Loggerhead sea turtle nesting in North Carolina: Applications of an aerial survey

Aerial surveys of the beaches of North Carolina were performed during two consecutive summers. From these surveys the first comprehensive picture of the relative density and distribution of loggerhead sea turtle nesting efforts in North Carolina was developed. The results of the 1981 survey were compared with those of concurrent ground surveys on several beaches in an attempt to obtain an accurate conversion factor for estimating total seasonal nesting activity from the aerial samples. It was concluded that an aerial survey is useful for determining relative density and distribution of nesting attempts. However, differential retention of crawl tracks on individual beaches precluded using aerial crawl surveys for total population estimates.     

Modeling the Effects of Environmental Factors on the Population of Fusarium oxysporum in Cucumber Continuously Cropped Soil

The influences of soil environmental parameters (water potential [W_p], pH, and temperature) on the indigenous population of Fusarium oxysporum (FO) over 5 years of continuously cropped cucumber (CCC) soil were studied. The use of response surface methodology to model the combined effects of environmental parameters on the soil log₁₀ FO internal transcribed spacer copies (ITSC) showed that high W_p of the soil, above –20 kPa, caused increased ITSC in the soil that was independent of the temperature and pH. Fusarium oxysporum was able to grow at all temperatures and pH values tested, and the greatest growth rate was observed at 23–24 °C and pH 5.3–5.4. The W_p is a crucial environmental factor that affects the growth of soil FO. This study should contribute to estimating the impact of environmental factors on the soil FO proliferation rate in CCC soil.     

Rodent control and food supplementation increase productivity of endangered San Clemente Loggerhead Shrikes (Lanius ludovicianus mearnsi)

Habitat loss and predation by exotic predators have contributed to the decline of many island populations of birds, including San Clemente Loggerhead Shrikes (Lanius ludovicianus mearnsi). This critically endangered subspecies has been the recipient of an extensive and expensive recovery effort, including a captive breeding and release program. We examined the effects of life-history characteristics, rainfall, and management, particularly food supplementation and rat (Rattus rattus) control, on the breeding productivity of 172 San Clemente Loggerhead Shrike pairs from 2000 to 2006. Annual fecundity and the number of fledglings reaching independence per pair varied with year and were closely correlated with prebreeding (November-March) precipitation levels. Annual fecundity increased as a result of management implemented between April and July each year. Shrike pairs receiving no management during this period produced a mean of 1.9 fledglings. Pairs receiving both food and rat control produced an average of 2.5 more fledglings than pairs receiving no management, while pairs receiving rat control alone produced an average of 1.1 more fledglings than pairs receiving no management during this period. Wild-origin females produced an average of 0.8 more fledglings per pair than captive-origin females, while older males produced an average of 0.9 more fledglings and independent young relative to inexperienced males. The effects of food supplementation and rat control on San Clemente Loggerhead Shrikes were most pronounced during dry years, suggesting such management should be emphasized when prebreeding precipitation levels are below historical averages. These techniques offer an effective means to increase breeding productivity of avian species in immediate threat of extinction.     

生态沟渠对中华鳖温室养殖排放水体的净化效果

研究采用生态沟渠技术体系——"水生植物(凤眼莲,Eichhornia crassipes)-微生物(枯草芽孢杆菌,Bacillus subtilis)-水生动物(螺蛳,Margarya)"共生系统联合净化处理中华鳖温室养殖排放水体,并连续数月采样分析处理污水中各项主要营养盐污染物指标的动态变化规律。结果表明:经过近5个月的生态沟渠技术体系处理,中华鳖温室养殖排放水体中总氮(TN)浓度减少75%,铵氮(NH4+-N)浓度减少91%,总磷(TP)浓度减少83%,化学需氧量(CODCr)减少62%,溶解氧(DO)增加近4倍,水体酸碱度(pH)维持在中性水平,处理污水由初始的黄色或棕色、浑浊逐渐转变为微黄色、微浑浊,且无异味。由此可知,利用生态沟渠技术体系——"水生植物-微生物-水生动物"共生系统联合修复中华鳖温室养殖排放水体效果显著,具有良好的推广和应用前景。     

Estimation of a Finite Population Mean and Total Using Population Ranks of Sample Units

This paper introduces new estimators for population total and mean in a finite population setting, where ranks (or approximate ranks) of population units are available before selecting sample units. The proposed estimators require selecting a simple random sample and identifying the population ranks of sample units. Selection of the sample can be performed with- or without-replacement. The population ranks of the selected units of with-replacement samples are determined among all population units. On the other hand, the ranks of the sample units of without-replacement samples are identified in two different ways: (1) The rank of a sample unit is determined sequentially among the remaining population units after excluding all previously ranked sample units from the population; (2) The ranks are determined among all units in the population. By conditioning on these population ranks, we construct a set of weighted estimators, develop a bootstrap re-sampling procedure to estimate the variances of the estimators, and construct percentile confidence intervals for the population mean and total. We show that the new estimators provide a substantial amount of efficiency gain over their competitors. We apply the proposed estimators to estimate corn production in one of the counties in Ohio.     

