Atmospheric, climatic and environmental research

Research conducted during the past year in the climate and atmospheric modeling programs was focused on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Prinicpal models are a one-dimensional radiative-convection model, a three-dimensional global climate model, and an upper ocean model. Principal application is the study of the impact of CO2, aerosols and the solar constant on climate. Also the performance of the International Satellite Cloud Climatology Project cloud detection algorithm was evaluated, concentrating initially on its application to geosynchronous data, with an eventual switch of the developed methodologies to data from polar orbiting satellites. In the process, a number of improvements were made, in particular: an improved technique for tracking small scale day to day variability in clear sky continental temperatures; a number of techniques for the statistical assessment of cloud detection uncertainties due to cloud types which are spatially and temporally invariant; and a method used to detect those cloudy regions which have long term spatial and temporal stability

Three dimensional global modeling of atmospheric CO2

A model was developed to study the prospects of extracting information on carbon dioxide sources and sinks from observed CO2 variations. The approach uses a three dimensional global transport model, based on winds from a 3-D general circulation model (GCM), to advect CO2 noninteractively, i.e., as a tracer, with specified sources and sinks of CO2 at the surface. The 3-D model employed is identified and biosphere, ocean and fossil fuel sources and sinks are discussed. Some preliminary model results are presented

A study of the removal of alkyl benzene sulfonate by means of a column packed with sand coated with ferric oxide

Iron, precipitated in the form of hydroxides on sand particles (-48 + 65 mesh) and stabilized by drying at 100°C for 10 hours, was utilized to remove alkyl benzene sulfonate (ABS) from aqueous solutions. Solutions containing a maximum of 5 mg/l ABS were passed through a glass column packed with treated sand. The ABS formed a complex with the iron precipitants which adhered to the sand particles. Preliminary work, in which solutions containing 10 mg/l ABS were treated with various concentrations of FeCl2 at the equivalence point (pH about 9.5), verified the fact that ABS could be removed by this type of treatment. The concentration of ABS was reduced from 10 mg/l to a limiting value of 4.5 mg/l by treating 100 ml of the ABS solution with 10 ml of 0.0071 N FeCl2 solution under these conditions. A glass column (1.5 inch inside diameter), filled to a depth of twelve inches with 516 gm sand treated in three runs with 10, 20, and 40 ml respectively of 0.0071 N FeCl2 solution, was used to evaluate the adsorption of ABS. The quantity of ABS adsorbed from solutions of 5 mg/l ABS, flowing through the column at rates of 100 ml/hr, was proportional to the amount of iron precipitated (0.12 gm ABS/gm iron) on the sand. The removal of the ABS is attributed solely to the influence of the precipitated iron since there was no measurable effects with an untreated column. The desorption of ABS with water was quantitative in the case of the sands treated with the quantities of iron less than 1.5 x 10-5 gm/gm sand. Approximately one-third of the ABS remained in the complexed form on the sand surface when 3 x 10-5 gm iron/gm sand was used to treat the sand. The specific resistance (to flow) of the sand increased from 2.87 x 107 ft/lb, for the untreated sand, to 3.75 x 107 ft/lb, for sand treated with the maximum amount of iron. The specific resistance of the treated sand saturated with ABS was slightly greater than the treated sand free of ABS (3.89 x 107 ft/lb maximum). The techniques utilized in this investigation can be used to evaluate other similar situations --Abstract, pages ii-ii

Uncertain Translation, Uncertain Benefit and Uncertain Risk: Ethical Challenges Facing First-in-Human Trials of Induced Pluripotent Stem (iPS) Cells

The discovery of induced pluripotent stem (iPS) cells in 2006 was heralded as a major breakthrough in stem cell research. Since then, progress in iPS cell technology has paved the way towards clinical application, particularly cell replacement therapy, which has refueled debate on the ethics of stem cell research. However, much of the discourse has focused on questions of moral status and potentiality, overlooking the ethical issues which are introduced by the clinical testing of iPS cell replacement therapy. First-in-human trials, in particular, raise a number of ethical concerns including informed consent, subject recruitment and harm minimisation as well as the inherent uncertainty and risks which are involved in testing medical procedures on humans for the first time. These issues, while a feature of any human research, become more complex in the case of iPS cell therapy, given the seriousness of the potential risks, the unreliability of available animal models, the vulnerability of the target patient group, and the high stakes of such an intensely public area of science. Our paper will present a detailed case study of iPS cell replacement therapy for Parkinson's disease to highlight these broader ethical and epistemological concerns. If we accept that iPS cell technology is fraught with challenges which go far beyond merely refuting the potentiality of the stem cell line, we conclude that iPS cell research should not replace, but proceed alongside embryonic and adult somatic stem cell research to promote cross-fertilisation of knowledge and better clinical outcomes

Gene editing could open up animal organ transplants into humans

The clinical potential and ethical difficulty posed by gene-editing technology, which can “find and replace” targeted genes, is seemingly endless. But while public attention is focused on whether we should use it to change the genes of embryos, application of the technology to genetically modify pig tissues and organs for transplantation into humans could potentially have a bigger and more immediate impact on human health. The transplantation of living cells, tissues, or organs from one species to another is known as xenotransplantation. It has long been championed as a solution to the shortage of human donor organs. Xenotransplantation could be used either as definitive therapy or to “buy time” while the patient waits for a human donor organ. While progress has been slow, trials have demonstrated benefit in patients with type 1 diabetes who are transplanted with porcine pancreatic cells. And gene-editing research published in October shows incredible promise for making xenotransplantation a reality. Xenotransplantation faces two major challenges: the risk of immune rejection and the risk of transmitting diseases from animals to humans (xenozoonosis)

