427 research outputs found
Stability of Q-switched 2 ÎŒm lasers
Q-switched lasers operating at wavelengths around 2â”m have many applications including materials processing and LIDAR. However, the low gain of the quasi-three-level gain media available at 2â”m can lead to problems with pulse-to-pulse fluctuations in their output, known as jitter. Here we present a methodology for characterising the level of jitter in a Q-switched laser and apply it to a Tm:YAP system. We also look at the causes of jitter and evaluate some methods of reducing it. The methodology developed here will aid in the development and characterisation of Q-switched lasers at any wavelength
Oral dosing for antenatal corticosteroids in the Rhesus macaque.
Antenatal corticosteroids (ACS) are standard of care for women at risk of preterm delivery, although choice of drug, dose or route have not been systematically evaluated. Further, ACS are infrequently used in low resource environments where most of the mortality from prematurity occurs. We report proof of principle experiments to test betamethasone-phosphate (Beta-P) or dexamethasone-phosphate (Dex-P) given orally in comparison to the clinical treatment with the intramuscular combination drug beta-phosphate plus beta-acetate in a Rhesus Macaque model. First, we performed pharmacokinetic studies in non-pregnant monkeys to compare blood levels of the steroids using oral dosing with Beta-P, Dex-P and an effective maternal intramuscular dose of the beta-acetate component of the clinical treatment. We then evaluated maternal and fetal blood steroid levels with limited fetal sampling under ultrasound guidance in pregnant macaques. We found that oral Beta is more slowly cleared from plasma than oral Dex. The blood levels of both drugs were lower in maternal plasma of pregnant than in non-pregnant macaques. Using the pharmacokinetic data, we treated groups of 6-8 pregnant monkeys with oral Beta-P, oral Dex-P, or the maternal intramuscular clinical treatment and saline controls and measured pressure-volume curves to assess corticosteroid effects on lung maturation at 5d. Oral Beta-P improved the pressure-volume curves similarly to the clinical treatment. Oral Dex-P gave more variable and nonsignificant responses. We then compared gene expression in the fetal lung, liver and hippocampus between oral Beta-P and the clinical treatment by RNA-sequencing. The transcriptomes were largely similar with small gene expression differences in the lung and liver, and no differences in the hippocampus between the groups. As proof of principle, ACS therapy can be effective using inexpensive and widely available oral drugs. Clinical dosing strategies must carefully consider the pharmacokinetics of oral Beta-P or Dex-P to minimize fetal exposure while achieving the desired treatment responses
A new Holocene record of geomagnetic secular variation from Windermere, UK
Paleomagnetic
secular
variation
(PSV)
records
serve
as
valuable
independent
stratigraphic
correlation
and
dating
tools
for
marine
and
terrestrial
sediment
sequences,
and
enhance
knowledge
of
geomagnetic
field
dynamics.
We
present
a
new
radiocarbon-dated
record
(WINPSV-12K)
of
Holocene
geomagnetic
secular
variation
from
Windermere,
updating
the
existing
1981
UK
master
PSV
curve.
Our
analyses
used
continuous
U-channel
samples
taken
from
the
center
of
four
sediment
cores
retrieved
from
Windermere
in
2012.
The
natural
remanent
magnetization
(NRM)
of
each
U-channel
was
measured
before
and
after
stepwise
alternating
field
(AF)
demagnetization
on
a
superconducting
rock
magnetometer
at
intervals
of
0.5-cm
or
1-cm.
The
NRM
data
reveal
a
stable
and
well-defined
primary
magnetization.
Component
declinations
and
inclinations
estimated
using
Principal
Component
Analysis
(PCA)
of
NRM
data
from
the
four
Windermere
cores
correlate
well
on
their
independent
radiocarbon
age
models.
The
four
records
were
stacked
using
a
sliding
window
bootstrap
method,
resulting
in
a
composite
Holocene
PSV
record
(WINPSV-12K).
On
millennial
timescales
WINPSV-12K
correlates
well
with
other
records
from
Western
Europe
and
the
northern
North
Atlantic
to
a
resolution
of
âŒ
1
kyr,
given
age
uncertainties
and
spatial
variability
between
records.
WINPSV-12K
also
compares
well
to
the
CALS10k.2
and
pfm9k.1a
model
predictions
for
Windermere.