Size Guide Number and Rosin–Rammler Approaches to describe Particle Size Distribution of Granular Organic-based Fertilisers

The physical properties of organic-based fertilisers are not well known. The main objective of this study was to evaluate the range of granule size distributions of organic-based fertilisers and compare five approaches used to describe their size distribution: (1) the size guide number N_SG and uniformity index; (2) the size range variation coefficient; (3) the uniformity coefficient; (4) the geometric standard deviation of the particle size diameter; and (5) the Rosin–Rammler function. Six mineral (MF), four bulk-blended organic-based (BOF), and ten compound organic-based fertilisers (COF) were studied. Standard N_SG boxes and Tyler sieves were used to measure their granule size distribution. The size guide number ranged from 200 to 246 for MF, from 204 to 216 for BOF and from 99 to 255 for COF. The uniformity index was higher for slow release MF and for COF with N_SG>210. All five distribution parameters separated the fertilisers into similar groups. The coefficient of uniformity was the least discriminating approach in grouping the fertilisers, while the geometric standard deviation and size range variation provided similar results and the Rosin–Rammler approach was the most discriminating. The N_SG and uniformity index were estimated with the Rosin–Rammler function. Comparisons between estimated and measured size guide numbers indicated that the Rosin–Rammler function performs better for MF and for spherical granule shapes. Differences between the uniformity index values were greater for BOF, COF, and for cylindrical-shaped granules. The Rosin–Rammler function was not accurate for homogeneous and binomial particle size distributions, or for cylindrical granule shapes. However, in all other cases, this function was more precise and presented many advantages over the other methods, including the fact that it covers the entire range of particle sizes and can be used to estimate other parameters.     

Multi-Site Integrated Population Modelling

We examine the performance of a method of integrated population modelling for the joint analysis of different types of demographic data on individuals that exist in, and move between, different sites. The value of the approach is demonstrated by a simulation study which shows substantial improvement in parameter estimation when site-specific census data are combined with demographic data. The multivariate normal approximation to a multi-state mark-recapture likelihood is evaluated, and the performance of a diagonal variance-covariance matrix for the approximation is also examined. The work is motivated by a study of great cormorants. Analysis of the cormorant data suggests that breeders survive better than non-breeders, and also that probabilities of recruitment to breeding have been declining over time for all the colonies of the study. Supplementary material, including notes on the computation of standard errors and extended simulation results, are available online.     

Estimation of Population Mean and Total in a Finite Population Setting Using Multiple Auxiliary Variables

This paper introduces a new sampling design in a finite population setting, where potential sampling units have a wealth of auxiliary information that can be used to rank them into partially ordered sets. The proposed sampling design selects a set of sampling units. These units are judgment ranked without measurement by using available auxiliary information. The ranking process allows ties among ranks whenever units cannot be ranked accurately with high confidence. The ranking information from all sources is combined in a meaningful way to construct strength-of-agreement weights. These weights are then used to select a single sampling unit for full measurement in each set. Three different levels of sampling design, level-0, level-1, and level-2, are investigated. They differ in their replacement policies. Level-0 sampling designs construct the sample by sampling with replacement, level-1 sampling designs constructs the sample without replacement of the fully measured unit in each set, and level-2 sampling designs construct the sample without replacement on the entire set. For these three designs, we estimate the first and second order inclusion probabilities and construct estimators for the population total and mean. We develop a bootstrap resampling procedure to estimate the variances of the estimators and to construct percentile confidence intervals for the population mean and total. We show that the new sampling designs provide a substantial amount of efficiency gain over their competitor designs in the literature.     

