Most ecological processes now show responses to anthropogenic climate change. In terrestrial, freshwater, and marine ecosystems, species are changing genetically, physiologically, morphologically, ...and phenologically and are shifting their distributions, which affects food webs and results in new interactions. Disruptions scale from the gene to the ecosystem and have documented consequences for people, including unpredictable fisheries and crop yields, loss of genetic diversity in wild crop varieties, and increasing impacts of pests and diseases. In addition to the more easily observed changes, such as shifts in flowering phenology, we argue that many hidden dynamics, such as genetic changes, are also taking place. Understanding shifts in ecological processes can guide human adaptation strategies. In addition to reducing greenhouse gases, climate action and policy must therefore focus equally on strategies that safeguard biodiversity and ecosystems.
Mammographic density (MD), representing connective and epithelial tissue (fibroglandular tissue, FGT) is a major risk factor for breast cancer. In an analysis of an autopsy series (Bartow SA, Pathak ...DR, Mettler FA. Radiographic microcalcification and parenchymal patterns as indicators of histologic "high-risk" benign breast disease. Cancer 1990; 66: 1721-1725, Bartow SA, Pathak DR, Mettler FA et al. Breast mammographic pattern: a concatenation of confounding and breast cancer risk factors. Am J Epidemiol 1995; 142: 813-819), MD was found to be strongly correlated with the collagen and epithelial content of the breast (Li T, Sun L, Miller N et al. The association of measured breast tissue characteristics with MD and other risk factors for breast cancer. Cancer Epidemiol Biomarkers Prev 2005; 14: 343-349), and another report showed that breast epithelium was highly concentrated in the areas of collagen concentration (Hawes D, Downey S, Pearce CL et al. Dense breast stromal tissue shows greatly increased concentration of breast epithelium but no increase in its proliferative activity. Breast Cancer Res 2006; 8: R24). Collagen comprises the overwhelming majority of the FGT, occupying an area on the slides obtained from the autopsy series some 15 times the area of glandular tissue. The relationship of MD with breast cancer risk appears likely to be due to a major extent to increasing epithelial cell numbers with increasing MD. FGT is also seen in breast magnetic resonance imaging (breast MRI) and, as expected, it has been shown that this measure of FGT (MRI-FGT) is highly correlated with MD. A contrast-enhanced breast MRI shows that normal FGT 'enhances' (background parenchymal enhancement, BPE) after contrast agent is administered(Morris EA. Diagnostic breast MR imaging: current status and future directions. Radiol Clin North Am 2007; 45: 863-880, vii., Kuhl C. The current status of breast MR imaging. Part I. Choice of technique, image interpretation, diagnostic accuracy, and transfer to clinical practice. Radiology 2007; 244: 356-378), and a recent study suggests that BPE is also a major breast cancer risk factor, possibly as important as, and independent of MD (King V, Brooks JD, Bernstein JL et al. BPE at breast MR imaging and breast cancer risk. Radiology 2011; 260: 50-60). BPE is much more sensitive to the effects of menopause and tamoxifen than is FGT (King V, Gu Y, Kaplan JB et al. Impact of menopausal status on BPE and fibroglandular tissue on breast MRI. Eur Radiol 2012; 22: 2641-2647, King V, Kaplan J, Pike MC et al. Impact of tamoxifen on amount of fibroglandular tissue, BPE, and cysts on breast MRI. Breast J 2012; 18: 527-534). Changes in MD and BPE may be most useful in predicting response to chemopreventive agents aimed at blocking breast cell proliferation. More study of the biological basis of the effects of MD and BPE is needed if we are to fully exploit these factors in developing chemopreventive approaches to breast cancer.
