Ecological implications of the correlation of avian footprints with wing characteristics: a mathematical approach

The characteristics of avian wings that evolved for flying appear to show a distinct relationship to the shape of the pes and walking abilities as reflected in footprints. Wing area, wing span and body weight data of modern birds were collected and analysed in order to quantify the possible correlation, which was previously only inferred from empirical data. Discriminant analysis demonstrated that avian wings can be divided into three habitat groups, in a similar way to footprints. Multiple regression analyses revealed that the avian wing loading and aspect ratio were correlated with the parameters of footprint shape and can be expressed by a simple equation. The results may reflect the adaptation of avian locomotion to habitat. The relationships between wing area and wing span, and between wing area and footprint area, which are apparent in modern avians, were derived and used to estimate wing area and wing span from the footprints of extinct Cretaceous avian taxa. The estimated values of body weight, wing span and wing area suggest that the trackmakers of Archaeornithipus meijidei, Hwangsanipes choughi and Yacoraitichnus avis had bodies similar to herons (or cranes), large sandpipers (or small sea birds) and medium‐sized gull‐like birds, respectively.     

Étude anthropologique d'empreintes de pas humains Holocènes de la sebkra El Azrag (République islamique de Mauritanie)

We carried out a series of research missions at sites in the Azrag area of Mauritania. The purpose was to obtain preliminary data on human footprints that have been discovered in the sediments of this palaeolake. The El Azrag (“multicoloured”) sebkra flat is a vast sink located 30 km from the mining town of Zouerat. It is 6 km long and 1.5 km wide and is part of a larger network of successive sinks running from Northeast to Southwest over a distance of more than 25 km along the El Hammami sand dune chain. Anthropological study of 118 footprints included direct and photogrammetric measurements. Findings demonstrated a wide variability in the measured parameters that cannot be adequately explained simply by the presence of children and adults of different sexes. Plantar weight bearing studied using the isthmus index and the morphology of the footprint seemed to be of the leukodermic type with a high arch. Comparison of these footprints with those of current inhabitants of the Azrag area of West Africa indicated greatest similarity with the Peuls and Maures from the Adrar especially with regard the length and width of the foot. Eleven trails of up to 21 footprints were studied. Our findings showed that the subject's gait was characterized by a difference in the weight-bearing area and step reach of the right and left foot, indicating that that the subject presented a deformity involving the lower extremities.     

Estimating body weight and habitat type from extinct avian and avian‐like theropod footprints

The relationship between body weight and footprint area of modern avians was derived and used to estimate the body weights of non‐avian theropods taxa from the Triassic to Cretaceous and extinct avian taxa from the Cretaceous periods. Geometric information, such as the area and shape of fossil tracks of extinct avians and non‐avian theropods, was used to estimate body weight and habitat type. The percentage prediction and standard error of estimates indicated that the body weight estimated from track area is comparable with body weight estimated from body fossils bones. Therefore, this approach is useful when the fossilized track record is richer than the fossilized skeletal record. The data sets for avians and reptiles were combined and used to derive a body weight–area relationship that may be applicable to a broader range of organisms, such as plantigrade quadrupeds and digitigrade bipeds. Additionally, scatter plots of the relationship between habitat type and footprint shape of modern avians were used to infer the habitat type of extinct avians. This finding suggests that the pes of animals, living in areas characterized by fluctuating water levels, and under conditions facilitating the preservation of footprints, were similar in form to those of extant semi‐aquatic avians.     

Flatfoot Diagnosis by a Unique Bimodal Distribution of Footprint Index in Children

Background

More than 1000 scientific papers have been devoted to flatfoot issue. However, a bimodal distribution of flatfoot indices in school-aged children has never been discovered. The purposes of this study were to establish a new classification of flatfoot by characteristic in frequency distribution of footprint index and to endue the classification with discrepancy in physical fitness.

