Threshold Decline in Mesoamerican Coral Growth and Resiliency

Caribbean coral reefs have been massively altered in recent decades due to human impacts, resulting in a dramatic reduction of live coral cover but quantitative data before the 1970s have not been available to assess how these changes came about1,2,3. We produced master chronologies of growth rates in massive Montastrea faveolata corals from the Mesoamerican reef tract that provide a method for extending records of coral health further back into the past. Our records reveal a unique reduction in growth rate associated with the 1998 coral bleaching event that has no parallel in the past 75 to 150 years. Of 92 cores collected from live coral heads in 2006-2007, 94% have severely reduced growth rates and 14% exhibit partial mortality scars in 1998-1999 whereas only 3 stress bands are found in single cores prior to 1998, and none of these cores exhibited earlier partial mortality. Some corals returned to pre-1998 extension rates by 2001, although corals in areas affected by sediment-laden runoff or high human population density still had not fully recovered by the time of sample collection eight years later. Previous episodic stresses like hurricane strikes and a warming event in 1983 more severe than 1998 had little to no effect on M. faveolata growth rates. The 1998 event apparently surpassed a threshold in coral tolerance precipitating a catastrophic shutdown in growth that had lasting effects throughout the Mesoamerican reef system but was particularly prolonged in areas exposed to other stressors. These findings suggest that projected increases in global temperatures over the next century are likely to result in drastic reductions in growth rather than a gradual decline in coral health, but that corals with fewer local stresses will be better able to survive bleaching events, underscoring the need for local conservation measures

Developmental aspects of nonverbal communication

Developmental differences in encoding and decoding abilities were investigated in this study with subjects ranging from 5 years to 88 years of age. The 94 white, middle-class males and females were placed into five age groups. Subjects were asked to encode each of six emotional expressions, after which they were presented with three decoding tasks. The video tape mode required subjects to decode the same six common nonverbal expressions of emotion (i.e., anger, surprise, fear, happiness, sadness, disgust). A second decoding task consisted of four expressions (anger, fear, sadness, happiness) which were schematically depicted. Subjects\u27 decoding of affect in a verbal context was assessed by means of an Emotional Situation Assignment List which presented emotional evoking situations for which the subject was asked to assign one of the six affect types. Subjects\u27 encoding accuracy did not change after 9 years of age. Decoding accuracy of animate faces and situational cues portrayed in video tape mini scenes increased with age to adulthood, until in old age a decline in accuracy was observed. Subjects\u27 identification of low, medium, and high intensity in expression increased in accuracy between the child! groups not increasing significantly for adults. Schematic face decoding accuracy for the youngest children, in contrast to their accuracy on the video tape labeling, was not different from adult accuracy. Young-, and mid-adult groups\u27 decoding performances did not differ. Few sex differences were found. The aged subjects showed the most inaccuracies in both decoding tasks. These results suggest that the differences between the children and adults may have resulted from a deficit in cognitive skills. The age differences between the aged subjects\u27 accuracy and the other adults\u27 accuracy is believed due, in part, to a cognitive style preference for problem: solving resulting from different life, styles

Examination of the mass-dependent Li depletion hypothesis by the Li abundances of the very metal-poor double-lined spectroscopic binary G166-45

The Li abundances of the two components of the very metal-poor ([Fe/H]=-2.5) double-lined spectroscopic binary G166-45 (BD+26 2606) are determined separately based on high resolution spectra obtained with the Subaru Telescope High Dispersion Spectrograph and its image slicer. From the photometric colors and the mass ratio the effective temperatures of the primary and secondary components are estimated to be 6350+/-100K and 5830+/-170K, respectively. The Li abundance of the primary (A(Li)=2.23) agrees well with the Spite plateau value, while that of the secondary is slightly lower (A(Li)=2.11). Such a discrepancy of the Li abundances between the two components is previously found in the extremely metal-poor, double-lined spectroscopic binary CS22876-032, however, the discrepancy in G166-45 is much smaller. The results agree with the trends found for Li abundance as a function of effective temperature (and of stellar mass) of main-sequence stars with -3.0<[Fe/H]<-2.0, suggesting that the depletion of Li at Teff ~ 5800K is not particularly large in this metallicity range. The significant Li depletion found in CS22876-032B is a phenomenon only found in the lowest metallicity range ([Fe/H]<-3).Comment: 3 figures, 1 table, to appear in ApJ

Realistic Ionizing Fluxes for Young Stellar Populations from 0.05 to twice solar metallicity

