Statistical methods for model comparison in parameter estimation problems for distributed systems

In this note we outline some recent results on the development of a statistical testing methodology for inverse problems involving partial differential equation models. Applications to several problems from biology are presented. The statistical tests, which are in the spirit of analysis of variance (ANOVA), are based on asymptotic distributional results for estimators and residuals in a least squares approach.Research supported in part under grants NSF MCS 8504316, NASA NAG-1-517, and AFOSRF-49620-86-C-0111. Part of this research was carried out while the first author was a visiting scientist at the Institute for Computer Applications in Science and Engineering (ICASE), NASA Langley Research Center, Hampton, VA, which is operated under NASA contracts NASI-18107 and NASI-18605     

Modeling insect dispersal and estimating parameters when mark-release techniques may cause initial disturbances

We consider the problem of quantitatively modeling movements of marked flea beetles in cultivated arrays of the cole crop, collards (Brassica oleraceae). Methods for the estimation of temporally and spatially dependent parameters in general dispersal models are outlined and a summary of our findings using these methods with flea beetle data is given.This research was supported in part by the National Science Foundation under NSF # MCS-8205335 and by the U.S. Air Force Office of Scientific Research under contract AFOSR 81-0198. Part of the research was carried out while this author was a Visiting Professor in the Department of Mathematics at Southern Methodist UniversityThis research was supported in part by the National Science Foundation under NSF # DEB-8207117This research was supported in part by the National Science Foundation under NSF # MCS-8200883. Part of the research was carried out while the first and third authors were visitors at the Institute for Computer Applications in Science and Engineering (ICASE), NASA Langley Research Center, Hampton, Virginia which is operated under NASA contracts NAS1-15810 and NAS1-16394     

Global harmonization in the care and use of laboratory animals for the space life science research]

Space researches are supported with the international space agencies, NASA and NASDA. Animal experiments on the space life science must conform to the NIH policies and the NASA guide for the care and use of laboratory animals. The goal of the NIH policies is to promote the humane care of animals used biomedical and behavioral research, teaching, and testing. In each institute, the Institutional Animal Care and Use Committee (IACUC) plays an important role in conformity with NIH policies. The IACUC is charged with developing, recommending and monitoring NIH/NASA (ARC and KSC) policies, guides and rules relating to animal acquisition, care and use. In ARC and KSC, investigators will be responsible only for activities directly related to the conduct of their animal experiments. Even if researchers have protocols of the space science in Japan, the animal experiment should be carried out under the global harmonized conditions in accordance with NIH policies and NASA guides.     

Preliminary observations on the birth and development ofPropithecus verreauxi to the age of six months

In this paper, preliminary observations are presented on the ontogency of one of the Malagasy prosimians,Propithecus verreauxi. Observations were carried out in the course of an eighteen-month study of the social organization and ecology of four, free-ranging groups. Parturition is described, together with data on the development of locomotor and feeding behavior, and on the changing nature of the infant's relationship with its mother and with other members of the group. The final section compares the results of this study with those of previous studies ofP. verreauxi and other lemur species. Tentative conclusions are drawn concerning aspects of social ontogeny inP. verreauxi and areas for future research are suggested which would clarify some of the remaining problems.     

Of pigs and men and research

A review of the role of pigs as an ideal experimental animal in human medical research is given, covering applications and analogies of sus scrofa in general medicine encompassing space medicine. It is also a report of some investigations carried out on Danish Landrace pigs that emphasize the similarities of swine and men. The musculoskeletal system, respiration, circulation, blood, lymph, digestion, metabolism, nutrition, excretion, endocrines, dermatological problems, and eyes are discussed along with other aspects to show the value of the pig when a large, human-like biomedical research animal is needed.Most of the findings and work reported here was carried out while Senior Research Scientist at the Danish Meat Research Institute, Roskilde, Dermark. Reprint requests should be directed to Postbox 67, DK-1003 Copenhagen K, Denmark.     

Space radiation research in Europe: flight experiments and ground-based studies

Exposure to space radiation has long been acknowledged as a potential showstopper for long-duration manned interplanetary missions. In an effort to gain more information on space radiation risk and to develop countermeasures, NASA initiated several years ago a Space Radiation Health Program, which is currently supporting biological experiments performed at the Brookhaven National Laboratory. Accelerator-based radiobiology research in the field of space radiation research is also under way in Russia and Japan. The European Space Agency (ESA) supports research in the field in three main directions: spaceflight experiments on the International Space Station; modeling and simulations of the space radiation environment and transport; and, recently, ground-based radiobiology experiments exploiting the high-energy SIS18 synchrotron at GSI in Germany (IBER program). Several experiments are currently under way within IBER, and so far, beams of C and Fe-ions at energies between 11 and 1,000 MeV/n have been used in cell and tissue targets.     

