5,192 research outputs found
Economic Evaluation of Organic and Inorganic Resources for Recapitalizing Soil Fertility in Smallholder Maize-based Cropping Systems of Central Kenya
Structural adjustments programs (SAPs) in the last two decades have eliminated all farm-support programs leading to low usage of fertilizers by Kenyan smallholders. One way of addressing this problem is use of organic nutrient resources. This paper examines their cost-effectiveness as capital investments in replenishment of Nitrogen (N), Phosphorus (P), Potassium (K) and soil organic matter (SOM) in smallholder, Maize-based cropping systems. On-farm trials were established in Maragwa and Kirinyaga Districts in 2003/04. Maize was planted in 3 replicates in randomised complete block design (RCBD) using different levels of organic and inorganic fertilizer resources. A blanket rate of 40kg P/ha was applied in all treatment except the control to increase organic N-utilization efficiency. The test crop was harvested, oven-dried and weighed. Net Present Values (NPV) were computed using Partial Budgeting Analysis Model. Increasing levels of inorganic N increased maize yields significantly (P<0.05). However, higher yields were necessary but not sufficient criteria to determine profitability of different treatments. Manure + 60 kg N/ha gave highest NPV (USD 564), Manure + 40kg N/ha gave second highest NPV (USD 511) in Maragwa District while Manure + 60kg N/ha gave highest NPV (USD 633) and Manure + 40kg N/ha second highest NPV (USD 618) in Kirinyaga District. These results suggested that higher N-levels were not necessarily the most economical. Use of organic resources with modest amounts of mineral fertilizers seemed more profitable and held the key to enhancement of nutrient budgets, food security and rural livelihoods.Natural resource capital, Net present values (NPV), Nutrient budgets, Smallholder farmers, Soil organic matter (SOM), Structural adjustment programs (SAPs), Crop Production/Industries, Land Economics/Use,
Persistent fluctuations in stride intervals under fractal auditory stimulation
Copyright @ 2014 Marmelat et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.Commission of the European Community and the Netherlands Organisation for Scientific Research
Parton Distributions for Event Generators
In this paper, conventional Global QCD analysis is generalized to produce
parton distributions optimized for use with event generators at the LHC. This
optimization is accomplished by combining the constraints due to existing
hard-scattering experimental data with those from anticipated cross sections
for key representative SM processes at LHC (by the best available theory) as
joint input to the global analyses. The PDFs obtained in these new type of
global analyses using matrix elements calculated in any given order will be
best suited to work with event generators of that order, for predictions at the
LHC. This is most useful for LO event generators at present. Results obtained
from a few candidate PDF sets (labeled as CT09MCS, CT09MC1 and CT09MC2) for LO
event generators produced in this way are compared with those from other
approaches.Comment: 35 pages, 19 figures, and 4 table
Pre-hospital intubation by anaesthesiologists in patients with severe trauma: an audit of a Norwegian helicopter emergency medical service
<p>Abstract</p> <p>Background</p> <p>Anaesthesiologists are airway management experts, which is one of the reasons why they serve as pre-hospital emergency physicians in many countries. However, limited data are available on the actual quality and safety of anaesthesiologist-managed pre-hospital endotracheal intubation (ETI). To explore whether the general indications for ETI are followed and what complications are recorded, we analysed the use of pre-hospital ETI in severely traumatised patients treated by anaesthesiologists in a Norwegian helicopter emergency medical service (HEMS).</p> <p>Methods</p> <p>A retrospective audit of prospectively registered data concerning patients with trauma as the primary diagnosis and a National Committee on Aeronautics score of 4 - 7 during the period of 1994-2005 from a mixed rural/urban Norwegian HEMS was performed.</p> <p>Results</p> <p>Among the 1255 cases identified, 238 successful pre-hospital ETIs out of 240 attempts were recorded (99.2% success rate). Furthermore, we identified 47 patients for whom ETI was performed immediately upon arrival to the emergency department (ED). This group represented 16% of all intubated patients. Of the ETIs performed in the ED, 43 patients had an initial Glasgow Coma Score (GCS) < 9. Compared to patients who underwent ETI in the ED, patients who underwent pre-hospital ETI had significantly lower median GCS (3 (3-6) vs. 6 (4-8)), lower revised trauma scores (RTS) (3.8 (1.8-5.9) vs. 5.0 (4.1-6.0)), longer mean scene times (23 ± 13 vs. 11 ± 11 min) and longer mean transport times (22 ± 16 vs. 13 ± 14 min). The audit also revealed that very few airway management complications had been recorded.</p> <p>Conclusions</p> <p>We found a very high success rate of pre-hospital ETI and few recorded complications in the studied anaesthesiologist-manned HEMS. However, a substantial number of trauma patients were intubated first on arrival in the ED. This delay may represent a quality problem. Therefore, we believe that more studies are needed to clarify the reasons for and possible clinical consequences of the delayed ETIs.</p
A consensus-based template for uniform reporting of data from pre-hospital advanced airway management
Background: Advanced airway management is a critical intervention that can harm the patient if performed poorly. The available literature on this subject is rich, but it is difficult to interpret due to a huge variability and poor definitions. Several initiatives from large organisations concerned with airway management have recently propagated the need for guidelines and standards in pre-hospital airway management. Following the path of other initiatives to establish templates for uniform data reporting, like the many Utstein-style templates, we initiated and carried out a structured consensus process with international experts to establish a set of core data points to be documented and reported in cases of advanced pre-hospital airway management. Methods: A four-step modified nominal group technique process was employed. Results: The inclusion criterion for the template was defined as any patient for whom the insertion of an advanced airway device or ventilation was attempted. The data points were divided into three groups based on their relationship to the intervention, including system-, patient-, and postintervention variables, and the expert group agreed on a total of 23 core data points. Additionally, the group defined 19 optional variables for which a consensus could not be achieved or the data were considered as valuable but not essential. Conclusion: We successfully developed an Utstein-style template for documenting and reporting pre-hospital airway management. The core dataset for this template should be included in future studies on pre-hospital airway management to produce comparable data across systems and patient populations and will be implemented in systems that are influenced by the expert panel.publishedVersio
Rotation of electromagnetic fields and the nature of optical angular momentum
The association of spin and orbital angular momenta of light with its polarization and helical phase fronts is now well established. The problems in linking this with electromagnetic theory, as expressed in Maxwell's equations, are rather less well known. We present a simple analysis of the problems involved in defining spin and orbital angular momenta for electromagnetic fields and discuss some of the remaining challenges. Crucial to our investigation is the duplex symmetry between the electric and magnetic fields
Pre-hospital advanced airway management by anaesthesiologists: Is there still room for improvement?
