Understanding the nature of streamflow response to precipitation inputs is at the core of hydrological applications and water resource management. Indices such as the base flow index, recession ...constant, and response lag of a watershed retain an important place in hydrology as metrics to compare watersheds and understand the impact of human activity, geology, geomorphology, soils, and climate on precipitation–runoff relations. Extracting characteristics of the hyetograph–hydrograph relationship is often done manually, which is time consuming and may result in subjective and potentially inconsistent outcomes. Here, we present a MATLAB‐based toolbox, called HydRun, for rapid and flexible rainfall–runoff analysis. HydRun uses a series of flexible routines to extract base flow from the hydrograph and then computes commonly used time instants of the rainfall–runoff relationship. HydRun provides users the flexibility to decide thresholds and limits of analysis, but objectively computes hydrometric indices. The toolkit includes a graphical user interface and example files. In this paper, we apply HydRun to 4 watersheds, 3 in Scotland and 1 in Canada, to demonstrate the software functions and highlight important decisions the user must make in its application.
Seasonality plays a critical role in cold mountain regions as variation in air temperature, ground thermal status, and precipitation phase alter the rate, timing and magnitude of hydrological and ...chemical transport. Additionally, cold mountain catchments can have highly variable topography, geology, permafrost, and landcover, which intrinsically add to this irregularity. Understanding how external and internal variability act to control mass fluxes requires sampling at a high spatial resolution over time, which rarely occurs in cold remote regions. In this work, we conduct five snapshot sampling surveys across 34 subcatchments during the ice‐free period in Wolf Creek Research Basin (a mesoscale montane subarctic catchment) and two additional winter surveys across a subset of sites to assess the drivers of variability in stream chemistry and discharge. We sampled for specific conductance (SpC), major ions, and dissolved organic carbon (DOC) and used statistical metrics and Bayesian mixing analysis to quantify patterns of flow and chemistry across space and time. Our results indicate patterns in both flow and chemistry remain largely consistent across seasons for all solutes. However, there was weaker correlation of chemistry between sites, suggesting asynchronous behaviour within the catchment. There was evidence of increasing production of ions and DOC along the stream network during high spring flows but not during low flows. Although concentrations and flows exhibit high seasonality in subarctic mountains, this seasonal variability does not alter spatial patterns that arise from highly variable catchment characteristics.
High spatial heterogeneity drives high spatial stability of discharge and chemistry in a cold subarctic mountain across all four seasons, despite high seasonality often present in cold regions.
Conspectus Immunotherapies harness an individual’s immune system to battle diseases such as cancer and autoimmunity. During cancer, the immune system often fails to detect and destroy cancerous ...cells, whereas during autoimmune disease, the immune system mistakenly attacks self-tissue. Immunotherapies can help guide more effective responses in these settings, as evidenced by recent advances with monoclonal antibodies and adoptive cell therapies. However, despite the transformative gains of immunotherapies for patients, many therapies are not curative, work only for a small subset of patients, and lack specificity in distinguishing between healthy and diseased cells, which can cause severe side effects. From this perspective, self-assembled biomaterials are promising technologies that could help address some of the limitations facing immunotherapies. For example, self-assembly allows precision control over the combination and relative concentration of immune cues and directed cargo display densities. These capabilities support selectivity and potency that could decrease off-target effects and enable modular or personalized immunotherapies. The underlying forces driving self-assembly of most systems in aqueous solution result from hydrophobic interactions or charge polarity. In this Account, we highlight how these forces are being used to self-assemble immunotherapies for cancer and autoimmune disease. Hydrophobic interactions can create a range of intricate structures, including peptide nanofibers, nanogels, micelle-like particles, and in vivo assemblies with protein carriers. Certain nanofibers with hydrophobic domains uniquely benefit from the ability to elicit immune responses without additional stimulatory signals. This feature can reduce nonspecific inflammation but may also limit the nanofiber’s application because of their inherent stimulatory properties. Micelle-like particles have been developed with the ability to incorporate a range of tumor-specific antigens for immunotherapies in mouse models of cancer. Key observations have revealed that both the total dose of antigen and display density of antigen per particle can impact immune response and efficacy of immunotherapies. These developments are promising benchmarks that could reveal design principles for engineering more specific and personalized immunotherapies. There has also been extensive work to develop platforms using electrostatic interactions to drive assembly of oppositely charged immune signals. These strategies benefit from the ability to tune biophysical interactions between components by altering the ratio of cationic to anionic charge during formulation, or the density of charge. Using a layer-by-layer assembly method, our lab developed hollow capsules composed entirely of immune signals for therapies in cancer and autoimmune disease models. This platform allowed for 100% of the immunotherapy to be composed of immune signals and completely prevents the onset of disease in a mouse model of multiple sclerosis. Layer-by-layer assembly has also been used to coat microneedle patches to target signals to immune cells in the dermal layer. As an alternative to layer-by-layer assembly, one step assembly can be achieved by mixing cationic and anionic components in solution. Additional approaches have created molecular structures that leverage hydrogen bonding for self-assembly. The creativity of engineered self-assembly has led to key insights that could benefit future immunotherapies and revealed aspects that require further study. The challenge now remains to utilize these insights to push development of new immunotherapeutics into clinical settings.