We present a new grid of ionizing fluxes for O and Wolf-Rayet stars for use with evolutionary synthesis codes and single star H II region analyses. A total of 230 expanding, non-LTE, line-blanketed model atmospheres have been calculated for five metallicities (0.05, 0.2, 0.4, 1 and 2 solar) using the WM-basic code of Pauldrach et al. (2001) and the CMFGEN code of Hillier & Miller (1998). The stellar wind parameters are scaled with metallicity for both O and W-R stars. We incorporate the new models into Starburst99 (Leitherer et al. 1999) and compare the ionizing outputs with Schaerer & Vacca (1998) and Leitherer et al. (1999). The changes in the output ionizing fluxes are dramatic, particularly below 228 A. We also find lower fluxes in the He I continuum for Z > 0.4 solar and ages < 7 Myr because of the increased line blanketing. We test the accuracy of the new models by constructing photoionization models. We show that for the dwarf O star grid, He I 5876/H beta decreases between Z = 1 and twice solar in a similar manner to observations (e.g. Bresolin et al. 1999) due to the increased effect of line blanketing. We therefore suggest that a lowering of the upper mass limit at high abundances is not required to explain the observations. For the case of an instantaneous burst, we plot the softness parameter "eta prime" against the abundance indicator R_23. The new models are coincident with the data of Bresolin et al. (1999), particularly during the W-R phase, unlike previous models which over-predict the hardness of the ionizing radiation.Comment: 21 pages, 15 postscript colour figures, includes mn2e.cls. To be published in MNRAS. Revised version containing modifications to Tables 1-

Survey of post-weaning management, growth and mortality of Merino weaners

Flock owner\u27s excessive use of supplementary feed, especially of hay, lack of knowledge of nutritional requirements of weaners and failure to follow recommended methods of internal parasite control were the main areas of inefficient management. Management of the weaners as observed in the first year, suggested that previous advice by the Department of Agriculture was not well accepted or had not reached some producers

The live sheep export industry

Australia\u27s live sheep trade to Middle Eastern countries is an important export industry. However, about 2 per cent of the sheep die, mainly during the sea voyage. The Western Australian Department of Agriculture has conducted a major research programme to improve the health and welfare of sheep during live export. The programme has\u27examined many aspects of the export sheep industry, and a substantial part of it has focused on why sheep die during sea transport

Duration of antibody response following vaccination against feline immunodeficiency virus

Objectives: Recently, two point-of-care (PoC) feline immunodeficiency virus (FIV) antibody test kits (Witness and Anigen Rapid) were reported as being able to differentiate FIV-vaccinated from FIV-infected cats at a single time point, irrespective of the gap between testing and last vaccination (0–7 years). The aim of the current study was to investigate systematically anti-FIV antibody production over time in response to the recommended primary FIV vaccination series. Methods: First, residual plasma from the original study was tested using a laboratory-based ELISA to determine whether negative results with PoC testing were due to reduced as opposed to absent antibodies to gp40. Second, a prospective study was performed using immunologically naive client-owned kittens and cats given a primary FIV vaccination series using a commercially available inactivated whole cell/inactivated whole virus vaccine (Fel-O-Vax FIV, three subcutaneous injections at 4 week intervals) and tested systematically (up to 11 times) over 6 months, using four commercially available PoC FIV antibody kits (SNAP FIV/FeLV Combo [detects antibodies to p15/p24], Witness FeLV/FIV [gp40], Anigen Rapid FIV/FeLV [p24/gp40] and VetScan FeLV/FIV Rapid [p24]). Results: The laboratory-based ELISA showed cats from the original study vaccinated within the previous 0–15 months had detectable levels of antibodies to gp40, despite testing negative with two kits that use gp40 as a capture antigen (Witness and Anigen Rapid kits). The prospective study showed that antibody testing with SNAP Combo and VetScan Rapid was positive in all cats 2 weeks after the second primary FIV vaccination, and remained positive for the duration of the study (12/12 and 10/12 cats positive, respectively). Antibody testing with Witness and Anigen Rapid was also positive in a high proportion of cats 2 weeks after the second primary FIV vaccination (8/12 and 7/12, respectively), but antibody levels declined below the level of detection in most cats (10/12) by 1 month after the third (final) primary FIV vaccination. All cats tested negative using Witness and Anigen Rapid 6 months after the third primary FIV vaccination. Conclusions and relevance: This study has shown that a primary course of FIV vaccination does not interfere with FIV antibody testing in cats using Witness and Anigen Rapid, provided primary vaccination has not occurred within the previous 6 months. Consequently, Witness and Anigen Rapid antibody test kits can be used reliably to determine FIV infection status at the time of annual booster FIV vaccination to help detect ‘vaccine breakthroughs’ and in cats that have not received a primary course of FIV vaccination within the preceding 6 months. The duration of antibody response following annual booster FIV vaccination and the resulting effect on antibody testing using PoC kits needs to be determined by further research. The mechanism(s) for the variation in FIV antibody test kit performance remains unclear

