Implementation of a marine reserve has a rapid but short-lived effect on recreational angler use

Changes in human behavior are a precursor to measurable impacts of no-take marine reserves. We investigated changes in recreational fishing site selection in response to the 2005 announcement of enforcement in a marine reserve in the Gulf of California, Mexico. We used a novel data set of daily self-reported boating destinations from emergency rescue logbooks for a recreational angling community from 2000 to 2008. Because the reserve system has no experimental control, we modeled the data two ways to test for robustness to model specification. We tested for changes in human fishing behavior with regression and fit a fleet-level discrete choice model to project a. counterfactual scenario. The counterfactual is the statistically constructed ex post expectation of the human behavior we would have observed if the reserve never existed. We included month and year fixed effects in our models to account for seasonal and interannual fluctuations in fishing behavior and catch rates. We detected a decrease in reserve use compared to the counterfactual, indicating that the reserve rapidly experienced a decrease in visitation. However, the reserve's effect to reduce trips diminished with time. These results indicate that the reserve is unlikely to meet its ecological goals without institutional changes that enhance compliance. This illustrates the value of human use data to understanding the processes underlying marine reserve function. We suggest that managers should consider human use with the same frequency, rigor, and tools as they do fishery stocks. Marine reserves directly affect people, and understanding human behavioral responses to marine reserves is an important step in marine reserve management.     

Sexual orientation harassment in the workplace: When do observers intervene?

Little is known about when and why observers of harassment incidents choose to intervene. On the basis of a model of observer intervention by Bowes‐Sperry and O'Leary‐Kelly (2005), we examined situational (directness of harassment, relationship to target, knowledge of target orientation, recurrence beliefs) variables as potential predictors of observer decisions to intervene when witnessing sexual orientation harassment. We also examined how costs and benefits analysis and recurrence beliefs relate to the level and immediacy of involvement. Relationship to the target, directness of the harassment, recurrence beliefs, knowledge of target orientation, and costs evidenced some connections to the nature of intervention. We discussed implications for organizations. Copyright © 2011 John Wiley & Sons, Ltd.     

Is natural hatching asynchrony optimal? An experimental investigation of sibling competition patterns in a facultatively siblicidal seabird

In unpredictable environments, any tactic that enables avian parents to adjust brood size and, thus, energy expenditure to environmental conditions should be favoured. Hatching asynchrony (HA), which occurs whenever incubation commences before clutch completion, may comprise such a tactic. For instance, the sibling rivalry hypothesis states that the hierarchy among chicks, concomitant to HA, should both facilitate the adjustment of brood size to environmental conditions and reduce several components of sibling competition as compared to synchronous hatching, at both brood and individual levels. We thus predicted that brood aggression, begging and feeding rates should decrease and that older chick superiority should increase with HA increasing, leading to higher growth and survival rates. Accordingly, we investigated the effects of an experimental upward and downward manipulation of HA magnitude on behaviour, growth and survival of black-legged kittiwake (Rissa tridactyla) chicks. In line with the sibling rivalry hypothesis, synchronous hatching increased aggression and tended to increase feeding rates by parents at the brood level. Begging rates, however, increased with HA contrary to our expectations. At the individual level, as HA magnitude increased, the younger chick was attacked and begged proportionally more often, experienced a slower growth and a higher mortality than its sibling. Overall, the occurrence of energetic costs triggered by synchronous hatching both for parents and chicks, together with the lower growth rate and increased mortality of the younger chick in highly asynchronous broods suggest that natural HA magnitude may be optimal.     

Partitioning tracer tests as a remediation metric: Case study at naval amphibious base little creek,Virginia Beach,Virginia

The partitioning tracer test (PTT) is a characterization tool that can be used to quantify the porespace saturation (S_N) and spatial distribution of dense nonaqueous phase liquids (DNAPLs) in the subsurface. Because the method essentially eliminates data interpolation errors by directly measuring a relatively large subsurface volume, it offers significant promise as a remediation metric for DNAPL‐zone remediation efforts. This article presents, in detail, the design and results of field PTTs conducted before and after a DNAPL‐zone treatment at the Naval Amphibious Base Little Creek, Virginia Beach, Virginia. The results from different tracers yield a relatively large range in S_N estimates, indicating notable uncertainty and presenting significant challenges for meaningful interpretation. Several potential interpretation methods are presented, resulting in an estimated DNAPL removal range of 15 to 109 L. While this range is large, it is consistent with the DNAPL removal (～30 L) determined from analysis of effluent concentration measurements collected during the remediation efforts. At this site, the initial and final S_N values are low, and the relatively inconsistent performance of the various tracers indicates that these levels are near the lower practical quantification limit for these PTTs; however, the effective lower quantification limit for these tests is unknown. Generally, an understanding of lower quantification limits is particularly important for interpretation of post‐remediation PTTs because S_N values are likely to be low (due to remediation efforts) and the S_N estimated from the PTT may be used to predict long‐term dissolved plume behavior and assess associated environmental risk. Partitioning tracer test quantification limits are test‐specific, as they are dependent on a variety of factors including analytical uncertainty, tracer breakthrough characteristics, and tracer data integration techniques. The results of this case study indicate that methods for estimating lower quantification limits for field PTTs require further development. © 2004 Wiley Periodicals, Inc.     

