547 research outputs found
Atlas and checklist of the bark and ambrosia beetles of Texas and Oklahoma (Curculionidae: Scolytinae and Platypodinae)
180 species of bark and ambrosia beetles (Curculionidae: Scolytinae and Platypodinae) are known to occur in Texas and Oklahoma. 175 species are known from Texas, 35 of which are reported here for the first time. 78 species are known from Oklahoma, 47 of which are new records for the state. Based on overall distribution patterns the largest group of species found in Texas and virtually all known from Oklahoma are widely distributed in eastern and southeastern North America, reaching their southwestern limits here. In the case of Texas other large elements include Neotropical elements shared with Mexico and a large number found in southwestern North America. New distribution and significant new host records are discussed. Distribution maps are included for most species and a checklist is provided as an appendix
The Ancient Tree Inventory: a summary of the results of a 15 year citizen science project recording ancient, veteran and notable trees across the UK
Ancient, veteran and notable trees are ecologically important keystone organisms and have tangible connections to folklore, history and sociocultural practices. Although found worldwide, few countries have such a rich history of recording and treasuring these trees as the UK, with its extensive Royal and aristocratic land ownership, unique land management methods and long-standing interest in natural history and species record collecting. As a result, the UK has collated an extensive database of ancient, veteran and notable trees called the Ancient Tree Inventory (ATI). The ATI is the result of a successful, long-term citizen science recording project and is the most comprehensive database of ancient and other noteworthy trees to date. We present here the first review of the ATI in its entirety since its initiation in 2004, including summaries of the UK ancient, veteran and notable tree distributions, the status and condition of the trees, and key information about the recording process and maintenance of the database. Statistical analysis of components of the dataset, comprising 169,967 tree records, suggest there are significant differences in the threats, size, form and location of different types of trees, especially in relation to taxonomic identity and tree age. Our goal is to highlight the value of the ATI in the UK, to encourage the development of similar ancient tree recording projects in other countries, and to emphasise the importance to conservation of continued efforts to maintain and expand databases of this kind
Using remote sensing and geographical information systems to classify local landforms using a pattern recognition approach for improved soil mapping
Thesis (PhDAgric)--Stellenbosch University, 2022.ENGLISH ABSTRACT: Presently, a major focus of digital soil mapping (DSM) in South Africa is unlocking the soil-landscape
relationships of legacy soil data by disaggregating the only source of contiguous soil information for South
Africa, the National Land Type Survey (LTS) (ARC, 2003). Each land type is best defined as a homogenous
mapping unit with a unique combination of terrain type, soil pattern and macroclimate properties (Paterson et
al., 2015). One of the prevailing reasons for the LTS longevity and continual temporal-interoperability is that
terrain description is expressly related to a suite of catenary soil property descriptions (Milne, 1936). These
terrain types are further divided into terrain morphological units (TMUs) representing a sequence of patterns
based on a 5-unit landscape model of 1-crest, 2-scarp, 3-midslope, 4-footslope and 5-valley bottom.
Importantly, dominant soil distribution patterns are defined by terrain units relying on an elementary terrain
topo-sequence pattern approach, with much of the work done on modelling soil variation related to variation
in terrain (van Zijl, 2019). Whilst the LTS remains a source of national interest, there is immense opportunity
to build on the existing soil inventory data rather than only focus on “breaking it down” (disaggregation).
However, what is needed is a standard operating procedure that not only leverages the ability of digital
elevation models (DEM) to explicate soil-landscape associations beyond the limited 5-unit landscape model
but allows better refinement of soil descriptions with landscape features. Only once the nuances of optimal
DEM parametrisation under controlled conditions are fully understood can the complete scope of DSM and
digital geomorphological mapping (DGM) applications be explored.
