Characterizing Land Use Impacts on Channel Geomorphology and Streambed Sedimentological Characteristics

Land use can radically degrade stream physical habitat via alterations to channel geomorphology and sedimentological characteristics. However, independent and combined influences such as those of agricultural and urban land use practices on channel geomorphology and substrate composition remain poorly understood. To further understanding of mixed land use influence on stream physical habitat, an intensive, 56 km hydrogeomorphological assessment was undertaken in a representative mixed land use watershed located in Midwestern USA. Sub-objectives included quantitative characterization of (1) channel geomorphology, (2) substrate frequency and embeddedness, and (3) relationships between land use, channel geomorphology, and substrate frequency and embeddedness. Channel geomorphology, and stream substrate data were directly measured at survey transects (n = 561) every 100 m of the entire 56 km distance of the reference stream. Observed data were averaged within five sub-basins (Sites #1 to #5) nested across an agricultural-urban land use gradient. Multiple regression results showed agricultural and urban land use explained nearly all of the variance in average width to depth ratios (R2 = 0.960; p = 0.020; n = 5), and maximum bank angle (R2 = 0.896; p = 0.052; n = 5). Streambed substrate samples of pools indicated significantly (p \u3c 0.001) increased substrate embeddedness at agricultural Site #1 (80%) located in the headwaters and urban Site #5 (79%) located in the lower reaches compared to rural-urban Sites #2 to #4 (39 to 57%) located in the mid-reaches of the study stream. Streambed substrate embeddedness samples of riffles that ranged from 51 to 72% at Sites #1 and #5, and 27 to 46% at Sites #2 to #4 were significantly different between sites (p = 0.013). Percent embeddedness increased with downstream distance by 5% km−1 with the lower urban reaches indicating symptoms of urban stream syndrome linked to degraded riffle habitat. Collectively, observed alterations to channel morphology and substrate composition point to land use alterations to channel geomorphology metrics correlated with increased substrate embeddedness outside of mid-reaches where bedrock channel constraints accounted for less than 3% of substrate frequency. Results from this study show how a hydrogeomorphological assessment can help elucidate casual factors, target critical source areas, and thus, guide regional stream restoration efforts of mixed-land-use watersheds

Assessing the Difference between Soil and Water Assessment Tool (SWAT) Simulated Pre-Development and Observed Developed Loading Regimes

The purpose of this research was to assess the difference between Soil and Water Assessment Tool (SWAT) simulated pre-development and contemporary developed loading regimes in a mixed-land-use watershed of the central United States (US). Native land cover based on soil characteristics was used to simulate pre-development loading regimes using The Soil and Water Assessment Tool (SWAT). Loading targets were calculated for each major element of a pre-development loading regime. Simulated pre-development conditions were associated with increased retention and decreased export of sediment and nutrients when compared to observed developed conditions. Differences between simulated pre-development and observed developed maximum daily yields (loads per unit area) of suspended sediment (SS), total phosphorus (TP), and total inorganic nitrogen (TIN) ranged from 35.7 to 59.6 Mg km−2 (SS); 23.3 to 52.5 kg km−2 (TP); and, 113.2 to 200.8 kg km−2 (TIN), respectively. Average annual maximum daily load was less during simulated pre-development conditions when compared to observed developed conditions by ranges of 1307 to 6452 Mg day−1 (SS), 0.8 to 5.4 kg day−1 (TP), and 4.9 to 26.9 kg day−1 (TIN), respectively. Hydrologic modeling results indicated that the differences in annual maximum daily load were causally linked to land use and land cover influence on sediment and nutrient loading. The differences between SWAT simulated pre-development and observed contemporary loading regimes from this study point to a need for practical loading targets that support contemporary management and integrated flow and pollutant loading regimes

A Case-Study Application of the Experimental Watershed Study Design to Advance Adaptive Management of Contemporary Watersheds

