bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimentelle Analyse der Dynamik von Zahnradgetrieben – Teil 1
Authors: Šmeringaiová Anna , Vojtko Imrich , Monková Katarína
Published: January 2015

Der vorliegende Beitrag befasst sich mit der Problematik der
experimentellen Bewertung der Dynamik bei Zahnradgetrieben. Das Ziel
war, eine Methodik zur Bewertung des dynamischen Verhaltens bei
Getrieben unterschiedlichen Typs bzw. von unterschiedlichen
technologischen oder konstruktiven Ausführungen unter gleichen
Betriebsbedingungen und bei gleichen Getrieben unter verschiedenen
Betriebsbedingungen aufzuarbeiten. Der erste Teil des Artikels
beschreibt das Prüfstandskonzept, die Entwicklung eines mathematischen
Modells des Prüfstands und eines Modells zur Computersimulation.
Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler
Authors: Bornmann Peter , Hemsel Tobias , Sextro Walter , Memoli Gianluca , Hodnett Mark , Zeqiri Bajram
Published: January 2015

Eine Vielzahl von Prozessen in der Chemie und Verfahrenstechnik kann durch Ultraschall positiv beeinflusst werden. Oftmals ist ultraschallinduzierte Kavitation der Hauptwirkmechanismus für die positiven Effekte der Beschallung. Daher ist es notwendig die Kavitationsaktivität während des Prozesses zu quantifizieren um die Beschallung für den jeweiligen Prozess optimal gestalten und überwachen zu können. Eine Möglichkeit der prozessbegleitenden Kavitationsdetektion ist die Auswertung der akustischen Emissionen von oszillierenden und kollabierenden Kavitationsblasen mittels Drucksensoren in der Flüssigkeit. Raue Prozessrandbedingungen wie hohe Temperaturen oder aggressive Flüssigkeiten erschweren es jedoch geeignete Sensoren zu finden. Als Alternative wurde daher die Nutzbarkeit der Rückwirkung von Kavitationsereignissen auf das elektrische Eingansgssignal des Ultraschallwandlers zur Quantifizierung von Kavitation untersucht. Die experimentelle Analyse hat ergeben, dass das Einsetzen und in einigen Fällen auch die Art der Kavitation auf Basis der Rückwirkung auf das Stromsignal des Ultraschallwandlers bestimmt werden kann. Die Stärke der Kavitation war hingegen nicht aus den Stromsignalen abzuleiten.
Stochastic Tunneling and Metastable States During the Somatic Evolution of Cancer
Authors: Ashcroft Peter , Michor Franziska , Galla Tobias
Published: January 2015

Tumors initiate when a population of proliferating cells accumulates a certain number and type of genetic and/or epigenetic alterations. The population dynamics of such sequential acquisition of (epi)genetic alterations has been the topic of much investigation. The phenomenon of stochastic tunneling, where an intermediate mutant in a sequence does not reach fixation in a population before generating a double mutant, has been studied using a variety of computational and mathematical methods. However, the field still lacks a comprehensive analytical description since theoretical predictions of fixation times are available only for cases in which the second mutant is advantageous. Here, we study stochastic tunneling in a Moran model. Analyzing the deterministic dynamics of large populations we systematically identify the parameter regimes captured by existing approaches. Our analysis also reveals fitness landscapes and mutation rates for which finite populations are found in long-lived metastable states. These are landscapes in which the final mutant is not the most advantageous in the sequence, and resulting metastable states are a consequence of a mutation–selection balance. The escape from these states is driven by intrinsic noise, and their location affects the probability of tunneling. Existing methods no longer apply. In these regimes it is the escape from the metastable states that is the key bottleneck; fixation is no longer limited by the emergence of a successful mutant lineage. We used the so-called Wentzel–Kramers–Brillouin method to compute fixation times in these parameter regimes, successfully validated by stochastic simulations. Our work fills a gap left by previous approaches and provides a more comprehensive description of the acquisition of multiple mutations in populations of somatic cells.
Fruit Flies in Biomedical Research
Authors: Wangler Michael F , Yamamoto Shinya , Bellen Hugo J
Published: January 2015

Many scientists complain that the current funding situation is dire. Indeed, there has been an overall decline in support in funding for research from the National Institutes of Health and the National Science Foundation. Within the Drosophila field, some of us question how long this funding crunch will last as it demotivates principal investigators and perhaps more importantly affects the long-term career choice of many young scientists. Yet numerous very interesting biological processes and avenues remain to be investigated in Drosophila, and probing questions can be answered fast and efficiently in flies to reveal new biological phenomena. Moreover, Drosophila is an excellent model organism for studies that have translational impact for genetic disease and for other medical implications such as vector-borne illnesses. We would like to promote a better collaboration between Drosophila geneticists/biologists and human geneticists/bioinformaticians/clinicians, as it would benefit both fields and significantly impact the research on human diseases.
Shaping and Geometrical Analysis of the Ring-type Test Samples Used in Dimensional Measurements by a Bench-Type Multisensor CMM
Authors: Wojciech Kapłonek  , Krzysztof Nadolny
Published: January 2015

