1,720 research outputs found
Evolution of cooperation among tumor cells
No full textThe evolution of cooperation has a well established theoretical framework based on game theory. This approach has made valuable contributions to a wide variety of disciplines, including political science, economics, and evolutionary biology. Existing cancer theory suggests that individual clones of cancer cells evolve independently from one another, acquiring all of the genetic traits or hallmarks necessary to form a malignant tumor. It is also now recognized that tumors are heterotypic, with cancer cells interacting with normal stromal cells within the issue microenvironment, including endothelial, stromal, and nerve cells. This tumor cell???stromal cell interaction in itself is a form of commensalism, because it has been demonstrated that these nonmalignant cells support and even enable tumor growth. Here, we add to this theory by regarding tumor cells as game players whose interactions help to determine their Darwinian fitness. We marshal evidence that tumor cells overcome certain host defenses by means of diffusible products. Our original contribution is to raise the possibility that two nearby cells can protect each other from a set of host defenses that neither could survive alone. Cooperation can evolve as byproduct mutualism among genetically diverse tumor cells. Our hypothesis supplements, but does not supplant, the traditional view of carcinogenesis in which one clonal population of cells develops all of the necessary genetic traits independently to form a tumor. Cooperation through the sharing of diffusible products raises new questions about tumorigenesis and has implications for understanding observed phenomena, designing new experiments, and developing new therapeutic approaches.Author manuscript. Published in final edited form as: Proc Natl Acad Sci U S A. 2006 September 5; 103(36): 13474-13479.The final published version of this article is located at: www.pnas.org/cgi/doi/10.1073/pnas.0606053103NIH U56 CA113004; to David E. AxelrodR.A. was supported by National Science Foundation (NSF) Grant SES-0240852. D.E.A. was supported by NSF Grant IIS-0312953, National Institutes of Health (NIH) Grant U56 CA113004, and New Jersey Commission on Cancer Research Grant 1076-CCR-SO. K.J.P. is an American Cancer Society Clinical Research Professor and is supported by NIH Grants CA69568, CA102872, and CA093900.NIH CA69568; to Kenneth J. PientaNIH CA102872; to Kenneth J. PientaNIH CA093900; to Kenneth J. PientaNSF SES-0240852; to Robert AxelrodNJ Commission on Cancer Research 1076-CCR-SO; to David E. AxelrodAlso available in PubMed Central. PMCID: PMC155738
To study, to party, or both? Assessing risk factors for non-prescribed stimulant use among middle and high school students
No full textThis study examines the risk factors predicting non-prescribed stimulant use (NPSU) among adolescents, with an emphasis on whether such factors are reflective of instrumental (e.g. studying) and/or recreational (e.g. partying) drug consumption settings. Using data from Monitoring the Future (2011), we employed a series of logistic regression models to establish predictors of 12-month self-reported Adderall or Ritalin use without a doctor’s note among 8th and 10th graders. Whereas studies of college students have found NPSU to correlate with instrumental motives and productivity-related demands, we find no association between NPSU and indicators of academic strain for this younger sample. Rather, we find that the age of onset and current use of alcohol, tobacco, and marijuana is most predictive of NPSU, which are substances generally associated with social and recreational consumption settings. These findings have potential implications for practitioners concerned with mitigating the harms of general prescription drug misuse, as interventions efforts informed by research conducted among college students may not readily apply to younger populations. Drawing from central tenets of developmental and life course criminology, we call for continued inquiry into the broader socialization and developmental processes that influence NPSU and other prescription drug use patterns prior to early adulthood.Peer reviewe
"We enter the fields of new: Kenneth Patchen, l'intelletto e l'intuizione"
No full textA partire da una citazione di Kenneth Patchen, "we enter the fields of new", l'autrice del saggio analizza la poesia "Thinking Rock" sulla base del binomio, in psicologia, "intelletto e intuizione".Starting from a quotation by Kenneth Patchen, "we enter the fields of new", the author of the essay analyses the poet's poem "Thinking Rock" on the basis of the difference, in psychology, of the terms "intellect" and "intuition"
Nya perspektiv på det romerska myntväsendet i det östra Medelhavsområdet under senrepublikansk och kejsartid
No full textThe Ph.D. thesis discusses the monetary development in Roman Syria and Judaea in the Late Republican and the Early Imperial Period, from a numismatic, archaeological and historical point of view. In effect, the work focuses on the 1st century B.C. to the 1st century A.D., that is, the assumed time of introduction of Roman denarii to the region.