settings Open AccessFeature PaperArticle A Case-Study Application of the Experimental Watershed Study Design to Advance Adaptive Management of Contemporary Watersheds by Jason A. Hubbart 1,*,Elliott Kellner 2 andSean J. Zeiger 3 1 West Virginia University, Institute of Water Security and Science, Davis College of Agriculture, Natural Resources and Design, Schools of Agriculture and Food, and Natural Resources, 3109 Agricultural Sciences Building, Morgantown, WV 26506, USA 2 West Virginia University, Institute of Water Security and Science, Davis College of Agriculture Natural Resources and Design, Division of Plant and Soil Sciences, 3011 Agricultural Sciences Building, Morgantown, WV 26506, USA 3 School of Natural Resources, University of Missouri, 203-T ABNR Building, Columbia, MO 65211, USA * Author to whom correspondence should be addressed. Water 2019, 11(11), 2355; https://doi.org/10.3390/w11112355 Received: 14 September 2019 / Revised: 30 October 2019 / Accepted: 6 November 2019 / Published: 9 November 2019 (This article belongs to the Special Issue Integrated Water Resources Research: Advancements in Understanding to Improve Future Sustainability) Download PDF Browse Figure Review Reports Cite This Paper Abstract Land managers are often inadequately informed to make management decisions in contemporary watersheds, in which sources of impairment are simultaneously shifting due to the combined influences of land use change, rapid ongoing human population growth, and changing environmental conditions. There is, thus, a great need for effective collaborative adaptive management (CAM; or derivatives) efforts utilizing an accepted methodological approach that provides data needed to properly identify and address past, present, and future sources of impairment. The experimental watershed study design holds great promise for meeting such needs and facilitating an effective collaborative and adaptive management process. To advance understanding of natural and anthropogenic influences on sources of impairment, and to demonstrate the approach in a contemporary watershed, a nested-scale experimental watershed study design was implemented in a representative, contemporary, mixed-use watershed located in Midwestern USA. Results identify challenges associated with CAM, and how the experimental watershed approach can help to objectively elucidate causal factors, target critical source areas, and provide the science-based information needed to make informed management decisions. Results show urban/suburban development and agriculture are primary drivers of alterations to watershed hydrology, streamflow regimes, transport of multiple water quality constituents, and stream physical habitat. However, several natural processes and watershed characteristics, such as surficial geology and stream system evolution, are likely compounding observed water quality impairment and aquatic habitat degradation. Given the varied and complicated set of factors contributing to such issues in the study watershed and other contemporary watersheds, watershed restoration is likely subject to physical limitations and should be conceptualized in the context of achievable goals/objectives. Overall, results demonstrate the immense, globally transferrable value of the experimental watershed approach and coupled CAM process to address contemporary water resource management challenges

Giant lasing effect in magnetic nanoconductors

We propose a new principle for a compact solid-state laser in the 1-100 THz regime. This is a frequency range where attempts to fabricate small size lasers up till now have met severe technical problems. The proposed laser is based on a new mechanism for creating spin-flip processes in ferromagnetic conductors. The mechanism is due to the interaction of light with conduction electrons; the interaction strength, being proportional to the large exchange energy, exceeds the Zeeman interaction by orders of magnitude. On the basis of this interaction, a giant lasing effect is predicted in a system where a population inversion has been created by tunneling injection of spin-polarized electrons from one ferromagnetic conductor to another -- the magnetization of the two ferromagnets having different orientations. Using experimental data for ferromagnetic manganese perovskites with nearly 100% spin polarization we show the laser frequency to be in the range 1-100 THz. The optical gain is estimated to be of order 10^7 cm^{-1}, which exceeds the gain of conventional semiconductor lasers by 3 or 4 orders of magnitude. A relevant experimental study is proposed and discussed.Comment: 4 pages, 3 figure

Use of marginal organs in kidney transplantation for marginal recipients: too close to the margins of safety?

<p>Abstract</p> <p>Objective</p> <p>Due to organ shortage, average waiting time for a kidney in Germany is about 4 years after start of dialysis. Number of kidney grafts recovered can only be maintained by accepting older and expanded criteria donors. The aim of this study was to analyse the impact of donor and recipient risk on kidney long-term function.</p> <p>Methods</p> <p>All deceased kidney transplantations were considered. We retrospectively studied 332 patients between 2002 and 2006; divided in 4 groups reflecting donor and recipient risk.</p> <p>Results</p> <p>Non-marginal recipients were less likely to receive a marginal organ (69 of 207, 33%) as compared to marginal recipients, of whom two-thirds received a marginal organ (p < 0.0001). Graft function significantly differed between the groups, but detrimental effect of marginal recipient status on eGFR after 12 months (-6 ml/min/1.73 qm, 95% CI -2 to -9) was clearly smaller than the effect of marginal donor status (-10 ml/min/1.73 qm, 95% CI -7 to -14).</p> <p>Conclusions</p> <p>As we were able to show expanded criteria donor has a far bigger effect on long-term graft function than the "extra risk" recipient. Although there have been attempts to define groups of recipients who should be offered ECD kidneys primarily the discussion is still ongoing.</p

Tactile defensiveness and impaired adaptation of neuronal activity in the Fmr1 knockout mouse model of autism