The routine measurements of various geometrical quantities in industrial applications are realized by use of a range of optical methods. Optical metrology is a dynamically developing area of the modern science and technology using a hardware solution from simple sensors to advanced computer-controlled measurement systems. In many specific applications dedicated measurement systems are required, which are characterized by much better metrological parameters and wider measuring capabilities than typical systems. Testing of such systems must be carried out on objects with similar properties as the actual objects produced in industrial conditions. The hybrid system for non-contact simultaneous assessment of the surface texture and dimension developed in Koszalin University of Technology (Koszalin, Poland) specially produced sets of ring-type samples with a variable external diameter φz=20.5-30±0.2 mm.
This paper presents theprogress of works related to the design, production and analysis of the geometrical dimensions of such sets of test samples prepared for dimensional assessment by using laser triangulation methods. All the stages of this work are all so described and detailed in this paper. These stages included: the determination of assumptions for the preparation of samples, the choosing and characterising of the materials used for samples, the machiningwith a specialized bench-type lathe SK-1, as well as the dimensional measurements used by simple hand measuring instruments and the advanced bench-type coordinate measuring machine Video-Check®-IP 250 produced by Werth Messtechnik GmbH. The results obtained, which were presented in the form of bar diagrams and detailing already discussed, confirmed the dimensional correctness of the machining that was carried out.
Childhood Behavior Problems and Age at First Sexual Intercourse: A Prospective Birth Cohort Study
Authors: Skinner S. Rachel , Robinson Monique , Smith Michael A. , Robbins Spring Chenoa Cooper , Mattes Eugen , Cannon Jeffrey , Rosenthal Susan L. , Marino Jennifer L. , Hickey Martha , Doherty Dorota A.
Published: January 2015

BACKGROUND AND OBJECTIVES:

Early first sexual intercourse (FSI) is a risk factor for unplanned teenage pregnancy, sexually transmitted infection, and adverse social, emotional, and physical health outcomes in adolescence and into adulthood. The aim of this study was to examine relationships between internalizing (eg, anxious/depressed, withdrawn) and externalizing (eg, delinquent, aggressive) behavior problems in childhood and age at FSI.

METHODS:

We used a large, population-based birth cohort (The Western Australian Pregnancy Cohort [Raine] Study) to address this question. Child behavior was measured by using the Child Behavior Checklist collected from parents at ages 2, 5, 8, 10, and 14 and scores calculated for total, internalizing, and externalizing behavior problems. At age 17, 1200 participants reported sexual behavior.

RESULTS:

Participants with clinically significant Child Behavior Checklist scores (T ≥60) were at increased risk for earlier first sexual intercourse (FSI) (<16 years). Adjusted odds ratios revealed that total and externalizing behavior problems from age 5 years onward significantly increased the risk of earlier FSI for boys. In girls, externalizing problems from age 10 years increased the risk for earlier FSI. Internalizing problems at ages 8 and 10 were significantly associated with early FSI for boys but not girls.

CONCLUSIONS:

Externalizing behavior from as early as 5 in boys and 10 in girls is a significant risk factor for earlier age at FSI. Adolescent sexual health promotion should consider early intervention in children with behavior problems, particularly boys.
A Comparison of Acute Treatment Regimens for Migraine in the Emergency Department
Authors: Bachur Richard G. , Monuteaux Michael C. , Neuman Mark I.
Published: January 2015

BACKGROUND AND OBJECTIVES:

Migraine headache is a common pediatric complaint among emergency department (ED) patients. There are limited trials on abortive therapies in the ED. The objective of this study was to apply a comparative effectiveness approach to investigate acute medication regimens for the prevention of ED revisits.

METHODS:

Retrospective study using administrative data (Pediatric Health Information System) from 35 pediatric EDs (2009–2012). Children aged 7 to 18 years with a principal diagnosis of migraine headache were studied. The primary outcome was a revisit to the ED within 3 days for discharged patients. The primary analysis compared the treatment regimens and individual medications on the risk for revisit.

RESULTS:

The study identified 32 124 children with migraine; 27 317 (85%) were discharged, and 5.5% had a return ED visit within 3 days. At the index visit, the most common medications included nonopioid analgesics (66%), dopamine antagonists (50%), diphenhydramine (33%), and ondansetron (21%). Triptans and opiate medications were administered infrequently (3% each). Children receiving metoclopramide had a 31% increased odds for an ED revisit within 3 days compared with prochlorperazine. Diphenhydramine with dopamine antagonists was associated with 27% increased odds of an ED revisit compared with dopamine antagonists alone. Children receiving ondansetron had similar revisit rates to those receiving dopamine antagonists.

CONCLUSIONS:

The majority of children with migraines are successfully discharged from the ED and only 1 in 18 required a revisit within 3 days. Prochlorperazine appears to be superior to metoclopramide in preventing a revisit, and diphenhydramine use is associated with increased rates of return.
Promoting Optimal Development: Screening for Behavioral and Emotional Problems
Authors: Weitzman Carol , Wegner Lynn ,   the SECTION ON DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS, COMMITTEE ON PSYCHOSOCIAL ASPECTS OF CHILD AND FAMILY HEALTH, COUNCIL ON EARLY CHILDHOOD, AND SOCIETY FOR DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS
Published: January 2015

This Clinical Report was reaffirmed December 2020.