The work benefits from the silver coin hoards of Khirbet Qumran recently published by the author. Though discovered as early as 1955 at Qumran, where the famous Dead Sea Scrolls had been found prior to that in 1947, most hoards remained unpublished until 2007. A second important source utilized is the so-called Tax Law from Palmyra in Syria. Its significance lies in the fact that Palmyra used to be one of the most important cities on the Silk Road, along which luxury goods were transported into the Roman Empire and Rome itself.
During the research conducted, studies of the provincial coinage of Judaea (A.D. 6-66) shed new light on the authority of the Roman governors in economic and monetary matters in eastern Mediterranean regions. Furthermore, a new suggestion as to the length of the mandate period of Pontius Pilate is made. The extent of Emperor Augustus monetary reforms as well as the military history of Judaea are discussed in the light of new analytical studies, which show that the production of Roman base metal coins appears to have been a highly controlled process, contrary to popular opinion. Statistical calculations related to the coin alloy revealed striking similarities with Roman and other local metalwork found in Israel; a fact previously unknown. Results indicate that both Roman and local metalwork consisted of outstandingly systematized practises and may have exploited the same metal sources.
Information: Kenneth Lönnqvist (*25.7.1962) has studied at the University of Helsinki since 1981. Furthermore, Lönnqvist has lived in the Mediterranean countries and the Near East, and made research there at various scientific institutions and universities for ca. 7 years. Contact and sales of thesis: [email protected] perspektiv på det romerska myntväsendet i det östra Medelhavsområdet under senrepublikansk och kejsartid Avhandlingen diskuterar den monetära utvecklingen i romerska Syrien och Judéen från senrepublikansk till tidig kejsartid ur en numismatisk, arkeologisk och historisk synvinkel. I praktiken fokuserar arbetet på emissionen av romerska mynt till Syria-Palestina, d.v.s. tiden från första århundradet f.Kr. till första århundradet e.Kr. Arbetet baserar sig på det av författaren 2007 publicerat myntmaterial eller silverskatterna från Khirbet Qumran. Skatterna hittades 1955 i Qumran, där de berömda Dödahavsrullarna upptäcktes redan 1947, men förblev opublicerade fram till 2007. En annan viktig källa utgörs av den romerska inskriften, den s.k. Tulltariffen från Palmyra (Syrien), som var en inkörsport för lyxvaror till Rom längs Sidenvägen.
Myntsystemet i romerska Judéen belyser på ett nytt sätt ämbetsmännens befogenheter i monetära angelägenheter i östra Medelhavsområdet. Vidare diskuteras tjänstemännens ämbetsperioder (bl.a. omdateras Pontius Pilatus mandatstid) samt omfattningen av kejsar Augustus myntreformer, och Judéens militärhistoria under första århundradet e.Kr. Metallanalyser visar att produktionen av kopparbaserade mynt var en noga kontrollerad process, i motsats till vad man tidigare antagit. Analyser av myntens spårämnessammansättning visar häpnadsväckande likheter med andra romerska och lokala materialgrupper funna på arkeologiska utgrävningar i Israel. Resultatet tyder delvis på att en del råvaror för tillverkningen kom till Mellanöstern från Europa, delvis också på att romerska mynt, romerskt metallverk, men också lokala metallhantverkare uttnyttjade samma råvarokällor
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Biological durability of cross-laminated timber connections
No full textMass timber (MT) offers viable eco-conscious solutions within the building industry, with its high strength ratings, dimensional stability, light weight and renewable nature enhancing its status as a low carbon alternative to conventional building materials like steel and concrete. Moisture intrusion, coupled with the inherent organic nature of wood pose significant durability and biodeterioration concerns that could potentially affect public trust in MT. The size of the elements, moisture variation, and presence of glue lines, all render existing methods used to evaluate biodeterioration in dimension lumber inadequate for MT. Hence, the biological durability attributes of MT elements are not fully understood. While evaluating the effects of biodeterioration on material properties of MT elements is worthwhile, these materials primarily serve as member elements within the structural system. Therefore, characterizing performance of bio-degraded multi-component systems will yield more beneficial results, providing information on the structural performance of damaged mass timber buildings and contributing data that could be used in engineering models (analytical and numerical) and service life prediction models.