Sensory hypersensitivity is a common symptom in autism spectrum disorders (ASDs), including Fragile X Syndrome (FXS), and frequently leads to tactile defensiveness. In mouse models of ASDs, there is mounting evidence of neuronal and circuit hyperexcitability in several brain regions, which could contribute to sensory hypersensitivity. However, it is not yet known whether or how sensory stimulation might trigger abnormal sensory processing at the circuit level or abnormal behavioral responses in ASD mouse models, especially during an early developmental time when experience-dependent plasticity shapes such circuits. Using a novel assay, we discovered exaggerated motor responses to whisker stimulation in young Fmr1 knockout (KO) mice (postnatal days (P) 14-16), a model of FXS. Adult Fmr1 KO mice actively avoided a stimulus that was innocuous to wild-type controls, a sign of tactile defensiveness. Using in vivo two-photon calcium imaging of Layer 2/3 barrel cortex neurons expressing GCaMP6s, we found no differences between wild-type and Fmr1 KO mice in overall whisker-evoked activity, though 45% fewer neurons in young Fmr1 KO mice responded in a time-locked manner. Notably, we identified a pronounced deficit in neuronal adaptation to repetitive whisker stimulation in both young and adult Fmr1 KO mice. Thus, impaired adaptation in cortical sensory circuits is a potential cause of tactile defensiveness in autism

Ground state cooling, quantum state engineering and study of decoherence of ions in Paul traps

We investigate single ions of $^{40}Ca^+$ in Paul traps for quantum information processing. Superpositions of the S$_{1/2}$ electronic ground state and the metastable D$_{5/2}$ state are used to implement a qubit. Laser light on the S$_{1/2} \leftrightarrow$ D$_{5/2}$ transition is used for the manipulation of the ion's quantum state. We apply sideband cooling to the ion and reach the ground state of vibration with up to 99.9% probability. Starting from this Fock state $|n=0>$, we demonstrate coherent quantum state manipulation. A large number of Rabi oscillations and a ms-coherence time is observed. Motional heating is measured to be as low as one vibrational quantum in 190 ms. We also report on ground state cooling of two ions.Comment: 12 pages, 6 figures. submitted to Journal of Modern Optics, Special Issue on Quantum Optics: Kuehtai 200

A Proper Motion for the Pulsar Wind Nebula G359.23-0.82, "the Mouse," Associated with the Energetic Radio Pulsar J1747-2958

The "Mouse" (PWN G359.23-0.82) is a spectacular bow shock pulsar wind nebula, powered by the radio pulsar J1747-2958. The pulsar and its nebula are presumed to have a high space velocity, but their proper motions have not been directly measured. Here we present 8.5 GHz interferometric observations of the Mouse nebula with the Very Large Array, spanning a time baseline of 12 yr. We measure eastward proper motion for PWN G359.23-0.82 (and hence indirectly for PSR J1747-2958) of 12.9+/-1.8 mas/yr, which at an assumed distance of 5 kpc corresponds to a transverse space velocity of 306+/-43 km/s. Considering pressure balance at the apex of the bow shock, we calculate an in situ hydrogen number density of approximately 1.0(-0.2)(+0.4) cm^(-3) for the interstellar medium through which the system is traveling. A lower age limit for PSR J1747-2958 of 163(-20)(+28) kyr is calculated by considering its potential birth site. The large discrepancy with the pulsar's spin-down age of 25 kyr is possibly explained by surface dipole magnetic field growth on a timescale ~15 kyr, suggesting possible future evolution of PSR J1747-2958 to a different class of neutron star. We also argue that the adjacent supernova remnant G359.1-0.5 is not physically associated with the Mouse system but is rather an unrelated object along the line of sight.Comment: 8 pages, 4 figures, emulateapj format. Accepted for publication in The Astrophysical Journa

Large hypomethylated blocks as a universal defining epigenetic alteration in human solid tumors

Background: One of the most provocative recent observations in cancer epigenetics is the discovery of large hypomethylated blocks, including single copy genes, in colorectal cancer, that correspond in location to heterochromatic LOCKs (large organized chromatin lysine-modifications) and LADs (lamin-associated domains). Methods: Here we performed a comprehensive genome-scale analysis of 10 breast, 28 colon, nine lung, 38 thyroid, 18 pancreas cancers, and five pancreas neuroendocrine tumors as well as matched normal tissue from most of these cases, as well as 51 premalignant lesions. We used a new statistical approach that allows the identification of large hypomethylated blocks on the Illumina HumanMethylation450 BeadChip platform. Results: We find that hypomethylated blocks are a universal feature of common solid human cancer, and that they occur at the earliest stage of premalignant tumors and progress through clinical stages of thyroid and colon cancer development. We also find that the disrupted CpG islands widely reported previously, including hypermethylated island bodies and hypomethylated shores, are enriched in hypomethylated blocks, with flattening of the methylation signal within and flanking the islands. Finally, we found that genes showing higher between individual gene expression variability are enriched within these hypomethylated blocks. Conclusion: Thus hypomethylated blocks appear to be a universal defining epigenetic alteration in human cancer, at least for common solid tumors. Electronic supplementary material The online version of this article (doi:10.1186/s13073-014-0061-y) contains supplementary material, which is available to authorized users