By current estimates, at any given time, approximately 11% to 20% of children in the United States have a behavioral or emotional disorder, as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Between 37% and 39% of children will have a behavioral or emotional disorder diagnosed by 16 years of age, regardless of geographic location in the United States. Behavioral and emotional problems and concerns in children and adolescents are not being reliably identified or treated in the US health system. This clinical report focuses on the need to increase behavioral screening and offers potential changes in practice and the health system, as well as the research needed to accomplish this. This report also (1) reviews the prevalence of behavioral and emotional disorders, (2) describes factors affecting the emergence of behavioral and emotional problems, (3) articulates the current state of detection of these problems in pediatric primary care, (4) describes barriers to screening and means to overcome those barriers, and (5) discusses potential changes at a practice and systems level that are needed to facilitate successful behavioral and emotional screening. Highlighted and discussed are the many factors at the level of the pediatric practice, health system, and society contributing to these behavioral and emotional problems.
The Impact of Marijuana Policies on Youth: Clinical, Research, and Legal Update
Authors:   COMMITTEE ON SUBSTANCE ABUSE, COMMITTEE ON ADOLESCENCE, Ammerman Seth D. , Ryan Sheryl A. , Adelman William P. , Levy Sharon , Gonzalez Pamela K. , Siqueira Lorena M. , Smith Vincent C. , Braverman Paula K. , Alderman Elizabeth Meller , Breuner Cora C. , Levine David A. , Marcell Arik V. , O’Brien Rebecca Flynn
Published: January 2015

This Policy Statement was reaffirmed January 2024.

This policy statement is an update of the American Academy of Pediatrics policy statement “Legalization of Marijuana: Potential Impact on Youth,” published in 2004. Pediatricians have special expertise in the care of children and adolescents and may be called on to advise legislators about the potential impact of changes in the legal status of marijuana on adolescents. Parents also may look to pediatricians for advice as they consider whether to support state-level initiatives that propose to legalize the use of marijuana for medical and nonmedical purposes or to decriminalize the possession of small amounts of marijuana. This policy statement provides the position of the American Academy of Pediatrics on the issue of marijuana legalization. The accompanying technical report reviews what is currently known about the relationships of marijuana use with health and the developing brain and the legal status of marijuana and adolescents’ use of marijuana to better understand how change in legal status might influence the degree of marijuana use by adolescents in the future.
Effects of propylene glycol on the metabolic status and milk production of dairy buffaloes
Authors: Abdel-Raheem S. M. , Abd-Allah M. , Senosy W. , Hussein H. A.
Published: January 2015

Objectives: The study was designed to investigate the effects of drenching with propylene glycol (PG) on body condition, serum metabolites and milk production during the transition period of dairy buffaloes. Material and methods: Animals were randomly allocated to a control group (n = 5) and a PG group of 10 buffaloes that were drenched with 500 ml of propylene glycol once daily from 10 (9 ± 3) days prepartum until 2 weeks postpartum. Ultrasound measurements of backfat thickness (BFT) were performed weekly, while blood samples were taken at –4, –2, 2, 4, 6, and 8 weeks from parturition for estimation of hematological and biochemical metabolites. Results: At –4, –3, and –2 weeks from calving, BFT did not differ between the two groups, but decreased after calving and was higher for the control group than the PG group at weeks –1 and 1. Hematological analysis revealed insignificant changes between the two groups. Serum concentrations of non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA) and glucose did not differ between the two groups before parturition. At 2 and 4 weeks from parturition, NEFA was higher for the control group than the PG group. Serum concentrations of BHBA were higher at 2, 4, 6, and 8 weeks in control animals than in treated buffaloes. In contrast, the glucose level was significantly increased in PG group when compared to the control group at week 2 postpartum (p < 0.05). Serum concentrations of total cholesterol, triglycerides, total proteins, albumin, and globulins did not differ significantly between the two groups (p > 0.05). Serum enzyme activities of aspartate aminotransferase and γ-glutamyl transferase were significantly higher in the control than in the PG group. In treated buffaloes significantly (p < 0.05) higher average 60-day milk yields were recorded (8.4 ± 0.22 vs. 10.7 ± 0.40 kg/day). Milk composition did not differ between the two groups. Conclusion and clinical relevance: Drenching of dairy buffaloes with propylene glycol may reduce the risk of ketosis, improve the metabolic status, and increase the milk yield.
Alimentäre Aufnahme von Opioid-Alkaloiden durch Pferde
Authors: Emmerich I. U. , Lachenmeier D. W. , Sproll C. , Monakhova Y. B. , Aboling S. , Bachmann U. , Vervuert I. , Hertzsch R.
Published: January 2015

