Current Tide Research Articles

Multi-task learning using non-linear autoregressive models and recurrent neural networks for tide level forecasting

Tide level forecasting plays an important role in environmental management and development. Current tide level forecasting methods are usually implemented for solving single task problems, that is, a model built based on the tide level data at an individual location is only used to forecast tide level of the same location but is not used for tide forecasting at another location. This study proposes a new method for tide level prediction at multiple locations simultaneously. The method combines nonlinear autoregressive moving average with exogenous inputs (NARMAX) model and recurrent neural networks (RNNs), and incorporates them into a multi-task learning (MTL) framework. Experiments are designed and performed to compare single task learning (STL) and MTL with and without using non-linear autoregressive models. Three different RNN variants, namely, long short-term memory (LSTM), gated recurrent unit (GRU) and bidirectional LSTM (BiLSTM) are employed together with non-linear autoregressive models. A case study on tide level forecasting at many different geographical locations (5 to 11 locations) is conducted. Experimental results demonstrate that the proposed architectures outperform the classical single-task prediction methods.

Nigeria’s Foreign Policy and Insecurity: Addressing the Missing Links and Reoccurring Issues

Insecurity is the biggest problem in Africa and nothing meaningful has been done by several sovereign states in Sub-Saharan Africa to stem the tide and its effects on nations all over the region. To this end, security has risen to be the dire need to be considered through the lens of foreign policy as an integral part of public administration and governance in Nigeria. Therefore, this paper specifically explored the missing links that gave rise to the problem of insecurity from foreign policy perspective; and the reoccurring issues that the ebb and flow of her foreign policy posed to Nigerian public space with major focus on Buhari’s Administration. Secondary data was employed to analyse the broad and specific objectives of this paper through a descriptive and explanatory method. The missing link in Nigeria’s foreign policy and security challenges spotted in the analysis are political ideology, globalization, poorly unchecked borderlands, and high rate of migration of criminal elements. The paper discovered some reoccurring issues in Nigeria’s foreign policy and security challenges. The paper concluded that all is not well with the country, because while the protectionist policy under President Buhari to a great extent blocked foreign trade, it left security of borderlands at the mercy of corrupt security personnel. Based on this, all hands must be on deck to exterminate the current tide in the wave of insecurity ravaging the country at all costs.

Genetic connectivity and population expansion inferred from multilocus analysis in Lutjanus alexandrei (Lutjanidae-Perciformes), an endemic snapper from Northeastern Brazilian coast.

Previous studies about the genetic diversity, connectivity and demographic history in Lutjanidae fishes have reported a common pattern of genetic homogeneity and expansion in populations from Western South Atlantic. In the present work, we inferred the population structure, the levels of genetic diversity and the demographic history of the Brazilian snapper Lutjanus alexandrei, a recently described and endemic species from Northeastern coast of Brazil. Five different fragments, including mitochondrial DNA (Control Region, Cyt b and ND4) and nuclear DNA (Myostatin and S7) regions were analyzed in 120 specimens of L. alexandrei from four localities in Northeastern Brazil, representing the first study of population genetics in this species. High levels of genetic diversity were observed following a panmictic pattern, probably related to the larval dispersal by the current tides along the Brazilian coast. In addition, both demographic history and neutrality tests indicated that L. alexandrei has undergone population expansion during Pleistocene. In this sense, the sea level variation from this period could have increased the available resources and suitable habitats for the Brazilian snapper.

The feminization of resistance: the narratives of #NiUnaMenos as social transformative action

ABSTRACT The Argentinean movement #NiUnaMenos (NUM) represents one of the most relevant transnational examples of Latin American feminist mobilization against gender-based violence and can be understood as vanguard of a current tide of feminized resistance on a global scale. This article addresses two central narratives in the discourses and social practices of three founders of the NUM; one about feminist mobilization as a social transformative moment that creates distinctive protest performances in the pursuing of a liveable life despite the challenging restrictive possibilities; and the other about the intersection between gender and class in the struggle against the neoliberal patriarchal precarization of life, related to the lack of the collective systems of social protection against gender-based violence. The analysis of these narratives highlights a feminization of resistance that promotes a radical transformation of the social system, where politics also at a micro level question capitalism, colonialism, and patriarchy by producing alternative knowledges, subjectivities, and epistemologies. Particularly, the study of the experience of enhanced precariousness created by the operation of patriarchal violence, and the resistance expressed in engendered alternative ethical and non-violent responses, reveals in the narratives the strength of a precarity awareness becoming a network of transnational and cross-identities solidarity.

Politics of Marginalisation of Igbo Nation in Nigerian Public Administration and Insecurity: A Blessing or a Curse?

