On the reproductive biology of the western Atlantic bluefin tuna, Thunnus thynnus

The Atlantic bluefin tuna, Thunnus thynnus, is a highly migratory species capable of traversing great distances throughout the North Atlantic Ocean, but spawning is known to occur only in the Mediterranean Sea and the Gulf of Mexico/Straits of Florida. The regulatory body charged with managing Atlantic bluefin tuna, the International Commission for the Conservation of Atlantic Tunas (ICCAT), currently recognizes two spawning stocks, eastern and western, separated by a management line at 45° W. The eastern stock spawns from May through July in the Mediterranean Sea with an age at first maturity of 3--4 years. Due in part to a moratorium on fishing for bluefin tuna in the Gulf of Mexico, considerably less research has been conducted on the western spawning stock, and, subsequently, knowledge about basic biological characteristics of this stock is lacking. The age at maturity for western bluefin tuna has been reported as 5--16 years and is a topic of debate among fisheries managers. For stock assessment and management, ICCAT assumes an age at maturity for western bluefin tuna of 9 years. While only two spawning grounds are known, fish of reproductively mature size routinely do not return to either of these two locations during the presumed spawning season indicating additional spawning grounds may exist. Atlantic bluefin tuna were sampled on and off the known spawning grounds, and maturity status was determined for male and female fish. All fish sampled on the spawning grounds (n=250) had mature gonads, and the spawning season in the north/central Gulf of Mexico was defined as April--June. Histological analyses showed a peak in oocyte maturation, and thus spawning activity, in May in the Gulf of Mexico sampling region. Actively spawning fish from the Mediterranean Sea were compared with those from the Gulf of Mexico. Realized fecundity and spawning periodicity were found to be similar for both stocks, but the western spawning stock sampled in the north/central Gulf of Mexico spawns one month earlier than the eastern stock. Fish sampled far from the known spawning grounds provided further information about the reproductive condition of western bluefin tuna. The youngest female and male to show signs of maturity had estimated ages of 6 years and 5 years, respectively. About one quarter of all females sampled contained vitellogenic or early atretic oocytes, and based on rates of atresia, it is unlikely these fish spawned in the Gulf of Mexico. These results provide more extensive information about the reproductive biology of western Atlantic bluefin tuna and revise the age at maturity for the western spawning stock. This lower size and age at maturity, coupled with new results from endocrinology and electronic tagging data, suggests alternative spawning grounds exist, and more comprehensive spatial and temporal sampling is necessary to understand the reproductive biology of Atlantic bluefin tuna

Examining Levels of Catecholamine Neurotransmitter Regulatory Proteins Within the Prefrontal Cortex of Rodents Following Traumatic Brain Injury

Traumatic brain injury (TBI) resulting from impact to the head can cause long lasting impairments of cognitive processes that lead to increased risk-taking behavior in clinical populations. Our laboratory has recently shown that female, but not age-matched male, rats increase preference for risky choices after multiple experimentally-induced mild TBI’s. Our overarching goal is to understand the neural mechanisms underlying TBI-induced increases in risk-taking behavior. The prefrontal cortex (PFC) plays a prominent role in risk-based decision making. Sub[1]regions of the PFC include the medial PFC (mPFC), the orbitofrontal cortex (OFC), and the anterior cingulate cortex (ACC), and these sub[1]regions play specific roles in decision-making processes. Catecholamine neurotransmitter circuits, such as the dopamine (DA) and norepinephrine (NE) systems, project to the PFC and modulate the PFC’s control over executive functions. Previous studies have demonstrated that both dopamine (DA) and norepinephrine (NE) transmitter levels are increased in the PFC immediately following TBI, which is then followed by a persistent hypo-catecholaminergic state. These results suggest that an imbalance of catecholamine levels within the PFC may underlie aberrant decision-making behavior following TBI; however, it is not presently known what processes contribute to TBI-induced catecholamine imbalance. Here we examined how levels of catecholamine neurotransmitter regulatory proteins responsible for packaging (VMAT2) and degrading (COMT and MAO) are altered to explain chronic decreases in DA and NE levels observed in the PFC following TBI. Age-matched adult male and female Long Evans rats (n=6-8) were exposed to either a single or a series of three closed head controlled cortical impact (CH-CCI) injuries over the course of one week. Rats were sacrificed and brain tissue (mPFC, OFC, and ACC) were collected and standard western blotting protocols were used to measure the levels of VMAT2, COMT, and MAO in each sub-region