The presence of phosphorus in borosilicate glass (at 0.1 – 1.3mol % P2O5) and in iron-phosphate glass (at 53mol % P2O5) stimulated the growth and metabolic activity of anaerobic bacteria in model ...systems. Dissolution of these phosphorus containing glasses was either inhibited or accelerated by microbial metabolic activity, depending on the solution chemistry and the glass composition. The breakdown of organic carbon to volatile fatty acids increased glass dissolution. The interaction of microbially reduced Fe(II) with phosphorus-containing glass under anoxic conditions decreased dissolution rates, whereas the interaction of Fe(III) with phosphorus-containing glass under oxic conditions increased glass dissolution. Phosphorus addition to borosilicate glasses did not significantly affect the microbial species present, however, the diversity of the microbial community was enhanced on the surface of the iron phosphate glass. Results demonstrate the potential for microbes to influence the geochemistry of radioactive waste disposal environments with implication for wasteform durability.
Vitrified radioactive waste is designed to immobilize long lived radionuclides for time periods up to 106 years until activity has decayed to safe levels. Radioactive elements are chemically incorporated in the glass network and so are released as the glass dissolves. It is, therefore, important to understand the durability of vitrified radioactive waste in subsurface environments to inform the safety case for their long-term disposal. This paper investigates glass-microbe interactions using non-active surrogates for radioactive waste glasses and relevant anaerobic microorganisms to build a mechanistic understanding of glass dissolution in complex natural environments.
Display omitted
•Phosphorous released from nuclear waste type glasses stimulated microbial metabolism•Biofilms formed on the surface of glass that contained both iron and phosphorous•Microbial metabolism affected the rate of glass dissolution•An increase in glass dissolution was associated with microbial production of volatile fatty acids•A decrease in glass dissolution was associated with microbial reduction of Fe(III) to Fe(II).
AbstractMorphological variation is sometimes used as an indicator of environmental stress in animals. Here, we assessed how multiple morphological traits covaried in
exposed to five common forms of ...environmental stress (high temperature, presence of predator cues, high salinity, low food abundance, and low Ca). We measured animal body length, body width, head width, eyespot diameter, and tail spine length along with mass in animals of five different ages (3, 6, 9, 12, and 15 d). There were strong allometric relationships among all morphological traits in reference animals and strong univariate effects of environmental stress on body mass and body length. We found that environmental stressors altered bivariate relationships between select pairwise combinations of morphological traits, with effects being dependent on animal age. Multivariate analyses further revealed high connectivity among body size-related traits but that eyespot diameter and tail spine length were less tightly associated with body size. Animals exposed to natural lake water with and without supplemental food also varied in morphology, with body size differences being suggestive of starvation and other unknown nutritional deficiencies. Yet our results demonstrate that the scaling of body morphological traits of
is largely invariant with possible context-dependent plasticity in eye size and tail spine lengths. The strong coordination of traits indicates tight molecular coordination of body size during development despite strong and varied environmental stress.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Global extinction drivers, including habitat disturbance and climate change, are thought to affect larger species more than smaller species. However, it is unclear if such drivers interact to affect ...assemblage body size distributions. We asked how these two key global change drivers differentially affect the interspecific size distributions of ants, one of the most abundant and ubiquitous animal groups on earth. We also asked whether there is evidence of synergistic interactions and whether effects are related to species’ trophic roles. We generated a global dataset on ant body size from 333 local ant assemblages collected by the authors across a broad range of climates and in disturbed and undisturbed habitats. We used head length (range: 0.22–4.55 mm) as a surrogate of body size and classified species to trophic groups. We used generalized linear models to test whether body size distributions changed with climate and disturbance, independent of species richness. Our analysis yielded three key results: 1) climate and disturbance showed independent associations with body size; 2) assemblages included more small species in warmer climates and fewer large species in wet climates; and 3) both the largest and smallest species were absent from disturbed ecosystems, with predators most affected in both cases. Our results indicate that temperature, precipitation and disturbance have differing effects on the body size distributions of local communities, with no evidence of synergistic interactions. Further, both large and small predators may be vulnerable to global change, particularly through habitat disturbance.