Bei einer Antidopingkontrolle und in einem Vergiftungsfall wurden im Urin von Pferden Opioid-Alkaloide nachgewiesen. In beiden Fällen gab es Anlass zur Vermutung, dass die Pferde mohnhaltige Futtermittel aufgenommen hatten. Zur Abklärung dieses Verdachts wurden mögliche Quellen für Opioid-Alkaloide in Deutschland mittels Literaturrecherche identifiziert und die im Intoxikationsfall vorliegenden Futterproben botanisch bzw. chemisch analysiert. Die Ergebnisse dieser Untersuchungen zeigten, dass beide Fälle vermutlich durch die in den Futtermitteln enthaltenen Mohnbestandteile verursacht wurden. Dies verdeutlicht eine bislang in Deutschland unterschätzte Gefährdung von Pferden durch mohnhaltige Futtermittel. Zur Vermeidung von positiven Dopingbefunden und Intoxikationen durch solche Futtermittel werden Empfehlungen gegeben und ein Grenzwert für Morphin im Pferdeurin bei Antidopingkontrollen vorgeschlagen.
O declínio: inserção internacional do Brasil (2011-2014)
Authors: Cervo Amado Luiz , Lessa Antônio Carlos
Published: January 2015

No artigo são examinados os fundamentos da inserção internacional do Brasil sob o primeiro governo da Presidente Dilma Rousseff (2011-2014). São analisadas as causas da perda de eficiência da estratégia de ação internacional adotada no governo de Luís Inácio Lula da Silva (2003-2010), a partir da elaboração de hipótese analítica relacionada com a ideia de declínio relativo.
Estimativas de parâmetros genéticos para características de crescimento de cordeiros mestiços Suffolk
Authors: Tamioso Priscilla Regina , Dias Laila Talarico , Teixeira Rodrigo de Almeida , Silva Cláudio José Araújo da
Published: January 2015

Objetivou-se estimar os coeficientes de herdabilidade e correlação genética entre os pesos ao nascer (PN) e à desmama (PD) de cordeiros mestiços Suffolk, pertencentes a rebanho experimental. Assim, foram testados quatro modelos, os quais consideraram o efeito genético aditivo direto (Modelo 1), os efeitos genético direto e de ambiente permanente materno (Modelo 2), os efeitos aditivo direto, de ambiente permanente e genético materno (cov a,m=0) (Modelo 3), e no Modelo 4, além daqueles contemplados no Modelo 3, foi considerada cov a,m≠0. Após comparar os modelos por meio do teste de razão de verossimilhança (LRT), observou-se que o 3 foi o mais adequado, sendo que as estimativas de herdabilidade foram de baixa magnitude para PN e PD, iguais a 0,08±0,009 e 0,24±0,17, respectivamente, indicando pequena possibilidade de resposta à seleção direta. Da mesma maneira, o coeficiente de correlação genética entre estas características foi 0,43±0,39, resultado que implica pequena possibilidade de resposta correlacionada. A inclusão dos efeitos maternos é necessária para a estimação adequada de parâmetros genéticos para as características avaliadas.
Análises coproparasitológicas de aves silvestres cativas
Authors: Snak Alessandra , Lenzi Paola Fernanda , Agostini Kira Maria , Delgado Luis Eduardo , Montanucci Cleuza Rocha , Zabott Marivone Valentim
Published: January 2015

Na maioria dos casos de parasitismo em aves cativas não há expressão de sinais clínicos. Esse fato aponta a importância da realização de exames parasitológicos frequentes nesses animais. O objetivo do presente trabalho foi realizar exames coproparasitológicos para monitorar as infecções parasitárias nas aves cativas no Parque Municipal Danilo Galafassi (Zoológico Municipal de Cascavel-PR), projeto aprovado pela Comissão de Ética e Bem-estar Animal (CEBEA) do Campus Palotina-UFPR, protocolo nº 29/2010. Foram analisadas 228 amostras de fezes de 37 espécies de aves cativas, provenientes de 22 recintos, no período de agosto de 2010 a julho de 2012. As fezes refrigeradas foram analisadas por meio dos métodos de flutuação de Willis-Mollay e de sedimentação simples de Hoffmann, Pons e Janer. Das amostras analisadas, 127 (55,7%) foram positivas e, destas, 55 (43,3%) apresentaram infecção mista. Os parasitos encontrados pertencem aos gêneros Strongyloides, Eimeria, Capillaria, Deletrocephalus e Isospora, às superfamílias Strongyloidea, Ascaroidea e Spiruroidea, à ordem Trichurida e à classe Cestoda. Os resultados dos exames dos recintos de Jabiru mycteia (tuiuiú) e Cariama cristata (seriema) foram negativos, em todo o período avaliado. Medidas higiênico-sanitárias e de controle da circulação de animais e pessoas foram instituídas para minimizar a infecção das aves, porém são necessárias novas análises para avaliação do impacto das mesmas.
Distribución vertical del banco de semillas de Euphorbia davidii Subils, en lotes agrícolas de la zona centro de la provincia de Buenos Aires, Argentina
Authors: Núñez Fré F.R. , Juan V.F. , Chantre G.
Published: January 2015

