The presence of anthropic activity in the coastal or riverine environment modifies the wave as well as the water and sediment current regime. In particular, the body of water around ports is an area ...where intense currents and sediment transport rates are usually present and can be affected by low water velocities that take place close to the entrance and inside the port basin. Consequently, sediment can be entrained and accumulated in such areas, creating problems to navigation. Ports and moorings are filled with fine sediments due to deposition resulting from solid transport. In particular, silt particles settle because of the weak vertical and lateral shearing of the velocity field. The result is that harbours frequently require ordinary maintenance dredging.
The dredging process involves the removal of sediment in its natural deposited condition by using either mechanical or hydraulic equipment. Dredging is a consolidated and proven technology, but involves considerable drawbacks. In particular, dredging has a notable environmental impact on marine flora and fauna, contributes to the mobility and diffusion of contaminants and pollutants already present in the silted sediments, obstructs navigation and is characterized by relatively high and low predictable costs.
This paper aims to provide an original structured overview of technologies alternative to dredging that have been tested in the past 50 years. More than 150 articles have been analysed to compare standard dredging technologies with market-ready competitors from techno-economic and environmental perspectives. In particular, the paper focuses on anti-sedimentation infrastructures and on innovative plant solutions characterized by low maintenance costs and by a very limited environmental impact. The final aim of the paper is to describe the currently available technologies that prevent port inlet and channel siltation and to classify them through a techno-economic and environmental impact assessment. The comparison shows that dredging has both the higher costs and environmental impact, while fixed sand by-passing plants are characterized by the lowest environmental impact and operation costs that are competitive with dredging.
•Dredging is no longer sustainable for sediment management.•Anti-sedimentation infrastructures, remobilising sediment systems, sand by-passing plants are reliable dredging alternatives.•Techno-economic comparison shows that sand by-passing systems are cost competitive with dredging.•Sand by-passing system results as the most sustainable due to high efficiency, low cost and low environmental impact.
Dengue has become a major global public health threat with almost half of the world's population living in at-risk areas. Vaccination would likely represent an effective strategy for the management ...of dengue disease in endemic regions, however to date there is only one licensed preventative vaccine for dengue infection. The development of a vaccine against dengue virus (DENV) has been hampered by an incomplete understanding of protective immune responses against DENV. The most clinically advanced dengue vaccine is the chimeric yellow fever-dengue vaccine (CYD) that employs the yellow fever virus 17D strain as the replication backbone (Chimerivax-DEN; CYD-TDV). This vaccine had an overall pooled protective efficacy of 65.6% but was substantially more effective against severe dengue and dengue hemorrhagic fever. Several other vaccine approaches have been developed including live attenuated chimeric dengue vaccines (DENVax and LAV Delta 30), DEN protein subunit V180 vaccine (DEN1-80E) and DENV DNA vaccines. These vaccines have been shown to be immunogenic in animals and also safe and immunogenic in humans. However, these vaccines are yet to progress to phase III trials to determine their protective efficacy against dengue. This review will summarize the details of vaccines that have progressed to clinical trials in humans.
•We elaborated a deep analysis of waste to energy plant sections.•Experimental tests have been carried on several kind of sewage sludge.•Design parameter has been extrapolated from analysis of test ...results.•Energy and mass balances has been developed for sewage sludge dewatering with waste heat from WtE plant.•Preliminary economic feasibility has been introduced.
Dewatered sewage sludge from Waste Water Treatment Plants (WWTPs) is encountering increasing problems associated with its disposal. Several solutions have been proposed in the last years regarding energy and materials recovery from sewage sludge. Current technological solutions have relevant limits as dewatered sewage sludge is characterized by a high water content (70–75% by weight), even if mechanically treated. A Refuse Derived Fuel (RDF) with good thermal characteristics in terms of Lower Heating Value (LHV) can be obtained if dewatered sludge is further processed, for example by a thermal drying stage. Sewage sludge thermal drying is not sustainable if the power is fed by primary energy sources, but can be appealing if waste heat, recovered from other processes, is used. A suitable integration can be realized between a WWTP and a waste-to-energy (WTE) power plant through the recovery of WTE waste heat as energy source for sewage sludge drying. In this paper, the properties of sewage sludge from three different WWTPs are studied. On the basis of the results obtained, a facility for the integration of sewage sludge drying within a WTE power plant is developed. Furthermore, energy and mass balances are set up in order to evaluate the benefits brought by the described integration.
•Fukushima Daiichi Unit 3 large portion of core melted and relocated in lower plenum.•RPV failed, debris was transferred to the pedestal interacting with concrete.•MCCI might have been minimal given ...the large amount of water existing in the pedestal.•D/W is expected to be widely contaminated due to RPV leak during core degradation.
