USE AND MULTIFACTORIAL RECONCILIATION OF UNIFACE REDUCTION MEASURES: A PILOT STUDY AT THE NOBLES POND PALEOINDIAN SITE

2017 ◽  
Vol 82 (4) ◽  
pp. 723-741 ◽  
Author(s):  
Michael J. Shott ◽  
Mark F. Seeman
Keyword(s):  
Pilot Study ◽  
Weibull Distribution ◽  
Principal Component ◽  
Stone Tools ◽  
Research Area ◽  
Degree Of Reduction ◽  
Component Loadings ◽  
The Many

How much stone tools are reduced and their form changed from first use to discard bears upon issues such as typological integrity, curation rate, and effects of occupation span. But degree of reduction depends partly upon the measures used to gauge it. Most studies involve single indices that gauge reduction in different ways or at different scales, so results are difficult to compare between studies. In this pilot study, we compare four allometric reduction measures—one each based on length, length:thickness ratio, volume, and mass, estimated by comparing observed values in discarded tools to estimated original values—for consistency when applied to an endscraper sample from the Nobles Pond Paleoindian site in Ohio, USA. Fitted to the Weibull distribution, all measures suggest attrition compared to experimental controls, but variation among them demands reconciliation. A multifactorial method that weights individual measures by their principal-component loadings suggests attritional discard at increasing rate as reduction advances. More importantly, it addresses the growing problem of reconciling the many reduction measures in use, a major concern in this expanding research area.

Comparison of Principal Component Solutions in Two Populations

Methodology ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Gregor Sočan
Keyword(s):  
Simulation Study ◽  
Principal Components ◽  
Common Factor ◽  
Principal Component ◽  
Component Model ◽  
Bootstrap Procedure ◽  
Factor Loadings ◽  
Component Loadings ◽  
Principal Component Model ◽  
Two Populations

Abstract. When principal component solutions are compared across two groups, a question arises whether the extracted components have the same interpretation in both populations. The problem can be approached by testing null hypotheses stating that the congruence coefficients between pairs of vectors of component loadings are equal to 1. Chan, Leung, Chan, Ho, and Yung (1999) proposed a bootstrap procedure for testing the hypothesis of perfect congruence between vectors of common factor loadings. We demonstrate that the procedure by Chan et al. is both theoretically and empirically inadequate for the application on principal components. We propose a modification of their procedure, which constructs the resampling space according to the characteristics of the principal component model. The results of a simulation study show satisfactory empirical properties of the modified procedure.

Iterative Supervised Principal Component Analysis-Driven Ligand Design for Regioselective Ti-Catalyzed Pyrrole Synthesis

2020 ◽  
Author(s):  
Xin Yi See ◽  
Benjamin Reiner ◽  
Xuelan Wen ◽  
T. Alexander Wheeler ◽  
Channing Klein ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
De Novo ◽  
Principal Component ◽  
Component Analysis ◽  
Catalyst Design ◽  
Data Driven ◽  
Initial Reaction ◽  
Training Set ◽  
Reaction Conditions ◽  
Component Loadings

<div> <div> <div> <p>Herein, we describe the use of iterative supervised principal component analysis (ISPCA) in de novo catalyst design. The regioselective synthesis of 2,5-dimethyl-1,3,4-triphenyl-1H- pyrrole (C) via Ti- catalyzed formal [2+2+1] cycloaddition of phenyl propyne and azobenzene was targeted as a proof of principle. The initial reaction conditions led to an unselective mixture of all possible pyrrole regioisomers. ISPCA was conducted on a training set of catalysts, and their performance was regressed against the scores from the top three principal components. Component loadings from this PCA space along with k-means clustering were used to inform the design of new test catalysts. The selectivity of a prospective test set was predicted in silico using the ISPCA model, and only optimal candidates were synthesized and tested experimentally. This data-driven predictive-modeling workflow was iterated, and after only three generations the catalytic selectivity was improved from 0.5 (statistical mixture of products) to over 11 (> 90% C) by incorporating 2,6-dimethyl- 4-(pyrrolidin-1-yl)pyridine as a ligand. The successful development of a highly selective catalyst without resorting to long, stochastic screening processes demonstrates the inherent power of ISPCA in de novo catalyst design and should motivate the general use of ISPCA in reaction development. </p> </div> </div> </div>