This study took a holistic approach to evaluate durability of Cross Laminated Timber (CLT) connection systems by evaluating the effect of moisture and subsequent fungal decay on properties of the connections. First, the redrying performance of CLT connections were assessed. Quasi-static cyclic test was used to evaluate the mechanical properties of water-saturated connections, following three drying regimes. Aggressive drying resulted in development of checks that were less apparent in mildly dried or air-dried assemblies. Nail fracture was the most common failure observed in the re-dried connections and was particularly prominent in aggressively dried specimens. Load carrying capacity did not decrease in the connection assemblies, irrespective of the drying schedule employed. All treated samples exhibited loss of stiffness after redrying, but air-dried samples were least impacted. Reduced energy dissipation was observed in initial cycles of loading protocol for redried connection assemblies, but connections generally recovered and dissipated energy at levels similar to controls in the later cycles. Of the three drying regimes studied, air drying yielded the most conservative results for the connection properties, albeit for an extended period of time. The mild drying schedule implemented in this study was associated with no material damage, yielding acceptable results in a reasonable timeframe. This regime could serve as a template for drying CLT in case of moisture intrusion.
In the second phase of this study, the effects of fungal decay on performance of connection assemblies made with four CLT species (Douglas-fir, Norway spruce, spruce pine fir, and southern yellow pine) were evaluated, following varying levels of exposure to two brown rot fungi species (Gloeophyllum trabeum and Rhodonia placenta). A recently developed modified method suitable for MT was used to evaluate the extent of fungal damage in the assemblies. Physical and mechanical properties of the connection systems were characterized over a 40-week exposure period. Following physical assessments of connection assemblies, regions around the glue line and exposed end grain of the CLT panels were identified as high-risk locations for fungal decay. R. placenta was the more aggressive test fungus, causing an average mass loss of 17.2 %, compared to 13.4 % observed in G. trabeum. Connection systems lost between 43 % and 57 % of their load carrying capacities over the 40 weeks of fungal exposure but significant differences were not observed until after 20 weeks of exposure. Energy dissipating capacities of the connections were severely affected, reducing by almost 90 % over the 40-week exposure period. Time-dependent regression models were developed to characterize connection performance and predict degradation in affected connection systems.
The third phase of the study evaluated the effects of fungal decay on dowel bearing strength of three CLT species (Douglas-fir, Norway spruce, and spruce pine fir) during 40 weeks of exposure to the same test fungi employed in the second phase of the study. Significant reductions in the dowel bearing strength of CLT were observed after 30 weeks of fungal inoculation. R. placenta was slightly more aggressive than G. trabeum, causing a 16.2 MPa reduction in dowel bearing strength of Douglas-fir after 40 weeks of exposure. Connection capacities estimated using National Design Specification yield models for dowel type fasteners and the dowel bearing strength of fungal damaged CLT were consistent with observed properties and were within 85 % of each other, especially in early stages of decay.
The results from this study are valuable to scientists, engineers, and mass timber end users. Drying schedules developed in the study can serve as a template for drying wet CLT with minimal damage. The data collected in the fungal decay connection study can serve as guide to scientists concerned with developing safety factors that can be incorporated into design of MT buildings in locations with high risks of fungal damage. Repair engineers, whose intentions are to determine the extent of fungal damage and residual capacity in affected MT connection systems would also find the results from this study useful. These data can further contribute to information needed for development of service life prediction models that could be used to estimate resilience and long term durability of mass timber buildings
. 30 Tomo II (1941-1946) Sexta Época (1939-1966). Anales del Instituto Nacional de Antropología e Historia
No full textPublicación que recopila y difunde cien años de trabajo de la antropología en México (1877-1977), integrada por documentos y manuscritos arqueológicos, antropológicos, históricos, geológicos, botánicos y lingüísticos.