How do stone knappers predict and control the outcome of flaking? Implications for understanding early stone tool technology

The aim of the current study was to provide detailed data on the skill at controlling conchoidal fracture, data that may be used to help infer the processes responsible for generating the technological diversity observed in Early Stone Age sites. We conducted an experiment with modern stone knappers with different skill levels and systematically analyzed not only the products of flaking (i.e., detached flakes) but also the intentions prior to flaking, as well as the actions taken to control the shape of a flake through direct hard-hammer percussion. Only modern stone knappers with extensive knapping experience proved capable of predicting and controlling the shape of a flake, which indicated the significant difficulty of controlling the shape of flakes. Evidence was found that knowing the consequence of a strike given to a core at hand requires the acute exploration of the properties of the core and hammerstone to comply with the higher-order relationship among potential platform variables, kinetic energy of the hammerstone at impact, and flake dimension that reflects the constraints of conchoidal fracture. We argue that without this ability, controlling the shape of a flake or the organized débitage of flakes observed in some of the Early Stone Age sites may not have been possible. We further suggest that, given the difficulty and the nature of the skill, the evidence of precise control of conchoidal fracture in the Early Stone Age record may be indicative of the recurrence of a learning situation that allows the transmission of the skill, possibly through providing the opportunities for first-hand experience.     

Survey of the literature on mechanoluminescence from 1605 to 2013

Mechanoluminescence (ML) is a type of luminescence induced by any mechanical action on solids. The light emissions induced by elastic deformation, plastic deformation and fracture of solids are called elastico ML (EML), plastico ML (PML) and fracto ML (FML), respectively. Whereas nearly 50% of all organic molecular solids and inorganic salts exhibit FML, only a few solids exhibit EML and PML. The EML and FML of certain solids are so intense that they can be seen during daylight with the naked eye. Mechanolumnescence has a great potential for use in different types of mechano‐optical devices such as stress sensors, damage sensors, impact sensors, fracture sensors and safety management monitoring systems. This article reports a survey of the literature from 1605 to 2013. Mechanoluminescence is studied by physicists, chemists, material scientists, geologists, medical scientists, engineers and technologists, among others and researchers will certainly benefit from the literature survey on ML given here. In addition, the field of mechanoluminescence may attract the interest of many new researchers. Copyright © 2014 John Wiley & Sons, Ltd.     

甘肃徐家城旧石器遗址石制品拼合研究

徐家城遗址是甘肃省新发现的含丰富旧石器文化遗物的遗址,主要埋藏于水洛河二级阶地上覆的马兰黄土中,年代在距今4.3~2.3万年间。徐家城遗址的拼合分析显示,4B、4C层剥片与石器加工行为是石制品空间分布形成的主要原因,但可能存在遗址使用时古人类对石制品位置改变的行为;4A层石制品零散分布可能反映了此时遗址处于古人类活动的边缘地带。遗址剥片方法以硬锤锤击法为主,石核剥片序列主要以转向为主,古人类对石料进行单层或多层开发;同时部分石器破碎后古人类可能对其进行再利用。平面分布显示发掘区内可能存在两个相对集中的剥片区域,并且古人类在同一区域剥片和加工石器。然因遗址石制品原料性质、发掘面积等局限性,拼合分析的优势并未在此项研究中尽现。今后此类研究应结合其他研究方法,综合多方面信息解释遗址形成过程、石器技术及遗址空间利用方式。     

Occupational Stress in Veterinary Nurses: Roles of the Work Environment and Own Companion Animal

ABSTRACT

Veterinary nursing has been identified as an occupation at risk for occupational stress and burnout, but a better understanding of job stressors and influencing factors is needed. The aim of this study was to examine occupational stress in a veterinary nursing population based on established work stress theories. This study sought to determine which environmental aspects of the work situation may be detrimental to well-being and which factors may operate to reduce job stress. A sample of South Australian veterinary nurses (n = 127) completed a postal questionnaire about their work environment (job demands and control, work social supports) and their psychological distress, work burnout, and job satisfaction, with a response rate of 76.5%. The potential influence of attachment to participants' own companion animals was investigated using the Owner Pet Relationship Scale. Hierarchical regressions then explored the contribution to psychological outcomes, of social support at work and attachment to own companion animal, after controlling for work load, exposure to euthanasia, contact with clients, work demands, and work control. While social support at work ameliorated occupational stress, attachment to companion animal was linked to decreased job satisfaction. Supportive interpersonal relations in the workplace have a key role in veterinary nurses' job satisfaction. Management skill training may have a role in the development of more satisfying workplaces for the veterinary nursing sector, which may have implications for the undergraduate and post-registration training of veterinary practice managers.     

