Large-scale Impact Research Articles

Drainage potential of degraded railway ballast considering initial gradation and intrusion of external fine materials

The aggregate in the ballast layer of the railway track structure degrades due to the splitting of single particles and the abrasion of the angular corners, resulting in a ballast course comprised of degraded aggregate with a lower drainage potential. In the present study, the hydraulic conductivity of clean, degraded and clay-fouled degraded ballast specimens was evaluated considering the initial particle size distribution of aggregate and the degradation mechanism to investigate the permeability of ballast fouled by both internal and external factors. First, degraded ballast aggregate was generated by using a large-scale impact loading testing apparatus. Then, a large-scale constant head permeability test was performed to estimate the hydraulic conductivity of degraded ballast aggregate contaminated with clay. Based on the obtained results, the flow regime through extremely degraded ballast remained between a completely turbulent regime (observed in the case of clean ballast) and a laminar flow regime. Darcy’s law was shown to be valid for degraded aggregate samples contaminated with clay. While the degradation of the aggregate had the expected effect of reducing hydraulic conductivity, the abrasion of asperities was shown to have an even greater impact on hydraulic conductivity. Also, the further degradation of aggregate under impact loading was shown to accelerate the reduction in the permeability of clay-fouled degraded ballast to an unacceptable extent.

The need for impact evaluation in electricity access research

Universal household electrification is a key component of the United Nations Sustainable Development Goals, but the evidence base for social and economic impacts of electricity access remains unclear. Here we report results from a systematic review of impact evaluations of household electrification based on five key outcome measures. We only find 31 studies that conduct statistical hypothesis tests to assess impacts. Among these, seven draw on a randomized experiment designed for causal inference. The randomized experimental studies generate fewer positive results than observational or quasi-experimental studies, such as correlational, instrumental variable, and difference-in-differences designs. These results call for a reassessment of what we know about the impacts of household electrification. They also call for major investment in impact evaluation of electricity access using randomized controlled trials, with a particular focus on when and how energy access interventions can furnish large benefits to their intended beneficiaries. Large-scale impact evaluations using experimental methods will require close collaboration between policymakers and researchers.

Examining the impact of medical legal partnerships in improving outcomes on the HIV care continuum: rationale, design and methods

BackgroundOver the past two decades, we have seen a nationwide increase in the use of medical-legal partnerships (MLPs) to address health disparities affecting vulnerable populations. These partnerships increase medical teams’ capacity to address social and environmental threats to patients’ health, such as unsafe housing conditions, through partnership with legal professionals. Despite expansions in the use of MLP care models in health care settings, the health outcomes efficacy of MLPs has yet to be examined, particularly for complex chronic conditions such as HIV.MethodsThis on-going mixed-methods study utilizes institutional case study and intervention mapping methodologies to develop an HIV-specific medical legal partnership logic model. Up-to-date, the organizational qualitative data has been collected. The next steps of this study consists of: (1) recruitment of 100 MLP providers through a national survey of clinics, community-based organizations, and hospitals; (2) in-depth interviewing of 50 dyads of MLP service providers and clients living with HIV to gauge the potential large-scale impact of legal partnerships on addressing the unmet needs of this population; and, (3) the development of an MLP intervention model to improve HIV care continuum outcomes using intervention mapping.DiscussionThe proposed study is highly significant because it targets a vulnerable population, PLWHA, and consists of formative and developmental work to investigate the impact of MLPs on health, legal, and psychosocial outcomes within this population. MLPs offer an integrated approach to healthcare delivery that seems promising for meeting the needs of PLWHA, but has yet to be rigorously assessed within this population.

Life cycle analysis of an innovative fluidized bed degreasing process

Abstract The present work focuses on a technical, economic and environmental evaluation of an alternative technology for the industrial washing of metal components. In particular, the Fluidized Bed Degreasing is presented as a valid alternative for the traditional ultrasonic washing technology. This technique involves the use of a fluidized bed of glass particles, stirred inside the bed; the component to be degreased is immersed in the latter and the impact of the particles on its surface determines the removal of the lightly adhered contaminants. The experimental results obtained on copper frames for the electronics industry have demonstrated its technological validity, as well as a large-scale economic and environmental impact study has verified the possibility of replacing the traditional technology on an industrial level. In fact, a saving of over 75% in the total production costs has been estimated, ensuring a production capacity comparable to industrial degreasing machines. Finally, the Life Cycle Analysis showed that the developed technology is over 50 times much more environmental friendly than the traditional one, ensuring lower impact potentials, due to the recovery of the processing oil, but above all to the lack of chemical solutions disposal.