This dissertation attempts to synthesise knowledge on theory, methods, and applications of using remote
sensing (RS) and geographical information systems (GIS) to classify local landforms using a pattern
recognition approach for improved soil mapping in the context of multiscale problems of digital terrain analysis
in KwaZulu-Natal. The dissertation is divided into three parts. Part one (Chapter 2) represents the DEM pre-
processing and generalisation method and establishes the protocols for soil-landscape covariate application
derived from various sensor platforms and spatial scales. Part two (Chapter 3) introduces the concept of
improved terrain unit mapping through the geomorphon approach and describes DEM optimisation for
standardised geomorphon representation for uniformly describing soil-landscape properties for inputs to DSM
applications. Finally, part three (Chapters 4 & 5) looks at applications of DEM sources and geomorphons first
from a holistic landscape context by linking digital terrain and soil-landscape analysis to geodiversity. Finally,
the benefit of improved RS and GIS combined with quantitative modelling approaches on improving natural
resource predictions are explored by modelling soil-ecotope and soil type mapping units and proposing
improvements to an existing DSS designed for KwaZulu-Natal Natal. Specifically, this research is organised
into four (4) research chapters with an overview of each chapter’s contribution outlined hereafter.
Chapter 2 accounts for the recognition and requirements of DEM generalisation from high to medium
resolution RS platforms and the influence these pre-processing approaches have on the extraction of a wide
range of terrain attributes. Digital elevation data are elemental in deriving primary topographic attributes that
are input variables to various regional soil-landscape models. DEMs' utility to extract different topographic
indices as primary inputs to DSM allows the generalised soil-formative relationship between topography and
soil characteristics to be measured quantitatively. Traditional landscape-scale approaches to extracting and
analysing soils remain subjective and an expensive last resort for large-scale regional soil distribution and
variability prediction. Selecting the right DEMs is a critical step in the development of any soil-landscape
model. Therefore, the ability to represent soil-landscape relationships rapidly and objectively between soil
properties and landscape position using emerging technologies and elevation data in a digital environment and
at varying scales is fundamental for using soil-landscape mapping as a regional planning tool. There is,
however, still varied consensus on the effect of DEM source and resolution on the application of these
topographic attributes to landscape and geomorphic characterisation within South Africa. However, Atkinson
et al. (2017) have shown that topographic variable extraction is highly dependent on the DEM source and
generalisation approach. However, while higher resolution DEMs may represent the “true” landscape surface
more accurately, they do not necessarily offer the best results for all extracted terrain variables for modelling
soil-landscape outputs. Given the convenience of a wide range of open-source elevation data for South Africa,
there is a need to quantify the impact that DEM generalisation approaches have on simplifying detailed DEMs
and compare the accuracy and reliability of results between high resolution and coarse resolution data on the
extraction of localised topographic variables as a primer for soil-landscape or digital soil models.
Chapter 3 explores the harmonisation of geomorphons derived from various RS platforms to define the
landscape character in central KwaZulu-Natal. Robust DGM approaches that can simplify and translate the
inclusion of “human knowledge” to automatic terrain classification across a broader spectrum of terrain
morphological units and a range of DEM spatial scales offer great potential for improved topographic and
landscape analysis and must have their utility investigated. Continual advances in quantitative modelling of
surface processes, combined with new spatio-temporal and geo-computational algorithms, have revolutionised
the auto-classification and mapping of landform components through the automated analysis of high-quality
DEMs. Therefore, a thorough assessment of the effects that different pixel resolution (grain size) and DEM
sources have on replicating observed geomorphic spatial patterns and representing selected terrain parameters
using advanced automated geomorphometric mapping approaches is necessary. Specifically, it would be
valuable to interrogate the self-adapting ability of these automated mapping approaches under regional
conditions to quantitatively analyse how the choice of terrain model and scale influences the extraction,
generalisation, and representation of digitally derived terrain attributes such as slope gradient, elevation and
terrain unit feature extent. Equally important is understanding how the variation in resulting terrain unit
representation is limited by spatial resolution discontinuities that ultimately influence the extraction and
representation of elementary soil properties.
Chapter 4 is a shift from the technical aspects of digital terrain preprocessing and modelling and instead
attempts to explore the contribution of gridded soil-landscape products to the abiotic landscape development
agenda. It would be worthwhile to contextualise and decode these technical aspects of terrain and soil analyses
to a holistic landscape development agenda. It is argued that current global environmental problems and
questions demand exploration into new scientific perspectives and improved related paradigms and
methodologies. Geodiversity (abiotic complexity) has not received the same level of attention as biodiversity
(biotic complexity) despite its intrinsic and indivisible linkages to ecosystem and landscape richness
characterisation. The ability to better describe the substrate in which biological and human activities occur is
of top standing and must have its potential explored. To date, only one landmark study has successfully
investigated the influence of environmental factors on geodiversity mapping in South Africa (Kori et al., 2019).