Methods/Principal Findings

In a longitudinal survey of physical fitness and body structure, weight bearing footprints and 3 physical fitness related tests were measured in 1228 school-aged children. Frequency distribution of initial data was tested by Kolmogorov-Smirnov test for normality and a unique bimodal distribution of footprint index was identified. The frequency distribution of footprint index manifests two distinct modes, flatfoot and non-flatfoot, by deconvolution and bootstrapping procedures. A constant intersection value of 1.0 in Staheli''s arch index and 0.6 in Chippaux-Smirak index could distinguish the two modes of children, and the value was constant in different age, sex, and weight status. The performance of the one leg balance was inferior in flatfoot girls (median, 4.0 seconds in flatfoot girls vs. 4.3 seconds in non-flatfoot girls, p = 0.04, 95% CI 0.404–0.484).

Discussion

The natural bimodality lends itself to a flatfoot classification. Bimodality suggests development of the child''s foot arch would be a leap from one state to another, rather than a continuous growth as body height and weight. The underlying dynamics of the human foot arch and motor development will trigger research prospects.     

From footprint morphometrics to the stature of fossil hominins: A common but uncertain estimate

Hominin footprints are a particular remain in paleoanthropology representing brief moments of life of extinct individuals. Footprints not only provide information on the locomotor behavior of fossil taxa but also on their body characteristics such as their stature. This stature is usually estimated from the length of the footprints based on the well-known foot length to stature ratio. However, footprint length does not result only from the foot length but of a combination of factors. Therefore, it is necessary to investigate the relationships between footprint length and stature of individuals using experimental approaches. Secondly, recent discoveries of fossil footprints have led to the estimation of statures from isolated footprints. However, such estimates may be biased because of the intraindividual morphometric variation of the footprints. Moreover, footprints may also be incomplete making it impossible to measure the length and therefore the estimation of a stature. The search for relationships between stature and other morphometric variables is therefore necessary to have the most accurate picture possible of the individuals who left these tracks. In this context, this article reports the results of an experimental study that aims to determine the relationships between the stature of individuals and different morphometric variables and to quantify the intraindividual variation of each variable. Thus, 21 morphometric variables were measured on a total of 175 experimental footprints left by 20 individuals in an experimental area composed of loose sand. Statistical analyses show that footprint lengths are not only the variables most correlated with stature but also those with the least intraindividual variation. However, estimation of stature from footprints left by fossil hominins is subject to three types of uncertainties: residuals from linear regression, intraindividual variation that can be particularly large in soft substrates, and the application of relationships defined on modern populations to fossil taxa.     

生态足迹理论方法的改进及应用

针对生态足迹理论关于耕地一年只耕种一次的假设,对生态足迹方法中的耕地类足迹用复种指数进行调整,使计算得到的耕地类足迹是人们所需要的耕地面积而不是复种面积.用改进的方法,对江苏省滨海县和阜宁县两个区域生态经济系统1995—2003年的情况进行了分析.结果表明:在1995—2003年,采用Wackernagel方法,滨海和阜宁的人均生态足迹分别由1.79hm2、1.38hm2增加为2.22hm2、2.81hm2,生态足迹中耕地足迹的比重分别由42.65%、45.73%下降为38.81%、38.85%;采用改进后的方法,滨海和阜宁的人均生态足迹则分别由1.43hm2、1.12hm2增加为1.88hm2、2.43hm2,生态足迹中耕地足迹的比重分别由28.45%、32.94%下降为22.89%、29.42%.表明采用改进后的方法所计算得到的生态足迹为土地面积,增强了生态足迹与生态承载力的可比性;使得生态足迹的大小及构成发生变化,更能准确表征人类对自然资源的利用程度.     

Experimentally generated footprints in sand: Analysis and consequences for the interpretation of fossil and forensic footprints

Fossilized footprints contain information about the dynamics of gait, but their interpretation is difficult, as they are the combined result of foot anatomy, gait dynamics, and substrate properties. We explore how footprints are generated in modern humans. Sixteen healthy subjects walked on a solid surface and in a layer of fine‐grained sand. In each condition, 3D kinematics of the leg and foot were analyzed for three trials at preferred speed, using an infrared camera system. Additionally, calibrated plantar pressures were recorded. After each trial in sand, the depth of the imprint was measured under specific sites. When walking in sand, subjects showed greater toe clearance during swing and a 7° higher knee yield during stance. Maximal pressure was the most influential factor for footprint depth under the heel. For other foot zones, a combination of factors correlates with imprint depth, with pressure impulse (the pressure‐time integral) gaining importance distally, at the metatarsal heads and the hallux. We conclude that footprint topology cannot be related to a single variable, but that different zones of the footprint reflect different aspects of the kinesiology of walking. Therefore, an integrated approach, combining anatomical, kinesiological, and substrate‐mechanical insights, is necessary for a correct interpretation. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