Dimensional analysis in mathematical biology. II

The application of dimensional analysis in biology is further illustrated by functional equations composed of dimensionless numbers and dealing with renal physiology, lung physiology and plant leaf shape. Dimensional variables and dimensionless numbers are examined from the viewpoint of numerical invariant properties of a certain physical system. Utilization of the method for problems such as design of an artificial kidney is considered briefly. A tabulation of variables useful in biology is given, with suggestions for a number of new dimensional entities. A continuation of the list of dimensionless invariants from Part I (Bull. Math. Biophysics,23, 355–376, 1961) is provided and includes terms pertaining to general physiology, geometric growth, metabolism, ecological interactions, muscle kinetics and other areas. It is pointed out that use of dimensionless ratios (similarity criteria) makes possible a direct comparison of form or shape factors and relative growth ratios with a variety of physical ratios, through the use of functional equations containing only dimensionless entities. Organismal similarity during growth and development, and between genetically related species, may be analyzed in terms of “automodel” or “self-similar” systems governed by certain dimensionless invariants. Tables of biological variables and dimensionless groupings are included.     

Upper Pennsylvanian Cherts Of The Forest City Basin: Missourian Stage

Abstract

Four previously undescribed midcontinental cherts are analyzed in terms of their identity and internal variability, geological context, source areas, procurement techniques, flaking properties, response to heat treatment, and geographic distribution.     

Quantitative Variations In Flaked Stone Debitage

Abstract

In an attempt to discern the quantitative parameters diagnostic of specific load applications (i.e.hard-and soft-hammer percussion and pressure flaking) used in flint knapping, approximately 1,500 experimentally produced flakes were analyzed. Load varieties were recorded during production, flakes were standardized as to plane size through graduated sieves, and weighed and measured for maximum thicknesses. Although the study indicates that hardand soft-hammer percussion do not yield significantly different debitage weights or thicknesses, pressure flakes can be differentiated from percussion spalls on the basis of these variables.     

关于北京人遗址第13层发现的石制品

关于北京人遗址第13层发现的两件石制品的性质,在中国学术界存在不同意见。本文作者认为:人工打制的石片和石器形式多种多样,有典型的,也有不典型的;自然营力能使石块破碎,甚至“加工”出具有一定形状的“石器”,但同样也是形式多种多样,有典型的和不典型的。对待这类问题,要从多方面去考虑,认识才较为客观,较为全面。     

石料力学性能分析在旧石器考古学研究中的应用

石料是石器制作过程中的重要因素,石料本身的力学性能不仅与古人类的原料利用方式密切相关,还会影响到石器打制方法、器物组合、甚至石器工业面貌。长期以来,旧石器考古学界对于石料力学性能的判断多基于简单的岩石矿物硬度和结构特征,实际上岩石的力学性能涵盖的内容远远超过其硬度和结构的范畴。本文使用力学研究的方法,通过对石料的单轴抗压强度测试,了解不同原料的力学性能,并将其与遗址出土石制品进行比较研究,尝试探讨岩石本身力学性能与石制品面貌之间的关系。     

Effect of Operating Parameters on the Spray Drying of Tomato Paste

The production of tomato powder from tomato paste using the spray drying technique has been investigated in this work. The influence of a number of process variables, namely, feed total solids, feed flow rate, feed temperature, air temperature, air flow rate, and starch addition on the physical properties of spray‐dried tomato powder was investigated. The product properties studied were total solids, average particle diameter, bulk density, and solubility. The increase in the feed total solids increased tomato powder total solids, particle size and bulk density and decreased its solubility, while the increase in the feed flow rate decreased tomato powder total solids and solubility, and increased the average particle size and bulk density.     

