Vocal gestures of shared syllable types in cardinals

AbstractIn songbirds, songs are learned by memorization and copying of tutor song and such copies can be remarkably accurate. However, it is not known whether acoustic similarity is generated by equally similar vocal gestures. We studied syringeal and respiratory motor patterns of syllable types shared by up to 6 individual cardinals (Cardinalis cardinalis) by recording bilateral bronchial airflow, subsyringeal aii sac pressure, and acoustic output

Motor control of crystallized song is modified by sensory feedback

Journal ArticleSong production requires precisely coordinated activity in the respiratory and syringcal (vocal organ) muscles. Crystallized adult song is characterized by acoustic and motor stereotypy which does not require auditory feedback, suggesting it is represented by fixed central motor programs. To determine if this adult motor pattern is modulated by sensory feedback, we briefly increased the respiratory pressure by injecting short (10 - 30 ms) puffs of air through a cannula into a cranial thoracic air sac of singing, adult male cardinals (Cardinalis cardinalis), while monitoring air sac pressure, the rate of airflow through each bronchus and the electromyogram (EMG) of abdominal expiratory muscles

Ontogeny of song lateralization in juvenile northern cardinals

Journal ArticleIn adult northern cardinals (Cardinatte cardinalis), the left and right sides of the syrinx cover different vocal registers such (hat fundamental frequencies below about 3.5 or 4 kHz are produced only by the left syrinx and higher frequencies are produced primarily by the light syrinx

Experimental support for a model of birdsong production

An experimental validation of an model for the production of birdsongs was discussed. The derivation of the model with functions whose time dependence came from recordings of muscle activities and air sac pressure was studied. It was found that birds' songs were recorded and compared with the synthetic songs. Some predictions of the model concerning the relative levels of activity in the gating muscles at the beginning and end of a syllable were also tested

Reproductive biology of female blue swimmer crabs in the temperate estuaries of south-eastern Australia

The blue swimmer crab (BSC, Portunus armatus) is an economically and culturally important species distributed throughout the coastal waters of the Indo-Pacific region. Reproduction of BSC is poorly understood in south-eastern Australia, a region that is experiencing substantial tropicalisation from global warming. We examined gonadal development, egg-mass relationships, and the influence of temperature on gonadal development and egg production within five different estuaries spanning ∼2.5° of latitude. A negative correlation between the gonadosomatic index (GSI, an index of gonadal development and reproductive investment) and hepatosomatic index (HSI, an index of energy storage) was observed in only the final stages of ovarian development. The weight of the egg mass increased logarithmically with body mass, accounting for up to 55% of total body mass, which was significantly larger than observed in other studies. Thermal performance curves showed a peak in individual reproductive output at a mean monthly temperature of ∼24°C, at which the individual egg mass weight reached a maximum and the HSI reached a minimum. Environmentally driven variation in BSC reproduction has implications for population productivity and inter-annual variation in recruitment

Long-term drivers of catch variability in south-eastern Australia's largest portunid fishery

Portunid crab fisheries are socially and economically valuable yet are characterised by high inter-annual variability. Competing hypotheses about factors contributing to this variability concern the environment, climate, and fisher behaviour. Here, we investigate variability in commercial catch, through a case study of the most heavily exploited estuary in southeastern Australia (Wallis Lake). Four main hypotheses were identified based on the broader portunid published literature: 1) Freshwater flow may cause poor recruitment due to increased offshore spawning and unfavourable dispersal of larvae, 2) Winter and spring harvesting may impact the following summer harvest by removing the spawning stock biomass (recruit overfishing); 3) Environmental factors including sea surface temperature and onshore winds may influence supply-side processes and recruitment success, contributing to catch fluctuations; and 4) Climatic indices such as the Inter Pacific Oscillation and Pacific Decadal Oscillation (PDO) may correlate with longer-term fluctuations in the fishery. We find evidence in support of hypotheses 2 and 4, with winter harvest negatively impacting the following January - April harvest and the PDO being positively correlated with January - April catch rates. Harvesting in June – November disproportionally impacts large females, and it may be possible to incorporate controls on winter fishing effort through co-management arrangements to achieve the best economic, environmental and social outcomes from the fishery. Such controls may lead to improved summer catch rates by protecting unspawned eggs during the winter months. The hypotheses explored here may provide insight in the variability observed in portunid fisheries around the world