The open-source release of self-replicating rapid prototypers (RepRaps) has created a rich opportunity for low-cost distributed digital fabrication of complex 3-D objects such as scientific ...equipment. For example, 3-D printable reactionware devices offer the opportunity to combine open hardware microfluidic handling with lab-on-a-chip reactionware to radically reduce costs and increase the number and complexity of microfluidic applications. To further drive down the cost while improving the performance of lab-on-a-chip paper-based microfluidic prototyping, this study reports on the development of a RepRap upgrade capable of converting a Prusa Mendel RepRap into a wax 3-D printer for paper-based microfluidic applications. An open-source hardware approach is used to demonstrate a 3-D printable upgrade for the 3-D printer, which combines a heated syringe pump with the RepRap/Arduino 3-D control. The bill of materials, designs, basic assembly, and use instructions are provided, along with a completely free and open-source software tool chain. The open-source hardware device described here accelerates the potential of the nascent field of electrochemical detection combined with paper-based microfluidics by dropping the marginal cost of prototyping to nearly zero while accelerating the turnover between paper-based microfluidic designs.
This study suggests that cold-ice processes may be more widespread than previously assumed, even within temperate glacial systems. We present the first systematic mapping of cold ice at the snout of ...the temperate glacier Midtdalsbreen, an outlet of the Hardangerjøkulen icefield (Norway), from 43 line kilometres of ground-penetrating radar data. Results show a 40 m wide cold-ice zone within the majority of the glacier snout, where ice thickness is <10 m. We interpret ice to be cold-based across this zone, consistent with basal freeze-on processes involved in the deposition of moraines. We also find at least two zones of cold ice up to 15 m thick within the ablation area, occasionally extending to the glacier bed. There are two further zones of cold ice up to 30 m thick in the accumulation area, also extending to the glacier bed. Cold-ice zones in the ablation area tend to correspond to areas of the glacier that are covered by late-lying seasonal snow patches that reoccur over multiple years. Subglacial topography and the location of the freezing isotherm within the glacier and underlying subglacial strata likely influence the transport and supply of supraglacial debris and formation of controlled moraines. The wider implication of this study is the possibility that, with continued climate warming, temperate environments with primarily temperate glaciers could become polythermal in forthcoming decades with (i) persisting thinning and (ii) retreat to higher altitudes where subglacial permafrost could be and/or become more widespread. Adversely, the number and size of late-lying snow patches in ablation areas may decrease and thereby reduce the extent of cold ice, reinforcing the postulated change in the thermal regime.
Observations are the foundation for understanding the climate system. Yet, currently available land meteorological data are highly fractured into various global, regional, and national holdings for ...different variables and time scales, from a variety of sources, and in a mixture of formats. Added to this, many data are still inaccessible for analysis and usage. To meet modern scientific and societal demands as well as emerging needs such as the provision of climate services, it is essential that we improve the management and curation of available land-based meteorological holdings. We need a comprehensive global set of data holdings, of known provenance, that is truly integrated both across essential climate variables (ECVs) and across time scales to meet the broad range of stakeholder needs. These holdings must be easily discoverable, made available in accessible formats, and backed up by multitiered user support. The present paper provides a high-level overview, based upon broad community input, of the steps that are required to bring about this integration. The significant challenge is to find a sustained means to realize this vision. This requires a long-term international program. The database that results will transform our collective ability to provide societally relevant research, analysis, and predictions in many weather and climate-related application areas across much of the globe.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A large number of investigations into the radiation doses from x-ray guided interventional cardiology procedures in children have been carried out in recent years. A review was conducted of these ...studies, gathering data on kerma area product (PKA), fluoroscopic screening time (FT), air kerma, and estimates of effective dose and organ doses. The majority of studies focus on PKA and FT with no estimation of dose to the patient. A greater than ten-fold variation in average PKA was found between different studies, even where data were stratified by patient age or weight. Typical values of PKA were 0.6-10 Gy · cm2 (<1 year/10 kg), 1.5-30 Gy · cm2 (1-5 years), 2-40 Gy · cm2 (5-10 years), 5-100 Gy · cm2 (10-16 years) and 10-200 Gy · cm2 (>16 years). PKA was lowest for heart biopsy (0.3-10 Gy · cm2 for all ages combined) and atrial septostomy (0.4-4.0 Gy · cm2), and highest for pulmonary artery angioplasty (1.5-35 Gy · cm2) and right ventricular outflow tract dilatation (139 Gy · cm2). Most estimates of patient dose were in the form of effective dose (typically 3-15 mSv) which is of limited usefulness in individualised risk assessment. Few studies estimated organ doses. Despite advances in radiation protection, recent publications have reported surprisingly large doses, as represented by PKA and air kerma. There is little indication of a fall in these dose indicators over the last 15 years. Nor is there much suggestion of a fall in doses associated with the use of flat panel detectors, as opposed to image intensifiers. An assessment of the impact of radiation dose in the context of overall patient outcome is required.