中国省际灰水足迹测度及荷载系数的空间关联分析

借鉴Hoekstra等提出的灰水足迹计算公式,从农业、工业及生活三方面计算了1998—2012年中国31个省市(自治区)的灰水足迹及其灰水足迹荷载系数。结果表明:1研究期间全国灰水足迹呈现波动趋势,1998年至2006年的灰水足迹呈现波动上升趋势;2007年开始,全国灰水足迹呈现下降趋势;农业在总灰水足迹的贡献率最高、工业最低;231个省市(自治区)15a灰水足迹荷载系数整体呈现小幅波动趋势。在全国内部也存在着明显的地区差异,大体分为5类,分别为高荷载地区、较高荷载区、中度荷载区、较低荷载区、低荷载区。3借助全局与局部空间自相关对全国31个省市(自治区)灰水足迹荷载系数进行空间关联格局分析可知,中国省级灰水足迹存在空间集聚现象且集聚现象逐渐减弱,其中H-H集聚区主要集中在华北地区,L-L集聚区主要集中在南方与青藏地区。通过全国灰水足迹测度与灰水足迹荷载系数空间关联格局分析为灰水足迹分析提供新的研究思路同时为区域可持续发展提供理论支持。     

Human Footprint Variation while Performing Load Bearing Tasks

Human footprint fossils have provided essential evidence about the evolution of human bipedalism as well as the social dynamics of the footprint makers, including estimates of speed, sex and group composition. Generally such estimates are made by comparing footprint evidence with modern controls; however, previous studies have not accounted for the variation in footprint dimensions coming from load bearing activities. It is likely that a portion of the hominins who created these fossil footprints were carrying a significant load, such as offspring or foraging loads, which caused variation in the footprint which could extend to variation in any estimations concerning the footprint’s maker. To identify significant variation in footprints due to load-bearing tasks, we had participants (N = 30, 15 males and 15 females) walk at a series of speeds carrying a 20kg pack on their back, side and front. Paint was applied to the bare feet of each participant to create footprints that were compared in terms of foot length, foot width and foot area. Female foot length and width increased during multiple loaded conditions. An appreciation of footprint variability associated with carrying loads adds an additional layer to our understanding of the behavior and morphology of extinct hominin populations.     

Quantitative Interpretation of Tracks for Determination of Body Mass

To better understand the biology of extinct animals, experimentation with extant animals and innovative numerical approaches have grown in recent years. This research project uses principles of soil mechanics and a neoichnological field experiment with an African elephant to derive a novel concept for calculating the mass (i.e., the weight) of an animal from its footprints. We used the elephant''s footprint geometry (i.e., vertical displacements, diameter) in combination with soil mechanical analyses (i.e., soil classification, soil parameter determination in the laboratory, Finite Element Analysis (FEA) and gait analysis) for the back analysis of the elephant''s weight from a single footprint. In doing so we validated the first component of a methodology for calculating the weight of extinct dinosaurs. The field experiment was conducted under known boundary conditions at the Zoological Gardens Wuppertal with a female African elephant. The weight of the elephant was measured and the walking area was prepared with sediment in advance. Then the elephant was walked across the test area, leaving a trackway behind. Footprint geometry was obtained by laser scanning. To estimate the dynamic component involved in footprint formation, the velocity the foot reaches when touching the subsoil was determined by the Digital Image Correlation (DIC) technique. Soil parameters were identified by performing experiments on the soil in the laboratory. FEA was then used for the backcalculation of the elephant''s weight. With this study, we demonstrate the adaptability of using footprint geometry in combination with theoretical considerations of loading of the subsoil during a walk and soil mechanical methods for prediction of trackmakers weight.     

