48 research outputs found
Technique for validating remote sensing products of water quality
Remote sensing of water quality is initiated as an additional part of the on going activities of the EAGLE2006 project.
Within this context intensive in-situ and airborne measurements campaigns were carried out over the Wolderwijd and
Veluwemeer natural waters. However, in-situ measurements and image acquisitions were not simultaneous. This poses
some constraints on validating air/space-borne remote sensing products of water quality. Nevertheless, the detailed insitu
measurements and hydro-optical model simulations provide a bench mark for validating remote sensing products.
That is realized through developing a stochastic technique to quantify the uncertainties on the retrieved aquatic inherent
optical properties (IOP).
The output of the proposed technique is applied to validate remote sensing products of water quality. In this processing
phase, simulations of the radiative transfer in the coupled atmosphere-water system are performed to generate spectra
at-sensor-level. The upper and the lower boundaries of perturbations, around each recorded spectrum, are then modelled
as function of residuals between simulated and measured spectra. The perturbations are parameterized as a function of
model approximations/inversion, sensor-noise and atmospheric residual signal. All error sources are treated as being of
stochastic nature. Three scenarios are considered: spectrally correlated (i.e. wavelength dependent) perturbations,
spectrally uncorrelated perturbations and a mixed scenario of the previous two with equal probability of occurrence.
Uncertainties on the retrieved IOP are quantified with the relative contribution of each perturbation component to the
total error budget of the IOP.
This technique can be used to validate earth observation products of water quality in remote areas where few or no in–
situ measurements are available
Synthesis of layered silicon-graphene hetero-structures by wet jet milling for high capacity anodes in Li-ion batteries
While silicon-based negative electrode materials have been extensively studied, to develop high capacity lithium-ion batteries (LIBs), implementing a large-scale production method that can be easily transferred to industry, has been a crucial challenge. Here, a scalable wet-jet milling method was developed to prepare a silicon-graphene hybrid material to be used as negative electrode in LIBs. This synthesized composite, when used as an anode in lithium cells, demonstrated high Li ion storage capacity, long cycling stability and high-rate capability. In particular, the electrode exhibited a reversible discharge capacity exceeding 1763 mAh g−1 after 450 cycles with a capacity retention of 98% and a coulombic efficiency of 99.85% (with a current density of 358 mA g−1). This significantly supersedes the performance of a Si-dominant electrode structures. The capacity fade rate after 450 cycles was only 0.005% per cycle in the 0.05–1 V range. This superior electrochemical performance is ascribed to the highly layered, silicon-graphene porous structure, as investigated via focused ion beam in conjunction with scanning electron microscopy tomography. The hybrid electrode could retain 89% of its porosity (under a current density of 358 mA g−1) after 200 cycles compared with only 35% in a Si-dominant electrode. Moreover, this morphology can not only accommodate the large volume strains from active silicon particles, but also maintains robust electrical connectivity. This confers faster transportation of electrons and ions with significant permeation of electrolyte within the electrode. Physicochemical characterisations were performed to further correlate the electrochemical performance with the microstructural dynamics. The excellent performance of the hybrid material along with the scalability of the synthesizing process is a step forward to realize high capacity/energy density LIBs for multiple device applications
Home birth and barriers to referring women with obstetric complications to hospitals: a mixed-methods study in Zahedan, southeastern Iran
<p>Abstract</p> <p>Background</p> <p>One factor that contributes to high maternal mortality in developing countries is the delayed use of Emergency Obstetric-Care (EmOC) facilities. The objective of this study was to determine the factors that hinder midwives and parturient women from using hospitals when complications occur during home birth in Sistan and Baluchestan province, Iran, where 23% of all deliveries take place in non- hospital settings.</p> <p>Methods</p> <p>In the study and data management, a mixed-methods approach was used. In the quantitative phase, we compared the existing health-sector data with World Health Organization (WHO) standards for the availability and use of EmOC services. The qualitative phase included collection and analysis of interviews with midwives and traditional birth attendants and twenty-one in-depth interviews with mothers. The data collected in this phase were managed according to the principles of qualitative data analysis.</p> <p>Results</p> <p>The findings demonstrate that three distinct factors lead to indecisiveness and delay in the use of EmOC by the midwives and mothers studied. Socio-cultural and familial reasons compel some women to choose to give birth at home and to hesitate seeking professional emergency care for delivery complications. Apprehension about being insulted by physicians, the necessity of protecting their professional integrity in front of patients and an inability to persuade their patients lead to an over-insistence by midwives on completing deliveries at the mothers' homes and a reluctance to refer their patients to hospitals. The low quality and expense of EmOC and the mothers' lack of health insurance also contribute to delays in referral.</p> <p>Conclusions</p> <p>Women who choose to give birth at home accept the risk that complications may arise. Training midwives and persuading mothers and significant others who make decisions about the value of referring women to hospitals at the onset of life-threatening complications are central factors to increasing the use of available hospitals. The hospitals must be safe, comfortable and attractive environments for parturition and should give appropriate consideration to the ethical and cultural concerns of the women. Appropriate management of financial and insurance-related issues can help midwives and mothers make a rational decision when complications arise.</p