Key
regionally-significant
PSV
inclination
features
of
WINPSV-12K
which
correlate
with
other
North
Atlantic
records
include
peaks
at
5â6,
8.5,
and
10 cal ka BP,
and
a
trough
at
7calkaBP.
Key
PSV
declination
features
include
the
eastward
swing
from
5.5â2.3 cal ka BP
followed
by
a
major
westward
excursion
at
2.3 cal ka BP,
peaks
at
1.1
and
7calkaBP,
and
troughs
at
5.4
and
8.2 cal ka BP,
with
the
caveat
that
an
estimated
magnetic
lock-in
delay
of
at
least
100â200 yr
is
present.
PSV
variations
on
1â3 kyr
timescales
are
interpreted
to
represent
strengthening
and
weakening
of
the
North
American
versus
the
Siberian
and
EuropeanâMediterranean
high-latitude
flux
lobes,
based
on
the
close
similarities
between
the
North
Atlantic
regional
records
and
the
antiphase
existing
in
the
East
Asian
Stack
record
and
the
North
East
Pacific
inclination
stack.
WINPSV-12K
provides
a
regionally-important
new
PSV
reference
curve
whose
prominent
features
may
serve
as
stratigraphic
markers
for
North
Atlantic
paleo-records
A new varve sequence from Windermere, UK, records rapid ice retreat prior to the Lateglacial Interstadial (GI-1)
Annually laminated sediments (varves) provide excellent temporal resolution to study rapid environmental change, but are rare in the early part of the Last Termination (âŒ19ââŒ11.7 ka BP). We present a new >400 varve year (vyr) varve sequence in two floating parts from Windermere, a lake at the southern margin of the mountains of northwest England. This sequence records the final retreat of the Windermere glacier at the southern edge of the Lake District Ice Cap during the transition from Heinrich Stadial 1 (âŒ18ââŒ14.7 ka BP) into the Lateglacial Interstadial (âŒ14.7ââŒ12.9 ka BP).
Laminated sediments from four lake cores from Windermere's northern and southern basins were investigated and shown to be varved. These sequences are integrated with seismic reflection evidence to reconstruct south-to-north deglaciation. Seismic and sedimentological evidence is consistent with gradual stepped ice retreat along the entire southern basin and into the northern basin between 255 and 700 vyr prior to the appearance of significant biota in the sediment that heralded the Lateglacial Interstadial, and had retreated past a recessional moraine (RM8) in the northern basin by 121 vyr prior to the interstadial. The Lateglacial Interstadial age of this biota-bearing unit was confirmed by 14C-dating, including one date from the northernmost core of âŒ13.5âŻcal ka BP. A change in mineralogy in all four cores as the glacier retreated north of the Dent Group (the northernmost source of calcareous bedrock) and a decrease in coarse grains in the varves shows that the ice had retreated along the entire North Basin at âŒ70 vyr prior to the Lateglacial Interstadial. The estimated retreat rate is 70â114âŻm yrâ1 although buried De Geer moraines, if annual, may indicate retreat of 120âŻm yrâ1 with a â„3 year stillstand at a recessional moraine halfway along the basin. The glacier then retreated north of the lake basin, becoming land-terminating and retreating at 92.5â49âŻm yrâ1.
The northernmost core has a varve sequence ending at least 111 vyr after the other core chronologies, due to the increased proximity to remnant ice in the catchment uplands into the early Lateglacial Interstadial. We show that almost all of the glacier retreat in the Windermere catchment occurred before the abrupt warming at the onset of the Lateglacial Interstadial, in keeping with similar findings from around the Irish Sea Basin, and suggesting a similar retreat timescale for other radial valley glaciers of the Lake District Ice Cap. The seismic and core evidence also show the potential for a much longer varve chronology extending at least 400 and potentially over 1000 vyr further back into Heinrich Stadial 1 (18â14.7 ka BP), suggesting that glacier retreat in the Windermere valley initiated at least before 15.5 ka BP and perhaps 16 ka BP
Invasive alien species â framework for the identification of invasive alien species of EU concern
Invasive alien species (IAS) are considered to be one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change (MEA 2005, GBO 2011). In recent years the European Commission (EC) has intensified their commitment to provide a comprehensive, problem-oriented, well-balanced and manageable solution to IAS in Europe. The text of a European Union (EU) Regulation is expected to be adopted soon. A core component of the Regulation is a list of âIAS of EU concernâ that will be drawn up together with European Member States (MS), based on scientifically robust risk assessments as laid down in the Regulation.