Natural gaits of the non-pathological flat foot and high-arched foot

There has been a controversy as to whether or not the non-pathological flat foot and high-arched foot have an effect on human walking activities. The 3D foot scanning system was employed to obtain static footprints from subjects adopting a half-weight-bearing stance. Based upon their footprints, the subjects were divided into two groups: the flat-footed and the high-arched. The plantar pressure measurement system was used to measure and record the subjects' successive natural gaits. Two indices were proposed: distribution of vertical ground reaction force (VGRF) of plantar and the rate of change of footprint areas. Using these two indices to compare the natural gaits of the two subject groups, we found that (1) in stance phase, there is a significant difference (p<0.01) in the distributions of VGRF of plantar; (2) in a stride cycle, there is also a significant difference (p<0.01) in the rate of change of footprint area. Our analysis suggests that when walking, the VGRF of the plantar brings greater muscle tension to the flat-footed while a smaller rate of change of footprint area brings greater stability to the high-arched.     

Determination of Sex from Footprint Dimensions in a Ghanaian Population

The present study sought to verify the utility and reliability of footprint dimensions in sex determination in a Ghanaian population. Bilateral footprints were obtained from 126 Ghanaian students (66 males and 60 females) aged 18–30 years at Koforidua Polytechnic using an ink pad and white papers. Seven dimensions–length of each toe (designated T1-T5) from the most anterior point of the toe to the mid-rear heel point, breadth at ball (BAB) and breadth at heel (BAH)–and the heel-ball (HB) index were obtained from each footprint. Some footprint dimensions (i.e. T2, T3, T4 and T5) showed statistically significant bilateral asymmetry in males only. All the footprint dimensions, except HB index, were significantly greater in males than females (p<0.001). Applied singly in discriminant function analysis, the footprint dimensions allowed 69.8%-80.3% of cases to be correctly classified into their sex groups; the accuracy of sex classification was higher using left footprints than right footprints. With all dimensions subjected to stepwise discriminant function analysis 80.3% and 77% of cases could be correctly classified, combining both T5 and BAH for left footprints and T1, BAB and BAH for left footprints respectively. The present study has demonstrated, for the first time among Ghanaian subjects, the utility and reliability of sex determination standards developed from footprint dimensions. The results thus provide the baseline for elaborated studies in the future.     

典型移民城市食物氮足迹估算分析——以深圳市为例

城市食物源氮消费产生的环境排放是全国氮污染的重要源头,城市食物氮足迹评估可反映维持城市人口基本食物需求的活性氮排放以及对周边环境的潜在影响。以典型移民城市深圳市为例,基于改进N-Calculator模型的基础上,估算了2010-2015年间因城市人口流动导致的城市食物氮足迹变化,并分析其时空异质性及其与城市化间的关系。结果表明：深圳市不同类型城市居民食物氮足迹不一致,其中常住户籍居民人均食物氮足迹从14.63 kg N a^-1增加至15.17 kg N a^-1,高于非户籍居民食物氮足迹13.09 kg N a^-1,其主要体现在瓜果、肉类、水产品等食物消费上。总体上,深圳城市食物氮足迹呈增长趋势,5年增幅11.50%,增幅最大为常住户籍居民食物氮足迹,但目前深圳非户籍居民的食物消费主导着城市食物氮足迹。深圳城市内部区域食物氮足迹呈高度空间异质性与聚集性,各区域增长量差异明显,街道尺度城市食物氮足迹增长热点主要分布在城市的西部沿海区域,部分热点区域单位增长量数量级比肩区级尺度单位的增长量,城市区域食物氮足迹与人口城市化的关联性不明显,但与经济城市化存在一定的关联性。当前城市移民落户趋势及居民高氮饮食倾向不利于城市氮足迹的削减,减少食物生产上游活性氮流失为深圳市贯彻粤港澳大湾区协同可持续发展的关键。     