As a participant in the Benchmark Study of the Accident at Fukushima Daiichi phase 2 project, which aims to improve our understanding of the Fukushima Daiichi (1F) nuclear power plant conditions, the Institute of Applied Energy has performed a comprehensive evaluation and analyses of the 1F units using the SAMPSON code. The objective of this study is to clarify the accident progression and the distribution of debris/fission products in the plant as well as evaluate points of uncertainty in severe accident codes. The paper presents the results obtained for 1F Unit 3. Firstly, a likely accident scenario is evaluated taking into account all of the available measurements and recent information obtained from plant investigations. Subsequently, the SAMPSON code is applied to confirm the validity of the estimated phenomena and explain points of uncertainty in the the accident. The calculation is performed over the course of three weeks following the scram, which is representative of the time it takes to achieve stable plant conditions according to theories of thermal-hydraulics and fission product settling. The analysis confirms that a large portion of the core melted and relocated in the lower plenum of Unit 3. Thereafter, due to lack of cooling, the reactor pressure vessel failed, which caused the debris to be gradually transferred to the pedestal, where it interacted with concrete, generating flammable gases. It is estimated that a small amount of debris may have remained in the lower plenum in the form of a solidified crust, while a considerable portion relocated to the pedestal with limited spread to the dry well due to prolonged top-flooded conditions.
In this paper, we consider the following conjecture, proposed by Brian Alspach, concerning partial sums in finite cyclic groups: given a subset
A
of
Z
n
\
{
0
}
of size
k
such that
∑
z
∈
A
z
≠
0
, it ...is possible to find an ordering
(
a
1
,
…
,
a
k
)
of the elements of
A
such that the partial sums
s
i
=
∑
j
=
1
i
a
j
,
i
=
1
,
…
,
k
, are nonzero and pairwise distinct. This conjecture is known to be true for subsets of size
k
≤
11
in cyclic groups of prime order. Here, we extend this result to any torsion-free abelian group and, as a consequence, we provide an asymptotic result in
Z
n
. We also consider a related conjecture, originally proposed by Ronald Graham: given a subset
A
of
Z
p
\
{
0
}
, where
p
is a prime, there exists an ordering of the elements of
A
such that the partial sums are all distinct. Working with the methods developed by Hicks, Ollis, and Schmitt, based on Alon’s combinatorial Nullstellensatz, we prove the validity of this conjecture for subsets
A
of size 12.
With brief psychiatric hospitalizations, the extent to which symptoms change is rarely characterized. We sought to understand symptomatic changes across Research Domain Criteria (RDoC) dimensions, ...and the extent to which such improvement might be associated with risk for readmission. We identified 3,634 individuals with 4,713 hospital admissions to the psychiatric inpatient unit of a large academic medical center between 2010 and 2015. We applied a natural language processing tool to extract estimates of the five RDoC domains to the admission note and discharge summary and calculated the change in each domain. We examined the extent to which symptom domains changed during admission, and their relationship to baseline clinical and sociodemographic features, using linear regression. Symptomatic worsening was rare in the negative valence (0.4%) and positive valence (5.1%) domains, but more common in cognition (25.8%). Most diagnoses exhibited improvement in negative valence, which was associated with significant reduction in readmission risk. Despite generally brief hospital stays, we detected reduction across multiple symptom domains, with greatest improvement in negative symptoms, and greatest probability of worsening in cognitive symptoms. This approach should facilitate investigations of other features or interventions which may influence pace of clinical improvement.
Scientific research on digitalization and its impact on business models has been growing exponentially in recent years. This has been particularly evident from 2010 onwards, following a landmark ...special issue published in Long Range Planning. This article offers an overview of the development of academic literature published between 2010 and 2019 with regards to the relationship between digitalization and business models in 198 peer-reviewed articles. By applying a novel methodological approach to compare results from different bibliometric analyses, such as the analysis of citations, co-citations, bibliographic coupling, and co-occurrences of keywords, we have identified the most influential journals, authors, and articles, as well as three thematic clusters (technological innovation, strategic management, and digital transformation). For each cluster, the most relevant contributions are presented. Promising research areas and future research directions are identified to address the existing gaps in knowledge.
Background
Animal models proposed to reproduce some of the human irritable bowel syndrome (IBS) symptoms are based on the hypothesis that psychosocial stressors play a pivotal role in the IBS ...etio‐pathology.
We investigated the wrap restraint stress (WRS) model with the aim to analyze the morphological changes of the entire colonic wall of these animals that showed some of the human IBS symptoms such as visceral hypersensitivity.