Using an array of multimodal environmental covariates, including hydrographic, lithostratigraphic,
pedological, climatic, topographic, solar morphometric and geomorphic variables, I aim to provide further
confirmation to regional and international geodiversity research agendas.
Chapter 5 culminates in applying quantitative DSM methods, with improved terrain representation, to classify
productive soil units (ecotopes) as a proposed methodology to improve the current Bioresource Report Writer
(BRW) soil-landscape recommendations. In KwaZulu-Natal, it has been accepted that detailed natural resource
information based on scientifically accurate and relevant criteria is required to develop spatial layers that
planners, developers, local government, and other stakeholders can use to guide future development. At
present, the KwaZulu-Natal Department of Agriculture and Rural Development (KZNDARD) can provide
high-level crop production approximations for various crops based on BioResource Units (BRU). However,
the BRW has not seen a significant revision for over two decades. Still, the natural resource information it
contains provides land managers, policymakers and farmers with invaluable access to regional and farm level
qualitative estimations of agricultural productivity. There is a need to preserve this information while
simultaneously providing modern measures of land management recommendation at multiple scales to the
end-user. Against this backdrop, access to readily interpretable soil and crop information is increasingly being
prioritised by provincial planning commissions as critical inputs to DSS for sustainable land management
within KwaZulu-Natal.AFRIKAANSE OPSOMMING: Tans ontsluit 'n groot fokus van digitale grond kartering (DSM) in Suid-Afrika die grond landskap verhoudings
van nalatenskap grond data deur die enigste bron van aaneenlopende grond inligting vir Suid-Afrika, die
Nasionale Grondtipe-opname (ARC, 2003) te distreun. Elke land tipe word die beste gedefinieer as 'n
homogene karterings eenheid met 'n unieke kombinasie van terrein tipe, grondpatroon en makro klimaat
eienskappe (Paterson et al. , 2015) . Een van die heersende redes vir die LTS-langlewendheid en voortdurende
temporale interoperabiliteit is dat terrein beskrywing uitdruklik verband hou met 'n reeks katalise
grondeiendom beskrywings (Milne, 1936). Hierdie terrein tipes word verder verdeel in terrein morfologiese
eenhede (TMUs) wat 'n reeks patrone verteenwoordig wat gebaseer is op 'n 5-eenheid landskap model van 1-
kuif, 2-serp, 3-midslope, 4-voet en 5-vallei bodem. Belangrik, dominante grond verspreidings patrone word
gedefinieer deur terrein eenhede wat staatmaak op 'n elementêre terrein topo-volgorde patroon benadering,
met baie van die werk gedoen op modellering grond variasie wat verband hou met variasie in terrein (van Zijl,
2019). Terwyl die LTS bly 'n bron van nasionale belang; daar is enorme geleentheid om voort te bou op die
bestaande grond voorraad data eerder as om net te fokus op "afbreek" (disaggregasie). Wat egter nodig is, is
'n standaard bedryfsprosedure wat nie net die vermoë van digitale hoogte modelle(DEM) gebruik om grond
landskap verenigings buite die beperkte 5-eenheid landskap model te vererger nie, maar beter verfyning van
grond beskrywings met landskap kenmerke moontlik te maak. Slegs sodra die nuanses van optimale DEM
parametrisasie onder beheerde toestande ten volle verstaan word, kan die volledige omvang van DSM- en
digitale geomorfologiese kartering (DGM) aansoeke ondersoek word.
Hierdie verhandeling poog om-kennis oor teorie, metodes en toepassings van ute sintetiseer om afstand
waarneming (RS) en geografiese inligtingstelsels (GIS) tesing om plaaslike land vorms te klassifiseer deur 'n
patroonherkenning benadering vir verbeterde grond kartering in die konteks van multiskaal probleme van
digitale terrein analise te klassifiseer. In KwaZulu-Natal. Die verhandeling word in drie dele verdeel. Deel
een (Hoofstuk 2) verteenwoordig die DEM-voor verwerker- en veralgemenings metode en vestig die
protokolle vir grondlandskap-kovariaat toediening afgelei van verskeie sensor platforms en ruimtelike skale.