Risk assessment is the technical and objective process of evaluating biological or other scientific and economic evidence to identify potentially invasive alien species and determine the level of invasion risk associated with a species or pathway and specifically whether an alien species will become invasive. An effective and robust risk assessment method is seen as an essential component of IAS management (Shine, Kettunen et al. 2010) and a fundamental element of an early warning and information system in Europe (Genovesi, Scalera et al. 2010).
The purpose of this project was to provide a review of available IAS risk analysis protocols and use this, coupled with expert opinion, to inform the development of minimum standards necessary to ensure effective risk assessment methods for the EU. Additionally we considered gaps in knowledge and scope of existing risk analysis methods. Thus, we provide recommendations for developing existing risk analysis methods within a framework of minimum standards. Methods compliant with the minimum standards will be of value for supporting the development of a draft list of âIAS of EU concernâ. Such a list should include species that are already established within the EU but also be extended to a scoping study to consider species that are not yet established but that may present a significant threat to Europe in the near future.
Task 1: Literature review and critical assessment of existing risk assessment methodologies on IAS
The purpose of the review was to critically assess the scope, robustness and effectiveness of current risk assessment methods and to provide information for their further development in the context of the study particularly underpinning the derivation of minimum standards.
More than 100 relevant publications were derived through a literature search. Only 70 publications provided original risk assessment protocols and their applications and of these 29 were selected through filtering to eliminate those which simply described the implementation of an existing protocol to a given geographic region or specific taxonomic groups without modification of the assessment protocol. These 29 protocols were examined further to derive key attributes of the risk assessment method to inform the development of minimum standards. Basic information for all 29 risk assessment methods was provided. Case studies for 14 of these protocols were included to provide further context for subsequent tasks. The 14 protocols included as case studies were selected on the basis of a number of criteria: relevance of the protocol to Europe, taxonomic breadth and/or geographic breadth, likely compliance with minimum standards and availability of experts with key involvement in the protocol to provide the case study.
At both the international and regional-level as well as among countries, there is huge variation in how the risks posed by alien species are assessed. Indeed risk assessment protocols vary widely in approach, objective, implementation and taxa covered, the majority are based on qualitative methods, even though the need to develop quantitative risk assessments has been recognised. Major hurdles preventing the use of quantitative risk assessment methods are the lack of data and challenges in interpretation and communication.
Two critical gaps were identified through this task: consideration of ecosystem services and evaluation of user-friendliness and consistency of outcomes. Very few risk assessment protocols reviewed specifically considered impacts on ecosystem services. Consistency in risk analysis has been recently discussed and assessed for pest risk analyses in the EU-funded project PRATIQUE and methods to improve consistency have been developed. PRATIQUE only considered the EPPO decision support scheme (EPPO DSS), however this work will be extended through consideration of additional risk assessments within the current EU-funded COST Action Alien Challenge.
Task 2: Develop minimum standards for risk assessment methodologies
The review of characteristics of risk assessments through task 1 resulted in a long-list of attributes. The derived attributes ranged from broad consideration of general characteristics including description of the species through to criteria relevant to the invasion process including likelihood of arrival, establishment and spread. Impacts were classified broadly and included biodiversity and socio-economic impacts alongside perspectives influencing impacts such as climate change. Additional consideration was given to implementation of the protocol including quality assurance and alignment with agreed international standards and policies such as the World Trade Organisation (WTO) and relevant EU Directives including the EU Marine Strategy Framework Directive (MSFD) and EU Water Framework Directive (WFD).
From the long-list the core project team developed and selected a draft short-list of attributes that were considered to be relevant for performing risk assessments of IAS. The short-list of minimum standards was agreed by the project team and preliminarily reviewed through a pre-workshop survey in Task 3.
Task 3: Risk assessment workshop
The overarching aim of the risk assessment workshop (27-28th March 2014) was to peer-review the derived short-list of minimum standards. The derived minimum standards are required to underpin evaluation of existing risk assessments and ensure they are fit for the purpose of supporting the development of a list of âIAS of EU concernâ.
We aimed to distil the critical components of a risk assessment that, through expert opinion and consensus, are agreed necessary to achieve overarching, robust and rigorous assessment of the risk of an IAS, regardless of the specific approach taken. Additionally consideration was given to recognized international guidelines and recommendations with relevance to the development of minimum standards for risk assessments.