Development, potentials, and challenges of the International Long-Term Ecological Research (ILTER) Network

In order to review the development, the potentials, and the challenges of the International Long-Term Ecological Research (ILTER) Network, the necessity for the development of the ILTER Network, the development of ILTER activities in the world, and the body structures of ILTER Network are described. As an example for showing the potentials of ILTER activities, exemplary results of tree growth studies carried out by the author utilizing long-term daily weather data at the Hubbard Brook Experimental Forest, New Hampshire, USA are presented and future potentials are discussed. At this time, as the ILTER Network is situated at a critical point, challenges for the ILTER Network are discussed with regard to its further development. In this review, the author tries to maintain that as the long-term ecological research, whose results can secure comparability in the dimension of time and space, can provide us with a fundamental basis for sound understanding and management of ecosystems, we can publicize the activities and findings from the ILTER Network to the public, on from local to international levels, to continue further efforts around the world for our sustainable future.     

Emphasis of biological research for space radiation]

The paper summarized issues, current status and the recent topics in biological research of space radiation. Researches to estimate a risk associated with space radiation exposure during a long-term manned space flight, such as in the International Space Station, is emphasized because of the large uncertainty of biological effects and a complexity of the radiation environment in space. The Issues addressed are; 1) biological effects and end points in low dose radiation, 2) biological effects under low dose rate and long-term radiation exposure, 3) modification of biological responses to radiation under space environments, 4) various aspects of biological end points vs. cellular and molecular mechanisms, 5) estimation of human risk associated with radiation exposure in space flight, 6) regulations for radiation exposure limits for space workers. The paper also summarized and introduced recent progress in space related radiation researches with various biological systems.     

Radiation risk in manned space flights

This paper addresses some of the pertinent questions relating to the assessment of radiation risk for humans in space; the paper is not intended as a comprehensive review. The radiation field is briefly summarised and doses to be expected are given based on recent on-board measurements. The problems in adapting terrestrial epidemiological data to the space situation are outlined. Apart from the intrinsic uncertainties in deriving risk factors the specific difficulties are mainly concerned with the effects of energetic charged particles for which no human data exist. The necessity for continuing ground-based research is stressed. Also discussed is whether the principles of radiation protection successfully applied on Earth are really suitable for the space situation or whether they should be replaced by a different approach.     

Biological treatment of a synthetic space mission wastewater using a membrane-aerated,membrane-coupled bioreactor (M2BR)

This paper describes the membrane-aerated, membrane-coupled bioreactor (M2BR), which was developed for wastewater treatment during long-term space missions because it achieves aeration and biomass separation using components that are compatible with microgravity conditions. In the experiments described herein, the M2BR was used to treat a synthetic wastewater formulated by NASA to simulate the wastewater typically collected during space missions. The M2BR was able to achieve more than 90% removal of both chemical oxygen demand (COD) and total nitrogen when it was fed a modified NASA wastewater that had a 4:1 COD to nitrogen ratio. When the full-strength synthetic wastewater was fed to the M2BR (COD:N=1), however, the nitrogenous pollutant removal efficiency was adversely affected because of either insufficient oxygen transfer to support nitrification (an air-fed M2BR) or insufficient electron donor to support denitrification (an oxygen-fed M2BR). In conclusion, the M2BR provides considerable promise for wastewater treatment during long-term space missions, although additional research is needed to identify the best approach to treat the space mission wastewater, which poses a unique challenge because of its low COD:N ratio.     