Deel twee (Hoofstuk 3) stel die konsep van verbeterde terrein eenheid kartering deur die geomorfon benadering
bekend en beskryf DEM-optimalisering vir gestandaardiseerde geomorfon verteenwoordiging om grond
landskap eienskappe eenvormig te beskryf vir insette tot DSM-toepassings. Ten slotte, deel drie (Hoofstukke
4 & 5) kyk na toepassings van DEM bronne en geomorfon eerste vanuit 'n holistiese landskap konteks deur
die koppeling van digitale terrein en grond landskap analise aan geodiversiteit. Ten slotte word die voordeel
van verbeterde RS en GIS gekombineer met kwantitatiewe modellerings benaderings op die verbetering van
natuurlike hulpbron voorspellings ondersoek deur grond-ekopeïen- en grondtipe karterings eenhede te
modelleer en verbeterings voor te stel aan 'n bestaande DSS wat vir KwaZulu-Natal ontwerp is. Spesifiek, tsy
navorsing is organiseer in vier (4) navorsing hoofstukke met 'n oorsig van elke hoofstuk se bydrae wat hierna
uiteengesit word.
Hoofstuk 2 is verantwoordelik vir die erkenning en vereistes van DEM veralgemening van hoë tot medium
resolusie RS platforms en die invloed wat hierdie preprocessing benaderings het op die onttrekking van 'n wye
verskeidenheid van terrein eienskappe. Digitale hoogte data is elementêr in die afleiding van primêre
topografiese eienskappe wat inset veranderlikes aan verskeie plaaslike grond landskap modelle is. DEMs se
nut om verskillende topografiese indekse as primêre insette tot DSM te onttrek, laat die algemene grond
vormende verhouding tussen topografie en grondeienskappe kwantitatief gemeet word. Tradisionele landskap
skaal benaderings tot die onttrekking en ontleding van grond bly subjektief en 'n duur laaste uitweg vir
grootskaalse streeks grond verspreiding en veranderlikheid voorspelling. Die keuse van die regte DEMs is 'n
kritieke stap in die ontwikkeling van enige grond landskap model. Daarom is die vermoë om grond landskap
verhoudings vinnig en objektief tussen grondeienskappe en landskap posisie te verteenwoordig deur
opkomende tegnologieë en hoogte data in 'n digitale omgewing te gebruik en op verskillende skale
fundamenteel vir die gebruik van grond landskap kartering as 'n streeksbeplanning instrument. Daar is egter
steeds uiteenlopende konsensus oor die uitwerking van DEM-bron en resolusie oor die toepassing van hierdie
topografiese eienskappe aan landskap- en geomorfiese karakterisering binne Suid-Afrika. Atkinson et al.
(2017) het egter getoon dat topografiese veranderlike onttrekking baie afhanklik is van die DEM-bron en
veralgemenings benadering. Alhoewel hoër resolusie-DEMs die "ware" landskap oppervlak meer akkuraat kan
verteenwoordig, bied hulle nie noodwendig die beste resultate vir alle onttrokke terrein veranderlikes vir die
modellering van grond landskap-uitsette nie. Gegewe die gerief van 'n wye verskeidenheid oopbron-hoogte
data vir Suid-Afrika, is dit 'n behoefte om die impak wat DEM-veralgemenings benaderings het op die
vereenvoudiging van gedetailleerde DEMs te kwantifiseer en die akkuraatheid en betroubaarheid van resultate
tussen hoë resolusie en growwe resolusie data te vergelyk oor die onttrekking van gelokaliseerde topografiese
veranderlikes as 'n primer vir grond landskap of digitale grond modelle.