Demonstrating high-precision photometry with a CubeSat: ASTERIA observations of 55 Cancri e

ASTERIA (Arcsecond Space Telescope Enabling Research In Astrophysics) is a 6U CubeSat space telescope (10 cm x 20 cm x 30 cm, 10 kg). ASTERIA's primary mission objective was demonstrating two key technologies for reducing systematic noise in photometric observations: high-precision pointing control and high-stabilty thermal control. ASTERIA demonstrated 0.5 arcsecond RMS pointing stability and $\pm$10 milliKelvin thermal control of its camera payload during its primary mission, a significant improvement in pointing and thermal performance compared to other spacecraft in ASTERIA's size and mass class. ASTERIA launched in August 2017 and deployed from the International Space Station (ISS) November 2017. During the prime mission (November 2017 -- February 2018) and the first extended mission that followed (March 2018 - May 2018), ASTERIA conducted opportunistic science observations which included collection of photometric data on 55 Cancri, a nearby exoplanetary system with a super-Earth transiting planet. The 55 Cancri data were reduced using a custom pipeline to correct CMOS detector column-dependent gain variations. A Markov Chain Monte Carlo (MCMC) approach was used to simultaneously detrend the photometry using a simple baseline model and fit a transit model. ASTERIA made a marginal detection of the known transiting exoplanet 55 Cancri e ($\sim2$~\Rearth), measuring a transit depth of $374\pm170$ ppm. This is the first detection of an exoplanet transit by a CubeSat. The successful detection of super-Earth 55 Cancri e demonstrates that small, inexpensive spacecraft can deliver high-precision photometric measurements.Comment: 23 pages, 9 figures. Accepted in A

Structural insights into Clostridium perfringens delta toxin pore formation

Clostridium perfringens Delta toxin is one of the three hemolysin-like proteins produced by C. perfringens type C and possibly type B strains. One of the others, NetB, has been shown to be the major cause of Avian Nectrotic Enteritis, which following the reduction in use of antibiotics as growth promoters, has become an emerging disease of industrial poultry. Delta toxin itself is cytotoxic to the wide range of human and animal macrophages and platelets that present GM2 ganglioside on their membranes. It has sequence similarity with Staphylococcus aureus β-pore forming toxins and is expected to heptamerize and form pores in the lipid bilayer of host cell membranes. Nevertheless, its exact mode of action remains undetermined. Here we report the 2.4 Å crystal structure of monomeric Delta toxin. The superposition of this structure with the structure of the phospholipid-bound F component of S. aureus leucocidin (LukF) revealed that the glycerol molecules bound to Delta toxin and the phospholipids in LukF are accommodated in the same hydrophobic clefts, corresponding to where the toxin is expected to latch onto the membrane, though the binding sites show significant differences. From structure-based sequence alignment with the known structure of staphylococcal α-hemolysin, a model of the Delta toxin pore form has been built. Using electron microscopy, we have validated our model and characterized the Delta toxin pore on liposomes. These results highlight both similarities and differences in the mechanism of Delta toxin (and by extension NetB) cytotoxicity from that of the staphylococcal pore-forming toxins

The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T_eff<5000 K and in metallicity estimates for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SDSS-III Sloan Extension for Galactic Understanding and Exploration-2 (SEGUE-2). The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) along with another year of data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at http://www.sdss3.org/dr

allodb: An R package for biomass estimation at globally distributed extratropical forest plots

Allometric equations for calculation of tree above-ground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratropics. Here we present an integrated R package, allodb, containing systematically selected published allometric equations and proposed functions to compute AGB. The data component of the package is based on 701 woody species identified at 24 large Forest Global Earth Observatory (ForestGEO) forest dynamics plots representing a wide diversity of extratropical forests. A total of 570 parsed allometric equations to estimate individual tree biomass were retrieved, checked and combined using a weighting function designed to ensure optimal equation selection over the full tree size range with smooth transitions across equations. The equation dataset can be customized with built-in functions that subset the original dataset and add new equations. Although equations were curated based on a limited set of forest communities and number of species, this resource is appropriate for large portions of the global extratropics and can easily be expanded to cover novel forest types