百色盆地高岭坡遗址的石制品

高岭坡旧石器遗址位于百色市田东县境内的林逢镇檀河村,文化层为右江南岸第4级阶地的砖红壤层。本文材料为1986~1995年发掘和采集的、由中国科学院古脊椎动物与古人类研究所收藏的834件石制品。石制品类型有石核、石片、工具、备料和断块;石片和断块占较大比例;工具既有手斧、手镐和砍砸器等重型工具,也有刮削器、凹缺器、石锥和鸟喙状器等轻型工具。两个类群在原料和毛坯选择上有明显差异。工具均采用锤击法,主要从较平的一面向较凸的另一面进行单向加工,辅以交互和错向加工。拼合石片以及大量细小石片、断块等的存在显示,该遗址为一处石器制造场所。     

怀来盆地西沟湾1号地点石制品的拼合研究

西沟湾1号地点位于河北省张家口市怀来县,AMS-¹⁴C测年显示其年代为距今4.1-3.4万年,属旧石器时代晚期。该地点埋藏于永定河右岸第二级阶地后缘,发掘面积约27 m²,出土石制品218件,其中41件可以拼合为14个拼合组,拼合成功率为18.8%;其拼合关系可分为拼对(conjoin)和拼接(join)两大类型,其中的组合形式主要包括石核与石片、石片与石片、石片与断块以及石锤与断块四大类。石制品的打击特征以及部分拼合组的剥片序列分析显示,西沟湾1号地点剥片方法为硬锤锤击法,石核剥片主要通过台面或剥片面的转向以实现对原料的多次开发和利用,剥片程度较高;综合各拼合组的空间分布状况,较高的石制品拼合率以及大多数石制品表面和边缘较为新鲜锋利的保存状态等信息,推测该地点在埋藏过程中受到的扰动程度较小,人类行为应是遗址形成的主要因素。     

Omeprazole as a potent activator of human cytosolic aldehyde dehydrogenase ALDH1A1

BackgroundAccumulation of lipid aldehydes plays a key role in the etiology of human diseases where high levels of oxidative stress are generated. In this regard, activation of aldehyde dehydrogenases (ALDHs) prevents oxidative tissue damage during ischemia-reperfusion processes. Although omeprazole is used to reduce stomach gastric acid production, in the present work this drug is described as the most potent activator of human ALDH1A1 reported yet.MethodsDocking analysis was performed to predict the interactions of omeprazole with the enzyme. Recombinant human ALDH1A1 was used to assess the effect of omeprazole on the kinetic properties. Temperature treatment and mass spectrometry were conducted to address the nature of binding of the activator to the enzyme. Finally, the effect of omeprazole was evaluated in an in vivo model of oxidative stress, using E. coli cells expressing the human ALDH1A1.ResultsOmeprazole interacted with the aldehyde binding site, increasing 4–6 fold the activity of human ALDH1A1, modified the kinetic properties, altering the order of binding of substrates and release of products, and protected the enzyme from inactivation by lipid aldehydes. Furthermore, omeprazole protected E. coli cells over-expressing ALDH1A1 from the effects of oxidative stress generated by H₂O₂ exposure, reducing the levels of lipid aldehydes and preserving ALDH activity.ConclusionOmeprazole can be repositioned as a potent activator of human ALDH1A1 and may be proposed for its use in therapeutic strategies, to attenuate the damage generated during oxidative stress events occurring in different human pathologies.     

Anticonvulsant use and fracture: a case-control study

Objectives:We aimed to investigate fracture risk associated with anticonvulsant use in a population-based sample of men and women.Methods:Data from 1,458 participants (51.8% women) with a radiologically confirmed incident fracture (cases) were compared to 1,796 participants (46.5% women) without fracture (controls). Lifestyle factors, medication use and medical history were self-reported. Associations between anticonvulsant use and fracture were explored using binary logistic regression following adjustment for confounders.Results:In men, fracture cases and controls differed in age, smoking history, education, alcohol use, and gonadal hormone supplementation. In women, fracture cases and controls differed by previous fracture history, alcohol use, physical activity levels and use of anti-fracture agents. After adjustment for age, pooled anticonvulsant use was associated with a 3.4-fold higher risk of fracture in men and a 1.8-fold higher risk in women. Following further adjustments for confounders these patterns persisted; a 2.8-fold higher fracture risk in men and a 1.8-fold higher fracture risk in women.Conclusions:Anticonvulsant use was associated with increased fracture risk, independent of demographic, lifestyle, medical and medication related factors. While further studies exploring potential underlying mechanisms are warranted, regular monitoring of bone health in anticonvulsant users with risk factors may be useful.     

