarchy of agents. The higher hierarchy agents compose of lower hierarchy agents. Higher level agents do not command lower level agents but they basically trigger or invoke lower level agents. Agents are functional entities and they interact with each other. One important part of the society of mind idea is that agents at the lowest level are the real workers. Higher level functionalities emerge as a result of the functioning of the lower level agents and the interactions between them. In agents of the mind project, computational distributed processing modules (DPM) are posited for corresponding anatomically defined assemblies and they are referred to as the agents of the mind. M1 is an anatomical area in the cerebral cortex which produces voluntary commands via its loops through basal ganglia and cerebellum. M1-DPM is a computational distributed processing module which simulates M1 area and its loops for voluntary commands production. We use Netlogo 3.1 agent-based programming environment to illuminate the properties of mind. In this work, the attractor network in cerebellar loop and the effects of Purkinje cell on production of motor commands have been studied. The results are reported in this paper

Inverted binding of non-natural substrates in strictosidine synthase leads to a switch of stereochemical outcome in enzyme-catalyzed Pictet-Spengler reactions

The Pictet-Spengler reaction is a valuable route to 1,2,3,4-tetrahydro-Β-carboline (THBC) and isoquinoline scaffolds found in many important pharmaceuticals. Strictosidine synthase (STR), catalyzes the Pictet-Spengler condensation of tryptamine and the aldehyde secologanin to give (S)-strictosidine as a key intermediate in indole alkaloid biosynthesis. STRs also accept shortchain aliphatic aldehydes to give enantioenriched alkaloid products with up to 99% e.e. STRs are thus valuable asymmetric organocatalysts for applications in organic synthesis. The STR catalysis of reactions of small aldehydes gives an unexpected switch in stereopreference, leading to formation of the (R)-products. Here we report a rationale for the formation of the (R)-configured products by the STR enzyme from Ophiorrhiza pumila (OpSTR) using a combination of X-ray crystallography, mutational and molecular dynamics (MD) studies. We discovered that short chain aldehydes bind in an inverted fashion compared to secologanin leading to the inverted stereopreference for the observed (R)-product in those cases. The study demonstrates that the same catalyst can have two different productive binding modes for one substrate – but give different absolute configuration of the products by binding the aldehyde substrate differently. These results will guide future engineering of STRs and related enzymes for biocatalytic applications