环境足迹的核算与整合框架——基于生命周期评价的视角

环境足迹及其与生命周期评价(LCA)的关系是工业生态学关注的新热点。从探讨环境足迹与LCA的关系入手,以碳足迹、水足迹、土地足迹和材料足迹为例,分别对每一项足迹指标两个版本的核算方法进行了比较。根据清单加和过程的特点,将所有足迹指标划分为基于权重因子和基于特征因子两类,总结了两者的适用性和局限性。在此基础上提出了一个环境足迹核算与整合的统一框架。该框架基于LCA视角建立,但对系统边界和清单数据的要求相对灵活,因而也适用于生命周期不甚明确的情形。研究在一定程度上揭示了足迹指标的方法学实质,同时也为环境影响综合评估提供了一条规范化的途径。     

A history and bibliography of the study of fossil vertebrate footprints in the British isles

A comprehensive account is given of the discovery and study of the fossil footprints of vertebrates in the British Isles. Brief summaries are given of work published in journals that are generally available to the geologist at large; however, since many papers were published in obscure books and journals, the illustrations in these are reproduced and the papers themselves directly quoted wherever appropriate. A number of specimens important in the history of British vertebrate ichnology are illustrated for the first time; in particular, the holotype of Chelichnus ingens Binney (1856), the “Kegworth footprint” from Leicestershire, the supposed “monotreme footprint” of Seeley (1899), and the first Iguanodon footprint to be described from Sussex (Tagart, 1846). Illustrations are given for the first time of footprints from the Forest Marble of Wiltshire thought to be those collected by Scrope (1831), of a footprint from the Permian of Warwickshire, mentioned by Vernon (1912), and of a footprint from Caithness. The account is extensively supplemented by text-figures of principal footprint types and, so far as possible, the present whereabouts of figured or described specimens is indicated. (Many, unfortunately, are lost.) An exhaustive bibliography of fossil vertebrate footprints from the British Isles is presented.Particular attention is paid to the important discoveries in the Cheshire Basin by the amateur geologists of the Liverpool region. An account of the work of Henry C. Beasley (1836–1919), the most eminent British worker in this field, is given for the first time; his portrait, and photographs relating to his work in the Storeton quarries, are published for the first time.The stratigraphical and palaeoecological significance of the footprints is assessed wherever possible and reasons are presented why a more extensive resumption of work in this field is desirable.     

Environmental and resource burdens associated with world biofuel production out to 2050: footprint components from carbon emissions and land use to waste arisings and water consumption

Environmental or ‘ecological’ footprints have been widely used in recent years as indicators of resource consumption and waste absorption presented in terms of biologically productive land area [in global hectares (gha)] required per capita with prevailing technology. In contrast, ‘carbon footprints’ are the amount of carbon (or carbon dioxide equivalent) emissions for such activities in units of mass or weight (like kilograms per functional unit), but can be translated into a component of the environmental footprint (on a gha basis). The carbon and environmental footprints associated with the world production of liquid biofuels have been computed for the period 2010–2050. Estimates of future global biofuel production were adopted from the 2011 International Energy Agency (IEA) ‘technology roadmap’ for transport biofuels. This suggests that, although first generation biofuels will dominate the market up to 2020, advanced or second generation biofuels might constitute some 75% of biofuel production by 2050. The overall environmental footprint was estimated to be 0.29 billion (bn) gha in 2010 and is likely to grow to around 2.57 bn gha by 2050. It was then disaggregated into various components: bioproductive land, built land, carbon emissions, embodied energy, materials and waste, transport, and water consumption. This component‐based approach has enabled the examination of the Manufactured and Natural Capital elements of the ‘four capitals’ model of sustainability quite broadly, along with specific issues (such as the linkages associated with the so‐called energy–land–water nexus). Bioproductive land use was found to exhibit the largest footprint component (a 48% share in 2050), followed by the carbon footprint (23%), embodied energy (16%), and then the water footprint (9%). Footprint components related to built land, transport and waste arisings were all found to account for an insignificant proportion to the overall environmental footprint, together amounting to only about 2%     

A combined morphometric analysis of foot form and its association with sex,stature, and body mass

