Application of remote sensing to hydrology

Streamflow forecasting and hydrologic modelling are considered in a feasibility assessment of using the data produced by remote observation from space and/or aircraft to reduce the time and expense normally involved in achieving the ability to predict the hydrological behavior of an ungaged watershed. Existing watershed models are described, and both stochastic and parametric techniques are discussed towards the selection of a suitable simulation model. Technical progress and applications are reported and recommendations are made for additional research

Groundwater sapping channels: Summary of effects of experiments with varied stratigraphy

Experiments in the recirculating flume sapping box have modeled valley formation by groundwater sapping processes in a number of settings. The effects of the following parameters on sapping channel morphology were examined: surface slope; stratigraphic variations in permeability cohesion and dip; and structure of joints and dikes. These kinds of modeling experiments are particularly good for: testing concepts; developing a suite of distinctive morphologies and morphometries indicative of sapping; helping to relate process to morphology; and providing data necessary to assess the relative importance of runoff, sapping, and mass wasting processes on channel development. The observations from the flume systems can be used to help interpret features observed in terrestrial and Martian settings where sapping processes are thought to have played an important role in the development of valley networks

Tine options for alleviating compaction in wheelings

Repeated trafficking and harvesting operations lead to high levels of compaction in inter-row wheelings used in asparagus (Asparagus officinalis) production. This reduces soil porosity and infiltration resulting in water ponding on the soil surface. Even on gently sloping land this can result in runoff generation and an increased risk of soil erosion. A winged tine (WT) is currently used by a leading asparagus grower to loosen compacted inter-row wheelings. In order to test the effectiveness of this tine for alleviating compaction and implications for runoff and soil erosion control, it was evaluated alongside several other tine configurations. These were a narrow tine (NT); a narrow tine with two shallow leading tines (NSLT); a winged tine with two shallow leading tines (WSLT); and a modified para-plough (MPP). Testing was conducted under controlled conditions on a sandy loam soil in the Soil Management Facility at Cranfield University, Bedfordshire, UK. Tine performance was assessed at 3 depths (175, 250 and 300 mm) by draught force; soil disturbance (both above and below ground); specific draught for a given level of soil disturbance; surface roughness; and estimated change in soil bulk density. The effectiveness of tines for compaction alleviation and potential for mitigating runoff and soil erosion varied with depth. The most effective tines were found to be the MPP NSLT and the WSLT at 175 mm, 250 mm and 300 mm depth, respectively

Factors associated with invasive lung aspergillosis and the significance of positive aspergillus culture after liver transplantation

From January 1981 to December 1990, 2180 patients underwent orthotopic liver transplantation at the University of Pittsburgh. Thirty-two patients (1.5%) were identified with invasive aspergillosis (29 lung, 2 intraabdominal, 1 meningitis). Of 29 patients with invasive lung disease, only 23 (79%) had positive culture (Aspergillus fumigatus, 20; Aspergillus flavus, 3). Forty-eight variables were analyzed and compared in 23 patients with invasive disease with positive cultures and 9 patients with colonization only. The variables associated with pulmonary invasive disease, by univariate analysis, were surgical time (P =.03), presence of laparotomies (P =.02), higher creatinine level at time of Aspergillus isolation (P =.01), and use of OKT3 (P =.02). However, in a multivariate analysis, only the last two (creatinine, OKT3) were associated with invasive lung aspergillosis. Of 4 patients with positive abdominal wound culture, 2 had local invasive aspergillosis. Therefore, positive cultures of Aspergillus organisms from respiratory secretions and wound drainage may represent invasive disease and should not be ignored. © 1992 the University of Chicago

A program to develop a high-energy density primary battery with a minimum of 200 watt hours per pound of total battery weight Seventh quarterly report, Jan. 1 - Mar. 31, 1966

Cathodic materials for high energy density storage batter

Defining Quality in Undergraduate Education

Objectives: This research brief explores the literature addressing quality in undergraduate education to identify what previous research has said about quality and to offer future directions for research on quality in undergraduate education. Method: We conducted a scoping review to provide a broad overview of existing research. Using targeted search terms in academic databases, we identified and reviewed relevant academic literature to develop emergent themes and implications for future research. Results: The exploratory review of the literature revealed a range of thoughtful discussions and empirical studies attempting to define quality in undergraduate education. Many publications highlighted the importance of including different stakeholder perspectives and presented some of the varying perceptions of quality among different stakeholders. Conclusions: While a number of researchers have explored and written about how to define quality in undergraduate education, there is not a general consensus regarding a definition of quality in undergraduate education. Past research offers a range of insights, models, and data to inform future research. Implication for Theory and/or Practice: We provide four recommendations for future research to contribute to a high quality undergraduate educational experience. We suggest more comprehensive systematic reviews of the literature as a next step

Using frost sensitive cover crops for timely nitrogen mineralisation and soil moisture management