Methods
Male Wistar rats were used and WRS was maintained for 2 h. Abdominal contractions (AC) were recorded in the colon‐rectum by balloon distension. Fecal pellets were quantitated. Colonic specimens were examined by routine histology, immunohistochemistry and western blot.
Key Results
WRS animals were characterized by: (i) increase in AC number and fecal pellets mean weight; (ii) clusters of mononucleated cells, increase in eosinophilic granulocytes and mast cells in the mucosa; (iii) increase in CGRP‐immunoreactive (IR) nerve fibers in the lamina propria; (iv) decrease in myenteric NK1r‐IR and nNOS‐IR neurons and in submucous nNOS‐IR neurons; (v) decrease in SP‐IR nerve fibers in the muscle wall; (vi) reduction in S100β‐IR glia in the entire colonic wall; (vii) increase in CRF1r‐IR myenteric neurons; (viii) no change in ChAT‐IR neurons, smooth muscle cells and interstitial cells of Cajal.
Conclusions and Inferences
The present results support the consistency of the WRS as a potential model where part of the human IBS signs and symptoms are reproduced. The changes in glial cells and in excitatory and inhibitory neurotransmitters might represent the substrate for the dysmotility and hypersensitivity.
This study aims to investigate possible morphological changes in the colonic wall of wrap restraint stress (WRS) rats and correlates the results with functional data to improve our understanding of irritable bowel syndrome (IBS) pathogenesis. WRS was maintained for 2 h. At the end, fecal pellets were quantitated and abdominal contractions were recorded in the colon‐rectum. Colonic specimens were examined by histology, immunohistochemistry, and western blot. The functional data showed a significant increase in fecal pellet production and the presence of a visceral hypersensitivity. The morphological findings showed the presence of a mucosal inflammation and important changes in nerve structures. The present results support the consistency of the WRS as a potential model for understanding IBS pathogenesis. The changes in nerve structures might represent the main substrates for dysmotility and visceral hypersensitivity. This is the first report of an increase in CRF1r expressing neurons. This datum fits well with the role of the receptor in mediating the stress responses and supports our hypothesis that changes in neurotransmission are mainly involved in the genesis of colonic dysmotility.
•On March 11th 2011 the Fukushima Daiichi Units 1 to 3 experienced station black out. This set in motion a chain of events leading to core meltdown.•Radioactive materials were released to the ...environment.•TEPCO has made many efforts to investigate the accident progressions.•Up to date no perfect calculations exists due to lack of knowledge of BWR phenomena.•Comparison between calculations and findings emphasize model development direction.
On March 11th 2011 the Great East Japan Earthquake and Tsunami hit the Fukushima Daiichi Nuclear Power Station. The Fukushima Daiichi Units 1 to 3 lost all DC and AC power supplies, which set in motion a chain of events that led to releases of radioactivity to the environment. Since then, TEPCO has made many efforts to investigate the accident progressions and the status of the reactors and containment vessels, mainly by using severe accident analysis code, such as MAAP, MELCOR and SAMPSON. However, there still exist several tens of unsolved issues to be investigated for the fully understanding of the accident. In recent years, massive amounts of information of the accident plants were obtained through the investigation activities by using robots or other devices. The investigation results suggested us the possibilities that some phenomena identifications established before the accident were incorrect. And also, there are many difficulties to reproduce the accident progressions of the Fukushima Daiichi unit 1 to 3, due to lack of knowledge real BWR plant accident phenomena. In this paper, we will introduce the special characteristics, which made difficult to reproduce the accident. And we will discuss how to use the investigation results obtained in Fukushima Daiichi NPP for the SA code validation by comparing with investigation results and calculation results.
Natural selection clearly favors the accumulation and storage of lipids in humans, predisposing women to store excess fat in gluteal regions and predisposing males to store excess fat in visceral ...regions. In addition, gender differences are reported with respect to the concentrations of circulating lipids and lipoproteins, with lower concentrations of total cholesterol and low density lipoprotein (LDL)-cholesterol in premenopausal women than in men. This latter evidence renders gender differences in fat distribution and whole-body lipid metabolism of particular interest with respect to the incidence and prevalence of human diseases. Although the mechanisms underlying gender-related differences in body fat distribution and lipid homeostasis remain to be fully determined, the reported differences appear to principally reflect the actions of the sex steroid hormone estrogen on whole-body lipid metabolism. In the present review, we dissect the role played by 17β-estradiol, the most active between estrogens, and by its receptors in regulating lipid homeostasis in adipose tissue, liver, and brain, evaluating the potential impact of this hormone in preventing lipid abnormalities.
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