bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling of solution spaces in multipreconditioned FETI methods applied to structural dynamics
Authors: Leistner Michael C. , Gosselet Pierre , Rixen Daniel J.
Published: June 2018

This article presents a new method to recycle the solution space of an adaptive multipreconditioned finite element tearing and interconnecting algorithm in the case where the same operator is solved for multiple right‐hand sides like in linear structural dynamics. It accelerates the computation from the second time step on by applying a coarse space that is generated from Ritz approximations of local eigenproblems, using the solution space of the first time step. These eigenproblems are known to provide very efficient coarse spaces but must usually be solved a priori at high computational cost. Their Ritz approximations are much smaller and less expensive to solve. Recycling methods based on Ritz approximations of global eigenproblems have been published for classical finite element tearing and interconnecting algorithms, but their efficient application to multipreconditioned variants is not possible. This article also presents the application of a simpler recycling procedure, which reuses plain solution spaces, to adaptive multipreconditioned finite element tearing and interconnecting. Numerical results of the application of the presented methods to four test cases are shown. The new Ritz approximation method leads to coarse spaces, which turn out to be as efficient as those obtained from solving the unreduced eigenproblems. It is the most efficient recycling method currently available for multipreconditioned dual domain decomposition techniques.
A hybridizable discontinuous Galerkin method for two‐phase flow in heterogeneous porous media
Authors: Fabien Maurice S. , Knepley Matthew G. , Rivière Béatrice M.
Published: June 2018

We present a new method for simulating incompressible immiscible two‐phase flow in porous media. The semi‐implicit method decouples the wetting phase pressure and saturation equations. The equations are discretized using a hybridizable discontinuous Galerkin method. The proposed method is of high order, conserves global/local mass balance, and the number of globally coupled degrees of freedom is significantly reduced compared to standard interior penalty discontinuous Galerkin methods. Several numerical examples illustrate the accuracy and robustness of the method. These examples include verification of convergence rates by manufactured solutions, common one‐dimensional benchmarks, and realistic discontinuous permeability fields.
Interpersonal Dynamics in Personality and Personality Disorders
Authors: Hopwood Christopher J.
Published: June 2018

Clinical and basic personality psychologists interact less than they should, given their similar interests. In clinical personality psychology, available evidence supports a transition from the current categorical system to a hierarchical trait scheme for diagnosing the stable features of personality disorder. However, trait models do not capture the dynamic aspects of personality disorders as they have been described in the clinical literature, and thus miss a clinically critical feature of personality pathology. In contrast, basic personality psychologists have coalesced around a consensual structure of individual differences and become increasingly interested in the dynamic processes that underlie and contextualize traits. But trait psychology models are not sufficiently specific to characterize dynamic personality processes. In this paper, I filter clinical descriptions of personality disorders through the lens of interpersonal theory to specify a recursive within–situation interpersonal pattern of motives, affects, behaviours, and perceptions that could contribute to the stable between–situation patterns of maladaptive behaviour of historical interest to both basic and clinical personality psychologists. I suggest that this interpersonal model adds specificity to recent proposals regarding processes in the basic personality literature and has significant potential to advance research on personality dynamics. © 2018 European Association of Personality Psychology
Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties
Authors: Yang Yanhua , Ding Zijun , Xia Jingcheng , Zheng Youxuan , Ding Shijin , Shen Yingzhong
Published: June 2018

To better understand the structure–property relationships, two novel aromatic diamines containing tetraphenyl fluorene (TPF) moiety through triphenylamine (TPA) unit and carbazole (Cz) unit modification are designed and synthesized, respectively. Four thermally stable and excellent solubility polyimides are prepared and characterized. The excellent film‐formation ability and thin film stability are investigated by X‐ray diffraction (XRD) and atom force microscopy (AFM) measurements, respectively. The memory devices are fabricated, PIs films with low water uptakes sandwiched between indium‐tin oxide (ITO) ground electrode and Al top electrode, and exhibit nonvolatile write‐once read‐many‐times (WORM) memory behaviors with low threshold voltages, due to increasing the retention time through regulating the energy level. The current conduction mechanisms of all devices are linearly fitted by theoretical conduction model. Molecular simulations are used to demonstrate switching mechanism and the memory effects. The experimental results provide a sight for the design‐adjustable switching voltage of memory devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1630–1644
Perceived doctor‐patient relationship and its association with demoralization in patients with advanced cancer
Authors: Quintero Garzón Leonhard , Koranyi Susan , Engelmann Dorit , Philipp Rebecca , Scheffold Katharina , Schulz‐Kindermann Frank , Härter Martin , Mehnert Anja
Published: June 2018

Background

Advanced diseases pose a great burden on patients and go hand in hand with existential concerns. Demoralization is considered as a syndrome of existential distress with a perceived inability to cope with loss of meaning in life and feelings of helplessness and hopelessness. Professional health care providers play an important role in providing support for patients and unfavorable conversational styles in their relationship can increase patient's distress. In this study, we examine the association between the patient's perceived relationship to health care providers and demoralization.