噶顺戈壁地表砾石粒度特征分析

对戈壁表面砾石粒径的研究,可帮助了解戈壁特征,分析戈壁造成自然灾害的原因,认识沙粒迁移、沙漠扩展以及指导防沙工程.本研究结合野外调查,分析噶顺戈壁洪积扇21个样点砾石的粒度组成、平均粒径、分选系数、偏度和峰度等粒度特征.结果表明:1)受洪水、重力与风蚀等作用的影响,戈壁地表砾石均以中砾为主(66.35％～95.04％).海拔最高处以石质为主(85.54％),平均粒径φ值为-9.09 (545.2 mm).砾石质量分数呈现出随海拔增加,中砾质量分数降低,而粗砾质量分数升高的趋势.2)粒度特征为:平均粒径φ值变化范围为-9.09(545.2mm)～-6.15 (153.9 mm);除样点12为分选中等外,其余样点的均处于分选较好以上水平(0.28 ～0.53);偏度以负偏为主导(80.95％),地表以细砾和中砾等细粒径砾石为主;峰度中,宽平和很宽平占整体的57.14％,中等占23.81％,尖窄和极尖窄占19.05％,显示砾石分布相对较均匀,在不同位置的砾石,具有微弱的地表过程差异性.3)分选系数与平均粒径之间,无明显的相关关系;而偏度与平均粒径间,存在正相关关系.研究结果对物源的岩性及戈壁发育环境具有重要的指示意义.     

Comparison of Activated Sludge Technologies by Particle Size Analysis

This paper analyses the influence of activated sludge technologies on the Particle Size Distribution (PSD) of urban wastewater treatment plants operating under real conditions. The activated sludge treatment systems selected for the analysis are the most widely used in wastewater treatment installations: (a) double step activated sludge, (b) medium load activated sludge, (c) prolonged aeration, and (d) membrane bioreactors The main quality parameters (suspended solids, turbidity, and COD) and PSD in the influent and effluent of each different activated sludge treatment were analyzed during 1?year. The PSD was fitted using the power law ( $ n\left( {{d_{\text{P}}}} \right) = \frac{{\partial {\text{N}}\left( {{d_{\text{p}}}} \right)}}{{\partial {d_{\text{p}}}}} = A \cdot d_{\text{p}}^{{ - b \cdot {\text{Log}}\left( {{d_{\text{p}}}} \right)}} $ ) obtaining coefficients A and b to define the particle distribution. Mathematical correlations between this coefficients and the rest of parameters studied were found $ \left( {\matrix{ {{\text{SS}} = {0}{.0126} \cdot {A^{{{0}{.781}}}},} &{{\text{Turbidity}} = 15.5814 + 1.164 \cdot {{10}^3} \cdot A{,}} &{{\text{COD}} = \frac{{1}}{{{0}{.0133} + \cdot \frac{{{49}{.85}}}{\text{A}}}}} \\ }<!end array> } \right) $ . The relation with the average particle size by mass was also found, ( $ {d_{\text{pma}}} = - 11.6502 + \frac{{50.4265}}{b} $ ). Moreover, a relation between PSD and the particle elimination efficiency of the secondary treatment was study, ( $ \eta = 0.1434 - \frac{{0.5602}}{{{A_{\text{rel}}}}} + \frac{{0.7490}}{{{b_{\text{rel}}}}} $ ). Finally, the particulate matter nature was assessed by SEM-EDX. It can be concluded that membrane bioreactor is the technology that produces the best water quality effluent due to physic process of particle separation by ultrafiltration membrane technology.     

乌鲁木齐城市土壤粒度特征分析

土壤粒度组成是土壤重要的物理特性之一,对提高绿洲城市土壤抗风蚀能力、持水能力和土壤养分等有重要意义。研究选用乌鲁木齐城市不同区域的45个表土样品,利用激光衍射粒度仪和扫描电镜分析土壤粒度特征。结果表明:1)研究区表层土壤颗粒中砂粒含量偏低,粉粒含量最大,不同采样区同粒级间含量差异性不大。2)研究区土壤颗粒总体较细,分选性差,偏度为正偏态近对称型,峰度为中等窄峰态。粒度参数的空间分布规律为城南平均粒径高于城北,分选系数与平均粒径变化趋势类似,样品多为正偏,建设用地土样的偏度值从北部到南部呈下降趋势,多数样地峰态值偏高。3)研究区土壤粒度频率分布曲线由近似正态分布的单峰和非正态分布的多峰构成,其中农用地样品为单峰曲线,表明沉积物存在单成因组分,而建设用地和未利用地为多峰,说明存在多成因组分。同时发现典型样点的电镜图与粒级含量分布结果具有相似性和一致性。     

Modeling of changes in tumor burden

Skin painting studies on transgenic mice have recently been approved by the Food and Drug Administration (FDA) for carcinogenicity testing. Data consist of serial skin tumor counts on the backs of shaved mice in each of several dose groups. Current methods for assessing the tumorigenicity of test compounds are based on generalized estimating equations and require large samples. This paper proposes a new framework for modeling of the change over time in the papilloma burden in each mouse. A latent variable underlying the observed papilloma response is assumed to follow a generalized linear mixed-effects transition model. The model accounts for heterogeneity among animals and serial dependency in the skin tumor counts. Extensions of existing Markov chain Monte Carlo procedures for Bayesian estimation in generalized linear mixed models are proposed. The methods are applied to data from a National Toxicology Program short-term carcinogenicity study of lauric acid.     

