Geometric explanation of anomalous finite-size scaling in high dimensions

We give an intuitive geometric explanation for the apparent breakdown of standard finite-size scaling in systems with periodic boundaries above the upper critical dimension. The Ising model and self-avoiding walk are simulated on five-dimensional hypercubic lattices with free and periodic boundary conditions, by using geometric representations and recently introduced Markov-chain Monte Carlo algorithms. We show that previously observed anomalous behaviour for correlation functions, measured on the standard Euclidean scale, can be removed by defining correlation functions on a scale which correctly accounts for windings.Comment: 5 pages, 4 figure

Why Levallois? A Morphometric Comparison of Experimental ‘Preferential’ Levallois Flakes versus Debitage Flakes

Background Middle Palaeolithic stone artefacts referred to as ‘Levallois’ have caused considerable debate regarding issues of technological predetermination, cognition and linguistic capacities in extinct hominins. Their association with both Neanderthals and early modern humans has, in particular, fuelled such debate. Yet, controversy exists regarding the extent of ‘predetermination’ and ‘standardization’ in so-called ‘preferential Levallois flakes’ (PLFs). Methodology/Principal Findings Using an experimental and morphometric approach, we assess the degree of standardization in PLFs compared to the flakes produced during their manufacture. PLFs possess specific properties that unite them robustly as a group or ‘category’ of flake. The properties that do so, relate most strongly to relative flake thicknesses across their surface area. PLFs also exhibit significantly less variability than the flakes generated during their production. Again, this is most evident in flake thickness variables. A further aim of our study was to assess whether the particular PLF attributes identified during our analyses can be related to current knowledge regarding flake functionality and utility. Conclusions/Significance PLFs are standardized in such a manner that they may be considered ‘predetermined’ with regard to a specific set of properties that distinguishes them statistically from a majority of other flakes. Moreover, their attributes can be linked to factors that, based on current knowledge, are desirable features in flake tools (e.g. durability, capacity for retouch, and reduction of torque). As such, our results support the hypothesis that the lengthy, multi-phase, and hierarchically organized process of Levallois reduction was a deliberate, engineered strategy orientated toward specific goals. In turn, our results support suggestions that Levallois knapping relied on a cognitive capacity for long-term working memory. This is consistent with recent evidence suggesting that cognitive distinctions between later Pleistocene hominins such as the Neanderthals and anatomically modern humans were not as sharp as some scholars have previously suggested

Lifted Worm Algorithm for the Ising Model

We design an irreversible worm algorithm for the zero-field ferromagnetic Ising model by using the lifting technique. We study the dynamic critical behavior of an energy estimator on both the complete graph and toroidal grids, and compare our findings with reversible algorithms such as the Prokof'ev-Svistunov worm algorithm. Our results show that the lifted worm algorithm improves the dynamic exponent of the energy estimator on the complete graph, and leads to a significant constant improvement on toroidal grids.Comment: 9 pages, 6 figure

Estimating the Richness of a Population When the Maximum Number of Classes Is Fixed: A Nonparametric Solution to an Archaeological Problem

Background: Estimating assemblage species or class richness from samples remains a challenging, but essential, goal. Though a variety of statistical tools for estimating species or class richness have been developed, they are all singly-bounded: assuming only a lower bound of species or classes. Nevertheless there are numerous situations, particularly in the cultural realm, where the maximum number of classes is fixed. For this reason, a new method is needed to estimate richness when both upper and lower bounds are known. Methodology/Principal Findings: Here, we introduce a new method for estimating class richness: doubly-bounded confidence intervals (both lower and upper bounds are known). We specifically illustrate our new method using the Chao1 estimator, rarefaction, and extrapolation, although any estimator of asymptotic richness can be used in our method. Using a case study of Clovis stone tools from the North American Lower Great Lakes region, we demonstrate that singly-bounded richness estimators can yield confidence intervals with upper bound estimates larger than the possible maximum number of classes, while our new method provides estimates that make empirical sense. Conclusions/Significance: Application of the new method for constructing doubly-bound richness estimates of Clovis stone tools permitted conclusions to be drawn that were not otherwise possible with singly-bounded richness estimates, namely, that Lower Great Lakes Clovis Paleoindians utilized a settlement pattern that was probably more logistical in nature than residential. However, our new method is not limited to archaeological applications. It can be applied to any set of data for which there is a fixed maximum number of classes, whether that be site occupancy models, commercial products (e.g. athletic shoes), or census information (e.g. nationality, religion, age, race)

LANGUAGE TEACHER IDENTITY CONSTRUCTION OF FOREIGN LANGUAGE TEACHING ASSISTANTS

Language teacher identity has been studied in several contexts in English Language Teaching (ELT) field; however, looking at language teacher identity in a United States context in which teachers from other countries teach their native languages as a foreign language has been a rare topic so far. Therefore, this phenomenological qualitative study investigated the lived experiences of four foreign language teaching assistants who lived and taught in the United States through Fulbright Foreign Language Teaching Assistant (FLTA) Program. The findings indicated four main emerging themes: (a) pedagogical shift, (b) cross-cultural awareness, (c) challenges, and (d) goals and expectations. These dynamic components shaped language teachers’ identity in this context. The results are presented under the framework of language teacher identity.  Implications as a guide for future FLTA teachers and for teacher exchange programs are provided. &nbsp