Euphorbia davidii Subils, es una maleza anual que está presente en la zona centro de la provincia de Buenos Aires, Argentina. Se realizaron estudios para determinar el banco de semillas de esta especie y su distribución vertical en lotes agrícolas de Azul y Olavarría. Se extrajeron 240 muestras de suelo, provenientes de 60 puntos distribuidos al azar, a cuatro niveles de profundidad: 0-5 cm, 5-10 cm, 10-15 cm y 15-20 cm. Las extracciones se realizaron dos veces al año, en mayo y en septiembre. Las muestras fueron procesadas y las semillas separadas por tamizado en húmedo. Se evaluó germinación y viabilidad mediante la prueba de trifeniltetrazolio. Se cuantificaron 30.000 y 15.000 semillas m-2, para los lotes de Azul y Olavarría, respectivamente. En Olavarría, el 79% de las semillas se encontraron de 0-5 cm, de profundidad, el 14%, de 5-10 cm y el 7% restante de 10-20 cm. En Azul se observó una distribución vertical más homogénea. El 55 % de las semillas se encontraron de 0-5 cm de profundidad, un 24% de 5-10 cm, el 16% de 10-15 cm y el 5% en el muestreo más profundo. Las diferencias en la distribución se asociaron al manejo de los lotes. En ambas localidades la viabilidad de semillas, provenientes del estrato superficial, superó el 70%. Las semillas de estratos superficiales recolectadas en el lote de Olavarría, inmediatamente después de la dehiscencia, presentaron dormición, en cambio en las semillas provenientes del lote de Azul para el mismo momento de muestreo, no se observó dormición.
Concepções de professores da educação especial (APAEs) sobre a aprendizagem e desenvolvimento do aluno com deficiência intelectual: um estudo a partir da teoria vigotskiana
Authors: Leonel Waléria Henrique dos Santos , Leonardo Nilza Sanches Tessaro
Published: January 2015

O presente estudo teve por objetivo identificar concepções de professores que atuam na educação especial sobre a aprendizagem e desenvolvimento de alunos com deficiência intelectual, buscando averiguar como estes compreendem esse processo, bem como suas percepções sobre o papel da mediação na aprendizagem. Foi desenvolvido em duas escolas de Educação Básica na modalidade de Educação Especial para deficiente intelectual (Associação de pais e amigos dos excepcionais) localizadas no Interior do Estado do Paraná. O estudo contou com a participação de oito professoras das séries iniciais do Ensino Fundamental, sendo quatro de cada escola. Os dados foram coletados mediante a técnica de entrevista semiestruturada. Estes foram analisados a partir da análise de conteúdo. Os principais resultados permitiram compreender que para as participantes da pesquisa a aprendizagem e desenvolvimento do aluno com deficiência ocorre de forma lenta, justificado pela limitação deste, e que a mediação docente não é vista como de fundamental importância para o aprendizado e desenvolvimento do mesmo. Estes resultados apontam para o fato destes professores estarem desenvolvendo sua prática pedagógica ancorada numa visão segregacionista do aluno com deficiência, com concepções reducionistas, enfatizando as limitações em detrimento das potencialidades. Dessa forma, é essencial um repensar sobre a deficiência e a educação escolar que vem sendo ofertada ao aluno com deficiência intelectual.
Measurement of permeability using a bench-top centrifuge
Authors: ANDERSON C. , SIVAKUMAR V. , BLACK J.A.
Published: January 2015

The commonly used British Standard constant head triaxial permeability test for testing of fine-grained soils is relatively time consuming. A reduction in the required time for soil permeability testing would provide potential cost savings to the construction industry, particularly in the construction quality assurance of landfill clay liners. The purpose of this paper is to evaluate an alternative approach of measuring permeability of fine-grained soils benefiting from accelerated time scaling for seepage flow when testing specimens in elevated gravity conditions provided by a centrifuge. As part of the investigation, an apparatus was designed and produced to measure water flow through soil samples under conditions of elevated gravitational acceleration using a small desktop laboratory centrifuge. A membrane was used to hydrostatically confine the test sample. A miniature data acquisition system was designed and incorporated in the apparatus to monitor and record changes in head and flow throughout the tests. Under enhanced gravity in the centrifuge, the flow through the sample was under ‘variable head' conditions as opposed to ‘constant head' conditions as in the classic constant head permeability tests conducted at 1g. A mathematical model was developed for analysis of Darcy's coefficient of permeability under conditions of elevated gravitational acceleration and verified using the results obtained. The test data compare well with the results on analogous samples obtained using the classical British Standard constant head permeability tests.
Natural selection by pulsed predation: survival of the thickest
Authors: Bijleveld Allert I. , Twietmeyer Sönke , Piechocki Julia , van Gils Jan A. , Piersma Theunis
Published: January 2015

Selective predation can lead to natural selection in prey populations and may alleviate competition among surviving individuals. The processes of selection and competition can have substantial effects on prey population dynamics, but are rarely studied simultaneously. Moreover, field studies of predator‐induced short‐term selection pressures on prey populations are scarce. Here we report measurements of density dependence in body composition in a bivalve prey (edible cockle, Cerastoderma edule) during bouts of intense predation by an avian predator (Red Knot, Calidris canutus). We measured densities, patchiness, morphology, and body composition (shell and flesh mass) of cockles in a quasi‐experimental setting, i.e., before and after predation in three similar plots of 1 ha each, two of which experienced predation, and one of which remained unvisited in the course of the short study period and served as a reference. An individual's shell and flesh mass declined with cockle density (negative density dependence). Before predation, cockles were patchily distributed. After predation, during which densities were reduced by 78% (from 232 to 50 cockles/m2), the patchiness was substantially reduced, i.e., the spatial distribution was homogenized. Red Knots selected juvenile cockles with an average length of 6.9 ± 1.0 mm (mean ± SD). Cockles surviving predation had heavier shells than before predation (an increase of 21.5 percentage points), but similar flesh masses. By contrast, in the reference plot shell mass did not differ statistically between initial and final sampling occasions, while flesh mass was larger (an increase of 13.2 percentage points). In this field study, we show that Red Knots imposed a strong selection pressure on cockles to grow fast with thick shells and little flesh mass, with selection gradients among the highest reported in the literature.
Consequences of employing amino acid vs. bulk‐tissue, stable isotope analysis: a laboratory trophic position experiment
Authors: Bowes R. E. , Thorp J. H.
Published: January 2015

