Temporal and spatial dynamics of spawning, settlement, and growth of gray snapper (Lutjanus griseus) from the West Florida shelf as determined from otolith microstructures

The goal of our study was to understand the spatial and temporal variation in spawning and settlement of gray snapper (Lutjanus griseus) along the West Florida shelf (WFS). Juvenile gray snapper were collected over two consecutive years from seagrass meadows with a benthic scrape and otter trawl. Spawning, settlement, and growth patterns were compared across three sampling regions (Panhandle, Big bend, and Southwest) by using otolith microstructure. Histology of adult gonads was also used for an independent estimate of spawning time. Daily growth increments were visible in the lapilli of snapper 11–150 mm standard length; ages ranged from 38 to 229 days and estimated average planktonic larval duration was 25 days. Estimated growth rates ranged from 0.60 to 1.02 mm/d and did not differ among the three sampling regions, but did differ across sampling years. Back-calculated fertilization dates from otoliths indicated that juveniles in the Panhandle and Big Bend were mainly summer spawned fish, whereas Southwest juveniles had winter and summer fertilization dates. Settlement occurred during summer both years and in the winter of 1997 for the southern portion of the WFS. Moon phase did not appear to be strongly correlated with fertilization or settlement. Histological samples of gonads from adults collected near the juvenile sampling areas indicated a summer spawning period

Relative Afterslip Moment Does Not Correlate With Aftershock Productivity:Implications for the Relationship Between Afterslip and Aftershocks

Aseismic afterslip has been proposed to drive aftershock sequences. Both afterslip moment and aftershock number broadly increase with mainshock size, but can vary beyond this scaling. We examine whether relative afterslip moment (afterslip moment/mainshock moment) correlates with several key aftershock sequence characteristics, including aftershock number and cumulative moment (both absolute and relative to mainshock size), seismicity rate change, b‐value, and Omori decay exponent. We select M w ≥ 4.5 aftershocks for 41 tectonically varied mainshocks with available afterslip models. Against expectation, relative afterslip moment does not correlate with tested aftershock characteristics or background seismicity rate. Furthermore, adding afterslip moment to mainshock moment does not improve predictions of aftershock number. Our findings place useful empirical constraints on the link between afterslip and potentially damaging M w ≥ 4.5 aftershocks and raise questions regarding the role afterslip plays in aftershock generation

The role of radiation in mesoscale flows: Physics, parameterizations, codes

The topics discussed include the following: an overview of radiation and mesoscale flows and lessons learned from the intercomparison of GCM radiative codes

The development and validation of a multivariable model to predict whether patients referred for total knee replacement are suitable surgical candidates at the time of initial consultation

Background: In previous studies, 50%-70% of patients referred to orthopedic surgeons for total knee replacement (TKR) were not surgical candidates at the time of initial assessment. The purpose of our study was to identify and cross-validate patient self-reported predictors of suitability for TKR and to determine the clinical utility of a predictive model to guide the timing and appropriateness of referral to a surgeon. Methods: We assessed pre-consultation patient data as well as the surgeon\u27s findings and post-consultation recommendations. We used multivariate logistic regression to detect self-reported items that could identify suitable surgical candidates. Results: Patients\u27 willingness to undergo surgery, higher rating of pain, greater physical function, previous intra-articular injections and patient age were the factors predictive of patients being offered and electing to undergo TKR. Conclusion: The application of the model developed in our study would effectively reduce the proportion of nonsurgical referrals by 25%, while identifying the vast majority of surgical candidates (\u3e 90%). Using patient-reported information, we can correctly predict the outcome of specialist consultation for TKR in 70% of cases. To reduce long waits for first consultation with a surgeon, it may be possible to use these items to educate and guide referring clinicians and patients to understand when specialist consultation is the next step in managing the patient with severe osteoarthritis of the knee

A Cross-Correlation Analysis of Mg II Absorption Line Systems and Luminous Red Galaxies from the SDSS DR5