Early stage blunting causes rapid reductions in stone tool performance

Palaeolithic stone technologies have never been investigated in terms of how sharpness influences their ability to cut. In turn, there is little understanding of how quickly stone cutting edges blunt, how past populations responded to any consequent changes in performance, or how these factors influenced the Palaeolithic archaeological record. Presented here is experimental data quantitatively detailing how variation in edge sharpness influences stone tool cutting performance. Significant increases in force (N) and material displacement (mm) requirements occur rapidly within early stages of blunting, with a single abrasive cutting stroke causing, on average, a 38% increase in the force needed to initiate a cut. In energetic terms, this equates to a 70% increase in work (J). Subsequent to early stages of blunting we identify a substantial drop in the impact of additional edge abrasion. We also demonstrate how edge (included) angle significantly influences cutting force and energy requirements and how it co-varies with sharpness. Amongst other conclusions, we suggest that rapid reductions in performance due to blunting may account for the abundance of lithic artefacts at some archaeological sites, the speed that resharpening behaviours altered tool forms, and the lack of microscopic wear traces on many lithic implements

Investigating the wording effect in scales based on the different dimension reduction techniques

Bu araştırmanın amacı, olumlu ve olumsuz madde sayısının dengeli olmadığı çok boyutlu bir ölçekten elde edilen verinin boyutluluğunun çok boyutlu madde tepki kuramı, DETECT ve faktör analizi yöntemlerine dayalı olarak incelenmesidir. Bu amaçla, araştırma kapsamında velilerin okula yönelik oluşturdukları algılarının ortaya çıkarılması amacıyla geliştirilmiş bir ölçek kullanılmıştır. Çalışma grubunda 1388 veli yer almıştır. Ölçeğin uygulanmasından elde edilen verinin boyutluluğu faktör analizi, çok boyutlu madde tepki kuramı ve DETECT analizine dayalı olarak incelenmiştir. Üç farklı boyutluluk analizine dayalı olarak verinin boyutluluğu incelendiğinde, tüm yöntemlerde ortak biçimde olumsuz maddelerin ayrı bir boyut oluşturduğu görülmüştür. Buna göre, olumsuz maddeler arasındaki ilişkilerin yalnızca ölçekle ölçülen özellikle açıklanamayacağı, olumsuz maddeler arasındaki ilişkiler üzerinde maddelerin ifade ediliş yönünün de etkili olduğu belirtilebilir. Bu araştırmanın bulguları, veri setinde her teknikte ortaya çıkan güçlü bir ifade etkisi olduğunu göstermiştir. Bu bulgulara dayalı olarak, araştırmacı ve uygulayıcılara olumlu ve olumsuz maddelerin birlikte kullanıldığı ölçeklerden elde edilen verinin boyutluluğunun incelenmesine ilişkin önerilerde bulunulmuştur.This study aims to examine the dimensionality of a dataset obtained from the application of a multidimensional scale which is not balanced in terms of the numbers of the positively and negatively worded items based on the item response theory, DETECT, and factor analysis. To this aim, a scale developed to measure parents' perceptions of their children's school was utilized. The study group consisted of 1,388 parents. The dimensionality of the dataset obtained from the scale was examined based on the item response theory, DETECT and factor analyses. The results of the three methods commonly revealed that the negatively worded items formed a separate cluster. Based on this finding, it can be stated that relations among the negatively worded items cannot only be explained by the intended trait with the scale, and the wording of the items also affect the relations among the negatively worded items. No matter what dimension reduction technique was used to analyze the data, the study results evidenced the existence of a strong wording effect in the data set. Based on the study results, some recommendations were given to researchers and practitioners regarding how to examine the dimensionality of a dataset obtained from a scale including both positively and negatively worded items

A Rare Cause of Precocious Puberty: Hepatoblastoma

Hepatoblastoma, an embryonal tumor, is one of the most common primary liver tumors in childhood. It secretes human chorionic gonadotropin (hCG), which can cause precocious puberty (PP). Herein, we present a case with PP who had enlarged penile size noticed during a diagnosis of hepatoblastoma. Laboratory examination revealed increased testosterone, alpha-fetoprotein (AFP), and hCG levels. Serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were within prepubertal ranges. The diagnosis of hepatoblastoma was made by liver biopsy. Chemotherapy was administered, and the patient was referred to surgery. Ten months later, testis volumes were below 4 ml bilaterally, and penile length was 5.5 cm. Serum testosterone, AFP, and hCG levels decreased. Resection of the tumor and chemotherapy are essential for the treatment of hepatoblastoma and they can eliminate the symptoms of PP