The workshop included participants from the project team (23 experts from nine organisations) and 12 additional invited experts. The invited experts and those from within the team represented a breadth of expertise from a variety of perspectives including taxonomic (all taxa, including pathogens), environmental (freshwater, marine and terrestrial), impacts (environmental, socio-economic and health) and disciplines (ecologists, economist, conservation practitioners, scientists, policy-makers, risk assessors). Many of the experts had been actively involved in the development, testing and implementation of risk assessment protocols for IAS.
The experts were invited to review and refine the list of attributes derived through Tasks 1 and 2 for inclusion as potential minimum standards. The long list of attributes of risk assessments derived through Task 1 and 2 were circulated in the form of a pre-workshop survey (using Survey Monkey) in which the experts were asked to rank the importance of each as a potential minimum standard on a scale of 1 (low importance) to 5 (high importance). Experts were also asked to provide additional attributes that were not apparent from the long-list.
The pre-workshop survey revealed a high level of consensus between all experts for most of the attributes. However one-third of the experts stated that a totally new EU-wide risk assessment system tailored for the new IAS Regulation should be developed. Attributes aligning with socio-economic aspects also appeared to cause division in responses by the experts. Furthermore, questions relating to cost-benefit led to a high degree of uncertainty with more than a third of participants responding âunsureâ. The disagreement or uncertainty expressed by respondents on these specific themes highlighted the need to ensure that socio-economic considerations were included as a substantial component of the workshop programme.
Clarity is an overarching requirement of risk assessment protocols to ensure consistency. It is of utmost importance that a protocol asks questions that are sufficiently clear and understandable for assessors. This is essential to ensure that responses (accompanied by an indication of level of uncertainty) deliver similar assessments for the same species in the same area, irrespective of the identity of the assessors â as long as these have the necessary expertise or are provided with the necessary information.
Fourteen criteria were agreed, through consensus methods, to represent the minimum standards. The minimum standards are:
1. Description (Taxonomy, invasion history, distribution range (native and introduced), geographic scope, socio-economic benefits)
2. Includes the likelihood of entry, establishment, spread and magnitude of impact
3. Includes description of the actual and potential distribution, spread and magnitude of impact
4. Has the capacity to assess multiple pathways of entry and spread in the assessment, both intentional and unintentional
5. Can broadly assess environmental impact with respect to biodiversity and ecosystem patterns and processes
6. Can broadly assess environmental impact with respect to ecosystem services
7. Broadly assesses adverse socio-economic impact
8. Includes status (threatened or protected) of species or habitat under threat
9. Includes possible effects of climate change in the foreseeable future
10. Can be completed even when there is a lack of data or associated information
11. Documents information sources
12. Provides a summary of the different components of the assessment in a consistent and interpretable form and an overall summary
13. Includes uncertainty
14. Includes quality assurance
Task 4: Screening of existing risk assessment methodologies
None of the analysed risk assessment protocols were fully compliant with the minimum standards. However, there were a number of protocols that appeared to be compliant with a sufficient number of the minimum standards or with the potential to be modified in accordance with the minimum standards to be included within Task 4.
The GB NNRA, EPPO DSS, Harmonia+ and ENSARS were the risk assessment protocols that most closely met the minimum standards, they are further referred to as "substantially compliant risk assessments". The risk assessments undertaken with the GB NNRA and EPPO DSS were accessible and included a range of species. Harmonia+ has potential as a risk assessment protocol with broad taxonomic and geographic applicability. It is a comprehensive risk assessment protocol, however it has only recently been published and currently no species have been formally assessed using this method. ENSARS includes assessments for a number of species but these are not yet formally published.
GB NNRA and Harmonia+ both currently lack inclusion of description of socio-economic benefits. However, experts representing these methods acknowledge a willingness to include this aspect as a priority in the future. The EPPO DSS and ENSARS already consider such benefits.
Consideration of possible effects on climate change in the foreseeable future was lacking in most protocols. However, the GB NNRA does include climate change considerations. ENSARS, Harmonia+ and EPPO fail to include climate change considerations within their protocols but could easily include this aspect as a priority for updates in the future.