Review of Recent Advances in the Study of Unsteady Turbulent Internal Flows

1995 ◽  
Vol 48 (4) ◽  
pp. 189-212 ◽  
Author(s):  
G. J. Brereton ◽  
R. R. Mankbadi
Keyword(s):  
Turbulent Flows ◽  
Turbulence Modeling ◽  
Unsteady Flows ◽  
Turbulence Models ◽  
Research Area ◽  
Transition To Turbulence ◽  
Measurement Technology ◽  
Internal Flows ◽  
Recent Advances ◽  
The Many

Turbulent flow which undergoes organized temporal unsteadiness is a subject of great importance to unsteady aerodynamic and thermodynamic devices. Of the many classes of unsteady flows, those bounded by rigid smooth walls are particularly amenable to fundamental studies of unsteady turbulence and its modeling. These flows are presently being given increased attention as interest grows in the prospect of predicting non-equilibrium turbulence and because of their relevance to turbulence–acoustics interactions, in addition to their importance as unsteady flows in their own right. It is therefore timely to present a review of recent advances in this area, with particular emphasis placed on physical understanding of the turbulent processes in these flows and the development of turbulence models to predict them. A number of earlier reviews have been published on unsteady turbulent flows, which have tended to focus on specific aspects of certain flows. This review is intended to draw together, from the diverse literature on the subject, information on fundamental aspects of these flows which are relevant to improved understanding and development of predictive models. Of particular relevance are issues of instability and transition to turbulence in reciprocating flows, the robustness of coherent structures in wall-bounded flows to forced perturbations (in contrast to the relative ease of manipulation in free shear flows), unsteady scalar transport, improved measurement technology, recent contributions to target data for model testing and the quasi-steady and non-steady rapid distortion approaches to turbulence modeling in these flows. The present article aims to summarize recent contributions to this research area, with a view to consolidating comprehension of the well-known basics of these flows, and drawing attention to critical gaps in information which restrict our understanding of unsteady turbulent flows.

Control of flexible manipulators: A survey

Robotica ◽  
2004 ◽  
Vol 22 (5) ◽  
pp. 533-545 ◽  
Author(s):  
M. Benosman ◽  
G. Le Vey
Keyword(s):  
Linear Models ◽  
Control Strategies ◽  
Research Area ◽  
Future Research ◽  
Complex Nature ◽  
Open Problems ◽  
Complex Models ◽  
The Many ◽  
The One ◽  
Flexible Arms

A survey of the field of control for flexible multi-link robots is presented. This research area has drawn great attention during the last two decades, and seems to be somewhat less “attractive” now, due to the many satisfactory results already obtained, but also because of the complex nature of the remaining open problems. Thus it seems that the time has come to try to deliver a sort of “state of the art” on this subject, although an exhaustive one is out of scope here, because of the great amount of publications. Instead, we survey the most salient progresses – in our opinion – approximately during the last decade, that are representative of the essential different ideas in the field. We proceed along with the exposition of material coming from about 119 included references. We do not pretend to deeply present each of the methods quoted hereafter; however, our goal is to briefly introduce most of the existing methods and to refer the interested reader to more detailed presentations for each scheme. To begin with, a now well-established classification of the flexible arms control goals is given. It is followed by a presentation of different control strategies, indicating in each case whether the approach deals with the one-link case, which can be successfully treated via linear models, or with the multi-link case which necessitates nonlinear, more complex, models. Some possible issues for future research are given in conclusion.

scholarly journals Thematic atlas of Italian oncological research: the analysis of public IRCCS

2021 ◽  
pp. 109-114
Author(s):  
Corrado Cuccurullo ◽  
Luca D’Aniello ◽  
Maria Spano
Keyword(s):  
Public Health ◽  
Health System ◽  
Quantitative Research ◽  
Public Health System ◽  
Medical Science ◽  
Large Body ◽  
Past Research ◽  
Research Area ◽  
Big Picture ◽  
The Many