A systematic review of operating room ventilation
Ventilation systems are the primary way of eliminating airborne pathogenic particles in an operating room (OR). However, such systems can be complex due to factors such as different surgical instruments, diverse room sizes, various staff counts, types of clothing used, different surgical types and duration, medications, and patient conditions. OR ventilation should provide a thermally comfortable environment for the surgical staff team members while preventing the patient from suffering from any extreme hypothermia. Many technical, logistical, and ethical implications need to be considered in the early stage of designing a ventilation system for an OR. Years of research and a significant number of publications have highlighted the controversy and disagreement among infection specialists, design engineers, and ventilation experts in this context. This review article aims to provide a good understanding of OR ventilation systems in the context of air quality and infection control from existing research and provide multidimensional insights for appropriate design and operation of the OR. To this end, we have conducted a systematic review of the literature, covering 253 articles in this context. Systematic review and meta-analyses were used to map the evidence and identify research gaps in the existing clinical, practical, and engineering knowledge. The present study is categorized into six research focuses: ventilation system, thermal comfort, staff work practice and obstacles, door operation and passage, air cleaning technology, emission rate, and clothing systems. In the conclusion, we summarize the key limitations of the existing studies and insights for future research direction
Comparative study of the implementation of tin and titanium oxide nanoparticles as electrodes materials in Li-ion batteries
Transition metal oxides potentially present higher specific capacities than the current anodes based on carbon, providing an increasing energy density as compared to commercial Li-ion batteries. However, many parameters could influence the performance of the batteries, which depend on the processing of the electrode materials leading to different surface properties, sizes or crystalline phases. In this work a comparative study of tin and titanium oxide nanoparticles synthesized by different methods, undoped or Li doped, used as single components or in mixed ratio, or alternatively forming a composite with graphene oxide have been tested demonstrating an enhancement in capacity with Li doping and better cyclability for mixed phases and composite anodes
Ups and downs of addiction harm reduction in Iran: key insights and implications for harm reduction policy and policing
Abstract Drug use is a critical behavioral disorder or a delinquency behavior (in the judiciary system's words) that comes with a burden at multiple levels: individual, community, public, and global. These social structures apply different interventions to reduce this burden in their field. Given the society as a whole, these structures must be harmonious and synergistic to optimize these endeavors in terms of cost–benefit. In practice, however, reducing the burden of addiction is followed by conflicting approaches by different organizations, in terms such as “eradicating drugs,” “eliminating drug users,” “obliterating addiction,” and ultimately, drug use harm reduction. In the harm reduction philosophy, drug use is recognized as an inescapable fact in human societies, and tries to control its personal and public consequences in different dimensions (health, economic, and social). Therefore, this approach includes broad measures such as: changing the pattern of consumption (from high-risk substances to less dangerous substances) through modification of the laws and law enforcement measures, distributing disposable syringes to prevent HIV transmission, providing basic life needs such as shelter for street-based drug users to reduce the social consequences like homelessness, prescribing substitute agonists to reduce the committing crime to obtain the needed drugs, and even the drug court program, which prevents the exacerbation of complications in a person with a chronic and relapsing disorder, due to the imposition of inappropriate sentences (like incarceration in unacceptable conditions). It is contrary to the approaches that aim to reduce the drug supply rate and drug use incidence and prevalence to zero. As a result of the conflict of interests, goals discrepancies, and differences in organizational culture, these approaches may contrast with each other. We see this in the harm reduction between the health system and law enforcement. Different factors affect the harmony or conflict between these two structures. This article addresses the impact of ideology, social conditions, and bureaucratic administration on the relationship between the health system and the police in drug use harm reduction in Iran
GEOSPATIAL TOOLS FOR PREVENTION OF URBAN FLOODS CASE STUDY: RIVER OF EL MALEH (CITY OF MOHAMMEDIA – MOROCCO)
Today, the prevention and the risk management occupy an important part of public policy activities and are considered as major components in the process of sustainable development of territories. Due to the expansion of IT processes, in particular the geomatics sciences, decision-makers are increasingly requesting for digital tools before, during and after the risks of natural disasters. Both, the geographic information system (GIS) and the remote sensing are considered as geospatial and fundamental tools which help to understand the evolution of risks, to analyze their temporality and to make the right decisions.
The historic events (on 1996, 2002 and 2010) which struck the city of Mohammedia and having caused the consequent damage to vital infrastructure and private property, require a thorough and rational analyze to benefit from it and well manage the floods phenomena.
This article present i) the contribution of the geospatial tools for the floods simulation of Oued of el Maleh city at various return periods. These tools allow the demarcation of flood-risk areas and so to make floods simulations in several scenarios (decadal flood, 20-year flood, 50-year flood, 100-year flood, 500-year flood & also millennial flood) and besides (ii) present a synthesis map combining the territorial stakes superposed on the flood scenarios at different periods of return