Design of a Mach-3 Nozzle for TBCC Testing in the NASA LaRC 8-ft High Temperature Tunnel

A new nozzle is being constructed for the NASA Langley Research Center 8-Foot High Temperature Tunnel. The axisymmetric nozzle was designed with a Mach-3 exit flow for testing Turbine-Based Combined-Cycle engines at a Mach number in the vicinity of the transition from turbojet to ramjet operation. The nozzle contour was designed using the NASA Langley IMOCND computer program which solves the potential equation using the classical method of characteristics. To include viscous effects, the design procedure iterated the MOC contour generation with CFD Navier-Stokes calculations, adjusting MOC input parameters until target nozzle-exit conditions were achieved in the Navier-Stokes calculations. The design process was complicated by a requirement to use the final 29.5 inches of an existing 54.5-inch exit-diameter Mach-5 nozzle contour. This was accomplished by generating a Mach-3 contour that matched the radius of the Mach-5 contour at the match point and using a 3rd order polynomial to create a smooth transition between the two contours. During the final evaluation of the design it was realized that the throat diameter is more than half that of the upstream mixing chamber. This led to the concern that large vortical structures generated in the mixer would persist downstream, affecting nozzle-exit flow. This concern was addressed by analyzing the results of three-dimensional, viscous, numerical simulations of the entire flowfield, from the exit of the facility combustor to the nozzle exit. An analysis of the solution indicated that large scale structures do not pass through the throat and that both the total temperature and species (CO2) are well mixed in the mixer, providing uniform flow to the nozzle and subsequently the test cabin

Achieving Very High PV Penetration

This article argues that optimally deployed intermittency solutions could affordably transform solar power generation into the firm power delivery system modern economies require, thereby enabling very high solar penetration and the displacement conventional power generation. The optimal deployment of these high‐penetration enabling solutions imply the existence of a healthy power grid, and therefore imply a central role for utilities and grid operators. This article also argues that a value‐based electricity compensation mechanism, recognizing the multifaceted, penetration‐dependent value and cost of solar energy, and capable of shaping consumption patterns to optimally match resource and demand, would be an effective vehicle to enable high solar penetration and deliver affordable firm power generation

Marine barite morphology as an indicator of biogeochemical conditions within organic matter aggregates

Marine barite is commonly used as a proxy to reconstruct past ocean productivity. Its distribution in the water column mirrors organic carbon fluxes since it precipitates within microenvironments in decomposing organic matter aggregates. Barite and barium proxies are therefore used to study various aspects of organic matter remineralization and the marine carbon cycle. Barite naturally occurs in a wide variety of crystal sizes and morphologies, but barite crystals that form in the ocean water column are dominantly 1–2 μm in length and have barrel-shaped morphologies. Here, we conducted a series of laboratory experiments to determine the physical and chemical conditions that yield barite crystals similar to marine barite. We found that barite saturation index, the presence and identity of organic compounds, and experiment duration all exert a strong influence on barite crystal size and morphology. Barrel-shaped, 1 μm length crystals resembling marine barite were produced in experiments with a barite saturation index of 2.5, soy phospholipid concentrations of ≥50 mg L−1, and experiment durations of ≤10 min. These findings help constrain the plausible biogeochemical conditions within the aggregate microenvironments in which marine barite precipitates. Relatively high experimental concentrations of phospholipids are consistent with the hypothesized involvement of extracellular polymeric substances in marine barite precipitation. Short experiment durations suggest that a favorable saturation state may be short-lived in marine organic matter aggregates. We present detailed mineralogical and crystallographic analyses of the crystals we synthesized to gain insight into barite crystal growth. This work deepens our understanding of the mechanisms behind marine barite precipitation and sheds light on microscale spatial and temporal dynamics within organic matter aggregates.U.S. Department of Defense National Defense Science and Engineering Graduate Student FellowshipGeological Society of Americ