Motivations behind citizen aid: Norwegian initiatives in The Gambia

Little is known about citizen aid initiatives originating in Norway, and they are not recognised as part of the official Norwegian development aid. Citizen aid initiatives are personal and small, and by themselves they do not raise large sums of money, nor do they individually have a large-scale development impact. But collectively, their influence on sponsors in Norway and on aid beneficiaries in the Global South might be substantial. Through qualitative interviews, this study explores the motivations of Norwegian founders of citizen aid initiatives, who run small development projects in The Gambia. The study finds that they are motivated by the very characteristics of these citizen aid initiatives which set them apart from formal development organisations. These include the initiatives’ small size, which allows for a personal closeness to and control over the projects. These features are often interconnected with motivations stemming from the founders’ personal experiences. The study finds that, inasmuch as the founders see the need for beneficiaries to be supported, they also experience a need to help themselves. The founders’ identities, as helpers and givers, are both formed and continually reinforced by their personal involvement in this specific type of aid work.

Changing dynamical control of early Asian summer monsoon in the mid-1990s

The seasonal evolution of the upper tropospheric South Asian high follows and influences underlying summer monsoon advancement. A strong connection between the South Asian high and westerly perturbation to the north suggests further planetary-scale dynamical control of the monsoon. In the mid-1990s, a clear location shift of the South Asian high in May–June was noted and was observed in fewer (more) frequencies of the high centers over the Indochina Peninsula (Iranian Plateau). Continental confinement of monsoonal circulation and precipitation was observed during 1995–2010, as opposed to larger-scale development in the Asia–Pacific region during 1979–1994. In view of early-summer monsoon evolution, a westward shifting and faster migration of the South Asian high may imply increased control of the midlatitude dynamics. By contrast, the convection over the tropical Western North Pacific (WNP) has an opposite and delayed contribution to monsoon advancement. After the mid-1990s than it had been previously, the midlatitude jet stream largely weakened over northern Africa and the East Asia–Pacific region, corresponding to an increase in the upper tropospheric geopotential heights north of the jet stream. Climate model experiments further reveal that the warming over Europe–Asia and temperature change in the North Atlantic can result in the change in midlatitude perturbations and the monsoon evolution in the mid-1990s, suggesting large-scale and dynamic impact on monsoon climatology.

Design Guidelines for MEMS Optical Accelerometer based on Dependence of Sensitivities on Diaphragm Dimensions

This work deals in specifying the design considerations while constructing a Micro Electro Mechanical Systems (MEMS) optical accelerometer working on capacitive sensing technique. Sensitivity is one of the most demanded characteristics of any sensor. The sensor considered is a MEMS capacitive accelerometer in which both displacement and capacitance are the primary sensing characteristics. This differential capacitive accelerometer causes change in displacement due to applied acceleration and further produces change in capacitance. So, the main focus in this work is to improve or select the suitable diaphragm dimensions of the differential capacitor in order to get optimal capacitive and displacement sensitivity. This is done for an Optical MEMS (MOEMS) based sensor where slight change has a large-scale impact. The electrical signal is converted to optical by adding an Optical Interferometer. Mach–Zehnder Interferometer (MZI) is used to carry out the intensity modulation which also gives protection in inflammable surroundings. This makes the system suitable for working in high temperature regions.

A new discrete element model for simulating a flexible ring net barrier under rockfall impact comparing with large-scale physical model test data

Flexible barriers are one of the effective mitigation measures to intercept high-energy falling rocks in mountainous areas, owing to its high ductility and excellent energy dissipation performance. This paper presents a newly developed flexible ring net barrier model based on the discrete element method (DEM) to simulate the rockfall impact on a flexible barrier. All the input mechanical parameters were calibrated by means of laboratory tests. The capabilities of the numerical model are evaluated by comparing the results from novel designed large-scale physical model impact tests. It is found that the new discrete element model is able to reproduce the behavior of a ring net barrier under rockfall impact. A good agreement with experimental data can be found regarding to boulder velocities, net elongations and tensile forces developed between ring net elements. In addition, the effects of boulder size, impact position, barrier inclination, and barrier initial slack on barrier response in a parametric study are investigated. The results from this study provide useful guidance for future design and optimization of rockfall barriers in engineering practice.