ESTIMATION OF SOIL MOISTURE FROM SEASAT SAR DATA1

ABSTRACT A study was made to determine if Seasat Synthetic Aperture Radar (SAR) data could be used to make practical estimates of soil moisture. Extensive ground measurements were collected at two primary sites near Guymon, Oklahoma, and Sublette, Kansas. The relative sensitivity of the SAR to differences in soil moisture, tillage roughness, and vegetation was determined. To validate the effects detected in the SAR data, an airborne scatterometer with a similar wavelength was flown repeatedly over the Guymon site. Soil moisture variations in the surface 2 cm and surface 15 cm of fields with bare soil, milo and alfalfa produce similar responses in the scattering coefficient from both systems. Roughness due to tillage in row crops produced as much as 12–15 dB increase in the scatterometer return. Most agricultural vegetation was effectively penetrated by the L-band frequencies; however, corn produced an exceptionally high radar return either standing or after combine harvesting. When corn had ripened, there was some evidence that tillage roughness could be detected through the canopy. Moderate tillage roughness produced by grain drill furrows caused over 12 dB increase in return when row directions changed from parallel to perpendicular with respect to the SAR look direction. Dramatic increases in return occurred when vegetation surfaces were wet. Increased radar returns from tillage roughness, some vegetation and wet vegetation surfaces, all dyanmic in nature, were significant and may limit the practical estimation of soil moisture from the radar data.     

Explosions in closed pipes containing baffles and 90 degree bends

There is a general lack of information on the effects of full-bore obstacles on combustion in the literature, these obstacles are prevalent in many applications and knowledge of their effects on phenomena including burning rate, flame acceleration and DDT is important for the correct placing of explosion safety devices such as flame arresters and venting devices. In this work methane, propane, ethylene and hydrogen–air explosions were investigated in an 18 m long DN150 closed pipe with a 90 degree bend and various baffle obstacles placed at a short distance from the ignition source. After carrying out multiple experiments with the same configuration it was found that a relatively large variance existed in the measured flame speeds and overpressures, this was attributed to a stochastic element in how flames evolved and also how they caused and interacted with turbulence to produce flame acceleration. This led to several experiments being carried out for one configuration in order to obtain a meaningful average. It was shown that a 90 degree bend in a long tube had the ability to enhance flame speeds and overpressures, and shorten the run-up distance to DDT to a varying degree for a number of gases. In terms of the qualitative effects on these parameters they were comparable to baffle type obstacles with a blockage ratios of between 10 and 20%.     

A noninvasive demographic assessment of sea lions based on stage-specific abundances

A pressing need exists to develop new approaches for obtaining information on demographic rates without causing further threats to imperiled animal populations. In this paper, we illustrate and apply a data-fitting technique based on quadratic programming that uses stage-specific abundance data to estimate demographic rates and asymptotic population growth rates (lambda). We used data from seven breeding colonies of California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Estimates of lambda were similar to those from previous studies relying on a diffusion approximation using trends in total abundance. On average, predicted abundances were within 24% of the observed value for the inverse estimation method and within 29% of the observed value for the diffusion approximation. Our results suggest that three of the seven populations are declining (lambda < 1), but as many as six may be at risk. Elasticity and sensitivity analyses suggest that population management in most sites should focus on the protection of adults, whose survival generally contributes the most to lambda. The quadratic programming approach is a promising noninvasive technique for estimating demographic rates and assessing the viability of populations of imperiled species.     

The influence of cosolvent and heat on the solubility and reactivity of organophosphorous pesticide DNAPL alkaline hydrolysis

The presented research concerned the compatibility of cosolvents with in situ alkaline hydrolysis (ISAH) for treatment of organophosphorous (OPP) pesticide contaminated sites. In addition, the influence of moderate temperature heat increments was studied as a possible enhancement method. A complex dense non-aqueous phase liquid (DNAPL) of primarily parathion (~50 %) and methyl parathion (~15 %) obtained from the Danish Groyne 42 site was used as a contaminant source, and ethanol and propan-2-ol (0, 25, and 50 v/v%) was used as cosolvents in tap water and 0.34 M NaOH. Both cosolvents showed OPP solubility enhancement at 50 v/v% cosolvent content, with slightly higher OPP concentrations reached with propan-2-ol. Data on hydrolysis products did not show a clear trend with respect to alkaline hydrolysis reactivity in the presence of cosolvents. Results indicated that the hydrolysis rate of methyl-parathion (MP3) decreased with addition of cosolvent, whereas the hydrolysis rate of ethyl-parathion (EP3) remained constant, and overall indications were that the hydrolysis reactions were limited by the rate of hydrolysis rather than NAPL dissolution. In addition to cosolvents, the influence of low-temperature heating on ISAH was studied. Increasing reaction temperature from 10 to 30 °C provided an average rate of hydrolysis enhancement by a factor of 1.4–4.8 dependent on the base of calculation. When combining 50 v/v% cosolvent addition and heating to 30 °C, EP3 solubility was significantly enhanced and results for O,O-diethyl-thiophosphoric acid (EP2 acid) showed a significant enhancement of hydrolysis as well. However, this could not be supported by para-nitrophenol (PNP) data indicating the instability of this product in the presence of cosolvent.