We analyze the cross-correlation of 2,705 unambiguously intervening Mg II (2796,2803A) quasar absorption line systems with 1,495,604 luminous red galaxies (LRGs) from the Fifth Data Release of the Sloan Digital Sky Survey within the redshift range 0.36<=z<=0.8. We confirm with high precision a previously reported weak anti-correlation of equivalent width and dark matter halo mass, measuring the average masses to be log M_h(M_[solar]h^-1)=11.29 [+0.36,-0.62] and log M_h(M_[solar]h^-1)=12.70 [+0.53,-1.16] for systems with W[2796A]>=1.4A and 0.8A<=W[2796A]<1.4A, respectively. Additionally, we investigate the significance of a number of potential sources of bias inherent in absorber-LRG cross-correlation measurements, including absorber velocity distributions and the weak lensing of background quasars, which we determine is capable of producing a 20-30% bias in angular cross-correlation measurements on scales less than 2'. We measure the Mg II - LRG cross-correlation for 719 absorption systems with v<60,000 km s^-1 in the quasar rest frame and find that these associated absorbers typically reside in dark matter haloes that are ~10-100 times more massive than those hosting unambiguously intervening Mg II absorbers. Furthermore, we find evidence for evolution of the redshift number density, dN/dz, with 2-sigma significance for the strongest (W>2.0A) absorbers in the DR5 sample. This width-dependent dN/dz evolution does not significantly affect the recovered equivalent width-halo mass anti-correlation and adds to existing evidence that the strongest Mg II absorption systems are correlated with an evolving population of field galaxies at z<0.8, while the non-evolving dN/dz of the weakest absorbers more closely resembles that of the LRG population.Comment: 21 pages, 19 figures; Published in Astrophysical Journa

Power laws of complex systems from Extreme physical information

Many complex systems obey allometric, or power, laws y=Yx^{a}. Here y is the measured value of some system attribute a, Y is a constant, and x is a stochastic variable. Remarkably, for many living systems the exponent a is limited to values +or- n/4, n=0,1,2... Here x is the mass of a randomly selected creature in the population. These quarter-power laws hold for many attributes, such as pulse rate (n=-1). Allometry has, in the past, been theoretically justified on a case-by-case basis. An ultimate goal is to find a common cause for allometry of all types and for both living and nonliving systems. The principle I - J = extrem. of Extreme physical information (EPI) is found to provide such a cause. It describes the flow of Fisher information J => I from an attribute value a on the cell level to its exterior observation y. Data y are formed via a system channel function y = f(x,a), with f(x,a) to be found. Extremizing the difference I - J through variation of f(x,a) results in a general allometric law f(x,a)= y = Yx^{a}. Darwinian evolution is presumed to cause a second extremization of I - J, now with respect to the choice of a. The solution is a=+or-n/4, n=0,1,2..., defining the particular powers of biological allometry. Under special circumstances, the model predicts that such biological systems are controlled by but two distinct intracellular information sources. These sources are conjectured to be cellular DNA and cellular transmembrane ion gradient

The 1995 Georges Bank Stratification Study and moored array measurements

The 1995 Geoges Bank Stratification Study (GBSS) was the first intensive process study conducted as part of the U.S. GLOBEC Northwest Atlantic/Georges Bank field program. The GBSS was designed to investigate the physical processes which control the seasonal development of stratification along the southern flank of Georges Bank during spring and summer. Past work suggested that during this period, larval cod and haddock tended to aggregate to the thermocline on the southern flank where higher concentrations of their copepod prey were found. A moored array was deployed as part of GBSS to observe the onset and evolution of sesonal stratification over the southern flank with sufficient vertical and horizontal resolution that key physical processes could be identified and quantified. Moored current, temperature, and conductivity (salinity) measurements were made at three sites along the southern flank, one on the crest, and one on the northeast peak of the bank. Moored surface meteorological measurements were also made at one southern flank site to determine the surface wind stress and heat and moisture fluxes. The oceanographic and meteorological data collected with the GBSS array during January-August 1995 are presented in this report. Meteorological data collected on National Data Buoy Center environmental buoys 44011 (Georges Bank), 44008 (Nantucket Shoals), and 44005 (Gulf of Maine) are included in this report for completeness and comparison with the GBSS southern flank meteorological measurements.Funding was provided by the National Science Foundation under Grant Numbers OCE-98-06379 and OCE-98-06445

