3,976 research outputs found
Electron Microscope Studies of Heteroduplex DNA from a Deletion Mutant of Bacteriophage phi X-174
A population of double-stranded replicative form of DNA molecules from bacteriophage phi X-174 carrying a deletion of about 9% of the wild-type DNA has been discovered in a sample cultivated under conditions where the phage lysozyme gene is nonessential. The structures of deleted monomers, dimers, and trimers were studied by the electron microscope heteroduplex method. The dimers and trimers are head-to-tail repeats of the deleted monomers. Some interesting examples of the dynamical phenomenon of branch migration in vitro have been observed in heteroduplexes of deleted dimer and trimer strands with undeleted monomer viral strands from the wild-type phage
A Ground Water Quality Summary for Alaska: a Termination Report
The expanding economic activity throughout the State of Alaska
has created an urgent demand for water resource data. Ground water
quality information is of particular interest since this is the most
used source for domestic and industrial supplies.
Many agencies and individuals have accumulated large quantities
of data but their value has been marginal due to a lack of distribution
to potential users. It was the original intent of the work reported
herein to gather, collate, and publish all ground water quality data
available in the files of university, state, and federal laboratories.
Soon after the inception of the project the major contributor, the
U.S. Geological Survey, found it was administratively impossible to
contribute either the monies or the data necessary to accomplish the
ultimate goals of the project -- An Atlas on Alaskan Ground Water
Qualities.
At the time the above decision was made the Institute felt too
much information was on hand to allow it to lay fallow. Therefore,
this report was prepared, In a more limited scope than originally
planned, to fill the need for a readily available source of information.The work upon which this report is based was supported by
funds provided by the U.S. Department of the Interior, Office of
Water Resources Research, Project Number A-024-ALAS and Agreement
Number 14-01-0001-1070
Family religious involvement and the quality of family relationships for early adolescents
Examination of association between the religious involvement (number of family religious activities, parental worship service attendance and parental prayer) and quality of family relationships with results indicating that religiously involved families of adolescents (ages 12-14) living in the U.S. are more like to have stronger family relationships than families that are not religiously active
Family religious involvement and the quality of family relationships for early adolescents
Examination of association between the religious involvement (number of family religious activities, parental worship service attendance and parental prayer) and quality of family relationships with results indicating that religiously involved families of adolescents (ages 12-14) living in the U.S. are more like to have stronger family relationships than families that are not religiously active
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Predicting early risk of chronic kidney disease in cats using routine clinical laboratory tests and machine learning.
BackgroundAdvanced machine learning methods combined with large sets of health screening data provide opportunities for diagnostic value in human and veterinary medicine.Hypothesis/objectivesTo derive a model to predict the risk of cats developing chronic kidney disease (CKD) using data from electronic health records (EHRs) collected during routine veterinary practice.AnimalsA total of 106 251 cats that attended Banfield Pet Hospitals between January 1, 1995, and December 31, 2017.MethodsLongitudinal EHRs from Banfield Pet Hospitals were extracted and randomly split into 2 parts. The first 67% of the data were used to build a prediction model, which included feature selection and identification of the optimal neural network type and architecture. The remaining unseen EHRs were used to evaluate the model performance.ResultsThe final model was a recurrent neural network (RNN) with 4 features (creatinine, blood urea nitrogen, urine specific gravity, and age). When predicting CKD near the point of diagnosis, the model displayed a sensitivity of 90.7% and a specificity of 98.9%. Model sensitivity decreased when predicting the risk of CKD with a longer horizon, having 63.0% sensitivity 1 year before diagnosis and 44.2% 2 years before diagnosis, but with specificity remaining around 99%.Conclusions and clinical importanceThe use of models based on machine learning can support veterinary decision making by improving early identification of CKD
Organizing activities and founding processes of new ventures
In this dissertation, I examine three aspects of organizational emergence: composition of founders' support networks, acquisition of external organizational knowledge, and a multidimensional approach to identifying emergent organizations. I draw on organizational, social capital, human capital, and social exchange theories to develop my hypotheses. Based on a random sample of nascent entrepreneurs in the United States, I found that founders rely heavily on their strong ties to solicit support; use their specific human capital to guide their acquisition of external knowledge; and follow unique founding processes that differ across industrial groups