Objectives: Morphometric analysis of footprints is a classic means for orthopedic diagnosis. In forensics and physical anthropology, it is commonly used for the estimation of stature and body mass. We studied individual variation and sexual dimorphism of foot dimensions and footprint shape by a combination of classic foot measurements and geometric morphometric methods. Methods: Left and right feet of 134 healthy adult males and females were scanned twice with a 3D optical laser scanner, and stature as well as body mass were recorded. Foot length and width were measured on the 3D scans. The 2D footprints were extracted as the plantar‐most 2 mm of the 3D scans and measured with 85 landmarks and semilandmarks. Results: Both foot size and footprint shape are sexually dimorphic and relate to stature and body mass. While dimorphism in foot length largely results from dimorphism in stature, dimorphism in footprint shape partly owes to the dimorphism in BMI. Stature could be estimated well based on foot length (R² = 0.76), whereas body mass was more closely related to foot width (R² = 0.62). Sex could be estimated correctly for 95% of the individuals based on a combination of foot width and length. Discussion: Geometric morphometrics proved to be an effective tool for the detailed analysis of footprint shape. However, for the estimation of stature, body mass, and sex, shape variables did not considerably improve estimates based on foot length and width. Am J Phys Anthropol 157:582–591, 2015. © 2015 Wiley Periodicals, Inc.     

Theoretical exploration for the combination of the ecological,energy, carbon,and water footprints: Overview of a footprint family

Over the past two decades, a continuously expanding list of footprint-style indicators has been introduced to the scientific community with the aim of raising public awareness of how humanity exerts pressures on the environment. A deeper understanding of the connections and interactions between different footprints is required in an attempt to support policy makers in the measurement and choice of environmental impact mitigation strategies. Combining a selection of footprints that address different aspects of environmental issues into an integrated system is, therefore, a natural step. This paper starts with the idea of developing a footprint family from which most important footprints can be compared and integrated. On the basis of literature review in related fields, the ecological, energy, carbon, and water footprints are employed as selected indicators to define a footprint family. A brief survey is presented to provide background information on each of the footprints with an emphasis on their main characteristics in a comparative sense; that is, the footprints differ in many aspects more than just the impacts they are addressed. This allows the four footprints to be complementarily used in assessing environmental impacts associated with natural resource use and waste discharge. We evaluate the performance of the footprint family in terms of data availability, coverage complementarity, methodological consistency, and policy relevance and propose solutions and suggestions for further improvement. The key conclusions are that the footprint family, which captures a broad spectrum of sustainability issues, is able to offer a more complete picture of environmental complexity for policy makers and, in particular, in national-level studies. The research provides new insights into the distinction between environmental impact assessment and sustainability evaluation, properly serving as a reference for multidisciplinary efforts in estimating planetary boundaries for global sustainability.     

Adjacent Sequences Influence DNA Repair Accompanying Transposon Excision in Maize

Mobile elements transposing via DNA intermediates often leave small rearrangements, or ``transposon footprints,' at sites where they excise. Each excision event leaves its own footprint and, at any given site, these vary in size and sequence. Footprint formation involves DNA repair of sequences flanking the element. We have analyzed the footprints formed by a 2-kb Ds element excising from six different sites in exons of the maize waxy (Wx) gene. We find that groups of footprints left at individual sites are surprisingly nonrandom; different excision products predominate consistently at each site. Less frequent footprints left by each insertion appear related to the predominant type. The data suggest that flanking sequences affect the DNA repair processes associated with element excision. Two models have been proposed to explain footprint formation, one featuring a 5' exonuclease and the other featuring hairpin loop formation and an endonuclease. Our data have interesting implications for both these models. Evidence is also presented to support the presence of a separate excision mechanism that can remove Ac/Ds elements without leaving any footprint and that operates in parallel with the footprint-forming mechanism.     

More than the mean—A note on heterogeneity aspects in the assessment of water footprints

Water footprints for a crop produced in a specific country are often provided as mean values. However, mean values do not account for the spatial heterogeneity of water footprints within a country that is caused by heterogeneous climate conditions and production techniques. To sufficiently inform decision makers, the underlying heterogeneity should thus also be presented. We provide an illustrate example of seed cotton production in 19 regions in Brazil and China. Even though grey water footprints in Brazil are on average smaller, it also contains the highest possible grey water footprint across all regions. To avoid misleading inference on water footprint estimates, their spatial heterogeneity should be indicated. This will enable decision makers to consider trade-offs between average values and potential extremes.