Methods

We used baseline data of a randomized control trial intervention study for advanced cancer patients (UICC‐Stage ≥ III; PHQ ≥ 9 and/or Distress‐Thermometer ≥5). We used a subscale of the QUAL‐EC‐P for assessing doctor‐patient relationship, Beck Depression Inventory‐II for depressive symptoms, a modified version of the MSAS as physiological symptom checklist, and the Demoralization Scale to assess demoralization. A hierarchical regression analysis was calculated.

Results

In our sample of 187 patients with stage III or IV cancer (62% women), demoralization was present in 53.4% (16% moderate demoralization; 37.4% high demoralization) of the patients. Relationship to health care provider was an independent predictor (β = −.33, t(186) = −6.70, P < .001) of demoralization.

Conclusions

Our findings underline the importance of the physician‐patient relationship in the context of coping with existential challenges in advanced cancer patients. Trainings on how to communicate and build a sustainable relationship with patients and their specific needs may increase the buffering effect of social support by the physicians on patient's existential distress.
In Situ Mass Spectrometric Reaction Monitoring of Atmospheric Corrosion Processes
Authors: Hölzl Georg , Schimo Gabriela , Luckeneder Gerald , Duchaczek Hubert , Kleber Christoph , Hassel Achim Walter
Published: June 2018

A set‐up for in situ mass spectrometric reaction monitoring of gas phase mediated reactions is presented. Important constructive parameters for a reaction chamber for the investigation of atmospheric corrosion processes is discussed. The presented cell is especially well suited for atmospheric corrosion studies but it can easily be modified to be applicable in other fields of research as well. The atmospheric corrosion of electrolytically deposited zinc surfaces on steel during wet‐ and dry‐cycles is investigated as a model reaction. Corrosion rates as well as current densities during the first wet‐ and dry cycle are calculated and discussed. Complementary scanning Kelvin probe (SKP) measurements are performed to show the electrochemical changes occurring at the metal/air‐interface throughout the corrosion process. Contact potential difference versus distance measurements performed in advance to determine the maximum measurement distance, which allows investigating rough salt loaded sample surfaces via SKP surface scans.
In Situ Characterization and Modification of β‐Ga2O3 Flakes Using an Ion Micro‐Probe
Authors: Peres Marco , Alves Luis C. , Rocha Flávia , Catarino Norberto , Cruz Carlos , Alves Eduardo , Silva Ana G. , Víllora Encarna G. , Shimamura Kiyoshi , Lorenz Katharina
Published: June 2018

In situ characterization of β‐Ga2O3 flakes during proton irradiation is performed using ionoluminescence and electrical measurements. The quenching of the native blue‐UV emission bands due to irradiation‐induced defects in real time is monitored by ionoluminescence. Measurements of the I–V characteristics during irradiation present a good response of Ga2O3 for particle detection and a good radiation resistance.
Unscented and square‐root unscented Kalman filters for quaternionic systems
Authors: Menegaz Henrique M.T. , Ishihara João Y.
Published: June 2018

Proper construction of an unscented Kalman filter (UKF) for unit quaternionic systems is not straightforward due to the incompatibility between the algebraic properties of the unit quaternions and the common real vector space operations (additions and scalar multiplications) needed in the steps of a filter algorithm. This work studies, in detail, all UKFs and square‐root UKFs for quaternionic systems proposed in the literature. First, we classify the algorithms according to the preservation of the unity norm of the quaternion variables. Second, we propose two new algorithms: the quaternionic additive unscented Kalman filter (QuAdUKF) and a square‐root variant of it. The QuAdUKF encompasses all known UKFs for quaternionic systems of the literature preserving, in all steps, the norm of the unit quaternion variables. Besides, it can also yield new UKFs with this norm preservation property. The QuAdUKF's square‐root variant has better properties in comparison with all the square‐root UKFs for quaternionic systems of the literature. Numerical experiments for a spacecraft attitude estimation problem illustrate the theoretical results.
Estimating contributions from nursery areas to fish stocks in freshwater systems using otolith fingerprints: The case of the streaked prochilod in the La Plata Basin (South America)
Authors: Avigliano E. , Pisonero J. , Sánchez S. , Dománico A. , Volpedo A. V.
Published: June 2018

Stock composition studies using otolith fingerprints have scarcely been developed in freshwater systems. In this context, the La Plata Basin is the second largest fluvial‐marine system of South America, where Prochilodus lineatus is the most important fishery resource. Despite the basin importance, estimation of mixed stock composition has not been explored yet. In this paper, the contribution of the two main nursery areas to two fishing stocks (Uruguay and Paraná rivers) of P. lineatus was evaluated using otolith's core microchemistry, considering two groups: subadult (2 years) and adult (4 years). Estimates were made using two maximum likelihood methods. Chemical composition of young‐of‐year fish caught in nursery areas in 2010 was used as baseline of the models, whereas chemical composition of the core of subadult and adult otoliths was used as sample of unknown origin. Results suggest that the subadult stock from Paraná was not mixed (contribution ~ 100%), whereas the stock from Uruguay had a contribution from the Paraná nursery (1.5 ± 1.2–17.9 ± 3.96%). For the adults, the degree of mixing increased and the contribution from both nursery areas to the Paraná and Uruguay stocks varied between 14.8 ± 4.18% and 85.2 ± 4.18%, respectively. The potential application of otolith fingerprints and maximum likelihood mixture models is here highlighted for determining the relative importance of recruitment sources of fish in the La Plata Basin. Because the contributions of the different nursery areas shared among several nations in turn affect the composition of internationally shared stocks, comprehensive management agreements at the basin level are necessary.
Value creation and value capture in governing shareholder relationships: Evidence from a policy experiment in an emerging market
Authors: Jia Nan , Shi Jing , Wang Yongxiang
Published: June 2018