An important metric of environmental health is food web structure because it reflects species richness, natural history diversity, and resource availability. While bulk‐tissue stable isotope analysis has proven valuable for food web studies, field conditions may severely restrict its use and data can be quite variable. Amino acid stable isotope analysis potentially reduces this variability, in part by eliminating the need for signatures near the trophic base because a single top consumer contains both the primary producer signature (constant phenylalanine signature) and information reflecting number of trophic transfers (a progressively increasing δ15N signature of glutamic acid).

To evaluate the ecological sensitivity and cost/benefits of the techniques, we conducted a laboratory food chain experiment with four trophic levels. Water fleas (Daphnia magna) were cultured on a diet of powdered algae and then fed daily to guppies (Poecilia reticulata) for three months. These invertivorous fishes were then consumed by piscivororus bluegill sunfishes (Lepomis macrochirus) for a subsequent three months. All members of the food web were analyzed for 15N values and degree of fractionation using both bulk‐tissue and amino acid stable isotope techniques.

Our experiment demonstrated that the amino acid technique more accurately identified the true trophic position (TP) and food chain length (FCL = maximum TP) with significantly less variability around mean values for each consumer trophic level. Moreover, use of amino acids requires significantly fewer replicates to identify TP. We discuss here the relative advantages and disadvantages of both approaches for determining TP and FCL and recommend that investigators switch as soon as possible to the amino acid isotope technique for determining FCL.
The Furbero Oil Field, Mexico
Authors: DeGolyer E.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 52, 1916, pages 268–280.

The Furbero oil field lies in the Gulf coastal plain of Mexico between the important ports of Tampico and Vera Cruz and about one-third of the distance between the two points from the latter (Lat. 20" 22' N., 97" 30' W. Gren.). It is in the State of Vera Cruz, about 14 miles west by south of the village of Papantla in the canton of the same name, and is the most southern of the developed oil fields of the Tampico-Tuxpam region being a distance of 50 miles south by east from the Potrero del Llano field and 42 miles in the same direction from the Alamo field. The field has been developed by the Oil Fields of Mexico Co. and is in the midst of a large block of lands owned or leased by them. Communication is through the port of Tuxpam with which it is connected by a narrow- gauge railway and 6-in. pipe line some 52 miles in length.

This field is of more than ordinary interest since it represents a type of oil deposit hitherto unknown. So far as I am aware, no other commercially valuable deposit of oil is known to occur under conditions of accumulation similar to those found here. The igneous nature of the so-called ‘sand’ encountered in drilling was not recognized until a number of wells had been drilled; and it was not until recently that the geological relations of the sill or laccolith, which gives rise to the accumulation of oil, were known and the so-called ‘anticline’ was known to be, in part at least, the result of igneous intrusion.

Geological surveys in this general region were made in 1900–1901 by

W. H. Dalton and in 1907–1909 by P. C. A. Stewart, F. W. Moon, Leonard V. Dalton, and Dr. Max Muhlberg. More recent surveys have been made, however, under the direction of the author, by E. L. Ickes, B. C. Belt, B. Hartley, and Harve Loomis. Notes of the earlier examinations were not available with the exception of the report by Dr. Muhlberg who apparently first recognized the true nature of the Furbero intrusion. This paper is indebted to his work and that of the more recent surveys for much of the detail regarding stratigraphy and to Messrs.

T.P. 052–21
A Modern Rotary Drill
Authors: Hughes Howard R.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 52, 1916, pages 620–626.

In drilling for water and oil to reasonable depths through the generally soft yielding clay and sand formation of the Coastal Plain of Texas, Louisiana, and Mississippi, the rotating method of drilling was adopted, ' principally on account of the easy and quick penetration, and the low cost of the drilling plant.

In favorable ground, free of heavy gravel and rock strata, as much as 1,600 ft. has been drilled in less than 36 hr., although such performances were of course rare.

Hydraulic rotary drilling, or, as it is now called, rotary drilling, was used in the above States as early as 1880. The plant consisted of an ordinary derrick, a 25-h.p. boiler, a small hoist, a steam pump, and a water swivel with hose attachment, and an ordinary flat diamond-pointed bit.

The successful drilling in of a phenomenal oil well by this process on Spindletop, near Beaumont, Texas, on Jan. 10, 1901, and the ascertained impracticability of drilling subsequent wells in the same locality by other methods (owing principally to heavy quicksand under pressure from be- low), brought rotary drilling into great prominence, practically to the exclusion of any other process throughout the Coastal Plain, and later on elsewhere.