Evaluating patterns of utilization of gene signature panels and impact on treatment patterns in patients with ductal carcinoma in situ of the breast

BackgroundBroad patterns of use of the gene signature panel Oncotype DX DCIS and its large-scale impact on postoperative administration of radiation therapy in women with ductal carcinoma in situ of the breast remain unclear. This study sought to evaluate the patterns of use of this gene signature panel in women with ductal carcinoma in situ and the impact of these tools on postoperative radiation therapy administration. MethodsThe National Cancer Database was queried for women with ductal carcinoma in situ treated with breast-conserving therapy who had information regarding whether a gene signature panel was performed between 2010 and 2015. Demographic characteristics, the characteristics of their ductal carcinoma in situ, and whether they received postoperative radiation therapy were compared among patients who did have a gene signature panel performed and those who did not. Patterns of radiation therapy administration were also evaluated based on the recurrence risk score by the gene signature panel. ResultsGene signature panel use increased over time, with a sharp increase in utilization occurring in 2015 (8.0% in 2015 vs 4.4% in 2014, P < .001). Patients with estrogen receptor–positive ductal carcinoma in situ were somewhat more likely to have a gene signature panel ordered (3.9% estrogen receptor positive vs 1.7% estrogen receptor negative, P < .001), as were patients with lower-grade ductal carcinoma in situ (4.5% grade I/II vs 3.1% grade III, P < .001). Gene signature panel utilization was associated with a decrease in the administration of postoperative radiation therapy (48.6% gene signature panel vs 83.4% no gene signature panel, P < .001). Among patients in whom a gene signature panel was performed, postoperative radiation therapy was administered in 81.9%, 72.0%, and 35.9% of patients with high-, intermediate-, and low-recurrence scores, respectively. ConclusionGene signature panel use in patients with ductal carcinoma in situ has increased over time and is more commonly used in women with lower-risk, clinicopathologic features to determine the magnitude of benefit afforded by radiation therapy. Gene signature panel use is associated with decreased rates of postoperative radiation therapy administration, particularly among patients with scores suggesting a low rate of recurrence.

Improved performance of ballasted tracks under impact loading by recycled rubber mats

Ballasted tracks at transition locations such as approaches to bridges and road crossings experience increasing degradation and deformation due to dynamic and high impact forces, a key factor that decreases the stability and longevity of railroads. One solution to minimise ballast degradation at the transition zones is using rubber energy absorbing drainage sheets (READS) manufactured from recycled tyres. When placed beneath the ballast layer, READS distributes the load over wider area and attenuate of the load over a longer duration thus decreasing maximum stress, apart from reducing the energy transferred to the ballast and other substructure components. Subsequently, the track substructure experiences less plastic deformation and degradation. These mats also provide an environmentally friendly and cost-effective alternative. In this study, a series of large-scale drop hammer impact tests was carried out to investigate how effectively the READS could attenuate impact loads and help mitigate ballast deformation and degradation. Soft and stiff subgrade were used to investigate the load-deformation response of ballast (with and without READS), subjected to impact loads from a hammer dropped from various heights (hd = 100–250 mm). Laboratory test results show that the inclusion of READS helps to reduce the dynamic impact load transferred to the ballast layer resulting in significantly less permanent deformation and degradation of ballast, apart from significant attenuation of load magnitude and vibration to the underlying subgrade layers.

Technical objects' ecological efficiency indicators control

Traditional automatic control systems do not solve the task of limiting the harmful effects of technical objects on the environment. The problem is to increase the effectiveness of means of its protection against the harmful effects of industry. Relevant is the use of indicators of environmental performance of technical objects as controlled parameters. A new approach to the control of technical objects is proposed. As the main control parameter it proposed to adopt the level of their ecological efficiency. Complicating circumstances of solving the problem is the insufficient knowledge of the factors of harmful effects on objects of living nature, their intensity, interrelation, mechanism, strength, and dynamics of exposure. Improving the economic efficiency of technical objects leads to an increase in their ecological efficiency. The solution to the problem is facilitated by the fact that traditional ACS should be left in action, adding to them an ecological efficiency control component. Heat-powerengineering has a large impact on the environment through emissions and discharges of harmful substances and heat. To give to ASC the functions of controlling the ecological efficiency of the boiler (for SOy emission), it is necessary to apply an additional, new control loop - regulator of SOy concentration in furnace gases. An urgent task in the use of direct control of the ecological efficiency of boiler-furnace systems is the development and production of physical quantity sensors, reflecting the level of aggressiveness of the source of hazard, working in real time. Direct control of indicators of ecological efficiency is much easier in other branches of industry, in particular, in its food branch, where objects do not have a large-scale complex negative impact on the environment.