Hoofstuk 3 ondersoek die harmonisering van geomorfon wat van verskeie RS-platforms afkomstig is om die
landskap karakter in Sentraal-KwaZulu-Natal te definieer. Robuuste DGM benaderings wat die insluiting van
"menslike kennis" kan vereenvoudig en vertaal na outomatiese terrein klassifikasie oor 'n breër spektrum van
terrein morfologiese eenhede en 'n verskeidenheid DEM ruimtelike skale bied groot potensiaal vir verbeterde
topografiese en landskap analise en moet hul nut ondersoek. Voortdurende vooruitgang in kwantitatiewe
modellering van oppervlak prosesse, gekombineer met nuwe spatio-temporale en geo-berekenings algoritmes,
het die ou toklassifikasie en kartering van land vorm komponente omwentel deur die outomatiese analise van
hoë gehalte DEMs. Daarom is 'n deeglike assessering van die effekte wat verskillende pixel resolusie (graan
grootte) en DEM-bronne het op die replisering van waargenome geomorfiese ruimtelike patrone en
verteenwoordig geselekteerde terrein parameters met behulp van gevorderde outomatiese geomorfon metriese
karterings benaderings nodig. Spesifiek, dit sal waardevol wees om die self-aanpassing vermoë van hierdie
outomatiese kartering benaderings onder streeks toestande te ondervra om kwantitatief te analiseer hoe die
keuse van terrein model en skaal die onttrekking, veralgemening en voorstelling van digitaal afgeleide terrein
kenmerke soos hellings gradiënt, hoogte- en terrein eenheid-funksie omvang beïnvloed. Ewe belangrik is om
te verstaan hoe die variasie in gevolglike terrein eenheid verteenwoordiging beperk word deur ruimtelike
resolusie-stakings wat uiteindelik die onttrekking en voorstelling van elementêre grondeienskappe beïnvloed
Hoofstuk 4 is 'n verskuiwing van die tegniese aspekte van digitale terrein voor verwerking en modellering en
poog eerder om die bydrae van geroosterde grond landskap produkte na die abiotiese landskap ontwikkelings
agenda te verken. Ek sou die moeite werd wees om hierdie tegniese aspekte van terrein- en grond ontledings
na 'n holistiese landskap ontwikkelings agenda te kontekstualiseer en te dekodeer. Daar word aangevoer dat
huidige globale omgewingsprobleme en vrae eksplorasie in nuwe wetenskaplike perspektiewe en verbeterde
verwante paradigmas en metodologieë vereis. Geodiversiteit (abiotiese kompleksiteit) het nie dieselfde vlak
van aandag as biodiversiteit (biotiese kompleksiteit) ontvang nie, ten spyte van sy intrinsieke en ondeelbare
verbande met ekosisteem- en landskap ryke karakterisering. Die vermoë om die substraat waarin biologiese
en menslike aktiwiteite voorkom, beter te beskryf, is van bostaande en moet sy potensiaal ondersoek. Tot op
hede het slegs een ander landmerk studie die invloed van omgewingsfaktore op geodiversiteits kartering in
Suid-Afrika (Kori et al. , 2019). Met behulp van 'n verskeidenheid multimodale omgewings kovariaat,
insluitend hidrografiese, lithostratigraphic, pedologiese, klimaat-, topografiese, son morfometriese en
geomorfiese veranderlikes, beoog ek om verdere bevestiging te gee aan streeks- en internasionale
geodiversiteits navorsing agendas.
Hoofstuk 5 kulmineer in die toepassing van kwantitatiewe DSM-metodes, met verbeterde terrein
verteenwoordiging, om produktiewe grondeenhede (ekotipes) te klassifiseer as 'n voorgestelde metodologie
om die huidige BRW-grondlandskap aanbevelings te verbeter. In KwaZulu-Natal is aanvaar dat gedetailleerde
natuurlike hulpbron inligting gebaseer op wetenskaplik akkurate en relevante kriteria nodig is om ruimtelike
lae te ontwikkel wat beplanners, ontwikkelaars, plaaslike regering en ander belanghebbendes kan gebruik om
toekomstige ontwikkeling te lei. Tans kan die KwaZulu-Natal Departement van Landbou en Landelike
Ontwikkeling (KZNDARD) hoëvlak-gewasproduksie-benaderings vir verskeie gewasse op grond van BRUs
verskaf. Die BRW het egter vir meer as twee dekades nie 'n beduidende hersiening gesien nie. Tog bied die
natuurlike hulpbron inligting wat dit bevat, grond bestuurders, beleidmakers en boere van onskatbare waarde
toegang tot streeks- en plaasvlak kwalitatiewe beramings van landbou produktiwiteit. Daar is 'n behoefte om
hierdie inligting te bewaar, terwyl dit terselfdertyd moderne maatreëls van grondbestuur aanbeveling op
verskeie skale aan die eindgebruiker verskaf. Teen hierdie agtergrond word toegang tot geredelik
interpreteerbare grond- en gewas inligting toenemend deur provinsiale beplanningskommissie geprioritiseer
as kritiese insette tot DSS vir volhoubare grondbestuur binne KwaZulu-Natal.Doctora
Heated aquatic microcosms for climate change experiments