This paper has been developed in the frame of the research project “V:ALERE 2019” focused on Italian public-owned Academic Medical Centers. The main aim of the project is to provide evidence, advice, and remarks to help the agents of the public health system to address the many challenges that they face. In recent years, there is an increasing recognition of the potential value of research evidence as one of the many factors considered by policymakers and practitioners. Even more, in the case of medical science, the analysis of research and its impact is indispensable, in light of its implications for public health. The starting point for mapping a research area is to review the related scientific literature because by synthesizing past research findings, it is possible to effectively use the existing knowledge base and advance lines of future researches. In this sense, bibliometrics becomes useful, by providing a structured analysis to a large body of information, to infer trends over time, themes researched, and to show the “big picture” of extant research. In particular, in this work, we focus our attention on the scientific production of the last 20 years of the Scientific Institutes for Research, Hospitalization, and Healthcare (IRCCS “Istituto di Ricovero e Cura a Carattere Scientifico”) specialized in the oncology research. IRCCS are biomedical institutions of relevant national interest that drive clinical assistance in strong relation to research activities. They are committed to being a benchmark for the whole public health system for both the quality of patient care and the innovation skills in the field of the organization. All the analyses were carried out by using the Bibliometrix, an open-source tool for quantitative research in scientometrics and bibliometrics that includes all the main bibliometric methods of analysis.

scholarly journals Metabolomics pilot study identifies circadian desynchronization and distinct intra-patient variability patterns in critical illness

2019 ◽  
Author(s):  
Elizabeth R. Lusczek ◽  
Lee Parsons ◽  
Jesse Elder ◽  
Stephen B. Harvey ◽  
Mariya Skube ◽  
...  
Keyword(s):  
Pilot Study ◽  
Circadian Rhythms ◽  
Vital Signs ◽  
Principal Component ◽  
Underlying Disease ◽  
Plasma Metabolites ◽  
Metabolic Profiles ◽  
Healthy Controls ◽  
Icu Patients ◽  
Sound Levels

AbstractBackgroundSynchronized circadian rhythms play a key role in coordinating physiologic health. Desynchronized circadian rhythms may predispose individuals to disease or be indicative of underlying disease. Intensive care unit (ICU) patients likely experience desynchronized circadian rhythms due to disruptive environmental conditions in the ICU and underlying pathophysiology. This observational pilot study was undertaken to determine if circadian rhythms are altered in ICU patients relative to healthy controls by profiling circadian rhythms in vital signs and plasma metabolites.MethodsWe monitored circadian rhythms in 5 healthy controls and 5 ICU patients for 24 hours. Heart rate and blood pressure were measured every 30 minutes, temperature was measured every hour, and blood was sampled for mass spectrometry-based plasma metabolomics every 4 hours. Bedside sound levels were measured every minute. Circadian rhythms were evaluated in vitals and plasma metabolites individually and in each group using the cosinor method.ResultsICU patient rooms were significantly louder than healthy controls’ rooms and average noise levels were above EPA recommendations. Healthy controls generally had significant circadian rhythms individually and as a group. While a few ICU patients had significant circadian rhythms in isolated variables, no significant rhythms were identified in ICU patients as a group, except in cortisol. This indicates a lack of coherence in circadian phases and amplitudes among ICU patients. Finally, principal component analysis of metabolic profiles showed surprising patterns in plasma sample clustering. Each ICU patient’s samples were clearly discernable in individual clusters, separate from a single cluster of healthy controls.ConclusionsICU patients’ circadian rhythms show significant desynchronization compared to healthy controls. Clustering of plasma metabolic profiles suggests that metabolomics could be used to track individual patients’ clinical courses longitudinally. Our results show global disordering of metabolism and the circadian system in ICU patients which should be characterized further in order to determine implications for patient care.