The European strategy on low dose risk research and the role of radiation quality according to the recommendations of the “ad hoc” High Level and Expert Group (HLEG)

Health effects of exposures at low doses and/or low dose rates are recognized as requiring intensive research activity to answer several questions. To address these issues at a strategic level in Europe, with the perspective of integrating national and EC efforts (in particular those within the Euratom research programmes), a “European High Level and Expert Group (HLEG) on low dose risk research” was formed and carried out its work during 2008. The Group produced a report published by the European Commission in 2009 and available on the website . The more important research issues identified by the HLEG were as follows: (a) the shape of dose–response for cancer; (b) the tissue sensitivities for cancer induction; (c) the individual variability in cancer risk; (d) the effects of radiation quality (type); (e) the risks from internal radiation exposure; and (f) the risks of, and dose response relationships for, non-cancer diseases. In this paper, the radiation quality issues are especially considered, since they are closely linked to health problems and related radioprotection in space and in emerging radiotherapeutic techniques (i.e., hadrontherapy). The peculiar features of low-fluence, high-LET radiation exposures can question in particular the validity of the radiation-weighting factor (w _R ) approach. Specific strategies are therefore needed to assess such risks. A multi-scale/systems biology approach, based on mechanistic studies coordinated with molecular-epidemiological studies, is considered essential to elucidate differences and similarities between specific effects of low- and high-LET radiation.     

In-vivo estimations of the nonlinear pressure-volume relationship of the aorta and instantaneous left ventricular volume

A method is presented in this paper for the in-vivo estimation of the nonlinear pressure-volume relationship of the human aorta. The method is based on nonlinear elastic reservoir theory and utilizes clinical data that can be obtained with a high degree of accuracy, namely stroke volume, end diastolic ventricular volume and aortic pressure trace data. The computational procedure is described and then carried out for six cardiac patients. A method for the estimation of instantaneous left ventricular volume during the ejection period based on the considered nonlinear elastic reservoir theory is also presented. The method is applied for the six cardiac patients cited and the results compared with those obtained for the same subjects by a method of estimation based on linear elastic reservoir theory described in a previous paper by the author (1969).     

NASA Radiation Biomarker Workshop, September 27-28, 2007

A summary is provided of presentations and discussions at the NASA Radiation Biomarker Workshop held September 27-28, 2007 at NASA Ames Research Center in Mountain View, CA. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including those exposed during long-duration space travel. Topics discussed included the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage after large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. A summary of conclusions is provided at the end of the report.     

Future opportunities for life science programs in space

Most space-related life science programs are expensive and time-consuming, requiring international cooperation and resources with trans-disciplinary expertise. A comprehensive future program in "life sciences in space" needs, therefore, well-defined research goals and strategies as well as a sound ground-based program. The first half of this review will describe four key aspects such as the environment in space, previous accomplishments in space (primarily focusing on amphibian embryogenesis), available resources, and recent advances in bioinformatics and biotechnology, whose clear understanding is imperative for defining future directions. The second half of this review will focus on a broad range of interdisciplinary research opportunities currently supported by the National Aeronautics and Space Administration (NASA), National Institute of Health (NIH), and National Science Foundation (NSF). By listing numerous research topics such as alterations in a diffusion-limited metabolic process, bone loss and skeletal muscle weakness of astronauts, behavioral and cognitive ability in space, life in extreme environment, etc., we will attempt to suggest future opportunities.     

基于内容分析法的中国垂直绿化研究进展

以墙面垂直绿化为研究对象,借助CNKI文献库,以垂直绿化及相关关键词检索文献。运用内容分析法,通过3个维度分析中国垂直绿化整体特征。集中分析2006—2015年文献资料,总结研究进展与研究趋势。研究目前主要探讨垂直绿化植物应用、构建技术、基质选择、灌溉技术等工程问题。植物应用贯穿整个研究过程,但主要关注植物选择,缺乏植物造景研究。新技术研究起步较晚,成果不断增加,但基质选择与灌溉技术的研究水平相对较低。此外,垂直绿化的效益研究逐渐成为热点方向,其实践应用也不断开展。为了完善垂直绿化体系,未来研究应朝学科交叉发展、系统性的理论研究及设计指导方法、景观绩效评价体系的建立3个方面继续深入进行。     

农林系统研究进展

综述了国内外农林系统的研究进展 ,介绍了农林系统的概念、产生背景和过程及主要的研究方向。从农林系统的结构和分类、农林系统小气候及系统效益评价等 3个方面对当前农林系统的研究现状进行了评述。重点从水分、温度、辐射、光照及人体舒适度等方面分析了农林系统小气候的研究状况 ;从化感作用和地下部分相互作用两个方面介绍了系统组分间的相互作用关系。同时指出农林系统类型较为单一、理论研究落后于实践、基础理论研究相对薄弱等研究中存在的问题。提出农林系统的研究应进一步加强多学科深层次、实质性的交流与合作 ,注重科研机构与生产基层的有机联系 ,加强理论基础研究 ,因地制宜地发展农林系统 ,更好地为生产实践服务。