Implications of new technologies for future food supply systems

The combination of advances in knowledge, technology, changes in consumer preference and low cost of manufacturing is accelerating the next technology revolution in crop, livestock and fish production systems. This will have major implications for how, where and by whom food will be produced in the future. This next technology revolution could benefit the producer through substantial improvements in resource use and profitability, but also the environment through reduced externalities. The consumer will ultimately benefit through more nutritious, safe and affordable food diversity, which in turn will also contribute to the acceleration of the next technology. It will create new opportunities in achieving progress towards many of the Sustainable Development Goals, but it will require early recognition of trends and impact, public research and policy guidance to avoid negative trade-offs. Unfortunately, the quantitative predictability of future impacts will remain low and uncertain, while new chocks with unexpected consequences will continue to interrupt current and future outcomes. However, there is a continuing need for improving the predictability of shocks to future food systems especially for ex-ante assessment for policy and planning

HD 219134 Revisited: Planet d Transit Upper Limit and Planet f Transit Nondetection with ASTERIA and TESS

HD 219134 is a K3V dwarf star with six reported radial-velocity discovered planets. The two innermost planets b and c show transits, raising the possibility of this system to be the nearest (6.53 pc), brightest (V = 5.57) example of a star with a compact multiple transiting planet system. Ground-based searches for transits of planets beyond b and c are not feasible because of the infrequent transits, long transit duration (~5 hr), shallow transit depths (<1%), and large transit time uncertainty (~half a day). We use the space-based telescopes the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) and the Transiting Exoplanet Survey Satellite (TESS) to search for transits of planets f (P = 22.717 days and M sin i = 7.3 ± 0.04M_⊕) and d (P = 46.859 days and M sin i = 16.7 ± 0.64M_⊕). ASTERIA was a technology demonstration CubeSat with an opportunity for science in an extended program. ASTERIA observations of HD 219134 were designed to cover the 3σ transit windows for planets f and d via repeated visits over many months. While TESS has much higher sensitivity and more continuous time coverage than ASTERIA, only the HD 219134 f transit window fell within the TESS survey's observations. Our TESS photometric results definitively rule out planetary transits for HD 219134 f. We do not detect the Neptune-mass HD 219134 d transits and our ASTERIA data are sensitive to planets as small as 3.6 R_⊕. We provide TESS updated transit times and periods for HD 219134 b and c, which are designated TOI 1469.01 and 1469.02 respectively

Genetic Analysis of Floral Symmetry in Van Gogh's Sunflowers Reveals Independent Recruitment of CYCLOIDEA Genes in the Asteraceae

The genetic basis of floral symmetry is a topic of great interest because of its effect on pollinator behavior and, consequently, plant diversification. The Asteraceae, which is the largest family of flowering plants, is an ideal system in which to study this trait, as many species within the family exhibit a compound inflorescence containing both bilaterally symmetric (i.e., zygomorphic) and radially symmetric (i.e., actinomorphic) florets. In sunflower and related species, the inflorescence is composed of a single whorl of ray florets surrounding multiple whorls of disc florets. We show that in double-flowered (dbl) sunflower mutants (in which disc florets develop bilateral symmetry), such as those captured by Vincent van Gogh in his famous nineteenth-century sunflower paintings, an insertion into the promoter region of a CYCLOIDEA (CYC)-like gene (HaCYC2c) that is normally expressed specifically in WT rays is instead expressed throughout the inflorescence, presumably resulting in the observed loss of actinomorphy. This same gene is mutated in two independent tubular-rayed (tub) mutants, though these mutations involve apparently recent transposon insertions, resulting in little or no expression and radialization of the normally zygomorphic ray florets. Interestingly, a phylogenetic analysis of CYC-like genes from across the family suggests that different paralogs of this fascinating gene family have been independently recruited to specify zygomorphy in different species within the Asteraceae