Lymphocytes of BRCA1 and BRCA2 germ-line mutation carriers, with or without breast cancer, are not abnormally sensitive to the chromosome damaging effect of moderate folate deficiency

Mutations in BRCA1 and BRCA2 genes may cause defective DNA repair and increase risk for breast cancer. Folate deficiency is associated with increased breast cancer risk and induces chromosome abnormalities. We hypothesised that BRCA1 and BRCA2 germ-line mutation carriers are more sensitive to the genome damaging effect of folate deficiency compared to healthy non-carrier controls and that this sensitivity is further increased in those carriers who develop breast cancer. We tested these hypotheses in lymphocytes cultured in medium containing 12 nM or 120 nM folic acid (FA) for 9 days and measured proliferative capacity and chromosomal instability using the cytokinesis-block micronucleus (CBMN) assay. BRCA1 and BRCA2 mutation carriers with or without breast cancer were not abnormally sensitive to FA deficiency-induced chromosome instability however BRCA2 mutation carriers had significantly reduced cell proliferation. FA deficiency reduced cell proliferation and increased micronucleus formation significantly accounting for 45-59% and 70-75% of the variance in these parameters compared to 0.3-8.5% and 0.2-0.3% contributed by BRCA1 or BRCA2 mutation carrier status respectively. The results of this study suggest that moderate folate deficiency has a stronger effect on chromosomal instability than BRCA1 or BRCA2 mutations found in breast cancer families.Sasja Beetstra, Carolyn Salisbury, Julie Turner, Meryl Altree, Ross McKinnon, Graeme Suthers and Michael Fenec

Laryngeal Nerve Activity During Pulse Emission in the CF-FM Bat, Rhinolophus ferrumequinum. I. Superior Laryngeal Nerve (External Motor Branch)

The activity of the external (motor) branch of the superior laryngeal nerve (SLN), innervating the cricothyroid muscle, was recorded in the greater horseshoe bat,Rhinolophus ferrumequinum. The bats were induced to change the frequency of the constant frequency (CF) component of their echolocation signals by presenting artificial signals for which they Doppler shift compensated. The data show that the SLN discharge rate and the frequency of the emitted CF are correlated in a linear manner

Analytic frameworks for assessing dialogic argumentation in online learning environments

Over the last decade, researchers have developed sophisticated online learning environments to support students engaging in argumentation. This review first considers the range of functionalities incorporated within these online environments. The review then presents five categories of analytic frameworks focusing on (1) formal argumentation structure, (2) normative quality, (3) nature and function of contributions within the dialog, (4) epistemic nature of reasoning, and (5) patterns and trajectories of participant interaction. Example analytic frameworks from each category are presented in detail rich enough to illustrate their nature and structure. This rich detail is intended to facilitate researchers’ identification of possible frameworks to draw upon in developing or adopting analytic methods for their own work. Each framework is applied to a shared segment of student dialog to facilitate this illustration and comparison process. Synthetic discussions of each category consider the frameworks in light of the underlying theoretical perspectives on argumentation, pedagogical goals, and online environmental structures. Ultimately the review underscores the diversity of perspectives represented in this research, the importance of clearly specifying theoretical and environmental commitments throughout the process of developing or adopting an analytic framework, and the role of analytic frameworks in the future development of online learning environments for argumentation

Genome-scale gene/reaction essentiality and synthetic lethality analysis

Synthetic lethals are to pairs of non-essential genes whose simultaneous deletion prohibits growth. One can extend the concept of synthetic lethality by considering gene groups of increasing size where only the simultaneous elimination of all genes is lethal, whereas individual gene deletions are not. We developed optimization-based procedures for the exhaustive and targeted enumeration of multi-gene (and by extension multi-reaction) lethals for genome-scale metabolic models. Specifically, these approaches are applied to iAF1260, the latest model of Escherichia coli, leading to the complete identification of all double and triple gene and reaction synthetic lethals as well as the targeted identification of quadruples and some higher-order ones. Graph representations of these synthetic lethals reveal a variety of motifs ranging from hub-like to highly connected subgraphs providing a birds-eye view of the avenues available for redirecting metabolism and uncovering complex patterns of gene utilization and interdependence. The procedure also enables the use of falsely predicted synthetic lethals for metabolic model curation. By analyzing the functional classifications of the genes involved in synthetic lethals, we reveal surprising connections within and across clusters of orthologous group functional classifications