Research Summary

Protecting minority shareholders is a central issue in corporate governance. A common tool of empowering minority shareholders is to curb controlling shareholders’ power of expropriating firm value, but this approach was rarely successful because of the resistance from powerful controlling shareholders. We examine an alternative way of empowering minority shareholders without directly fighting with controlling shareholders. A major corporate governance reform in China gave minority shareholders a decision right over certain actions that affected the creation of firm value. We demonstrate that the greater the extent to which minority shareholders’ actions can influence the firm's value ex post, the more value controlling shareholders concede to minority shareholders ex ante. This effect becomes even stronger when controlling shareholders are able to expropriate a larger portion of firm value.

Managerial Summary

Minority shareholders often have to contend with excessive extraction of firm value by powerful controlling shareholders, particularly in emerging markets. When this tension is considered as a zero‐sum game in which every gain to controlling shareholders has to come from a loss to minority shareholders, controlling shareholders strongly resist any effort to empower minority shareholders. We propose an alternative approach to empower minority shareholders. A major reform of Chinese listed firms bestowed on minority shareholders decision rights to take certain actions that could ex post create a larger “pie” (firm value) for all shareholders. We find that controlling shareholders give away greater value ex ante to minority shareholders to induce more of these actions. Consequentially, minority shareholders are more effectively empowered when they can affect firm value.
Realization of Foldable Polymer Solar Cells Using Ultrathin Cellophane Substrates and ZnO/Ag/ZnO Transparent Electrodes
Authors: Li Hongjiang , Liu Xiaohui , Wang Weiyan , Lu Yuehui , Huang Jinhua , Li Jia , Xu Junjun , Fan Pengxuan , Fang Junfeng , Song Weijie
Published: June 2018

Foldable solar cells have attracted increasing attention for portable and wearable applications. The challenge to achieve foldability is free from the formation of cracks under large strain. Our mechanical simulations suggests that a reduction in substrate thickness from 150 to 25 μm is a means to mitigate the strain in polymer solar cells under folding with extremely small curvature radius of sub‐millimeter. The polymer solar cells are experimentally prepared on ultrathin 25 μm cellophane substrates with ZnO/ultrathin Ag/ZnO (OMO) transparent electrodes, instead of conventional ITO, composing a typical device structure, cellophane/OMO/ZnO/PTB7‐Th:PC71BM/MoO3/Al. The solar cells exhibit a power conversion efficiency of 5.94% and a power weight ratio of 2.11 W g−1. After folding the solar cells for 35 cycles, the conversion efficiency still maintained 92% of the initial value, which is mainly ascribed to the synergistic effects of ultrathin substrates and the OMO electrodes, as inferred from the stable resistance of the cellophane/ZnO/ultrathin Ag/ZnO even after 50 folding cycles. This work paves the way toward realizing superior foldability not only in solar cells, but also in other optoelectronic devices.
Heterogeneous signcryption with keyword search for wireless body area network
Authors: Omala Anyembe Andrew , Ali Ikram , Li Fagen
Published: June 2018

Wireless body area network (WBAN) is composed of sensors that capture and transmit physiological data to an application provider's (AP) remote server. When integrated into the Internet of Things (IoT) infrastructure, WBAN data can be accessed from anywhere and at anytime. A secure storage and access mechanism to this sensitive data is necessary within a heterogeneous IoT. Searchable encryption (SE) provides secure method that could be used by an AP for example, hospital employees to securely access a patient's medical record. This is achieved by sending a trapdoor function to remote server. In this paper, we propose a new SE technique based on a signcrypted keyword and a designated tester. It is constructed from Li et al.'s practical signcryption scheme. In the proposed scheme, a data owner (WBAN) operates in certificateless cryptography, while a designated tester (server) and a receiver are both in public key infrastructure environment. We use both authenticity and confidentiality property of a signcryption scheme to proof that our scheme is provably secure against keyword guessing attack. A quantitative analysis on performance against other certificateless SE schemes shows that our scheme is computationally lightweight during keyword‐ciphertext and trapdoor generation.
Enhancing ambition levels in nationally determined contributions—Learning from Technology Needs Assessments
Authors: Hofman Erwin , van der Gaast Wytze
Published: June 2018