The method, as its name implies, involves the rotation of a pipe by means of machinery placed on the derrick floor. A drill bit attached to the lower end cuts a clearance for the drill pipe, with much the same motion and effect as an auger. Water forced through the drill pipe by means of a pump, and escaping through the bit, removes the cuttings and returns to-the surface outside the drill pipe. In this manner the hole is kept open, permitting the drill stem to rotate freely.

The pressure of the column of muddy water holds up the walls of the hole until it has been cased.

Practically all the wells of the Gulf coast region, numbering nearly 10,000, have been drilled with this system. During the last five years its use has been extended to many other States and countries.

T.P. 051–41
The Dehydrating Oil Plant of Nevada Petroleum Co., California
Authors: Hardison B.J.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 52, 1916, pages 627–634.

In the fall of 1912, the appearance of water in the oil of the Nevada Petroleum Co., Coalinga, Cal., made necessary the installation of a dehydrating plant to reduce the water below the 3 per cent limit prescribed by the agency.

Unlike the mining industry, technical literature of the oil industry is limited and extremely unsatisfactory. Until the recent efforts of the Petroleum and Gas Committee of the American Institute of Mining Engineers, no concerted movement has been instituted to secure publication of papers dealing with the problems of the oil business, and because of the additional fact that dehydrating of oil has not been practiced in California to any extent up to comparatively recent time, it was found necessary to experiment in order to determine the most satisfactory plan for this purpose.

It is easy to write regarding successful enterprises, but, while not so pleasant, it is equally desirable to write of failures so that others may be saved the loss incident to such investments.

The water in this oil occurs both free and as an emulsion. Free water easily settles out, but the emulsion requires treatment. So far as can be determined, the emulsion consists of globules of water surrounded and enveloped by a film of oil. Starting with this hypothesis the theory has been evolved that in order to break up this emulsion the water must be heated at least to boiling point, when an explosion takes place destroying the globule. Unfortunately, this condition was not recognized in the installation of the first plant, which was planned on the following lines:

A heater was arranged so that all the oil from the wells could be heated before reaching the shipping tanks, these being already fitted with coils for steam heating. Tanks were filled with about 4 ft. of water, live steam was turned into the coils and the water brought nearly to the boiling point, when the heated oil was run in. This for a time was partly successful, but the length of time necessary to apply this heat was too great for practical operating.

T.P. 051–42
Oil and Gas Possibilities of Kentucky
Authors: Fohs F. Julius
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 52, 1916, pages 649–656.

With portions of two coal basins within its borders and a few scattered fields already developed, the question arises: What is the future of Kentucky as an oil-producing State? Is the long list of failures due to lack of commercial pools, or unintelligent prospecting? A study of its beds and irregularities of structure points not only to a large waste of development money on unpromising areas, but also to the presence of a few structures well worthy of development.

The surface rocks of Kentucky show in succession more than 4,000 ft. of Paleozoic sediments and more than 2,000 ft. of Cretaceous, Tertiary, and more recent deposits. Folding and erosion have brought these beds to the surface, where they have been observed and studied in detail by my associate, James H. Gardner, myself, and others. This has given opportunity to observe the beds offering suitable reservoirs and having the proper impermeable covering; also the mapping of outcrops and out- crop lines, taken in conjunction with available well records, indicates that certain areas are worth testing, and with even greater definiteness shows areas which should be excluded, as devoid of possibilities. West of the Tennessee River, Cretaceous, Tertiary, and Quaternary sediments occur so that all trace of ancient folding is obliterated, the sediments overlapping unconformably Mississippian rocks. This area embraces 2,000 square miles, or one-twentieth of the area of the State, the Paleozoic rocks covering the remainder. Since there is nothing upon which to base the location of tests for oil and gas in the Cretaceous- Tertiary beds of Kentucky, the Paleozoic area will be chiefly considered.

The distribution of Paleozoic rocks in Kentucky is centered about the north-northeast striking Cincinnati geanticline, bringing to the surface on the Jessamine dome the oldest rocks exposed in the State, those of the Devonian, Silurian, and Ordovician systems. On either flank of this great earth-arch are the Mississippian rocks, sloping gradually beneath the coal-measure basins to the west and to the east. West of the western coal basin, and. between it and the Cretaceous-Tertiary rocks further west, is a high area of Mississippian rocks. Crossing the State in an east-west direction is the Chestnut Ridge anticline (a disturbance recently shown by Mr. Gardner to extend from the Ozarks to the Appalachian), consisting in Kentucky of the Rough Creek uplift, the Kentucky River fault zone, and the Warfield anticline.

T.P. 051–46
Geosynclines and Petroliferous Deposits
Authors: Daly Marcel R.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 57, 1917, pages 1054–1070.

In a preceding paper the writer has pointed out some apparent relationship between the distribution, on the surface of the globe, of the known hydrocarbon deposits and the disposition of the principal zones of deformation of the earth's body (geosynclines). He wishes to present some further remarks on this subject.