Management Outcomes in Splenic Injury: A Statewide Trauma Center Review

OBJECTIVE: Clinical pathways now highlight both observation and operation as acceptable initial therapeutic options for the management of patients with splenic injury. The purpose of this study was to evaluate treatment trends for splenic injury in all North Carolina trauma centers over a 6-year period. METHODS: Splenic injuries in adults over a 6-year period (January 1988-December 1993) were identified in the North Carolina Trauma Registry using ICD-9-CM codes. Patients were divided into four groups by method of management: 1) no spleen operation, 2) splenectomy, 3) definitive splenorrhaphy, and 4) splenorrhaphy failure followed by splenectomy. The authors examined age, mechanism of injury, admitting blood pressure, and severity of injury by trauma score and injury severity score. SUMMARY BACKGROUND DATA: Comparisons were made between adult (17-64 years of age) and geriatric (older than 65 years of age) patients and between patients with blunt and penetrating injury. Resource utilization (length of stay, hospital charges) and outcome (mortality) were compared. RESULTS: One thousand two hundred fifty-five patients were identified with splenic injury. Rate of splenic preservation increased over time and was achieved in more than 50% of patients through nonoperative management (40%) and splenorrhaphy (12%). Splenorrhaphy was not used commonly in either blunt or penetrating injury. Overall mortality was 13%. Geriatric patients had a higher mortality and resource utilization regardless of their mechanism of injury or method of management. CONCLUSIONS: Nonoperative management represents the prevailing method of splenic preservation in both the adult and geriatric population in North Carolina trauma center hospitals. Satisfactory outcomes and economic advantages accompany nonoperative management in this adult population

The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific

The extinct giant shark Otodus megalodon is the last member of the predatory megatoothed lineage and is reported from Neogene sediments from nearly all continents. The timing of the extinction of Otodus megalodon is thought to be Pliocene, although reports of Pleistocene teeth fuel speculation that Otodus megalodon may still be extant. The longevity of the Otodus lineage (Paleocene to Pliocene) and its conspicuous absence in the modern fauna begs the question: when and why did this giant shark become extinct? Addressing this question requires a densely sampled marine vertebrate fossil record in concert with a robust geochronologic framework. Many historically important basins with stacked Otodus-bearing Neogene marine vertebrate fossil assemblages lack well-sampled and well-dated lower and upper Pliocene strata (e.g., Atlantic Coastal Plain). The fossil record of California, USA, and Baja California, Mexico, provides such an ideal sequence of assemblages preserved within well-dated lithostratigraphic sequences. This study reviews all records of Otodus megalodon from post-Messinian marine strata from western North America and evaluates their reliability. All post-Zanclean Otodus megalodon occurrences from the eastern North Pacific exhibit clear evidence of reworking or lack reliable provenance; the youngest reliable records of Otodus megalodon are early Pliocene, suggesting an extinction at the early-late Pliocene boundary (∼3.6 Ma), corresponding with youngest occurrences of Otodus megalodon in Japan, the North Atlantic, and Mediterranean. This study also reevaluates a published dataset, thoroughly vetting each occurrence and justifying the geochronologic age of each, as well as excluding several dubious records. Reanalysis of the dataset using optimal linear estimation resulted in a median extinction date of 3.51 Ma, somewhat older than a previously proposed Pliocene-Pleistocene extinction date (2.6 Ma). Post-middle Miocene oceanographic changes and cooling sea surface temperature may have resulted in range fragmentation, while alongside competition with the newly evolved great white shark (Carcharodon carcharias) during the Pliocene may have led to the demise of the megatoothed shark. Alternatively, these findings may also suggest a globally asynchronous extinction of Otodus megalodon