Under the Paris Agreement, countries are to develop nationally determined contributions (NDCs) every 5 years, outlining their climate targets and plans. In order to ease this task, countries may use the experiences with the Technology Needs Assessment (TNA) program. In this paper, lessons with TNAs since 2001 are described, and it is analyzed how countries, with a focus on developing countries, may use these lessons in strengthening and implementing their successive NDCs. While some developing countries have already used the results of their TNA process in their NDC development, countries could benefit from following the TNA process, its stakeholder involvement, and the multi‐criteria decision analysis (MCDA) methodology, to strengthen their NDCs. Countries face challenges in their NDC with regard to the embedding of the contribution into the national development strategy, getting from plans to implementation, and the mobilization of finance. Through the positive and negative experiences with TNAs, countries can overcome these challenges. It is argued that all countries can use the TNA or parts thereof in their NDC process. For developing countries (mainly Least Developed Countries and Small Island Developing States) the TNA is useful for capacity building, strategy development, and the preparation of projects for investment with international support. Emerging markets and newly‐industrialized countries can use the TNA as a participatory approach for strategy development. Developed countries generally do not need the entire TNA process, but the participatory approaches and MCDA can be used to fine‐tune modeled strategies.

This article is categorized under:

Energy and Climate > Economics and Policy

Energy and Climate > Climate and Environment

Energy and Development > Climate and Environment
Biadjoint scalar tree amplitudes and intersecting dual associahedra
Authors: Frost Hadleigh
Published: June 2018

Abstract

We present a new formula for the biadjoint scalar tree amplitudesm(α|β) based on the combinatorics of dual associahedra. Our construction makes essential use of the cones in ‘kinematic space’ introduced by Arkani-Hamed, Bai, He, and Yan. We then consider dual associahedra in ‘dual kinematic space.’ If appropriately embedded, the intersections of these dual associahedra encode the amplitudesm(α|β). In fact, we encode all the partial amplitudes atn-points using a single object, a ‘fan,’ in dual kinematic space. Equivalently, as a corollary of our construction, alln-point partial amplitudes can be understood as coming from integrals over subvarieties in a toric variety. Explicit formulas for the amplitudes then follow by evaluating these integrals using the equivariant localisation formula. Finally, by introducing a lattice in kinematic space, we observe that our fan is also related to the inverse KLT kernel, sometimes denoted$$ {m}_{\alpha^{\prime }}\left(\alpha \Big|\beta \right) $$mα′α|β.
Hypophosphatemia as a Predictor of Organ‐Specific Complications Following Gastrointestinal Surgery: Analysis of 8034 Patients
Authors: Sadot Eran , Zheng Jian , Srouji Rami , Strong Vivian E. , Gönen Mithat , Balachandran Vinod P. , D’Angelica Michael I. , Allen Peter J. , DeMatteo Ronald P. , Kingham T. Peter , Fong Yuman , Weiser Martin R. , Jarnagin William R.
Published: June 2018

Background

Organ‐specific complications (OSC) remain serious potential sequela of gastrointestinal surgery. Hypophosphatemia correlates with poor outcomes and may be a harbinger of OSC after gastrointestinal surgery. Our goal was to describe and evaluate the relationship between postoperative phosphate levels and OSC.

Methods

Consecutive patients who underwent pancreatic, colorectal, or gastric resections were analyzed. OSC were defined as those resulting from the failure of at least one anastomosis performed during the primary resection, manifesting as an anastomotic leak, fistula, and/or intra‐abdominal abscess. Postoperative serum phosphate levels and other recognized OSC risk factors were compared among patients who did and did not develop OSC.

Results

A total of 8034 patients who underwent pancreatic (n = 397), colorectal (n = 5808), or gastric (n = 1829) resections were included in the study. In each resection group, the majority of patients experienced hypophosphatemia postresection with the nadir on postoperative day (POD) 2, and the subgroups that developed OSC exhibited lower phosphate levels on POD3–7. On multivariate analysis, lower phosphate level on POD3 remained significantly associated with OSC following pancreatic resection [median (interquartile range) mmol/L, 0.65 (0.53–0.76) vs. 0.71 (0.61–0.84), p = 0.045] and colorectal resection [0.71 (0.61–0.87) vs. 0.77 (0.65–0.94), p = 0.006], and lower phosphate level on POD4 remained associated with OSC following gastric resection [0.87 (0.74–1.03) vs. 0.96 (0.81–1.13), p = 0.049].

Conclusion

This study identified a consistent trajectory of serum phosphate levels following 3 different gastrointestinal operations and association between early postoperative phosphate levels and OSC. Persistent lower phosphate levels should raise the level of concern for evolving postoperative leak and may lead to earlier radiographic evaluation and treatment.
Risk Adjustment Is Necessary in Value-based Outcomes Models for Infected TKA
Authors: Courtney P. Maxwell , Boniello Anthony J. , Della Valle Craig J. , Lee Gwo-Chin
Published: June 2018

Background

The Medicare Access and CHIP Reauthorization Act of 2015 provides the framework to link reimbursement for providers based on outcome metrics. Concerns exist that the lack of risk adjustment for patients undergoing revision TKA for an infection may cause problems with access to care.

Questions/purposes

(1) After controlling for confounding variables, do patients undergoing revision TKA for infection have higher 30-day readmission, reoperation, and mortality rates than those undergoing revision TKA for aseptic causes? (2) Compared with patients undergoing revision TKA who are believed not to have infections, are patients undergoing revision for infected TKAs at increased risk for complications?