A multicriteria proposal for large-scale solar photovoltaic impact assessment

ABSTRACTLarge-scale photovoltaic (LSPV) may cause significant changes in the environment and lead to detrimental impacts on the natural and anthropic environments. First, this paper reviews the scholarly literature to collect data regarding the different environmental impacts occurring during LSPV installation and operation. Secondly, methods used in the Environmental Impact Assessment (EIA) for LSPV are evaluated through a sample of 20 EIAs. This shows that there are flaws in the methodology used in the EIAs that support environmental licensing of LSPV. In this context, this work proposes a multicriteria approach that aims to convey the main environmental and socio-economic aspects of LSPV and assess impact magnitude and importance. The method is built on the needs to improve EIA for the licensing of solar projects in Brazil. The model offers a structured approach that incorporates detailed criteria that reflect direct and indirect impacts of both terrestrial and floating PV and is designed to provide the assessment magnitude and estimate scenarios according to different stakeholder’s views.

Dietary Patterns: A New Therapeutic Approach for Depression?

The field of nutritional psychiatry is a fast-growing one. Although initially, it focused on the effects of vitamins and micronutrients in mental health, in the last decade, its focus also extended to the dietary patterns. The possibility of a dietary cost-effective intervention in the most common mental disorder, depression, cannot be overlooked due to its potential large-scale impact. A classic review of the literature was conducted, and studies published between 2010 and 2018 focusing on the impact of dietary patterns in depression and depressive symptoms were included. We found 10 studies that matched our criteria. Most studies showed an inverse association between healthy dietary patterns, rich in fruits, vegetables, lean meats, nuts and whole grains, and with low intake of processed and sugary foods, and depression and depressive symptoms throughout an array of age groups, although some authors reported statistical significance only in women. While most studies were of cross-sectional design, making it difficult to infer causality, a randomized controlled trial presented similar results. The association between dietary patterns and depression is now well-established, although the exact etiological pathways are still unknown. Dietary intervention, with the implementation of healthier dietary patterns, closer to the traditional ones, can play an important role in the prevention and adjunctive therapy of depression and depressive symptoms. More large-scale randomized clinical trials need to be conducted, in order to confirm the association between high-quality dietary patterns and lower risk of depression and depressive symptoms.

How is implementation research applied to advance health in low-income and middle-income countries?

This paper examines the characteristics of implementation research (IR) efforts in low-income and middle-income countries (LMICs) by describing how key IR principles and concepts have been used in published health...

Equine Fecal Microbiota Changes Associated With Anthelmintic Administration

The gastrointestinal microbiota (GIM) plays an essential role in maintaining intestinal homeostasis with disruptions having profound effects on the wellbeing of the host animal. Parasitic infection is a long-standing issue for the equine industry, and the use of anthelmintic drugs for parasite control has long been standard practice. The impact of anthelmintic treatment on the GIM in healthy horses is not well known. This study evaluated the hypothesis that anthelmintic administration will alter the equine fecal microbiota in horses without an observed helminth infection. Ten horses were treated with a single dose of QUEST PLUS (active ingredients: Moxidectin and Praziquantel) (Zoetis), and fecal samples were collected before and after treatment. Amplicon sequencing data were quality filtered, processed, and analyzed using QIIME2. Anthelmintic treatment corresponded with a small but significant decrease in alpha diversity (P-value < .05). Analysis of taxonomic abundances before and after treatment with DESeq2 identified 21 features that were significantly different after treatment (Padj-value < .05). Differences in beta diversity associated with treatment were not significant and potentially suggest factors unique to the individual may play an essential role in the specific responses observed. Overall, the present study does not indicate a broad, large-scale impact on the GIM after anthelmintic treatment. The results do, however, suggest the potential of individualized responses that are based instead on host factors. Identification of these factors and investigation of their impact on the host/microbiota relationship will contribute significantly to our understanding of the role of the microbiome in horse health.

Effects of particle size and cushioning thickness on the performance of rock-filled gabions used in protection against boulder impact

A gabion is one of the most commonly used cushioning layers to shield protection structures against boulders entrained in debris flow. Despite the prevalence of gabions, their cushioning performance is highly variable because of the wide range of rock sizes and cushioning thicknesses that are recommended in the literature. Correspondingly, the dynamic response of gabion cushioning layers varies dramatically. In this study, large-scale pendulum impact tests were used to calibrate a discrete element model. Subsequently, a parametric study was carried out to discern the effects of particle size and cushioning thickness on the impact load and transmitted load exerted by a boulder. Results reveal that as the particle size in the cushioning layer decreases, the force chains collapse more easily, and the expansion angle of strain energy increases. To optimize the performance of a gabion cushioning layer, practitioners should reduce the size of the particles to a normalized particle radius of about 0.1. A normalized particle radius less than 0.2 ensures that the expansion angle of strain energy is large enough — greater than 45° in this study — so as to enable load spreading across the barrier. To eliminate the effects of energy reflecting off the barrier and directed back to the point of impact, which augments the impact load, the cushioning layer thickness should be greater than three times the radius of the boulder.