Observations and data from long‐term experimental watersheds are the foundation of hydrology as a geoscience. They allow us to benchmark process understanding, observe trends and natural cycles, and ...are prerequisites for testing predictive models. Long‐term experimental watersheds also are places where new measurement technologies are developed. These studies offer a crucial evidence base for understanding and managing the provision of clean water supplies, predicting and mitigating the effects of floods, and protecting ecosystem services provided by rivers and wetlands. They also show how to manage land and water in an integrated, sustainable way that reduces environmental and economic costs.
Key Points
Hydrological data collected over many decades give us the greatest insights into how the water cycle “works” and is changing
Such data have proven essential in understanding and managing water supplies, floods, and other ecosystem services
We need to protect long‐term studies, promote them, and make data available; their value to society increases over time
Flow regimes are critical for determining physical and biological processes in rivers and their classification and regionalization traditionally seeks to link patterns of flow to physiographic, ...climate and other information. There are many approaches to, and rationales for, catchment classification, with those focused on streamflow often seeking to relate a particular response characteristic to a physical property or climatic driver. Rationales include such topics as prediction in ungauged basins (PUB), and providing guidance for model selection in poorly understood hydrological systems. The annual daily hydrograph (ADH) is a first‐order easily visualized integrated expression of catchment function, and over many years the average ADH is a distinct hydrological signature that differentiate catchments from each other. In this study, we use t‐SNE, a state‐of‐the‐art technique of dimensionality reduction, to classify 17 110 ADHs for 304 reference catchments in mountainous Western North America. t‐SNE is chosen over other conventional methods of dimensionality reduction (e.g., PCA) as it presents greater separability of ADHs, which are projected on a 2D map where the similarities are evaluated according to their map distance. We then utilize a Deep Learning encoder to upgrade the non‐parametric t‐SNE to a parametric approach, enhancing its capability to address ‘unseen’ samples. Results showed that t‐SNE successfully clustered ADHs of similar flow regimes on the 2D map and allowed more accurate classification with KNN. In addition, many compact clusters on the 2D map in the coastal Pacific Northwest suggest information redundancy in the local streamflow network. The t‐SNE map provides an intuitive way to visualize the similarity of high‐dimensional data of ADHs, groups catchments with like characteristics, and avoids the reliance on subjective hydrometric indicators.
t‐SNE converts Annual Daily Hydrographs (ADHs) into a 2D map, where ADHs from different western North American flow regimes show distinct clusters. This provides an intuitive way to visualize and compare the similarity among a large number of hydrographs. Incorporating a Deep Learning encoder, we provide a convenient tool to project new hydrographs on to the map, identify similar counterparts and establish the flow regime for any given ADH.
The nature of the TRAPPIST-1 exoplanets Grimm, Simon L.; Demory, Brice-Olivier; Gillon, Michaël ...