Methods

We queried the American College of Surgeons National Surgical Quality Improvement Program database for patients undergoing revision TKA from 2012 to 2015 identified by Current Procedural Terminology (CPT) codes 27486, 27487, and 27488. Of the 10,848 patients identified, four were excluded with a diagnosis of malignancy (International Classification of Diseases, 9th Revision code 170.7, 170.9, 171.8, or 198.5). This validated, national database records short-term outcome data for inpatient procedures and does not rely on administrative coding data. Demographic variables, comorbidities, and outcomes were compared between patients believed to have infected TKAs and those undergoing revision for aseptic causes. A multivariate logistic regression analysis was performed to identify independent factors associated with complications, readmissions, reoperations, and mortality.

Results

After controlling for demographic factors and medical comorbidities, TKA revision for infection was independently associated with complications (odds ratio [OR], 3.736; 95% confidence interval [CI], 3.198-4.365; p < 0.001), 30-day readmission (OR, 1.455; 95% CI, 1.207-1.755; p < 0.001), 30-day reoperation (OR, 1.614; 95% CI, 1.278-2.037; p < 0.001), and 30-day mortality (OR, 3.337; 95% CI, 1.213-9.180; p = 0.020). Patients with infected TKA had higher rates of postoperative infection (OR, 3.818; 95% CI, 3.082-4.728; p < 0.001), renal failure (OR, 36.709; 95% CI, 8.255-163.231; p < 0.001), sepsis (OR, 7.582; 95% CI, 5.529-10.397; p < 0.001), and septic shock (OR, 3.031; 95% CI, 1.376-6.675; p = 0.006).

Conclusions

Policymakers should be aware of the higher rate of mortality, readmissions, reoperations, and complications in patients with infected TKA. Without appropriate risk adjustment or excluding these patients all together from alternative payment and quality reporting models, fewer providers will be incentivized to care for patients with infected TKA.

Level of Evidence

Level III, therapeutic study.
Crohn's disease versus Yersinia enterocolitica infection — case report — a difficult differential diagnosis
Authors: Almeida Clarissa Maria Gomes de , Maluf Fauze Camargo , Maluf Feres Camargo , Lanzoni Valeria P. , Kiss Desidério Roberto , Almeida Maristela Gomes de
Published: June 2018

The aim of this report is to present an unusual case of Crohn's disease affecting the terminal ileum; whose principal differential diagnosis was Yersinia enterolocolitica infection, as the histological features of the resected ileum was common to both diseases. We also describe how the infectious etiology was discarded and the implications for the patient follow-up.
Adult Buried Penis Repair with Escutcheonectomy and Split-Thickness Skin Grafting
Authors: Strother Marshall C. , Skokan Alexander J. , Sterling Matthew E. , Butler Paris D. , Kovell R. Caleb
Published: June 2018

Aim

To describe a technique for surgical correction of adult buried penis, including a technique for skin graft harvesting from the escutcheonectomy specimen itself, with an emphasis on remaining open questions in the literature.

Methods

We present our method for surgical correction of adult buried penis with a review of the literature.

Main Outcome Measure

Components of successful buried penis repair include return of directed voiding, elimination of local skin inflammation and infection, improvement in hygiene, return of sexual functioning, cosmesis, and patient satisfaction. To date, there are no broadly accepted tools for comprehensive measurement of outcomes after buried penis repair.

Results

Adult buried penis repair is generally associated with excellent rates of satisfaction and improvement in functioning. Currently available data are extremely limited; however, they do suggest that, when in doubt, more aggressive debridement of diseased tissue combined with split-thickness skin grafting may provide superior outcomes. Split-thickness skin grafts are associated with excellent rates of successful graft take, even in cases of severe preoperative pathology and patient comorbidity. Although these grafts come at the cost of some increased surgical morbidity, they are associated with low rates of major complications. Morbidity can be further significantly decreased by harvesting the graft from the excised escutcheon itself, a technique that we present here.

Conclusion

Surgical correction of adult buried penis is safe and effective; however, future work is required to further optimize outcomes and reduce surgical morbidity.
Surgeons Corner: Cavernoscopy for Rear Tip Extender Removal
Authors: Thirumavalavan Nannan , Hoover Christopher R.V. , Gross Martin S.
Published: June 2018

Introduction

Cavernoscopy (using a cystoscope in the corpora) is traditionally used to retrieve rear tip extenders (RTEs) that are embedded at the time of removal or replacement of inflatable penile prostheses.

Aim

To describe indications and techniques of cavernoscopy.

Methods

We describe our preferred method of cavernoscopy to retrieve retained rear tips and present a thorough review of the literature regarding cavernoscopy.

Main Outcome Measure

Ability of cavernoscopy to retrieve embedded rear tips without causing complications.

Results

Cavernoscopy is feasible anecdotally in case reports, but other less-invasive methods of retrieving RTEs seem to have similar efficacy.

Conclusion

Cavernoscopy is a technically feasible procedure that can be attempted as part of a stepwise algorithm for removing retained RTEs.
VII Interpretations and Conjectures
Authors: Ford James A. , Quimby George I.
Published: June 2018

A comparison of Tchefuncte traits suggests that there are three groupings or foci which at present comprise the Tchefuncte culture. The Copell site on Pecan Island, although a single site, represents the first group. The absence of pottery, presence of artifacts with burials, interment in a cemetery, and other traits tend to isolate this component from other Tchefuncte groupings.