Effect of Bisphosphonates on Fracture Incidence in Young Adults With Low Bone Density

ObjectiveTo assess the effect of bisphosphonates on fracture incidence in young adults over a 5-year follow-up period.MethodsBased on the Kaiser Permanente electronic health record, this retrospective study investigated patients aged 19 to 40 years with abnormal bone density (either any Z-score of ≤−2 standard deviation [SD] or any T-score of ≤−2.5 SD). The incidence and time to fracture between the control (patients with <6 months of bisphosphonate exposure) and treatment (patients with ≥6 months of bisphosphonate use within 4 years of their first dual energy x-ray absorptiometry scan) groups were compared. Comparisons were analyzed with Χ² test for categorical variables and Wilcoxon rank sum test for continuous variables.ResultsA total of 422 patients met the inclusion and exclusion criteria. Fractures occurred in 18 patients (5.0%) of the control group (n = 358) and 5 patients (7.8%) of the treatment group (n = 64; P = .37). T-scores were significantly lower in the treatment group (−2.53 ± 0.58 SD) than those in the control group (−2.30 ± 0.80 SD; P = .002) but did not correlate with fracture risk. No significant differences were found in total fracture incidence (hazard ratio = 1.54; 95% confidence interval, 0.26-6.26). Similarly, no correlation was noted between the length of bisphosphonate therapy and fracture incidence (odds ratio = 0.99; 95% confidence interval, 0.966-1.026).ConclusionIn summary, we did not find a clear correlation of fracture incidence with the use of bisphosphonates in young adults. Further research into the pathophysiology, specific etiologies, and treatment options in this population is needed.     

Armonización de bases de datos para el estudio de la fragilidad en personas mayores: Estudio INTAFRADE

ObjectivesThe main objective of the present work is to evaluate the feasibility of harmonising the available information from different independent databases, in order to build an integrated database to study frailty.Material and methodsThis work is based on the European project, Integral Approach to the Transition between Frailty and Dependence on older adults: Patterns of occurrence, identification tools and model of care (INTAFRADE), developed by 4 groups, 3 in Spain and one in France. Each partner provided their databases related to the study of frailty. As a previous step to the creation of an integrated database the characteristics and variables included in each study were mapped, specifying whether their harmonisation was possible or not.ResultsA total of 30 different variables that corresponded to 8 dimensions were identified: Sociodemographic and social characteristics, health status, lifestyle habits, anthropometric measures, other physical measurements, use of health services, and adverse health results. Of them all, 28 (93%) variables were harmonisable, although only 20% were present in all databases, with 47% in 3 of them. In relation to the frailty instruments, all of them were lacking at least 50% of the items. The harmonisation process will allow us to jointly analyse information available on 2,361 people.ConclusionsThe European INTAFRADE study will allow a deeper understanding of the frailty process in older people by harmonising information from heterogeneous databases.     

Determinants of Physiological and Perceived Physiological Stress Reactivity in Children and Adolescents

Aims

Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity.

Method

In a stratified sample of 363 children (7–12 years) and 344 adolescents (13–20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure.

Results

Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant.

Conclusions

As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness.     

Heat Treating of Chert: Methods of Interpretation and Their Application

Abstract

The practice of heating chert to facilitate its flaking has been documented for primitive cultures widely distributed in time and space. The basic procedure for interpreting evidence of prehistoric heat treating is analogy with ethnographic and experimental findings. When this procedure is properly structured in its logic and employs suitable measures of physical property change, sound inferences are possible. In Kentucky, evidence for heat treating of cherts by various prehistoric groups is emerging and indicates that the practice was important in several cultural periods and was practiced widely in the state.