The Igbo nation is an important constituent part in the Nigerian political constituency. Yet they remain politically marginalized and enslaved and consequently treated as a second class citizen in the Nigerian project. According to the nature of this research, a desk research with great reliance on the secondary method of data collection and observation was used in: assessing the extent of the marginalisation of Igbo nation; establishing the relationship between marginalisation and insecurity in Nigeria; and examining whether the marginalisation is a blessing or curse. The paper discovered that the current tide of marginalisation is a blessing to the marginalised and a curse to the unity and sustainable development of Nigeria as a sovereign state. It is herein recommended that the principle of inclusivism should be manifestly practiced. In this regard, the Igbo man should not be merely tolerated in his own home. He must be allowed to be a stakeholder in matters that concern him as a part of the general system. It concluded that, for public administration to serve the need of the people, it must be devoid of marginalisation and allied factors such as: divide and rule, corruption, nepotism, tribal sentiments and other associated ills that make public administration unworkable. The implication of the study for practice is that if we continue to approach marginalisation separately from the issue of insecurity in which indices like human right abuses, inequality, unemployment and social exclusion on the basis of tribal and religious classifications are not tackled with utmost seriousness, insecurity will remain a nagging challenge in Nigeria. Therefore, there is a correlation between marginalisation and insecurity.

Optimisation of Parameters in a German Bight Circulation Model by 4DVAR Assimilation of Current and Water Level Observations

Uncertain parameters in a 3D barotropic circulation model of the German Bight are estimated with a variational optimisation approach. Surface current measurements from a high frequency (HF) radar are used in combination with acoustic Doppler current profiler (ADCP) and tide gauge observations as input for a 4DVAR assimilation scheme. The required cost function gradients are estimated using an adjoint model code. The focus of the study is on systematic errors of the model with the control vector including parameters of the bathymetry, bottom roughness, open boundary forcing, meteorological forcing as well as the turbulence model. The model uses the same bathymetry, open boundary forcing, and metereological forcing as the operational model run at the Federal Maritime and Hydrographic Agency (BSH). The baroclinic BSH model is used as a reference to put the performance of the optimised model into perspective. It is shown that the optimised model has better agreement with HF radar data and tide gauge observations both within the fortnight training period and the test period 1 month later. Current profile measurements taken at two platforms indicate that both models have comparable error magnitudes at those locations. The optimised model was also compared with independent drifter data. In this case, drifter simulations based on the BSH model and the respective operational drift model including some surface wave effects were used as a reference. Again, these comparison showed very similar results overall, with some larger errors of the tuned model in very shallow areas, where no observations were used for the tuning and surface wave effects, which are only explicitly considered in the BSH model, play a more important role. The tuned model seems to be slightly more dissipative than the BSH model with more energy entering through the western boundary and less energy leaving toward the north. It also became evident that the 4DVAR cost function minimisation process is complicated by momentum advection, which leads to non-differentiable dependencies of the model with respect to the control vector. It turned out that the omission of momentum advection in the adjoint code still leads to robust estimates of descent directions.

The Sustainability of Waste Management Models in Circular Economies

The circular economy (CE) is considered a key economic model to meet the challenge of sustainable development. Strenous efforts are focused on the transformation of waste into resources that can be reintroduced into the economic system through proper management. In this way, the linear and waste-producing value chain problems are solved, making them circular, and more sustainable solutions are proposed in those chains already benefiting from circular processes, so that waste generation and waste are reduced on the one hand, and on the other, the non-efficient consumption of resources decreases. In the face of this current tide, there is another option that proposes a certain nuance, based on the premise that, although circular systems promote sustainability, it does not mean that they are in themselves sustainable, given that, in the first place, the effects of CE on sustainable development are not fully known and, on the other hand, the CE model includes the flow of materials, with only scant consideration of the flow of non-material resources (water, soil and energy). This paper aims to contrast both currents from an empirical viewpoint. To achieve this, a sustainability analysis of the circular waste management systems measured through a sustainability indicator, the carbon footprint (CF), as a main sustainable indicator in climate change action, is carried out. A crucial difference between circular models that promote waste management and those that do not is found in the collective systems of extended producer responsibility (or CPR). One of the most efficient recycling processes in Europe, waste tire management, has been chosen. Thus, the aim is to verify the sense of including environmental sustainability indicators, as CF, in the process of these systems. A sustainability management model (SBA) applies to End-of Life tire collection systems (ELT). This model is based on the accumulation of environmental impacts through the activities that generate them. To be transparent, this study requires a publicly recognized CF, so the study is focused on SIGNUS, the main Spanish waste tires CPR. The results achieved allow us to conclude that CF is much lower using CPR than non-linear processes. Despite the role that CPR have in the management and use of waste as secondary raw material, it is a priority to focus efforts on their redesign in order to reduce waste. In terms of circular economy, all actions are necessary in order to achieve system efficiencies, even when externalities occur in this process.

Challenging Islamist Populism in Indonesia through Catholic Youth Activism

This paper reports data from a study of young Catholic activists. They were concerned about the expansion of Islamist populism in democratic Muslim-majority Indonesia. They actively built inter-faith coalitions with local liberal Muslim youth groups and with pan-national Nahdlatul Ulama (NU), the largest independent Islamic organisation in the world. Islamist populism prioritises religious identity over the national identity of citizenship. In framing their citizenship activism against the current tide of Islamist populism, the informants in our study selectively engaged aspects of Catholic theology. They articulated their religious identity as coterminous with a nationalist identity centred on multi-faith tolerance and harmony. That discourse in itself refutes a key principle of Islamist populism in Indonesia, which argues for primordial entitlement.