The three shell midden sites, Tchefuncte, Little Woods, and Big Oak Island form another grouping. The construction and use of shell middens, presence of certain types of bone and shell artifacts, and styles of chipped flint projectile points differentiate these midden sites from the others.

The third grouping is represented by the two mound sites, Lafayette and Lake Louis. The traits of circular mounds, differences in the styles of projectile points, and absence of other Tchefuncte traits delimit this focus.

A number of traits held in common, or traits which overlap from one component or site to another, link all of these groupings together to form the Tchefuncte culture. For instance, burial traits and styles of bone implements link the Copell site with the midden sites of the Tchefuncte period. The midden sites and the mound sites are bound together by common types of pottery and pipes. For the reader who disagrees with our interpretations, or who has a better method, we have listed all of our traits in the summaries of each component (Chapter II).
Preceramic Cultures in Chicama and Virú
Authors: Bird Junius B.
Published: June 2018

This is a tentative résumé of the work done on the preceramic horizons in Chicama and Virú valleys as a part of the Virú Valley Project of 1946. Before summarizing the results of excavations in the old midden deposits, mention should be made of the recent physiographic changes in the Virú Valley. These have a definite connection with the prehistory.

The drainage of the south arm of the valley starts at an elevation of slightly over 4000 meters with the two highest forks on the flanks of a 4200 meter peak. This section is today completely ice free, but as the general level for glacial moraines in this part of Peru runs between 3200 and 3400 meters, with one moraine in the Callejon de Huaylas down to 1800 meters, it is obvious that the physiography of the valley was once influenced by water either discharged directly from glaciers or draining from a greater area of condensation.
Peruvian Stylistic Influences in Ecuador
Authors: Collier Donald
Published: June 2018

Several attempts have been made in the past to recognize in prehistoric Ecuador the influence of various Peruvian horizon styles. These Peruvian influences, if real, are of considerable chronological and historical importance. It is my purpose to examine and assess them by considering three groups of Ecuadorean materials, namely, ceramics, gold, and gilded copper from Azuay, and carved stone from Manabí.

In order to interpret fully the meaning of Peruvian resemblances in Ecuador, it is necessary to know the relative chronological position of the Ecuadorean materials showing these resemblances. Unfortunately, despite the advantage of a widely distributed Inca horizon style in Ecuador, which serves to identify the terminal phases of regional archaeological sequences, there is no satisfactory chronological system for the country as a whole, nor for any one of its regions.
The McClallum Middle Fraser Collection
Authors: Smith Marian W.
Published: June 2018

All of the artifacts of the McClallum Middle Fraser Collection were found on the McClallum farm a few miles northwest of Agassiz, British Columbia. A large habitation site is located on the farm on a ridge facing what may once have been a water connection between Harrison Lake and the Fraser River. This habitation site was mapped in 1945, and has been described elsewhere. In that year, the Columbia University Summer Field Party studied the collection and introduced Mr. McClallum to Mr. A. E. Pickford, then of the Provincial Museum, Victoria, who joined the party for a few days. The collection was moved to the museum under his direction.
Physical Stratigraphy
Authors: King Arden R.
Published: June 2018

It is proposed to discuss the physical aspects of the stratigraphy before entering into a discussion of the cultural remains of the Cattle Point site. The reasons for this are manifold. First, the differentiation of the strata on a purely physical basis will give us some idea of the different occupations of the site. Second, the widely differing nature of the layers offers some opportunity of dating the cultural remains in terms of strata which show time and content differences. Third, the shell and animal remains of the strata provide still another basis for differentiating the archaeological remains of the site. These reasons, and many more which will come out in the following discussion, serve as adequate cause for considering the physical aspects of the strata before the cultural.

In the three main areas of the site which were excavated we find distinct stratification. There exists a correlation between all three areas of the site as well.
Ornaments and Decorated Objects
Authors: King Arden R.
Published: June 2018

Canine tooth: 1 (L 3.75). Large canine tooth with grooving at tip of the root for attachment to a string or thong. From the Late phase (Fig. 17,1).

Constricted neck pendant: 1 (L 3.1; breadth of base 1.5; breadth of neck 0.9; breadth of head 1.3). A finely ground and polished pendant of generalized rectanguloid shape. The grinding has produced a constriction near one end, isolating that end as a head for attachment. Encircling the head end are two grooves. The bottom end has one encircling groove. A perforation runs laterally through the pendant at the constriction. Elliptical cross section. From the Developmental phase (Fig. 17,2).
Un-Dating the Canadian Arctic
Authors: McGhee Robert , Tuck James A.
Published: June 2018

While the C-14 Method of dating has perhaps been the most important tool ever developed for prehistorians, the results of this technique have not been an unmixed blessing. This is especially true in the far north where wood charcoal, the standard medium for C-14 determinations in most other areas, is only infrequently recovered. Other substances—bone, ivory, blubber, and skin from sea mammals; sod, grass, and peat; bone and antler from terrestrial mammals; and occasionally driftwood or locally available twigs either burned or unaltered—have been submitted for radiocarbon analysis in the hope of unraveling the complex relationships between man and nature in the Arctic through the development of accurate absolute chronologies of events which characterized Eskimo prehistory during the last four or five thousand years.

