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451.
Hugh Drummond Roxana Torres Cristina Rodríguez Juarez Sin-Yeon Kim 《Behavioral ecology and sociobiology》2010,64(4):647-655
In multitudinous breeding colonies, kin interactions could go unnoticed because we are unaware of the kinship among adults
we observe. Evidence of cooperation and competition between close adult kin in a blue-footed booby colony was sought by analyzing
patterns of natal dispersal and proximity of nests. Male and female recruits nested closer to their own natal sites than to
their parents’ current sites. Males (only) dispersed less far when both parents were present than when no parent or one parent
was present, but not selectively close to fathers versus mothers when these were divorced. Neither parental presence nor parental
proximity affected breeding success of recruits of either sex. Although distances between the nests of simultaneously recruiting
broodmates were unrelated to their sex, males dispersed 13.1 m less when a sister was present than when a brother was present.
Neither sex was affected in its dispersal distance by the presence or hatching order/dominance of a broodmate. Neither sex
was affected in its breeding success by the presence versus absence of a broodmate, although female success increased with
proximity of their brothers. Parents and sisters may actively or passively help males establish their first territories near
their natal sites and nearby brothers may help females in their first breeding attempts; otherwise, boobies do not influence
each other’s natal dispersal and first breeding success. It appears that boobies do not nest selectively close to or far from
their parents, offspring, or broodmates. Why there is apparently so little cooperation and altruism between close adult relatives
in booby colonies is puzzling. 相似文献
452.
Over-stabilisation and eutrophication affect many dune systems in north-west Europe. This leads to lower diversity of typical dune species and an accumulation of soil nutrients. Existing management techniques to remove excess nutrients include mowing, with removal of cuttings, and turf stripping. A new restoration technique called topsoil inversion or deep ploughing may also be able to counter some of the negative effects of eutrophication. It simulates the burial of established soils with fresh mineral sand, by inverting the soil profile. A trial was carried out on two small blocks of eutrophic dune grassland in North Wales, UK. Nutrient-rich surface soils were buried beneath mineral sub-sand using a double-bladed plough, designed to plough to depths of up to 100 cm. Results show that the organic soil horizons were buried to a depth of 80 cm, and covered with 40–50 cm of mineral sand. The pH and organic matter of the surface layers became comparable to those of mobile dunes. Fifteen months after ploughing, bare sand cover was still 70–90%, but significant sand loss through wind erosion resulted in a thinning of the mineral sand over-burden, leaving the buried organic layer closer to the surface. Natural vegetation colonisation was slow, with the first surviving plants observed after 8 months. The majority of species present at 15 months were present before ploughing and had regenerated from rhizomes or root fragments. The effect of excluding disturbance caused by rabbits, people and dogs was assessed within fenced areas. After 11 months, vegetation cover was greater in the fenced areas than in plots exposed to disturbance, therefore disturbance replaced physical conditions as the dominant influence on plant growth and establishment. These early results suggest the trial has been partially successful, but that topsoil inversion could be combined with other methods such as turf stripping or by stabilisation of the ploughed surface by planting with pioneer species, depending on the ultimate restoration goal. 相似文献
453.
Un Bong Baek Kwon Sang Ryu Amkee Kim Seung Hoon Nahm 《Journal of Loss Prevention in the Process Industries》2009,22(6):971-974
Many researchers have been interested in the nondestructive measurement methods for estimating components damage in order to assure the safe service of steel structures. It is recognized that the evaluating techniques based on magnetic measurement can offer a great potential because of high susceptibility to the change of several metallurgical factors. Magnetic property such as coercive force was measured. The coercive force at room temperature monotonously increased with the increase of frequency. The correlation between the magnetic properties of used material and that of un-used material was studied. The coercive force gradient at room temperature increased with the increase of aging. Hence the estimating method using magnetic properties allows one to evaluate the extent of material aging for reactor pressure vessel. 相似文献
454.
Seong Kon Lee Gento Mogi Jong Wook Kim 《Journal of Loss Prevention in the Process Industries》2009,22(6):915-920
To provide national energy security in the 21st century, establishing a long-term strategic energy technology development is essential through selection and specialization. We established a strategic energy technology roadmap (ETRM) taking economic spin-offs, commercial potential, inner capacity, and technical spin-off into account. In this research, we suggest an integrated multi-criteria decision making (MCDM) approach, which is composed of more than two criteria as the assessment of the optimal alternatives and solutions in the real world with the fuzzy theory and analytic hierarchy process (AHP), to prioritize the weights of energy technologies of ETRM as we allocate R&D budget using a fuzzy analytic hierarchy process. Building technology is the most preferred technology in the sector of energy technologies against high oil prices. And the coal technology and transportation technology follows and take the 2nd and 3rd place with the fuzzy AHP approach. 相似文献
455.
J.S. Kim W. Yang Y. Kim S.H. Won 《Journal of Loss Prevention in the Process Industries》2009,22(6):943-949
As an effort to improve the prediction of hydrogen dispersion in the atmosphere, effects of buoyancy acting on the hydrogen jets formed by releasing from high pressure vessels are investigated analytically and experimentally. For the analytical study, an integral analysis for buoyant jets and flames is carried out to yield the closed formula describing the jet and flame shapes, including their trajectory and horizontal and vertical lengths corresponding to the critical concentrations. Because the density of hydrogen after releasing from high pressure storage conditions is much close to that of helium than that of hydrogen at room temperature, helium is used as the hydrogen surrogate for the buoyant jet experiments, which were performed by visualizing the jet dispersing in the atmosphere up to the jet Reynolds number Re ~ 2400. The trajectories obtained by the integral analysis and experiments agree relatively well until the transition to turbulence occurs. A further estimate for jets and flames is made by using the integral analysis as a preliminary design to the experiments involving a much greater hydrogen release. Once the comparative investigation of the larger scale experiments with the integral analysis, we anticipate that a more universal hydrogen jet and flame data can be obtained, which perhaps leads to a better safety distance of hydrogen stations. 相似文献
456.