Revisiting the value of pre-hospital tracheal intubation: an all time systematic literature review extracting the Utstein airway core variables
Introduction: Although tracheal intubation (TI) in the pre-hospital setting is regularly carried out by emergency medical service (EMS) providers throughout the world, its value is widely debated. Heterogeneity in procedures, providers, patients, systems and stated outcomes, and inconsistency in data reporting make scientific reports difficult to interpret and compare, and the majority are of limited quality. To hunt down what is really known about the value of pre-hospital TI, we determined the rate of reported Utstein airway variables (28 core variables and 12 fixed-system variables) found in current scientific publications on pre-hospital TI. Methods: We performed an all time systematic search according to the PRISMA guidelines of Medline and EMBASE to identify original research pertaining to pre-hospital TI in adult patients. Results: From 1,076 identified records, 73 original papers were selected. Information was extracted according to an Utstein template for data reporting from in-the-field advanced airway management. Fifty-nine studies were from North American EMS systems. Of these, 46 (78%) described services in which non-physicians conducted TI. In 12 of the 13 non-North American EMS systems, physicians performed the pre-hospital TI. Overall, two were randomised controlled trials (RCTs), and 65 were observational studies. None of the studies presented the complete set of recommended Utstein airway variables. The median number of core variables reported was 10 (max 21, min 2, IQR 8-12), and the median number of fixed system variables was 5 (max 11, min 0, IQR 4-8). Among the most frequently reported variables were “patient category” and “service mission type”, reported in 86% and 71% of the studies, respectively. Among the least-reported variables were “co-morbidity” and “type of available ventilator”, both reported in 2% and 1% of the studies, respectively. Conclusions: Core data required for proper interpretation of results were frequently not recorded and reported in studies investigating TI in adults. This makes it difficult to compare scientific reports, assess their validity, and extrapolate to other EMS systems. Pre-hospital TI is a complex intervention, and terminology and study design must be improved to substantiate future evidence based clinical practice
The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium
The glauconite-rich Diest Formation in central and north Belgium contains sands in the Campine subsurface and the hilly Hageland area that can be distinguished from each other. The Hageland Diest Sands member contains no stratigraphically relevant fossils while in the Campine subsurface dinoflagellate cysts are common and show a stratigraphic range covering the entire Tortonian stage. K-Ar dates were determined for glauconite from 13 selected samples spread over both areas. A glauconite date corresponding to the earliest Tortonian indicates newly formed glauconite was incorporated into a greensand at the base of the Diest Formation in the central Campine area. All other dates point at reworked glauconite and can be organized in two groups, one reflecting a Burdigalian age and another reflecting a Langhian age. These data and the thickness and glauconite content of the Diest Formation imply massive reworking of older Miocene deposits.
The paleogeographic implications of these data lead to the tentative recognition of two Tortonian sedimentary sequences. An older one corresponding to dinoflagellate biochron DN8 comprises the Deurne Member, part of the Dessel Member, the Hageland Diest member, the eastern Campine Diest member and some basal sands of the Diest Formation in the central Campine. A younger sequence corresponding to dinoilagellate biochrons DN9 and 10 was strongly influenced by the prograding proto-Rhine delta front in the Roer Valley Graben to the northeast. The subsiding Campine basin was filled from east to west during this second cycle
Risk assessment of pre-hospital trauma airway management by anaesthesiologists using the predictive Bayesian approach
<p>Abstract</p> <p>Introduction</p> <p>Endotracheal intubation (ETI) has been considered an essential part of pre-hospital advanced life support. Pre-hospital ETI, however, is a complex intervention also for airway specialist like anaesthesiologists working as pre-hospital emergency physicians. We therefore wanted to investigate the quality of pre-hospital airway management by anaesthesiologists in severely traumatised patients and identify possible areas for improvement.</p> <p>Method</p> <p>We performed a risk assessment according to the predictive Bayesian approach, in a typical anaesthesiologist-manned Norwegian helicopter emergency medical service (HEMS). The main focus of the risk assessment was the event where a patient arrives in the emergency department without ETI despite a pre-hospital indication for it.</p> <p>Results</p> <p>In the risk assessment, we assigned a high probability (29%) for the event assessed, that a patient arrives without ETI despite a pre-hospital indication. However, several uncertainty factors in the risk assessment were identified related to data quality, indications for use of ETI, patient outcome and need for special training of ETI providers.</p> <p>Conclusion</p> <p>Our risk assessment indicated a high probability for trauma patients with an indication for pre-hospital ETI not receiving it in the studied HEMS. The uncertainty factors identified in the assessment should be further investigated to better understand the problem assessed and consequences for the patients. Better quality of pre-hospital airway management data could contribute to a reduction of these uncertainties.</p
- …