Ponds and shallow lakes are likely to be strongly affected by climate change, and by increase in environmental temperature in particular. Hydrological regimes and nutrient cycling may be altered, plant and animal communities may undergo changes in both composition and dynamics, and long-term and difficult to reverse switches between alternative stable equilibria may occur. A thorough understanding of the potential effects of increased temperature on ponds and shallow lakes is desirable because these ecosystems are of immense importance throughout the world as sources of drinking water, and for their amenity and conservation value. This understanding can only come through experimental studies in which the effects of different temperature regimes are compared. This paper reports design details and operating characteristics of a recently constructed experimental facility consisting of 48 aquatic microcosms which mimic the pond and shallow lake environment. Thirty-two of the microcosms can be heated and regulated to simulate climate change scenarios, including those predicted for the UK. The authors also summarise the current and future experimental uses of the microcosms
Non-Reacting Spray Characteristics of Gasoline and Diesel With a Heavy-Duty Single-Hole Injector
Gasoline compression ignition (GCI) is a promising combustion technology that could help alleviate the projected demand for diesel in commercial transport while providing a pathway to achieve upcoming CO2 and criteria pollutant regulations for heavy-duty engines. However, relatively high (i.e., diesel-like) injection pressures are needed to enable GCI across the entire load range while maintaining soot emissions benefits and managing heat release rates. There have only been a limited number of previous studies investigating the spray characteristics of light distillates with high-pressure direct-injection hardware under charge gas conditions relevant to heavy-duty applications. The current work aims to address this issue while providing experimental data needed for calibrating spray models used in simulation-led design activities. The non-reacting spray characteristics of two gasoline-like fuels relevant to GCI were studied and compared to ultra-low-sulfur diesel (ULSD). These fuels shared similar physical properties and were thus differentiated based on their research octane number (RON). Although RON60 and RON92 had different reactivities, it was hypothesized that they would exhibit similar non-reacting spray characteristics due to their physical similarities. Experiments were conducted in an optically accessible, constant volume combustion chamber using a single-hole injector representing high-pressure, common-rail fuel systems. Shadowgraph and Mie-scattering techniques were employed to measure the spray dispersion angles and penetration lengths under both non-vaporizing and vaporizing conditions. Gasoline-like fuels exhibited similar or larger non-vaporizing dispersion angle compared to ULSD. All fuels followed a typical correlation based on air-to-fuel density ratio indicating that liquid density is the main governing fuel parameter. Injection pressure had a negligible effect on the dispersion angle. Gasoline-like fuels had slower non-vaporizing penetration rates compared to ULSD, primarily due to their larger dispersion angles. As evidenced by the collapse of data onto a non-dimensional penetration correlation over a wide range of test conditions, all fuels conformed to the expected physical theory governing non-vaporizing sprays. There was no significant trend in the vaporizing dispersion angle with respect to fuel type which remained relatively constant across the entire charge gas temperature range of 800–1200 K. There was also no discernable difference in vapor penetration among the fuels or across charge temperature. The liquid length of gasoline-like fuels was much shorter than ULSD and exhibited no dependence on charge temperature at a given charge gas pressure. This behavior was attributed to gasoline being limited by interphase transport as opposed to mixing or air entrainment rates during its evaporation process. RON92 had a larger non-vaporizing dispersion angle but similar penetration compared to RON60. Although this seems to violate the original similarity hypothesis for these fuels, the analysis was made difficult due to the use of different injector builds for the experiments. However, RON92 did show a slightly larger vapor dispersion angle than RON60 and ULSD. This observation was attributed to nuanced volatility differences between the gasoline-like fuels and indicates that vapor dispersion angle likely relies on a more complex correlation beyond that of only air-to-fuel density ratio. Finally, RON92 showed the same quantitative liquid length and insensitivity to charge gas temperature as RON60
Urban Knowledge Arenas:Re-thinking Urban Knowledge and Innovation. Final Report of Cost Action C20