- Estudio dental y radiográfico de las mutilaciones dentarias por Samuel Fastlicht. - Análisis de algunos carácteres somáticos de la población de San Miguel Totolapan, Gro. por Johanna Faulhaber. - Teotihuacan: ofrendas de los templos de Quetzalcóatl por Daniel Fernando Rubín de la Borbolla. - Exploraciones arqueológicas en el Totonacapan meridional (Región de Misantla, Ver.) por José García Payón. - El friso de los caciques por Hugo Moedano Köer. - Estudios etnobiológicos, III. Contribuciones mexicanas al conocimiento de la etnobiología del maíz por Manuel Maldonado Koerdell. - Los zapotecos de Choapan, Oaxaca por Julio de la Fuente. - La alimentación tarasca por Silvia Rendón. - Música precortesiana por Jesús C. Romero. - Danzas mexicanas por Raúl G. Guerrero - Notas sobre lugares de Oaxaca, con especial referencia a la toponimia zapoteca por Julio de la Fuente. - Una visita a los indígenas amuzgos de México por George M. Cowan. - Nombres clasificadores, chontales por Margaret Harris. - Palabras y frases de las lenguas tarahumaras y guarijío por Kenneth S. Hilton. - Mapa de Popotla por Alfonso Caso. - La misión del historiador José de J. Núñez y Domínguez en archivos de Europa (1937-1939) por José de J. Núñez y Domínguez. - Noticias sobre algunos archivos hispanoamericanos por María Castelo de Zavala. - La función económica del encomendero en los orígenes del régimen colonial, Nueva España (1525-1531) por José Miranda. - Juan Moritz Rugendas y su colección de pinturas costumbristas por Federico Hernández Serrano
"Objects Lost and Found: Kenneth Patchen's Poetics of the Letter"
No full textIn "Oggetti perduti e ritrovati: Kenneth Patchen e la poetica della lettera" gli aspetti storici e letterari di una poesia di Kenneth Patchen,"Poem in the form of a Letter: to Lauro de Bosis", sono esplorati analiticamente al fine di individuarne gli aspetti 'oggettivi' derivati dalla lezione di Zukofski che, negli anni trenta, iniziò a promuove l'oggettivismo in poesia, seguito da poeti come Ron Silliman, Bob Perelman e Rachel Blau DuPlessis ai nostri giorni.A poem by Kenneth Patchen "Poem in the form of a Letter: to Lauro de Bosis" is explored analytically by the author in order to discover its 'objective' aspects as derived from the lesson of Zukofsky who, in the thirties, set out to promote the "objectivism" in poetry, and was followed by poets like Ron Silliman, Bob Perelman and Rachel Blau DuPlessis, who are very active in today’s “objective” panorama
Impact of scour on lateral resistance of wind turbine monopiles: An experimental study
No full textThe majority of offshore wind structures are supported on large-diameter, rigid monopile foundations. These piles may be subjected to scour due to the waves and currents that causes a loss of soil support and consequently decreases the pile capacity and system stiffness. The results of numerical models suggest that the shape of the scour hole affects the magnitude of pile capacity loss; however, there is a dearth of experimental test data that quantify this effect. This paper presents a series of centrifuge model tests on an instrumented model pile that investigates the effects of scour-hole geometry on the response of a laterally loaded pile embedded in sand. The pile instrumentation allowed load–displacement and p–y (soil reaction – displacement) curves to be derived. Three scour geometries (global, local wide, and local narrow) and three scour depths (1D, 1.5D, and 2D; where D is pile diameter) were modelled. For all three scour types, pile moment capacity decreased almost linearly with increase of scour depth. Simple empirical relations were proposed to evaluate the detrimental influence of scour on the pile moment capacity. A new method has been developed to allow designers to quantify the effect of scour-hole shape and severity of scour on the pile response.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
Lateral response of rigid monopiles subjected to cyclic loading: Centrifuge modelling
No full textIn this study, a total number of 20 centrifuge tests were carried out to investigate monopile behaviour under lateral cyclic loading. The instrumented model pile simulates an offshore wind turbine foundation with an embedment ratio of 5 installed in sand layers with two relative densities of 80% and 50%. The influence of the directional characteristic and amplitude of cyclic load on pile lateral behaviour was studied. The data analysis focused on the influence of cyclic load on the accumulation of lateral displacement and evolution of secant stiffness of the foundation system. The most damaging cyclic load type (which can cause the most accumulated pile displacement) is identified as two-way loading, and it was observed that cyclic load always increases the pile secant stiffness. A new model for the prediction of evolution of accumulated displacement and change in secant stiffness has been formulated. An example of the procedure developed is presented for a typical field monopile subjected to cyclic loading. Lastly, the performance of the new model is demonstrated and predicted results are compared with field test data. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
Trust, social capital, civil society, and democracy
No full textThe importance of trust has long been emphasised by social and political theorists from Locke and Tocqueville to Putnam and civil society theorists. However, individual survey data casts substantial doubt on this powerful tradition of thought. There is little evidence of (1) an overlap between social and political trust, (2) a syndrome of trust and membership of voluntary organizations, and (3) the existence of trusting/distrusting dispositions among individuals. However, at the aggregate national level there is evidence to support the theory, and the author concludes that the classic theory is correct but needs modification and qualification
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