Petroleum deposits, or their derivatives or descendants, are found through the whole range of sedimentary strata, from the pre-Cambrian to the Quaternary. For instance, the pre-Beltian (Shuswap) series of the Canadian Cordillera are interbedded with limestones which are some- times rich in carbonaceous matter (Sieamous limestone); and the Beltian system of the same region contains layers of argillites and dolomitic lime- stones which are equally high in carbon This carbon may be interpreted as the last remnant of hydrocarbons previously contained in the rocks. On the other hand, the actual formation of hydrocarbons under conditions that would eventually permit their deposition in modern sediments is conceded by some geologist. Between these two extreme limits, bitumens are found indifferently in all sedimentaries. They constitute a continuous series, some kind of a large family, whose individual members may be entitled to a community of origin and probably represent the different stages of evolution of the primitive, parent matter. The kinship between petroleum and such substances as asphalt, ozocerite, manjak, grahamite, albertite, etc., is well known; and E. H. Cunninggam-Craig has recently shown how intimately shale fields and oil fields are connected.

T.P. 057–53
Funnel and Anticlinal-ring Structure Associated with Igneous Intrusions in the Mexican Oil Fields
Authors: Garfias V.R. , Hawley H.J.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 57, 1917, pages 1071–1088.

Introduction

For a number of years the senior author has been interested in the various geologic and engineering problems involved in the development of the petroliferous districts of northeaster Mexico, having in a previous paper endeavored to present a summarized statement of the information relating to the geology and soil resources of this region.

Of the many interesting geologic phenomena, perhaps those which have been the object of most speculation relate to the igneous intrusions which, in place, have a controlling influence on the accumulation of oil in commercial quantities, a relationship which has been tentatively explained by various observers with as many interestingly different views.

The authors of the present paper aim to record, in the course of a general discussion of the various viewpoints, some additional data, and present further tentative conclusions with a view to rounding out an up-to-date summary of the subject.

The greater part of the area in question lies in the State of Vera Cruz, only a northwest fraction being in the State of San Luis Potosi. Vera Cruz is bounded on the north by the State of Tamaulipas, the northernmost of the Mexican States along the Gulf.

The topography of the States of Tamaulipas and Vera Cruz and of Texas and Louisiana to the north, is controlled by the Gulf costal plain which in northern Vera Cruz has an average width of about 60 miles, the transitional topography between that of the rugged flanks of the Sierra and the lowlands of the coast being made up of a series of terraces and irregular hills and valleys.

Geology and Structure

The greater part of the mainland of Mexico is made up of Tertiary and later effusive rocks and of sedimentaries of Cretaceous age.

T.P. 057–54
Principles of Natural-Gas Leasehold Valuation
Authors: Wyer Samuel S.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 57, 1917, pages 782–798.

Magnitude and Economic Importance

The magnitude and economic importance of the problem of correctly valuing natural-gas leaseholds become evident when we consider that:Natural gas is handled in 55 per cent of the gas distributing plants in the United States.Present known natural-gas acreage forms 47 per cent of the total known mineral-land acreage in the United States.Five acres of land are now required to protect and maintain continuous service to each of the 2,000,000 domestic natural-gas consumers in the United States.The cost of acquiring and maintaining this acreage of an expendible resource represents a substantial part of the cost of the natural-gas service to the consumer." The right of a citizen by means of his ownership of or his mining leases on land to draw gas from beneath its surface is property and sometimes valuable property." '

A large number of other court decisions have established the basic legal principle that the right to drill for gas within a given area constitutes an interest in the land itself, and is necessarily an exclusive property right.

Definition of Vested Interests or Rights

" Vested interests are economic interests which are legally recognized to be such that they cannot be impaired by public action, directly or indirectly, without indemnification. Vested interests are largely property interests. The recognition of an interest as a vested interest gives it some of the attributes of property, and by American courts it would be comprised in their very inclusive concept of property. Other-wise than through property, vested interests generally arise through contract."

T.P. 056–41
Petroleum Connected with the Recovery of Petroleum from Unconsolidated Sands
Authors: Kobbe William H.
Published: January 2015

Published in Petroleum Transactions, AIME, Volume 57, 1917, pages 799–830.

Introduction

The word recovery as used in this paper is applied in its broader sense and not limited to wells producing from horizons of unconsolidated sands. Certain problems connected with the winning of petroleum from such horizons present themselves while drilling is in progress and should be considered before drilling is commenced wherever unconsolidated sands are expected. Maximum recovery depends not alone upon efficient pumping methods but also upon the selection of a proper drilling system and the completion of a well especially adapted to the extraction of these oil-bearing sands.

Drilling

Determining Factors in Selection of Method

The selection of a drilling method for the development of a region in which the oil reservoir consists of unconsolidated sands is bases on the following considerations:Character of the formations overlaying the reservoir;thickness of the oil-bearing stratum or strata;thickness and character of water or gas sands;gas pressure to be encountered or expected;total depth of well.

Character of the Formations Overlaying the Reservoir

The strata overlaying the reservoir may consist of beds of shales, clays, sands and other soft materials, or they may be slates, limestones and sandstones consolidated to all degrees of hardness. Very often the overlaying strata and predominantly of soft materials but interbedded with harder formations. Likewise, soft materials but interbedded with harder formations Likewise, soft strata are encountered at different horizons in an overburden consisting almost entirely of the harder sedimentaries.

T.P. 056–42