Most prehistorians engaged in Arctic research have long been aware of gross inconsistencies in the results obtained from C-14 laboratories, and several specialists from these laboratories have offered suggestions for correcting our anomalous results. To date, however, no one seems to have taken the trouble to collect radiocarbon determinations from the Arctic and evaluate them with respect to the known but only partially explained discrepancies between dates obtained on wood charcoal and those obtained on other substances. The following attempt to do so for Arctic Canada and northern Greenland is an indication of what might be accomplished by a less indiscriminate use of radiocarbon dates.
Pre-Dorset and Dorset Artifacts: The View from Lake Harbour
Authors: Maxwell Moreau S.
Published: June 2018

Throughout the geographic and temporal range of dorset there is little yet documented to indicate major cultural changes. The Pre-Dorset part of the Paleoeskimo continuum is better known by its lithic artifacts, and to date too few sites have produced non-lithic ones to afford a clear picture of technological development. On the other hand, there is enough available information on the two periods to indicate that some non-lithic artifacts reflect a regularity in the shifting styles of discrete attributes over those thirty-five hundred years involved. Such minor style shifts do not readily appear functional in the sense of producing a more efficiently adaptive weapon, and some seem to entail more manufacturing energy coupled to greater risk of breakage without apparent gain in efficiency. Regardless of the reasons for these changes in style, they appear to occur simultaneously over relatively broad areas and appear to indicate an intensity of information exchange and cultural conformity within such areas. This is most notable within what has been called the core area (see Introduction): a region including North Baffin and Bylot Islands, the Fury and Hecla Straits, Southampton, Coats, and Mansel Islands, both shores of Hudson Strait, and southern Baffin Island at least as far north as Cumberland Sound. As McGhee (this volume) has suggested, there are periods in which this stylistic homogeneity extended into the High Arctic, and different periods in which the Central Arctic as far west as Victoria Island (but not the High Arctic) participated in many of these discrete style shifts.
Environmental Factors in the Evolution of Dorset Culture: A Marginal Proposal for Hudson Bay
Authors: Fitzhugh William
Published: June 2018

Despite continued attention from archaeologists the origin of Dorset culture in the Eastern Arctic remains a persistent problem in northern prehistory. The transition from late Pre-Dorset to early Dorset culture is marked by a relatively rapid and consistent typological shift throughout a large geographic area at between about 1000 and 800 B.C. Although hampered by a distinct paucity of information, available chronological and distributional data do not supply a ready explanation for such consistent changes over such a wide-flung territory. However, the lack of a time slope and the presence of regional variants do not suggest that Dorset origins will be found in a single locale; rather, the transition appears to have occurred throughout a band of interacting populations within the core area of the eastern Central Arctic. Subsequent changes may be seen as a result of stylistic evolution, diffusion, and migration into more peripheral regions during the maximum extension of the Dorset sphere.
Radiocarbon Dates and Early Man
Authors: Roberts Frank H. H.
Published: June 2018

The results of carbon 14 tests on materials falling within the early man category are in some respects as surprising as a few of those in other fields, but on the whole they are reasonably satisfactory. Because of the regional distribution of the samples and the number of people who sent them in, several nominally belonging in this group are discussed elsewhere. The latter include Gypsum cave, Leonard rockshelter, the early horizons in California and Oregon and the material from South America.

The age of the well-known Folsom complex caused considerable comment when the figure pertaining to the type site was released. The average of 4283 ± 250 years obtained from sample 377 was entirely too low in the opinion of many archaeologists and geologists and was completely out of line with dates for other materials known to be later stratigraphically. Because of this, Harold J. Cook, who provided the charcoal used in the test, returned to and carefully reexamined the Folsom quarry in 1950.
Comments on Radiocarbon Dates from Mexico
Authors: de Terra Helmut
Published: June 2018

In the Summer of 1949, I was asked to 1 cooperate in securing appropriate samples from important Mexican sites. These, I suggested, should be selected with a view of obtaining new data on three significant problems: early man and associated geologic formations, the Archaic cultures, and the monumental civilizations of Teotihuacan and Monte Alban. This choice was dictated by the prevailing chronologic uncertainties of prehistoric cultures in Mexico and by my previous geologic approaches to time sequences in the Basin of Mexico. Computations from glacial, lake and erosion phenomena had suggested that previous age estimates, notably those presented by Vaillant (1944) and other archaeologists, had been unduly conservative. This was especially evident in the case of the basic pottery levels, known as the early Archaic or early Middle cultures, then assumed to have existed about 2100 to 1600 years ago.
The Lascaux Cave
Authors: Movius Hallam L.
Published: June 2018