Introduction to Positive Psychology: Overview and Controversies
Since his first formal address in 1998 by Martin Seligman, the significant growth and accomplishments of the positive psychology have been universally noted. Notable breakthroughs include the inception of the International Positive Psychology Association in 2007 and the First World Congress of Positive Psychology in 2009. However, much concern has also arisen in conjunction with the development of positive psychology. For example, Gable and Haidt (2005) argued that the assumption of positive psychology implies the rest of the field must be negative psychology. These controversies are not only limited to the foundation of positive psychological principles and understanding the controversies is requisite to ensuring the correct implementation of positive psychology. In this regard, the authors first describe a fundamental tenet of positive psychology in the areas of positive emotion, positive traits, and positive institutions. Further details on controversies and challenges in each area of concern are discussed, leading to the conclusion that positive psychology is a reputable subdiscipline of psychology
Women as a Force Multiplier for Bringing Nuclear Forensic Capabilities to the International Stage
In 2009, the US Department of Energy National Nuclear Security Administration’s (NNSA’s) Defense Nuclear Nonproliferation Program initiated a new nuclear forensics outreach effort under its Confidence Building Measures Program. Little did they know that the timing could not have been better. This article focuses on the early years (2009–2015) of the NNSA’s international nuclear forensics outreach, specifically the efforts and experiences of the women who helped establish this program, building it from a fledgling, bilateral effort into an enduring technical capacity provider engaging with dozens of countries and multilateral organizations. At the onset of the program, nuclear forensics was an emerging priority within the US Government and receiving increased focus from international organizations through high-level diplomatic efforts such as the Nuclear Security Summit and Global Initiative to Combat Nuclear Terrorism. Additionally, working-level initiatives were gaining traction through the International Atomic Energy Agency and the Nuclear Forensics International Technical Working Group. Over the next 6 years, a small team comprising a uniquely large number of women NNSA federal, contract, and national laboratory staff served as key leaders engaging with the international community to strengthen global technical nuclear forensics capacity and best practices.
The program continues today under the Nuclear Smuggling Detection and Deterrence Program as Investigation Support. The experiences shared here detail a unique time period when the new technical discipline of nuclear forensics was beginning to mature and gain international traction. The authors have made every effort to remember history correctly and be as inclusive as possible. A wealth of training, guidance, and exercise documentation was developed in the 2009–2015 time frame, much of which still serves as the foundation for today’s even more extensive program and community of dedicated technical and diplomatic practitioners
A Review of the Proposed KIsi Offset-Secant Method for Size-Insensitive Linear-Elastic Fracture Toughness Evaluation
Recently proposed modifications to ASTM E399 would provide a new size-insensitive approach to analyzing the force-displacement test record. The proposed size-insensitive linear-elastic fracture toughness, KIsi, targets a consistent 0.5mm crack extension for all specimen sizes by using an offset secant that is a function of the specimen ligament length. The KIsi evaluation also removes the Pmax/PQ criterion and increases the allowable specimen deformation. These latter two changes allow more plasticity at the crack tip, prompting the review undertaken in this work to ensure the validity of this new interpretation of the force-displacement curve. This paper provides a brief review of the proposed KIsi methodology and summarizes a finite element study into the effects of increased crack tip plasticity on the method given the allowance for additional specimen deformation. The study has two primary points of investigation: the effect of crack tip plasticity on compliance change in the force-displacement record and the continued validity of linear-elastic fracture mechanics to describe the crack front conditions. The analytical study illustrates that linear-elastic fracture mechanics assumptions remain valid at the increased deformation limit; however, the influence of plasticity on the compliance change in the test record is problematic. A proposed revision to the validity criteria for the KIsi test method is briefly discussed
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