42,029 research outputs found
Assessment of Effectiveness of Buffer Zones in Removing Impurities in Runoff from Areas Treated with Poultry Litter. Part II: Source Areas to Buffer Areas Ratio Effects
Vegetative filter strips (VFS) are known to reduce runoff losses of nutrients. solids. and other materials from land areas treated with fertilizers . Although VFS effectiveness is known to depend partially on the relative lengths of filter and pollutant source areas. there is little experimental evidence available to quantify this dependence. This is particularly the case when VFS are implemented down-slope of pasture areas treated with animal manures such as poultry litter. This study assessed the influences of pollutant source area (treated with poultry litter) and VFS lengths on VFS removal of total Kjeldahl nitrogen (TKN). ammonia nitrogen (NH3 -N ). nitrate nitrogen (N03-N). ortho-phosphorus (P04-P). total phosphorus (TP). total organic carbon (TOC). total suspended solids (TSS). and fecal coliform (FC) fromincoming runoff for a silt loam soil with fescue cover. Litter-treated lengths of 6.1. 12.2. and 18.3 m with corresponding VFS lengths of up to 18.3 m. 12.2 m. and 6.1 m. respectively, were examined. Runoff was produced from simulated rainfall applied at 50 mm/h for 1 h of runoff. Concentrations of the parameters analyzed were unaffected by litter treated length but demonstrated a first-order decrease with increasing VFS length except in the cases of TSS and FC. Mass transport of TKN. NH3-N. P04-P. and TP increased with increasing litter-treated length (due to increased runoff) and decreased (approximately first-order) with increasing VFS length. Effectiveness of the VFS in terms of TKN. NH3-N. P04 -P. and TP removal from runoff ranged from 6.5 to 96.3% depending on the particular parameter. litter-treated length. and VFS length. The data collected during this study can be helpful in developing and testing simulation models of VFS performance and can thus aid in design of VFS for pasture areas treated with poultry litter
The Increasing Diversity of America\u27s Youth
This brief documents how unfolding demographic forces have placed todayâs children and youth at the forefront of Americaâs new racial and ethnic diversity. Authors Kenneth M. Johnson, Andrew Schaefer, Daniel T. Lichter, and Luke T. Rogers discuss how the rapidly changing racial and ethnic composition of the youth population has important implications for intergroup relations, ethnic identities, and electoral politics. They report that diversity is increasing among Americaâs youth because there are more minority children and fewer non-Hispanic white children. Minority births exceeded non-Hispanic white births for the first time in U.S. history in 2011 according to Census Bureau estimates. Both the declining number of non-Hispanic white women of prime child-bearing and growing numbers of minority women contributed to this change as did differential fertility rates. The largest gains in child diversity between 2000 and 2012 were in suburban and smaller metropolitan areas. Yet, child diversity is geographically uneven, with minimal diversity in some areas of the country and significant diversity in other areas. They conclude that natural population increaseâparticularly fertility ratesâwill continue to reshape the racial and ethnic mix of the country, and this change will be reflected first among the nationâs youngest residents
Decoding the Mechanism for the Origin of Dark Matter in the Early Universe Using LHC Data
It is shown that LHC data can allow one to decode the mechanism by which dark
matter is generated in the early universe in supersymmetric theories. We focus
on two of the major mechanisms for such generation of dark matter which are
known to be the Stau Coannihilation (Stau-Co) where the neutralino is typically
Bino like and annihilation on the Hyperbolic Branch (HB) where the neutralino
has a significant Higgsino component. An investigation of how one may
discriminate between the Stau-Co region and the HB region using LHC data is
given for the mSUGRA model. The analysis utilizes several signatures including
multi leptons, hadronic jets, b-tagging, and missing transverse momentum. A
study of the SUSY signatures reveals several correlated smoking gun signals
allowing a clear discrimination between the Stau-Co and the HB regions where
dark matter in the early universe can originate.Comment: 7 pages, 5 figs, 2 columns, Accepted for publication in Physical
Review
Physical outcome measure for critical care patients following intensive care discharge
Introduction: The aim of this study was to evaluate the most suitable
physical outcome measures to be used with critical care patients following
discharge. ICU survivors experience physical problems
such as reduced exercise capacity and intensive care acquired
weakness. NICE guideline âRehabilitation after critical illnessâ (1) recommends
the use of outcome measures however does not provide
any specific guidance. A recent Cochrane review noted wide variability
in measures used following ICU discharge (2).
Methods: Discharged ICU patients attended a five week multidisciplinary
programme. Patientsâ physical function was assessed during
the programme, at 6 months and 12 months post discharge. Three
outcome measures were included in the initial two cohorts. The Six
Minute Walk Test (6MWT) and the Incremental Shuttle Walk test
(ISWT) were chosen as they have been used within the critical care
follow up setting (2). The Chester Step Test (CST) is widely thought
to be a good indicator of ability to return to work (one of the programmes
primary aims). Ethics approval was waived as the
programme was part of a quality improvement initiative.
