631 research outputs found
The Effect of Air Temperature on the Incubation Period and Hatching Success of In Situ Loggerhead Sea Turtle (Caretta caretta) Clutches in Broward County, Florida
The survival rates of pre-emergent sea turtle hatchlings are critically dependent upon temperature. This study aims to determine if changes in air temperature have influenced the incubation time and/or the survivorship of the pre-emergent loggerhead sea turtle (Caretta caretta) hatchlings for past sea turtle nesting seasons in Broward County. Air temperature data within the hatching seasons of 1999 to 2009 was obtained from the NOAA National Climatic Data Center’s Fort Lauderdale beach station. The loggerhead sea turtle hatching data collected by the Broward County Sea Turtle Conservation Program from the same time period was examined to assess the potential effects of air temperature on the hatching success and the incubation duration. This was performed primarily to determine if any trends or significance exist in the relationships among the aforementioned parameters. More specifically an analysis of trends in mean yearly sea turtle incubation durations was assessed and any correlations between incubation times and hatching success were also examined. Furthermore the relationship between incubation durations and mean seasonal and intraseasonal air temperature fluctuations was tested for significance. Preliminary results for this study have shown a significant upward trend in the seasonal average incubation durations from 2003 to 2009 (t-test, p \u3c 0.05). The mean incubation period for this study was 50.78 + 1.2 (mean + SD). Over the seasons the mean daily air temperature fluctuated between yearly averages of 23.3 and 26.9 °C and had an overall mean of 25.98 + 1.9 °C (mean + SD). Statistical analyses indicate a significant negative association between the incubation duration and the average daily air temperature (t-test, p \u3c\u3c 0.001). Further work pertaining to intra-seasonal analysis continues to be in progress. In Broward County alone, there was a continuous reduction in the number of loggerhead nests deposited each year throughout this study period. Determining if the effects of air temperature have significantly influenced loggerhead sea turtle clutches in Broward County might provide future insights for sustaining the survival rates of sea turtles in this area
Relativistic Corrections to the Sunyaev-Zel'dovich Effect for Clusters of Galaxies. IV. Analytic fitting formula for the Numerical Results
We present an accurate analytic fitting formula for the numerical results for
the relativistic corrections to the thermal Sunyaev-Zel'dovich effect for
clusters of galaxies. The numerical results for the relativistic corrections
have been obtained by numerical integration of the collision term of the
Boltzmann equation. The fitting is carried out for the ranges 0.02 < theta_{e}
< 0.05 and 0 < X < 20, where theta_{e} = k_{B}T_{e}/m_{e}c^{2}, X =
omega/k_{B}T_{0}, T_{e} is the electron temperature, omega is the angular
frequency of the photon, and T_{0} is the temperature of the cosmic microwave
background radiation. The accuracy of the fitting is generally better than
0.1%. The present analytic fitting formula will be useful for the analyses of
the thermal Sunyaev-Zel'dovich effect for high-temperature galaxy clusters.Comment: 11 pages + 1 table + 2 figures, LaTeX with AASMS macro. Accepted by
Astrophysical Journal for publicatio
Dewetting of Glassy Polymer Films
Dynamics and morphology of hole growth in a film of power hardening
viscoplastic solid (yield stress ~ [strain-rate]^n) is investigated. At
short-times the growth is exponential and depends on the initial hole size. At
long-times, for n > 1/3, the growth is exponential with a different exponent.
However, for n < 1/3, the hole growth slows; the hole radius approaches an
asymptotic value as time tends to infinity. The rim shape is highly asymmetric,
the height of which has a power law dependence on the hole radius (exponent
close to unity for 0.25 < n < 0.4). The above results explain recent intriguing
experiments of Reiter, Phys. Rev. Lett, 87, 186101 (2001).Comment: 4 pages, 5 figures, RevTe
Diurnal variation and size dependence of the hygroscopicity of organic aerosol at a forest site in Wakayama, Japan: their relationship to CCN concentrations
Formation of biogenic secondary organic aerosol (BSOA)
and its subsequent evolution can modify the hygroscopicity of the organic
aerosol component (OA) in the forest atmosphere, and affect the
concentrations of cloud condensation nuclei (CCN) there. In this study,
size-resolved aerosol hygroscopic growth at 85 % relative humidity and
size-resolved aerosol composition were measured using a hygroscopic tandem
differential mobility analyzer and an aerosol mass spectrometer,
respectively, at a forest site in Wakayama, Japan, in August and September
2015. The hygroscopicity parameter of OA (κorg) presented daily
minima in the afternoon hours, and it also showed an increase with the increase in particle dry diameter. The magnitudes of the diurnal variations in
κorg for particles with dry diameters of 100 and 300 nm were on
average 0.091 and 0.096, respectively, and the difference in κorg between particles with dry diameters of 100 and 300 nm was on
average 0.056. The relative contributions of the estimated fresh BSOA and
regional OA to total OA could explain 40 % of the observed diurnal
variations and size dependence of κorg. The hygroscopicity
parameter of fresh BSOA was estimated to range from 0.089 to 0.12 for
particles with dry diameters from 100 to 300 nm. Compared with the use of
time- and size-resolved κorg, the use of time- and
size-averaged κorg leads to under- and over-estimation of the
fractional contribution of OA to CCN number concentrations in the range from
−5.0 % to 26 %. This indicates that the diurnal variations and
size dependence of κorg strongly affect the overall
contribution of OA to CCN concentrations. The fractional contribution of
fresh BSOA to CCN number concentrations could reach 0.28 during the period
of intensive BSOA formation. The aging of the fresh BSOA, if it occurs,
increases the estimated contribution of BSOA to CCN number concentrations by
52 %–84 %.</p
Phenomenological theory of a scalar electronic order: application to skutterudite PrFe4P12
By phenomenological Landau analysis, it is shown that a scalar order
parameter with the point-group symmetry explains most properties
associated with the phase transition in PrFeP at 6.5 K. The
scalar-order model reproduces magnetic and elastic properties in
PrFeP consistently such as (i) the anomaly of the magnetic
susceptibility and elastic constant at the transition temperature, (ii)
anisotropy of the magnetic susceptibility in the presence of uniaxial pressure,
and (iii) the anomaly in the elastic constant in magnetic field. An Ehrenfest
relation is derived which relates the anomaly of the magnetic susceptibility to
that of the elastic constant at the transition.Comment: 16 pages, 9 figure
- …