Consideration of the effects of IAS on ecosystem services was almost consistently lacking in the risk assessment protocols. This was identified through the literature review (Tasks 1 and 2) but was confirmed through Task 4. IAS impacts on biodiversity, ecosystem patterns and processes, ecosystem services and related socio-economic implications are clearly interlinked. Therefore, there are foreseen to be overlaps in how these different impacts are determined in practice: the identification of impacts on biodiversity and ecosystem characteristics clearly forms the basis for impacts on ecosystem services whereas identifying the impacts on ecosystem services form a key conceptual basis for assessing the foreseen socio-economic impacts of IAS invasion. These overlaps â or synergies - should be taken into consideration when developing these three minimum standards further in the future. It is foreseen that a dedicated guidance on how to assess the impact on ecosystem services, in the context of EU risk assessments for IAS, would need to be developed.
Task 5: Screening of potential âIAS of EU Concernâ and proposal of a list
Prioritisation of potential âIAS of EU concernâ is essential to both target IAS interventions at the species constituting the highest risks and for allocating the limited resources available for invasion management based on feasibility of outcomes. The establishment of a risk analysis framework, in consultation with the EC, would ensure a coherent and coordinated response to risks of EU relevance which could be termed âIAS of EU concernâ.
The main objective of the study was to analyse a set of species that have been risk assessed using protocols meeting the minimum standards to develop the list of âIAS of EU concernâ. As a result of the analysis in Task 4, it was apparent that none of the existing protocols screened, tested and discussed within Task 3 meet the full set of minimum standards.
We proceeded with the analysis of the list of 80 species provided by the Commission against those protocols for risk assessment that were considered as âsubstantially compliantâ. Due to the lack of risk assessment protocols compliant with the minimum standards, it was not possible to obtain a fully compliant list of proposed âIAS of EU concernâ as initially foreseen. However, four risk assessment protocols, namely the EPPO DSS, ENSARS, GB NNRA and Harmonia+, were selected as they meet âmostâ minimum standards and included a breadth of species in existing assessments. The lists generated from the four selected protocols were thus cross-tabulated against the list of 80 species provided by the EC. It is important to note that some of the existing assessments (most notably within GB NNRA, ENSARS and Harmonia+) apply to a restricted area within Europe and so caution in extrapolating outcomes to a European-scale is required.
In total 50 species are included within the draft list of proposed âIAS of EU concernâ and these were identified through the âsubstantially compliantâ risk assessments as posing a medium to high risk on biodiversity and/or human health and the economy. Of these 37 are from GB NNRA, 18 from EPPO and one from ENSARS. Seven of the species were assessed within more than one protocol. The list includes 14 species in addition to those within the original list provided by the EC.
The draft list of proposed âIAS of EU concernâ includes 25 plants, 12 vertebrates, 13 invertebrates of which most are found in the terrestrial and freshwater environments (24 and 20 respectively whereas only six marine species are included). The draft list is constrained by inclusion of only the IAS for which a âsubstantially compliantâ risk assessment is available. Furthermore, there are inherent limitations of a list of proposed âIAS of EU concernâ compiled on the basis of risk assessment protocols which do not fully comply with the agreed minimum standards. This is reflected in a number of shortcomings or inconsistencies resulting from the outcomes of the four protocols which were used to draft the list of proposed âIAS of EU concernâ.
Concluding remarks and key recommendations
Available risk assessment protocols that meet the minimum standards are an important step in developing a list of âIAS of EU concernâ. Refinements to existing risk assessment protocols are required to ensure they include consideration of ecosystem services, climate change and adverse impacts on socio-economic benefits. As these criteria are encompassed it will be necessary to critically test and evaluate the performance of these modified protocols as it is necessary to improve consistency of outcomes.
Support should be given to enable developments to modify risk assessment protocols within their mandate to comply with the new EU Regulation. This should include the development of appropriate guidance on the interpretation and use of minimum standards where required. Additionally the importance of national impact assessment protocols should be recognised with consideration given to modifications of methods to provide a scientific basis for EU assessments. These assessments should serve as source to identify potential additional âIAS of EU concernâ and evaluation of the list.
Impact assessments are not compliant with the minimum standards because of lack of consideration of mechanisms of introduction and establishment. However, impact assessments provide a detailed basis upon which to quantify the impacts of IAS and include aspects that could be considered for inclusion within full risk assessments. The risk assessment methods based on the protocol devised by EPPO DSS, namely GB NNRA and ENSARS, provide a basis on which to begin developing a list of âIAS of EU concernâ. However, the breadth of species considered relevant is influenced by the original purposes of both protocols. Harmonia+ is a new and promising risk assessment method. It will be essential to consider the relevance of this protocol as one of the key players going forward.