不同风沙土壤颗粒的分形特征

应用土壤颗粒的重量与粒径分布原理来描述了古尔班通古特沙漠地风沙土壤颗粒的分形特征。通过对10种样品颗粒的机械组成进行分析,分别计算出了它们的分形维数(D=2.3237～2.9347),并分析了其与流动风沙土、半固定风沙土和固定风沙土之间的关系。分析结果表明,风沙土壤结构具有明显的分形特征,其粒径分布分形维数为2～3。土粒表面分形维数与2～0.2mm间的土粒含量存在显著的负相关;而与0.02～0.002mm和<0.002mm的颗粒含量存在显著的正相关,表现为随着土壤质地从流动风沙土、半固定风沙土到固定风沙土的变化,其土粒表面的平均分形维数呈依次增高。土粒表面分形维数与三种典型风沙土壤有机质含量为极显著正相关,而与其硬度为显著负相关。     

Effect of Soil Sample Size on Saturated Soil Hydraulic Conductivity

Saturated hydraulic conductivity (K_sat) is regarded as a key soil physical variable to determine soil infiltration rate, percolation depth and other hydrological processes. The purpose of this study was to determine the best soil sampling’s ring size for measuring K_sat. For this purpose, 25 rings with five different diameters (2, 3, 4, 5 and 6 inch) and with the same depth of 20 cm (five replicates) were hammered in close vicinity to each other into the ground of undisturbed loess deposits of a small farm to measure K_sat and bulk density. Hydraulic conductivity was measured at three constant loads of 22, 27 and 32 cm. The results showed that the ring with the internal diameter of 6 inches had the minimum variation coefficient and maximum K_sat for all the three hydraulic heads. In addition, the bulk density of this ring size was less than the other rings.     

Sequentially Extracted Arsenic from Different Size Fractions of Contaminated Soils

Five soils from Austria that have high contents of arsenic (As)due to anthropogenic and/or geogenic sources were separated intosand, silt, and clay fractions. The distribution of As among theparticle-size fractions was clay >> silt > sand. Theparticle-size fractions were analysed according to an 8-stepsequential extraction procedure (SEP) designed to assess theprimary reservoirs and extractability of As. Steps 1 and 2,(i.e. NH₄NO₃ and (NH₄)₂SO₄) extractedthe least As, while considerably greater amounts were extractedin steps 3, 4 and 5 (i.e. NH₄H₂PO₄,NH₂OH-HCl, and NH₄F). The greatest amounts of As wereextracted in steps 6 and 7, both NH₄-oxalate extractantstargeting the amorphous and crystalline oxide fractions. Theresidual fraction (step 8) was typically low. The extraction ofthe clays contained generally more As in steps 3 to 8, while Asrelease in the first two steps was typically highest in the sandand silt fractions. These findings are in accord with factoranalysis indicating that the extractants of the SEP areseparated into weak (steps 1 and 2) and strong (steps 3 to 8)extractants. SEP data along with microprobe analyses (X-raymicroanalyses) indicate that most As is associated with Fe andis therefore not readily mobile. Anyhow, As could be releasedupon changes in redox potential or pH. The greaterextractability of As from sand fractions using weak extractantsmay explain the higher toxicity of As in coarse-textured soils,as found in previous studies.     

Size and charge characteristics of kaolinitic soils in SE Queensland

Some kaolinitic soils derived from basaltic material contain 2:1 minerals as a discrete phase and/or interstratified with kaolin as determined by X-ray diffraction (XRD) and by chemical analysis of DCB-treated clays, while others show little or no evidence of 2:1 minerals. Mineral impurities were not detected by electron diffraction in the latter group. There is good agreement between the interpretation of XRD traces and the SiO₂/Al₂O₃ ratio given by chemical analysis. Some kaolin is seen by electron microscopy to be of very small particle size, and two distinct morphological types have been recognized. High surface area measurements are consistent with fine particular size. These profiles contain kaolin with higher than normal CEC and permanent negative charges which cannot be accounted for by the presence of 2:1 clay minerals alone and which are attributed to a degree of isomorphous substitution. This substitution and/or mineral impurities may have limited kaolin crystal growth during neoformation.