نتایج جستجو برای: ratio dating

تعداد نتایج: 516686  

2002
David S. WHITLEY Ronald I. DORN

A central problem in archaeological research has been the chronometric dating of petroglyphs (rock engravings). Recent improvements in the understanding of the chemistry of rock varnish (or patina) that develops on rock surfaces in arid regions has resulted in the development of a calibrated dating technique, cation-ratio (CR) dating. This is based on calibrating chemical changes in minor and m...

2016
Edmond Pui-Hang Choi Janet Yuen-Ha Wong Herman Hay-Ming Lo Wendy Wong Jasmine Hin-Man Chio Daniel Yee-Tak Fong

Dating applications (apps) on smartphones have become increasingly popular. The aim of this study was to explore the association between the use of dating apps and risky sexual behaviours. Data were collected in four university campuses in Hong Kong. Subjects completed a structured questionnaire asking about the use of dating apps, sexual behaviours, and sociodemographics. Multiple linear and l...

2003
RONALD I. DORN

Rock varnish coats many surfaces of geomorphic and archaeologic interest in arid lands. All varnish dating techniques are limited by the time lag between the exposure of a surface to subaerial processes and the onset of varnishing. They are valid only where manganese is not remobilized after deposition, for example, in most arid environments. The premise of a new age-determination method, catio...

Journal: :Pediatrics 2004
Jay G Silverman Anita Raj Karen Clements

OBJECTIVES To assess the annual prevalence of physical violence from dating partners among a representative sample of sexually experienced adolescent girls attending US public and private high schools, as well as sexual risk behaviors and pregnancy among this population. DESIGN, SETTING, PARTICIPANTS, AND MEASURES Female students (9th through 12th grade) (N = 6864) participating in the 2001 N...

Journal: :Science 2007
Gary Haynes David G Anderson C Reid Ferring Stuart J Fiedel Donald K Grayson C Vance Haynes Vance T Holliday Bruce B Huckell Marcel Kornfeld David J Meltzer Julie Morrow Todd Surovell Nicole M Waguespack Peter Wigand Robert M Yohe

Waters and Stafford (Reports, 23 February 2007, p. 1122) provided useful information about the age of some Clovis sites but have not definitively established the temporal span of this cultural complex in the Americas. Only a continuing program of radiometric dating and careful stratigraphic correlations can address the lingering ambiguity about the emergence and spread of Clovis culture.

Journal: :Journal of interpersonal violence 2010
Fang A Yan Donna E Howard Kenneth H Beck Teresa Shattuck Melissa Hallmark-Kerr

This study examined the association between dating violence victimization and psychosocial risk and protective factors among Latino early adolescents. An anonymous, cross-sectional, self-reported survey was administered to a convenience sample of Latino youth (n = 322) aged 11 to 13 residing in suburban Washington, D.C. The dependent variable was physical dating violence; the independent variab...

ژورنال: علوم آب و خاک 2015
اسفندیارپور بروجنی, عیسی , سرمست, معصومه, فرپور, محمدهادی ,

Physical, chemical, and microscopic properties together with mineralogy are among useful techniques for dating and paleoclimatological interpretation and identification of varnishes. The present research was performed to evaluate the application of stone varnish in dating and landform development investigations in southern dry lands of Giroft area, Kerman Province. The mantled pediment was iden...

2017
Zhao Gao Qi Yang Xiaole Ma Benjamin Becker Keshuang Li Feng Zhou Keith M. Kendrick

Language may have evolved as a signal of mental fitness. However, it remains unclear what language form and topic men use to covertly signal mate quality. In this study 69 men created compliments to impress unfamiliar women they chose to either date or work with and provided hand scans to compute 2D4D ratio as a proxy for prenatal testosterone exposure and masculinity indicator. Compliments wer...

2000
W. J. Percival L. Miller R. J. McLure J. S. Dunlop

We present the results of a deep K-band imaging study which reveals the host galaxies around a sample of 14 luminous radio-quiet quasars. The K-band images, obtained at UKIRT, are of sufficient quality to allow accurate modelling of the underlying host galaxy. Initially, the basic structure of the hosts is revealed using a modified Clean deconvolution routine optimised for this analysis. Two of...

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