A critical issue exists in the simplification of extrapolating national or regional assessments to the total area of the EU. The EU is rich in biodiversity and is a highly heterogeneous and large territory and so risk assessments of IAS may differ substantially when different regions are considered. Consideration of European biogeographic regions as contex for existing national risk assessments protocols would be appropriate. It is essential to ensure that risk assessments undertaken for restricted regions within Europe (such as the GB NNRA, ENSARS and Harmonia+) have relevance to the EU as outlined above. Review of the applicability of such assessments for EU relevance is unlikely to be trivial for many IAS. Re-assessment of risks identified through national risk assessment protocols at the EU level (with consideration of biogeographic regions) through scientific experts should be prioritised.
Further development of the list of proposed âIAS of EU concernâ is necessary and should involve scientific experts based on the framework provided by the new EU Regulation. It will be essential to develop a process for consolidating the draft list of proposed âIAS of EU concernâ through involvement of scientific experts. The list of proposed âIAS of EU concernâ will need to be reviewed on a regular basis to ensure it remains current as the number of new arrivals escalates. Equally the knowledge underpinning our understanding of invasions and environmental change will improve and additional relevant concepts will emerge. Therefore, periodically it will be necessary not only to review the list of proposed âIAS of EU concernâ but also the framework of minimum standards upon which it is based as, for example, understanding increases and evidence suggests the need to modify minimum standards or indeed include additional minimum standards.
Consideration of the establishment of a formal procedure for evaluating the list of proposed âIAS of EU concernâ after 2016 should be prioritised. It will be essential to provide support for cooperation between scientific experts (responsible for the risk assessments) and the Member State and stakeholder experts (responsible for the risk management and communication). Indeed before the final list of âIAS of EU concernâ is determined risk management factors should be taken into account, such as how widespread the species is within the EU, what benefits are associated with the species and the cost-benefit of adding the species to the list of âIAS of EU concern"
Recommended from our members
LDRD final report on "fundamentals of synthetic conversion of CO2 to simple hydrocarbon fuels" (LDRD 113486).
Energy production is inextricably linked to national security and poses the danger of altering the environment in potentially catastrophic ways. There is no greater problem than sustainable energy production. Our purpose was to attack this problem by examining processes, technology, and science needed for recycling CO{sub 2} back into transportation fuels. This approach can be thought of as 'bio-inspired' as nature employs the same basic inputs, CO{sub 2}/energy/water, to produce biomass. We addressed two key deficiencies apparent in current efforts. First, a detailed process analysis comparing the potential for chemical and conventional engineering methods to provide a route for the conversion of CO{sub 2} and water to fuel has been completed. No apparent 'showstoppers' are apparent in the synthetic route. Opportunities to improve current processes have also been identified and examined. Second, we have also specifically addressed the fundamental science of the direct production of methanol from CO{sub 2} using H{sub 2} as a reductant
Palaeoseismology from microfabric and geochemical analysis of lacustrine sediment, Windermere, UK
Lake sediments commonly contain detrital layers that record events such as floods or earthquakes but these may be disturbed or partially destroyed by bioturbation. Here we use a novel combination of techniques to relate microscopic sediment fabric features to lake-basin scale processes. X-radiography and micro-XRF of cores are complemented by backscattered electron imagery and energy dispersive X-ray microanalysis of resin-embedded sediment. Together, the microfabric and geochemical methods enable the identification of clay-layer mass transport deposits despite bioturbational mixing of the original end members. Two cores with robust radionuclide chronologies contain correlative clay layers dated to 1979 (1974â1982) and 1979â1980 (1973â1986) respectively. These clay layers likely represent the distal turbidite generated by a major mass flow deposit identified from multibeam swath bathymetry and sediment grab sampling. A likely trigger for the mass flow and associated turbidity current is the 4.7 ML 1979 Carlisle earthquake. The lake basin slope was likely preconditioned for failure by increased sedimentary biogenic gas production and sediment in-wash as a result of anthropogenic activities, coupled with sediment disruption and dredging. This study highlights the effectiveness of microstratigraphic techniques in the recognition and characterisation of event layers in sediments where bioturbative disruption has occurred
Recommended from our members
Summary report : universal fuel processor.