Sung-Wook Yoon Dong-Ho Rie Ha-Young Kim 《Journal of Loss Prevention in the Process Industries》2009,22(6):954-957
The aim of this research is to find the optimum smoke extraction rate through the ventilation shaft in case of a fire in a long road tunnel. Furthermore, it is also investigated whether the current emergency ventilation design practice using a vertical shaft can limit the smoke propagation from a fully loaded gasoline tank lorry fire. For this research, scaled model experiments were carried out using a 20 m- long model tunnel with a vertical shaft. A CFD modeling tool was also extensively utilized to investigate the extremely dangerous situation in which a fully loaded gasoline tank lorry is burning inside a long road tunnel. 相似文献
457.
This study investigated efficiency of in situ enhanced biological denitrification of nitrate-contaminated groundwater which employs a well-to-well circulation in a shallow zone where oxygen might give an adverse affect on the denitrification processes. The numerical model developed for the efficiency test included sequential aerobic and nitrate-based respiration, multi-Monod kinetics of reactive components, growth and decay of biomass, and denitrification inhibition associated with the presence of oxygen. Moreover, reaction kinetics for production of toxic intermediates such as nitrite and nitrous oxide were also included in the model. The developed model was applied to the analysis of enhanced in situ denitrification using an injection/extraction well pair. To evaluate the relative remediation effectiveness, comparisons were made between a continuous fumarate injection test (CFIT) system and a pulsed fumarate injection test (PFIT) system, where both systems had the same total fumarate mass injected into the aquifer. The PFIT system was preferable to the CFIT system because of the high possibility of occurrence of clogging in the latter case at the injection well, with no other significant advantages found in either the CFIT or the PFIT system. Accordingly, this developed numerical model is useful to predict and evaluate an in situ bioremediation by denitrification in aquifers. 相似文献
458.
Studies show that Whites tend to show the lowest level of support for affirmative action (AA) policies. Opponents of AA often argue that this is because it violates principles of meritocracy. However, self‐interest (based on social identification with those adversely affected) could also explain their opposition. In three studies, we varied whether an Asian or White male is adversely affected by AA to test another explanation; namely, that Whites' fairness judgments are based on both the adversely affected person's race and the fairness evaluator's ideological beliefs. Although we found some support for the meritocratic explanation, this was not sufficient to explain why Whites view AA as (un)fair. Instead, we found strong support for our prediction that Whites who are opposed to equality perceive more unfairness when a White (vs. Asian) was harmed by AA, whereas Whites who endorse egalitarian ideologies perceive the opposite. This finding suggests that neither self‐interest nor meritocratic explanations can fully account for Whites' opposition to AA. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
459.
Sang-Keun Song Zang-Ho Shon Ki-Hyun Kim 《Atmospheric environment (Oxford, England : 1994)》2009,43(18):3015-3023
The photochemical oxidation and dispersion of reduced sulfur compounds (RSCs: H2S, CH3SH, DMS, CS2, and DMDS) emitted from anthropogenic (A) and natural (N) sources were evaluated based on a numerical modeling approach. The anthropogenic emission concentrations of RSCs were measured from several sampling sites at the Donghae landfill (D-LF) (i.e., source type A) in South Korea during a series of field campaigns (May through December 2004). The emissions of natural RSCs in a coastal study area near the D-LF (i.e., source type N) were estimated from sea surface DMS concentrations and transfer velocity during the same study period. These emission data were then used as input to the CALPUFF dispersion model, revised with 34 chemical reactions for RSCs. A significant fraction of sulfur dioxide (SO2) was produced photochemically during the summer (about 34% of total SO2 concentrations) followed by fall (21%), spring (15%), and winter (5%). Photochemical production of SO2 was dominated by H2S (about 55% of total contributions) and DMS (24%). The largest impact of RSCs from source type A on SO2 concentrations occurred around the D-LF during summer. The total SO2 concentrations produced from source type N around the D-LF during the summer (a mean SO2 concentration of 7.4 ppbv) were significantly higher than those (≤0.3 ppbv) during the other seasons. This may be because of the high RSC and SO2 emissions and their photochemistry along with the wind convergence. 相似文献
460.
Chul H. Song Mi E. Park En J. Lee Jae H. Lee Bo K. Lee Dong S. Lee Jhoon Kim Jin S. Han Kwang J. Moon Yutaka Kondo 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2168-2173
Simultaneous measurements of gaseous species and fine-mode, particulate inorganic components were performed at the University of Seoul, Seoul in Korea. In the simultaneous measurements, a certain level of nitrous acid (HONO) was observed in the gas-phase, indicating possible heterogeneous HONO production on the surface of the ambient aerosols. On the other hand, high particulate nitrite (NO2?) concentrations of 1.41(±2.26) μg/m3 were also measured, which sometimes reached 18.54 μg/m3. In contrast, low HONO-to-NO2 ratios of 0.007(±0.006) were observed in Seoul. This indicates that a significant fraction of HONO is dissolved in atmospheric aerosols. Around the Seoul site, sufficient alkalinity may have been provided to the atmospheric aerosols from the excessive presence of NH3 in the gas-phase. Due to the alkaline particulate conditions (defined in this study as a particle pH >~3.29), the HONO molecules produced at the surface of the atmospheric aerosols appeared to have been converted into particulate nitrite, thereby preventing their further participation in the atmospheric O3/NOy/HOx photochemical cycles. It was estimated that a minimum average of 65% of HONO was captured by alkaline, anthropogenic, urban particles in the Seoul measurements. 相似文献