The Lascaux Cave, one of the most important single sites of upper Palaeolithic art ever discovered, is located near Montignac (Dordogne), 16 miles up the Vézère River from the famous town of Les Eyzies. It was found in September 1940 by two French schoolboys out rabbit hunting. Called the “Versailles of Prehistoric Man,” Lascaux ranks among the world's oldest and most remarkable art galleries. It has been completely sealed off from the outside world since late upper Pleistocene times, and it is now generally believed that the majority of the paintings are upper Perigordian (Gravettian) in date—Phase 2 in the upper Palaeolithic art sequence of western Europe. That they were produced during a time of climatic amelioration, possibly the one known as the Achen retreat, is borne out by the fact that the animals depicted belong much more to a steppe and forest type of fauna, than they do to a colder tundra group. For example, there are no mammoths and no reindeer shown, but there are many horses, a considerable quantity of cattle, bison and several ibexes.
Discussion of the Geologic Material Dated by Radiocarbon, a Brief
Authors: Flint Richard Foster
Published: June 2018

Results from the geologic material are necessarily spotty, owing to the difficulties involved in obtaining samples that were both suitable for assay and derived from horizons whose stratigraphic position is known unequivocally. Many samples assayed were taken from horizons whose stratigraphic position is subject to doubt.

Two general results have emerged from the assay of samples of primarily geologic significance: (1) The dates obtained fall roughly into the same order as the stratigraphic sequence of deposits from which the corresponding samples were collected. From this it is inferred that most of the dates are acceptable as to relative position. (2) The dates obtained are generally more recent than had been believed by many geologists. A result of this nature has been welcomed by some, who believe it is more consistent with the observed slight weathering and erosion of the latest drift sheets than are the older dates current hitherto.
Problems related to delimiting the culture areas of Asia
Authors: Bacon Elizabeth E.
Published: June 2018

Since 1944, the writer has given some thought to the problems of marking out the culture areas of Asia, although there has not been opportunity for anything like a comprehensive trait distribution study of the continent (Bacon & Hudson, 1945; Bacon, 1946). This paper, then, must be regarded only as a tentative second step in formulating some of the problems involved, and in mapping the culture areas of the continent (cf. Naroll, 1950, for mapping of Bacon, 1946).

Sapir defined culture areas as “groups of geographically contiguous tribes that exhibit so many cultural traits in common as to contrast with other such groups” (1949, p. 425). Although in Asia we are frequently dealing with nations rather than with tribes, Sapir's definition appears for the most part to be as acceptable for Asia as Wissler and Kroeber found it for North America and Herskovits for Africa.
Some Problems in the Relationship between Tlingit Archaeology and Ethnology
Authors: de Lacuna Frederica
Published: June 2018

In 1949, I undertook an archaeological and ethnological survey of northern Tlingit territory in Alaska. Whereas a good deal was known about Tlingit ethnology, the archaeology of these people was virtually unexplored. Although the northern Tlingit have a culture which is in many respects less rich than that of their southern neighbors, they were presumably middlemen in passing on to the latter those cultural influences which eminated from the Asiatic North Pacific. Also in northern Tlingit territory we ought to find an archaeological horizon or horizons characterized by those traits which link the ancient cultures of the Aleut and Pacific Eskimo area and the Coast Salish area.

The tribal territories of the Yakutat on the Gulf of Alaska and of the Angoon or Hootznuwu on Admiralty Island near the center of the southeastern Alaskan archipelago were found to be the most promising for a study of Tlingit culture history, and accordingly in 1950 a whole season was spent at Angoon.
2. History
Authors: Heyerdahl Thor , Skjölsvold Arne
Published: June 2018

A brief synopsis of post-Spanish activities in the Galapagos will here be included since the prehistory of the islands may be better appreciated against the background of known historic events.

The group was visited for the first time by Europeans in 1535, when a ship carrying the Bishop of Panama, Tomás de Berlanga, was helplessly caught by the offshore current while sailing southwards along the mainland coast bound for Peru. In the area where El Niño and the Humboldt Current join forces Berlanga's sailing vessel was caught in a 6-day lull and immediately started a rapid drift away from the coast. After drifting helplessly in the doldrums for 10 days the vessel came in sight of an island on the 10th day of March. In a subsequent report from Tomás de Berlanga to the Emperor of Spain, dated the 26th of April, 1535, the Bishop speaks of the futile search for water on this newly discovered island where the ship's crew encountered strange iguanas resembling serpents and tortoises so large that each one could carry a man on its back.
6. Additional Archaeological Evidence from the Galápagos
Authors: Heyerdahl Thor , Skjölsvold Arne
Published: June 2018

In 1954, 2 years after our expedition to the Galápagos, the group was visited by J. C. Courier and C. Hall of the Walt Disney Galápagos Expedition, which made use of some of the local guides that had served in our expedition and were thus trained in the general search for surface archaeology. In a letter from Mr. Couffer (dated Dec. 18, 1954), he states that their expedition visited a tiny bight behind Cabo Colorado on the coast of Santa Cruz Island. In this bight (which was not visited by our expedition) they found a cleared landing place for small boats, with the lava rocks stacked to form a small sea wall. Ashore, at the bottom of a shallow valley, they found quantities of European artifacts, such as “broken heavy demijohn material, broken glassware, fragments of clay pipes, iron artifacts, European chinaware, and other recent material.”