The United States produces only about 1/3 of the more than 20 million barrels of petroleum that it consumes daily. Oil imports into the country are roughly equivalent to the amount consumed in the transportation sector. Hence the nation in general, and the transportation sector in particular, is vulnerable to supply disruptions and price shocks. The situation is anticipated to worsen as the competition for limited global supplies increases and oil-rich nations become increasingly willing to manipulate the markets for this resource as a means to achieve political ends. The goal of this project was the development and improvement of technologies and the knowledge base necessary to produce and qualify a universal fuel from diverse feedstocks readily available in North America and elsewhere (e.g. petroleum, natural gas, coal, biomass) as a prudent and positive step towards mitigating this vulnerability. Three major focus areas, feedstock transformation, fuel formulation, and fuel characterization, were identified and each was addressed. The specific activities summarized herein were identified in consultation with industry to set the stage for collaboration. Two activities were undertaken in the area of feedstock transformation. The first activity focused on understanding the chemistry and operation of autothermal reforming, with an emphasis on understanding, and therefore preventing, soot formation. The second activity was focused on improving the economics of oxygen production, particularly for smaller operations, by integrating membrane separations with pressure swing adsorption. In the fuel formulation area, the chemistry of converting small molecules readily produced from syngas directly to fuels was examined. Consistent with the advice from industry, this activity avoided working on improving known approaches, giving it an exploratory flavor. Finally, the fuel characterization task focused on providing a direct and quantifiable comparison of diesel fuel and JP-8
Perancangan Peraga LED Terprogram Berbasis Mikrokontroler AT89C52
Dengan tersedianya mikrokontroler yang memiliki berbagai fasilitas serta murahnya
harga PC yang ditawarkan, maka peluang untuk merancang peralatan pengendalian LED untuk
berbagai keperluan menjadi sangat terbuka. Tujuan dari penelitian ini adalah merancang dan
menguji peraga LED terprogram berbasis mikrokontroler AT89C52. Alat penampil LED matrik
dirancang data-nya bisa dimasukan secara otomatis, sehingga LED dapat menampilkan data
dengan segera. Perancangan sistem penampil LED matrik yang dibuat meliputi dua bagian
utama yaitu bagian perangkat keras dan bagian perangkat lunak. Perangkat keras meliputi
mikrokontroler AT89C52 sebagai pusat pengontrol, penggerak kolom dan penggerak baris serta
LED matrik untuk menampilkan data. Perangkat lunak meliputi bahasa mesin mikrokontroler
dan untuk berhubungan dengan PC menggunakan Borland Delphi. Pengujian dilakukan dengan
membandingkan tampilan LED matrik dengan data masukan dari PC. Alat ini dapat
mengendalikan dan menampilkan LED sesuai data yang diberikan. LED matrik dapat
menampilkan empat baris teks yang masing-masing baris maksimal enam karakter, gambar
serta animasi running text (teks berjalan)
Screening Patients with a Family History of Colorectal Cancer
OBJECTIVES: To compare screening practices and beliefs in patients with and without a clinically important family history. DESIGN: We mailed a brief questionnaire asking about family history and a second, longer survey asking about knowledge of and beliefs about colorectal cancer to all respondents with a family history and a random sample of respondents without a family history of colorectal cancer. We reviewed electronic medical records for screening examinations and recording of family history. PARTICIPANTS: One thousand eight hundred seventy of 6,807 randomly selected patients ages 35â55Â years who had been continuously enrolled in a large multispecialty group practice for at least 5Â years. MEASUREMENTS: Recognition of increased risk, screening practices, and beliefsâall according to strength of family history and patientâs age. RESULTS: Nineteen percent of respondents reported a family history of colorectal cancer. In 11%, this history was strong enough to warrant screening before age 50Â years. However, only 39% (95% CI 36, 42) of respondents under the age of 50Â years said they had been asked about family history and only 45% of those with a strong family history of colorectal cancer had been screened appropriately. Forty-six percent of patients with a strong family history did not know that they should be screened at a younger age than average risk people. Medical records mentioned family history of colorectal cancer in 59% of patients reporting a family history. CONCLUSIONS: More efforts are needed to translate information about family history of colorectal cancer into the care of patients
- âŠ