Cover crops can be utilised to lower soil nitrate leaching. However, depending on the species grown and cover crop termination management this may lead to nitrogen (N) immobilisation and/or depletion of soil moisture available to the following cash crop, potentially impacting on crop yields. Cover crop management is also dependent on using herbicides to terminate growth prior to planting the next crop. We used an alternative method for cover crop termination by capitalising on plant senescence by frost in a multi-species cover crop established over-winter between wheat and maize. The cover crops accumulated greater quantities of N than the control. However, upon cover crop senescence due to cold temperatures, the partially terminated cover crop significantly increased topsoil available N from December to late February. This available N in the topsoil could be susceptible to leaching although this was not observed in our study. Cover crops did not have a significant prolonged effect on soil moisture over winter and late spring. The following maize yields were not significantly different between the control and cover crop treatment. Frost sensitive cover crop species could not be reliably terminated under a temperate climate, but provided a continuous supply of soil available N as the plants senesced. Depending on the soil moisture and weather conditions in the spring there could be a N leaching risk although this could be mitigated by establishing early spring crops

Rapid Evolution of Testis Size Relative to Sperm Morphology Suggests that Post-Copulatory Selection Targets Sperm Number in \u3cem\u3eAnolis\u3c/em\u3e Lizards

Post-copulatory sexual selection is thought to be responsible for much of the extraordinary diversity in sperm morphology across metazoans. However, the extent to which post-copulatory selection targets sperm morphology versus sperm production is generally unknown. To address this issue, we simultaneously characterized the evolution of sperm morphology (length of the sperm head, midpiece and flagellum) and testis size (a proxy for sperm production) across 26 species of Anolis lizards, a group in which sperm competition is likely. We found that the length of the sperm midpiece has evolved 2–3 times faster than that of the sperm head or flagellum, suggesting that midpiece size may be the most important aspect of sperm morphology with respect to post-copulatory sexual selection. However, testis size has evolved faster than any aspect of sperm morphology or body size, supporting the hypothesis that post-copulatory sexual selection acts more strongly upon sperm production than upon sperm morphology. Likewise, evolutionary increases in testis size, which typically indicate increased sperm competition, are not associated with predictable changes in sperm morphology, suggesting that any effects of post-copulatory selection on sperm morphology are either weak or variable in direction across anoles. Collectively, our results suggest that sperm production is the primary target of post-copulatory sexual selection in this lineage

Structure and expression of the maize (Zea mays L.) SUN-domain protein gene family: evidence for the existence of two divergent classes of SUN proteins in plants

<p>Abstract</p> <p>Background</p> <p>The nuclear envelope that separates the contents of the nucleus from the cytoplasm provides a surface for chromatin attachment and organization of the cortical nucleoplasm. Proteins associated with it have been well characterized in many eukaryotes but not in plants. SUN (Sad1p/Unc-84) domain proteins reside in the inner nuclear membrane and function with other proteins to form a physical link between the nucleoskeleton and the cytoskeleton. These bridges transfer forces across the nuclear envelope and are increasingly recognized to play roles in nuclear positioning, nuclear migration, cell cycle-dependent breakdown and reformation of the nuclear envelope, telomere-led nuclear reorganization during meiosis, and karyogamy.</p> <p>Results</p> <p>We found and characterized a family of maize SUN-domain proteins, starting with a screen of maize genomic sequence data. We characterized five different maize <it>ZmSUN </it>genes <it>(ZmSUN1-5)</it>, which fell into two classes (probably of ancient origin, as they are also found in other monocots, eudicots, and even mosses). The first (<it>ZmSUN1</it>, <it>2</it>), here designated canonical C-terminal SUN-domain (CCSD), includes structural homologs of the animal and fungal SUN-domain protein genes. The second (<it>ZmSUN3, 4, 5</it>), here designated plant-prevalent mid-SUN 3 transmembrane (PM3), includes a novel but conserved structural variant SUN-domain protein gene class. Mircroarray-based expression analyses revealed an intriguing pollen-preferred expression for <it>ZmSUN5 </it>mRNA but low-level expression (50-200 parts per ten million) in multiple tissues for all the others. Cloning and characterization of a full-length cDNA for a PM3-type maize gene, <it>ZmSUN4</it>, is described. Peptide antibodies to ZmSUN3, 4 were used in western-blot and cell-staining assays to show that they are expressed and show concentrated staining at the nuclear periphery.</p> <p>Conclusions</p> <p>The maize genome encodes and expresses at least five different SUN-domain proteins, of which the PM3 subfamily may represent a novel class of proteins with possible new and intriguing roles within the plant nuclear envelope. Expression levels for <it>ZmSUN</it>1-4 are consistent with basic cellular functions, whereas <it>ZmSUN</it>5 expression levels indicate a role in pollen. Models for possible topological arrangements of the CCSD-type and PM3-type SUN-domain proteins are presented.</p