Enhancing governance and strengthening advocacy for policy change of large Collective Impact initiatives

Nutrition issues are increasingly being addressed through global partnerships and multi‐sectoral initiatives. Ensuring effective governance of these initiatives is instrumental for achieving large‐scale impact. The Collective Impact (CI) approach is an insightful framework that can be used to guide and assess the effectiveness of this governance. Despite the utility and widespread use of this approach, two gaps are identified: a limited understanding of the implications of expansion for an initiative operating under the conditions of CI and a lack of attention to advocacy for policy change in CI initiatives. In this paper, a case study was undertaken in which the CI lens was applied to the advocacy efforts of Alive & Thrive (A&T), UNICEF and partners. The initiative expanded into a regional movement and achieved meaningful policy changes in infant and young child feeding policies in seven countries in Southeast Asia. These efforts are examined in order to address the two gaps identified in the CI approach. The objectives of the paper are (a) to examine the governance of this initiative and the process of expansion from a national to a regional, multilayered initiative, with attention to challenges, adaptations, and key elements, and (b) to compare advocacy in the A&T–UNICEF initiative and in typical CI initiatives and gain insight into how the practice of advocacy for policy change can be strengthened in CI initiatives.

How does a large-scale disaster impact on the used-car market? A case study of the Great East Japan Earthquake and Tsunami

The aim of this paper is to examine how a large-scale natural disaster impacts on the used-car market. This paper particularly tries to clarify what type of cars and what kinds of car features were demanded in damaged areas and when. We conduct a case study on the Great East Japan Earthquake and Tsunami of 2011 and compare the used-car prices in damaged areas and non-damaged areas. The finding of this paper is that after the Great East Japan Earthquake and Tsunami, cheaper used cars and used cars with larger carrying capacity were needed in damaged areas. In addition, we find that car types which people in the damaged areas needed depend on the phase of recovery.

Herbivory of oil-exposed submerged aquatic vegetation Ruppia maritima.

Oil spills, such as the Deepwater Horizon spill in the Gulf of Mexico, have the potential to dramatically alter coastal food webs through a variety of mechanisms. While oil can have direct impacts on primary producers through toxicity and shading, it is also possible that more subtle, indirect changes to the interactions among organisms could alter energy flow through the ecosystem. Here, we present the results of a series of manipulative experiments to determine the impacts of oil exposure on herbivory of Ruppia maritima, one of the most common species of submerged vegetation found in the region impacted by the 2010 Deepwater Horizon oil spill. In previous experiments, R. maritima was grown in a range of manipulated sediment oil concentrations. Using plant tissue from this experiment, we analyzed the effects of oil on plant chemical composition and found that plant carbon:nitrogen ratio (C:N) was reduced by as much as 21% in plants exposed to higher concentrations of oil. Given that nitrogen plays a key role in herbivore preference patterns, we performed herbivory assays and found oil-contaminated plants were preferred by herbivores in choice trials, although subsequent no-choice experiments indicated herbivores consumed less oil-contaminated tissue. We hypothesize the reason for this is that more tissue of higher C:N content is needed to meet similar metabolic demands while avoiding the potentially negative impacts of feeding on contaminated tissues. These results indicate that substantial food web alterations may occur via enhanced consumption of oil-exposed plants and provides vital information necessary to assess the large-scale impact of oil on submerged macrophytes.

Experimental study of rock-sheds constructed with PE fibres and composite cushion against rockfall impacts

To improve the impact resistance of rock-sheds, polyethylene (PE) fibres and expandable polyethylene (EPE) foams are proposed for structural construction. With PE fibres added into the matrix, the ductility and the impact resistance ability of concrete can be enhanced. Moreover, to reduce the dead load and impact load, EPE foam is utilized to replace some sand layers, forming a composite cushion. A series of large-scale rockfall impact experiments were carried out on four prototype models. Under a low- and medium-impact energy, compared to the traditional sand cushion, the composite cushion was more favoured to reduce the impact loading and was more suitable to resist multiple impacts. With the addition of fibres, the integrity of the concrete matrix was improved. The fibre concrete had a better energy dissipation capacity than that of the plain concrete. In addition, more cracks occurred in the plain concrete. When subjected to high energy, the reinforced concrete model was damaged with a large deformation and many fragments. However, the maximum deformation of the PE fibre-reinforced concrete model was very small, and almost no spalling or fragments were found. These results indicate that when constructed using PE fibres and EPE foams, the capability to resist the impact loading of rock-sheds can be significantly improved.