Credit Card Use and Risks in the E-Market

2013 ◽  
pp. 214-232
Author(s):  
Huong Ha
Keyword(s):  
Pilot Study ◽  
Consumer Protection ◽  
Credit Card ◽  
Online Shopping ◽  
Research Area ◽  
The Body ◽  
Policy Recommendations ◽  
Credit Card Fraud ◽  
Body Of Knowledge ◽  
Credit Card Use

This chapter aims to (1) examine the awareness and experience of undergraduates in Melbourne, Australia of current and potential online risks, (2) explore how undergraduates deal with online incidents, and (3) make policy recommendations on how to enhance e-consumer protection. A total of 802 valid responses were received from the surveys conducted in Melbourne, Australia in 2007-2008. Findings demonstrate that most of the respondents were not aware of online incidents which could lead to credit card fraud. A number of them have encountered online incidents. Also, several respondents would less likely seek help from government and/or non-government organisations when encountering online incidents. Overall, credit card use and risks in the e-market is an under-research area in Australia, and this is a pilot study in this field. Findings from this chapter would contribute to the body of knowledge of credit card use and debt due to online shopping, and e-consumer protection.

Constrained clustering method for class-based storage location assignment in warehouse

2016 ◽  
Vol 116 (4) ◽  
pp. 667-689 ◽  
Author(s):  
Chao-Lung Yang ◽  
Thi Phuong Quyen Nguyen
Keyword(s):  
Principal Component ◽  
Constrained Clustering ◽  
Clustering Method ◽  
Content Type ◽  
Assignment Model ◽  
Retrieval Efficiency ◽  
Storage Location ◽  
Component Loadings ◽  
Location Assignment

Purpose – Class-based storage has been studied extensively and proved to be an efficient storage policy. However, few literature addressed how to cluster stuck items for class-based storage. The purpose of this paper is to develop a constrained clustering method integrated with principal component analysis (PCA) to meet the need of clustering stored items with the consideration of practical storage constraints. Design/methodology/approach – In order to consider item characteristic and the associated storage restrictions, the must-link and cannot-link constraints were constructed to meet the storage requirement. The cube-per-order index (COI) which has been used for location assignment in class-based warehouse was analyzed by PCA. The proposed constrained clustering method utilizes the principal component loadings as item sub-group features to identify COI distribution of item sub-groups. The clustering results are then used for allocating storage by using the heuristic assignment model based on COI. Findings – The clustering result showed that the proposed method was able to provide better compactness among item clusters. The simulated result also shows the new location assignment by the proposed method was able to improve the retrieval efficiency by 33 percent. Practical implications – While number of items in warehouse is tremendously large, the human intervention on revealing storage constraints is going to be impossible. The developed method can be easily fit in to solve the problem no matter what the size of the data is. Originality/value – The case study demonstrated an example of practical location assignment problem with constraints. This paper also sheds a light on developing a data clustering method which can be directly applied on solving the practical data analysis issues.

Bordered pit and ray morphology involvement in elm resistance to Ophiostoma novo-ulmi

2009 ◽  
Vol 39 (2) ◽  
pp. 420-429 ◽  
Author(s):  
Juan A. Martín ◽  
Alejandro Solla ◽  
Luis G. Esteban ◽  
Paloma de Palacios ◽  
Luis Gil
Keyword(s):  
Vessel Wall ◽  
Fungal Growth ◽  
Principal Component ◽  
Dutch Elm Disease ◽  
Mean Values ◽  
Anatomical Features ◽  
Wall Area ◽  
Pit Membrane ◽  
Vessel Wall Area ◽  
Component Loadings

The main objective of this study was to identify differential anatomical features between Ulmus pumila L. and Ulmus minor Mill. clones resistant to Dutch elm disease and U. minor clones susceptible to Dutch elm disease, with a focus on the intervascular pits and medullary rays. Resistant elms showed lower mean values than susceptible elms for pit membrane diameter, pit aperture area, pit membrane abundance per vessel-wall area, ray width, and ray tangential area. A principal component analysis of the parameters measured revealed slight differentiation between species but clearly grouped U. minor clones according to their susceptibility group. In comparison with susceptible elms, the pit structure observed in resistant elms may limit passive fungal spread within the sapflow, lower the probability of fungal cells passively reaching pit membranes, and reduce the vulnerability of the xylem to cavitation. Similarly, the ray structure observed in the resistant elms is likely to reduce the amount of easily accessible nutrients available for fungal growth as well as the rate of radial colonization in comparison with susceptible elms. Examination of the principal component loadings suggested that susceptible U. minor clones were mainly characterized by enhanced values of pit membrane abundance per vessel-wall area relative to resistant U. minor trees.

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