Astronomy and astrophysics (Berlin),
05/2018, Letnik:
613
Journal Article, Web Resource
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Context. The TRAPPIST-1 system hosts seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. As such, it represents a remarkable setting to study the formation and evolution of ...terrestrial planets that formed in the same protoplanetary disk. While the sizes of the TRAPPIST-1 planets are all known to better than 5% precision, their densities have significant uncertainties (between 28% and 95%) because of poor constraints on the planet’s masses. Aims. The goal of this paper is to improve our knowledge of the TRAPPIST-1 planetary masses and densities using transit-timing variations (TTVs). The complexity of the TTV inversion problem is known to be particularly acute in multi-planetary systems (convergence issues, degeneracies and size of the parameter space), especially for resonant chain systems such as TRAPPIST-1. Methods. To overcome these challenges, we have used a novel method that employs a genetic algorithm coupled to a full N-body integrator that we applied to a set of 284 individual transit timings. This approach enables us to efficiently explore the parameter space and to derive reliable masses and densities from TTVs for all seven planets. Results. Our new masses result in a five- to eight-fold improvement on the planetary density uncertainties, with precisions ranging from 5% to 12%. These updated values provide new insights into the bulk structure of the TRAPPIST-1 planets. We find that TRAPPIST-1 c and e likely have largely rocky interiors, while planets b, d, f, g, and h require envelopes of volatiles in the form of thick atmospheres, oceans, or ice, in most cases with water mass fractions less than 5%.
One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that ...is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star-named TRAPPIST-1-makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces.
We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well‐known long‐term study sites in northern/cold regions. These spanned a ...decreasing temperature gradient from Bruntland Burn (Scotland), Dorset (Canadian Shield), Dry Creek (USA), Krycklan (Sweden), to Wolf Creek (northern Canada). Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. The degree to which potential soil water sources could explain the isotopic composition of xylem water was assessed quantitatively using overlapping polygons to enclose respective data sets when plotted in dual isotope space. At most sites isotopes in xylem water from angiosperms showed a strong overlap with soil water; this was not the case for gymnosperms. In most cases, xylem water composition on a given sampling day could be better explained if soil water composition was considered over longer antecedent periods spanning many months. Xylem water at most sites was usually most dissimilar to soil water in drier summer months, although sites differed in the sequence of change. Open questions remain on why a significant proportion of isotopically depleted water in plant xylem cannot be explained by soil water sources, particularly for gymnosperms. It is recommended that future research focuses on the potential for fractionation to affect water uptake at the soil‐root interface, both through effects of exchange between the vapour and liquid phases of soil water and the effects of mycorrhizal interactions. Additionally, in cold regions, evaporation and diffusion of xylem water in winter may be an important process.
We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well‐known long‐term study sites in northern/cold regions. Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. At all sites except one, water sources of angiosperms could be associated with soil water, while the sources of water uptake by gymnosperms were much less easily explained.
Factors affecting HLA expression: A review Carey, B. Sean; Poulton, Kay Victoria; Poles, Anthony
International journal of immunogenetics,
October 2019, Letnik:
46, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The detection and semiquantitative measurement of circulating human leucocyte antigen (HLA)‐specific antibodies is essential for the management of patients before and after transplantation. In ...addition, the pretransplant cross‐match to assess the reactivity of recipient HLA antibody against donor lymphocytes has long been the gold standard to prevent hyperacute rejection. Whilst both of these tests assume that recipient HLA‐specific antibody is the only variable in the assessment of transplant risk, this is not the case. Transplant immunologists recognize that some HLA antigens are expressed at levels a magnitude lower than others (e.g., HLA‐C, HLA‐DQ), but within loci, and between different cell types there are many factors that influence HLA expression in both resting and activated cells. HLA is not usually expressed without the specific promoter proteins NLRC5, for HLA class I, and CIITA, for class II. The quantity of HLA protein production is then affected by factors including promoter region polymorphisms, alternative exon splice sites, methylation and microRNA‐directed degradation. Different loci are influenced by multiple combinations of these control mechanisms making prediction of HLA regulation difficult, but an ability to measure the cellular expression of each HLA antigen, in conjunction with knowledge of circulating HLA‐specific antibody, would lead to a more informed algorithm to assess transplant risk.
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