s
Space weather induced Geomagnetically Induced Currents (GICs) that are hazardous to power networks at high latitudes are often the result of rapid changes in near‐Earth space current systems such ...as the auroral electrojets and field‐aligned currents. GIC activity at low‐middle latitudes may be driven by currents that are more relevant to these regions such as the ring or magnetopause current systems. Solar wind shocks create rapid changes in the magnetopause current that manifest as large step changes in the geomagnetic field at the Earth's surface, often referred to as geomagnetic sudden impulses (SIs), that are effective drivers of GIC activity in power networks at low‐middle latitudes. This paper describes the results of a study into the relationship between the driver of SIs, solar wind shocks, and their potential impact on power systems in the Australian region, as quantified by a GIC‐index. The initial data set for analysis was produced by programmatically scanning solar wind data obtained from the ACE satellite spanning the period 1998–2008 for solar wind shocks. For each identified solar wind shock, geomagnetic field data from the Australian region were analyzed to determine the corresponding SI and GIC‐index. Statistical analyses of GIC‐indices and various solar wind parameters associated with the shocks resulted in an empirical model that is a function of solar wind dynamic pressure, geomagnetic latitude, and change in solar wind speed with good operational predictive capability. This model was further assessed using online catalogs of solar wind shock events.
Plain Language Summary
During energetic solar eruptions large clouds of charged particles and magnetic field from the sun's outer atmosphere, or corona, may be ejected into interplanetary space. These clouds are typically referred to as coronal mass ejections or CMEs and propagate in the continuous background stream of charged particles and magnetic field emanating from the sun referred to as the solar wind. CMEs may impact the Earth's magnetic field, compressing its outer boundary on the dayside and significantly enhancing current systems in the near‐Earth space environment. These currents generate electromagnetic fields that propagate to Earth and manifest as unwanted currents in power systems and long resource pipelines. This paper analyses the abrupt change in the Earth's magnetic field created during CME impact in terms of an index that quantifies the potential hazard to power systems, the Geomagnetically Induced Current (GIC)‐index, against the associated characteristic signatures of CMEs in solar wind data observed by satellites located upstream of the Earth toward the sun. A statistical analysis of solar wind data and GIC‐index data derived from magnetic field measurements over the Australian region is used to determine a forecast model that can provide warnings for the Australian power sector with sufficient lead time to implement mitigating actions.
Key Points
Geomagnetic sudden impulses caused by solar wind shocks create Geomagnetically Induced Currents (GICs) that may be hazardous to power systems at low‐to‐middle latitudes
Statistical analysis of solar wind shocks and GIC‐index data derived from magnetic field measurements over the Australian region
Statistical model is a function of solar wind dynamic pressure, speed, and geomagnetic latitude with good out‐of‐sample predictive power
PDF