Inference of Tidal Elevation in Shallow Water Using a Vessel-Towed Acoustic Doppler Current Profiler
Vessel-towed acoustic Doppler current profilers (ADCPs) have been widely used to measure velocity profiles. Since the instrument is usually mounted on a catamaran floating on the surface, previous studies have used the water surface as the reference level from which the vertical coordinate for the velocity profile is defined. However, because of the tidal oscillation, the vertical coordinate thus defined is time-dependent in an Earth-coordinate system, which introduces an error to the estimated harmonic constants for the velocity. As a result, the total transport will also be in error. This is particularly a problem in shallow waters where the tidal elevation is relatively large. Therefore tidal elevation needs to be resolved to make a correct harmonic analysis for the velocity. The present study is aimed at resolving the tidal elevation change in shallow water using a vessel-towed ADCP. Semidiurnal and diurnal tidal elevations across the lower Chesapeake Bay have been determined using a vessel-towed ADCP. Data from four cruises ranging from 25 to 92 hours in 1996 and 1997 are used. Water depth averaged every 30 s by the ADCP is studied by harmonic and statistical analysis. By selecting only the data within a narrow band (similar to 320 m) over the planned transect, we are able to improve the reliability of the data. We then grid the depth data along the 16 km transect into 200 equal segments and use harmonic analysis to resolve the semidiurnal and diurnal tidal variations within each segment. We find that (1) the depth data from the ADCP contain both semidiurnal and diurnal signals that can be resolved, from which the surface elevation can be inferred, (2) the major error appears to come from spatial variation of the depth, (3) the semidiurnal and diurnal tidal variations of elevation inferred over Aat bottom topography account for almost 100% of the total variability, while those measurements over large bottom slopes account for a much lower percentage of the total variability, (4) at least 70% of the variability of depth can be explained by semidiurnal and diurnal tides if the bottom slope is smaller than 0.006, and (5) the spatial variation of both amplitude and phase of the elevation along the transect appears to be small with a slightly lower tidal amplitude at the south of the Chesapeake Bay entrance, consistent with the Coriolis effect. The inferred elevations from the ADCP readings are consistent with sea level measurements at a tide station 10 km inside the estuary
Ariel - Volume 4 Number 4
Editors
David A. Jacoby
Eugenia Miller
Tom Williams
Associate Editors
Paul Bialas
Terry Burt
Michael Leo
Gail Tenikat
Editor Emeritus and Business Manager
Richard J. Bonnano
Movie Editor
Robert Breckenridge
Staff
Richard Blutstein
Mary F. Buechler
Meg Brunt
Steve Glinks
Len Grasman
Alice M. Johnson
J.D. Kanofsky
Tom Lehman
Dave Mayer
Bernie Odd
Have the public's expectations for antibiotics for acute uncomplicated respiratory tract infections changed since the H1N1 influenza pandemic? A qualitative interview and quantitative questionnaire study
Objective: To investigate the effect of the H1N1 influenza pandemic on the public's expectations for a general practice consultation and antibiotic for acute respiratory illness. Design: Mixed methods. Participants: Qualitative interviews: 17 participants with acute respiratory tract infection (RTI) visiting English pharmacies. Face-to-face survey: about 1700 adults aged 15 years and older were recruited from households in England in January 2008, 2009 and 2011. Results: The qualitative data indicated that the general public had either forgotten about the 'swine flu' (H1N1 influenza) pandemic or it did not concern them as it had not affected them directly or affected their management of their current RTI illness. Between 2009 and 2011, we found that there was little or no change in people's expectations for antibiotics for runny nose, colds, sore throat or cough, but people's expectations for antibiotics for flu increased (26%e32%, p=0.004). Of the 1000 respondents in 2011 with an RTI in the previous 6 months, 13% reported that they took care of themselves without contacting their general practitioners and would not have done so before the pandemic, 9% reported that they had contacted their doctor's surgery and would not have done so before the pandemic and 0.6% stated that they had asked for antibiotics and would not have done so before the pandemic. In 2011, of 123 respondents with a young child (0-4 years) having an RTI in the previous 6 months, 7.4% requested antibiotics and would not have done so before the pandemic. Unprompted, 20% of respondents thought Tamifl
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