Gene editing advance re‐ignites debate on the merits and risks of animal to human transplantation

In Australia and internationally, the shortage of organ and tissue donors significantly limits the number of patients with critical organ or tissue failure who are able to receive a transplant each year. The rationale for xenotransplantation – the transplantation of living cells, tissues or organs from one species to another – is to meet this shortfall in human donor material. While early clinical trials showed promise, particularly in patients with Type I diabetes whose insulin dependence could be temporarily reversed by the transplantation of porcine islet cells, these benefits have been balanced with scientific, clinical and ethical concerns revolving around the risks of immune rejection and the potential transmission of porcine endogenous retroviruses (PERV) or other infectious agents from porcine grafts to human recipients. However, the advent of CRISPR/Cas9, a revolutionary gene editing technology, has re-ignited interest in the field with the possibility of genetically engineering porcine organs and tissues that are less immunogenic and have virtually no risk of PERV transmission. At the same time, CRISPR/Cas9 may also open up myriad possibilities for tissue engineering and stem cell research which may complement xenotransplantation research by providing an additional source of donor cells, tissues and organs for transplantation into patients. The recent international symposium on gene editing, organised by the US National Academy of Sciences, highlights both the enormous therapeutic potential of CRISPR/Cas9 and the raft of ethical and regulatory challenges that may follow its utilisation in transplantation and in medicine more generally

Is streamflow increasing? Trends in the coterminous United States

International audienceAn increasing trend in global streamflow has been variously attributed to climate change, land use, and a reduction in plant transpiration under higher CO2 levels. To separate these influences, we use a subset of ~1000 United States Geological Survey stream gauges primarily from small, minimally disturbed watersheds to estimate annual streamflow per unit area since 1920 on a uniform grid over the coterminous United States. We find that although streamflow has indeed increased over this period taken as a whole, this increase has not been uniform in time but concentrated in the late 1960s, when precipitation increased. Since the early 1990s, both precipitation and streamflow show nonsignificant declining trends. Multiple regression of streamflow against precipitation, temperature and CO2 suggests that higher CO2 levels may increase streamflow, presumably due to the physiological plant response to CO2, but that this positive response is more than offset by the concomitant increasing evaporation due to global warming, so that the net impact of greenhouse gas emissions has been to increase evaporation and reduce streamflow. The suppression of plant transpiration through higher CO2 levels seems to be particularly important for sustaining high streamflow in recent decades in the Great Plains, where precipitation is concentrated during the growing season

Estimates of oceanic surface wind speed and direction using orthogonal beam scatterometer measurements and comparison of recent sea scattering theories

The wind direction properties of radar backscatter from the sea were empirically modelled using a cosine Fourier series through the 4th harmonic in wind direction (referenced to upwind). A comparison with 1975 JONSWAP (Joint North Sea Wave Project) scatterometer data, at incidence angles of 40 and 65, indicates that effects to third and fourth harmonics are negligible. Another important result is that the Fourier coefficients through the second harmonic are related to wind speed by a power law expression. A technique is also proposed to estimate the wind speed and direction over the ocean from two orthogonal scattering measurements. A comparison between two different types of sea scatter theories, one type presented by the work of Wright and the other by that of Chan and Fung, was made with recent scatterometer measurements. It demonstrates that a complete scattering model must include some provisions for the anisotropic characteristics of the sea scatter, and use a sea spectrum which depends upon wind speed

Treatment of hilar cholangiocarcinoma (Klatskin tumors) with hepatic resection or transplantation

Background: Because of the rarity of hilar cholangiocarcinoma, its prognostic risk factors have not been sufficiently analyzed. This retrospective study was undertaken to evaluate various pathologic risk factors which influenced survival after curative hepatic resection or transplantation. Methods: Between 1981 and 1996, 72 patients (43 males and 29 females) with hilar cholangiocarcinoma underwent hepatic resection (34 patients) or transplantation (38 patients) with curative intent. Medical records and pathologic specimens were reviewed to examine the various prognostic risk factors. Survival was calculated by the method of Kaplan- Meier using the log rank test with adjustment for the type of operation. Survival statistics were calculated first for each kind of treatment separately, and then combined for the calculation of the final significance value. Results: Survival rates for 1, 3, and 5 years after hepatic resection were 74%, 34%, and 9%, respectively, and those after transplantation were 60%, 32%, and 25%, respectively. Univariate analysis revealed that T-3, positive lymph nodes, positive surgical margins, and pTNM stage III and IV were statistically significant poor prognostic factors. Multivariate analysis revealed that pTNM stage 0, I, and II, negative lymph node, and negative surgical margins were statistically significant good prognostic factors. For the patients in pTNM stage 0-II with negative surgical margins, 1-, 3-, and 5-year survivals were 80%, 73%, and 73%, respectively. For patients in pTNM stage IV-A with negative lymph nodes and surgical margins, 1-, 3-, and 5- year survivals were 66%, 37%, and 37%, respectively. Conclusions: Satisfactory longterm survivals can be obtained by curative surgery for hilar cholangiocarcinoma either with hepatic resection or liver transplantation. Redefining pTNM stage III and IV-A is proposed to better define prognosis