Results: Data was collected for the initial patients attending the
programme (n = 13), median age was 52 (IQR = 38-72), median ICU
LOS was 19 days (IQR = 4-91), median APACHE II was 23 (IQR = 19-41)
and 11 were men. One patient was so physically debilitated that the
CST or ISWT could not be completed however a score was achieved
using the 6MWT. Another patient almost failed to achieve level 1 of
the ISWT. Subsequent patients for this project (total n = 47) have all
therefore been tested using the 6MWT. Good inter-rater and intrarater
reliability and validity have been reported for the 6MWT (3).
Conclusions: Exercise capacity measurement is not achievable for
some patients with either the ISWT or the CST due to the severity of
their physical debilitation. Anxiety, post-traumatic stress disorder and
depression are common psychological problems post discharge (4),
therefore using a test with a bleep is not appropriate. Therefore, the 6MWT is the most appropriate physical outcome measure to be used
with critical care patients post discharge
Instability of nonminimally coupled scalar fields in the spacetime of slowly rotating compact objects
Nonminimally coupled free scalar fields may be unstable in the spacetime of
compact objects. Such instability can be triggered by classical seeds or, more
simply, by quantum fluctuations giving rise to the so-called {\em vacuum
awakening effect}. Here, we investigate how the parameter space which
characterizes the instability is affected when the object gains some rotation.
For this purpose, we focus on the stability analysis of nonminimally coupled
scalar fields in the spacetime of slowly spinning matter shells.Comment: 11 pages, 6 figure
Classification of pain and its treatment at an intensive care rehabilitation clinic
Introduction
Treatment in an Intensive Care Unit (ICU) often necessitates uncomfortable
and painful procedures for patients throughout their admission.
There is growing evidence to suggest that chronic pain is
becoming increasingly recognised as a long term problem for patients
following an ICU admission [1]. Intensive Care Syndrome: Promoting
Independence and Return to Employment (InS:PIRE) is a five
week rehabilitation programme for patients and their caregivers after
ICU discharge at Glasgow Royal Infirmary. This study investigated the
incidence and location of chronic pain in patients discharged from ICU
and classified the analgesics prescribed according to the World Health
Organization analgesic
Methods
The InS:PIRE programme involved individual sessions for patients and
their caregivers with a physiotherapist and a pharmacist along with
interventions from medical, nursing, psychology and community services.
The physiotherapist documented the incidence and pain location
during the assessment. The pharmacist recorded all analgesic medications
prescribed prior to admission and at their clinic visit. The patientâs
analgesic medication was classified according to the WHO pain ladder
from zero to three, zero being no pain medication and three being
treatment with a strong opioid. Data collected was part of an evaluation
of a quality improvement initiative, therefore ethics approval was
waived.
Results
Data was collected from 47 of the 48 patients who attended the rehabilitation
clinic (median age was 52 (IQR, 44-57) median ICU LOS
was 15 (IQR 9-25), median APACHE II was 23 (IQR 18-27) and 32 of
the patients were men (67 %)). Prior to admission to ICU 43 % of patients
were taking analgesics and this increased to 81 % at the time
of their clinic visit. The number of patients at step two and above on
the WHO pain ladder also increased from 34 % to 56 %.
Conclusions
Of the patients seen at the InS:PIRE clinic two-thirds stated that they
had new pain since their ICU admission. Despite the increase in the
number and strength of analgesics prescribed, almost a quarter of
patients still complained of pain at their clinic visit. These results confirm
that pain continues to be a significant problem in this patient
group. Raising awareness in primary care of the incidence of chronic
pain and improving its management is essential to the recovery
process following an ICU admission
Quantum versus classical instability of scalar fields in curved backgrounds
General-relativistic stable spacetimes can be made unstable under the
presence of certain nonminimally coupled free scalar fields. In this paper, we
analyze the evolution of linear scalar-field perturbations in spherically
symmetric spacetimes and compare the classical stability analysis with a
recently discussed quantum field one. In particular, it is shown that vacuum
fluctuations lead to natural seeds for the unstable phase, whereas in the
classical framework the presence of such seeds in the initial conditions must
be assumed.Comment: 5 pages, 1 figure; condensed and revised version matching published
on
Synergy and Group Size in Microbial Cooperation
Microbes produce many molecules that are important for their growth and development, and the consumption of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Though the production of these public goods molecules has been studied intensely, little is known of how the benefits accrued and costs incurred depend on the quantity of public good molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density with a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether or not and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an âevolutionary trapâ which can stymie the establishment and maintenance of cooperation. By allowing density dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results for experimental design
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