Application of Inclined Steel-Pipe Piles in Ocean Engineering

Huo, S.; Zhu, M.; Dai, G., and Gong, W., 2020. Application of inclined steel-pipe piles in ocean engineering. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 284–287. Coconut Creek (Florida), ISSN 0749-0208.The bearing capacity of the structure foundation in the ocean engineering is required to be very high due to the long-term bearing complex loads such as wind load, wave load, earthquake and current tide. The inclined steel-pipe pile foundation is widely used in the ocean engineering because its bearing capacity is better than that of the straight pile. Compared with the common steel-pipe piles, the construction and testing of inclined steel-pipe piles are more difficult, with few researches at home and abroad. In this paper, an engineering example is introduced, in which the inclined steel-pipe piles are used as the foundation, and the pile driving barge is used to hammer them to complete the foundation construction of the footbridge. In addition, in order to determine their bearing capacity, the O-cell method is used to carry out field tests on two inclined steel-pipe piles for the first time in China. Finally, the test shows that the bearing capacity of one of the inclined steel-pipe piles is not enough. Then, the pile driving barge is used to hammer it. After the second O-cell test, it is found that the bearing capacity meets the design requirements.

Does it matter where they come from? This is the duty of humanity

The author describes his personal experience as a young refugee from a revolution in Europe, through his later intimate contact with three refugee communities in the course of decades of work in Asia, and reflects upon the greater context of the numerous issues impacting on decision-making and enveloping the sphere of refugees. Especially in the current tide of millions displaced, it is not possible in times of crises to simply segue in an attempt to harmonize the exceedingly complex situation. All components of the inter-related issues and results, namely causes of flight, reception outside their home countries, plans for resettlement and actual resettlement, as well as retaining some level of communication with those left behind need to be understood through improved, proactive planning and preparation.

Coastal engineering Study on the Impacts of Wharf Design on Hydrodynamic Forces in Sansha Bay Geo Spatial Environment

ABSTRACT To better understand the hydrodynamic characteristics of Sansha Bay and how they are changed by the addition of a wharf, this study takes the design of the wharf on Changyao Island as an example. It uses the MIKE21 model to study the variation of tidal current velocity, tide direction and silt buildup before and after the construction of the wharf. The research results show that:1. The design solution of the wharf is feasible. 2. The included angle between the main axis of the wharf and the tides’ direction is chosen to be less than 10º. 3. After the construction of the wharf, the peak tidal flow velocity that passes through the pile foundation of the wharf and the dike behind the wharf decreases by 10% to 15% and 30% to 50%, respectively. The range of the influence of buildings on the tidal current velocity is 900 m around the buildings. 4. The final siltation the upstream and downstream of the main axis of the wharf is 0.30 to 0.70 m, that on the dike at the rear edge of the wharf is 0.60 to 1.40 m from the wharf, and the final scour depth on the waterway of wharf apron is 0.03 to 0.05m.

Comparison of spatial scale variability of shoot density and epiphytic leaf assemblages of Halophila stipulacea and Cymodocea nodosa on the Eastern Coast of Tunisia

A study was undertaken to compare the patterns of spatial variability, epiphytic percentage cover, and distribution of epiphytic fauna and flora between the two adjacent seagrasses Cymodocea nodosa and the invasive species Halophila stipulucea. Samples were taken at six stations separated by 600 m and exposed to different current conditions. The stations G2 and G5 were affected by a high current tide, while G4 was directly exposed to the northern marine currents. The station G3 was situated in the middle of a Posidonia oceanica bed and was less exposed to hydrodynamism, whereas the other stations were relatively protected. Results indicate that for both H. stipulacea and C. nodosa, shoot density and epiphytic cover biomass decreased when exposed to high levels of hydrodynamic activity. In terms of epiphytic leaf assemblages, our results showed significant differences for the two host plants in their mean cover and for the six stations at the largest and smallest spatial scale. Our observations highlight the dominance of Rhodophyta and the low number of epiphytic species and the epiphytic cover on H. stipulacea compared to C. nodosa. In addition, results indicate the absence of two taxa Hydrozoans and Annelida in the epiphytic assemblage of H. stipulacea leaves.

Occurrence, transportation, and distribution difference of typical herbicides from estuary to bay

In several watersheds, agricultural activities are the cause of pollution, mainly due to the discharge of herbicides. Often, these herbicide plumes are transported to the surrounding bays. Samples of water, suspended particulate sediments (SPSs), and sediments from 37 sites in the Jiaozhou Bay in the western Pacific Ocean were collected in April 2018. The total concentrations of atrazine and acetochlor in these samples were analyzed, that showed different patterns in each sampled area. Atrazine had 2–3 times higher concentrations in coastal areas and bays compared to the estuary, indicating that it had a higher residence time in the marine environment. In contrast, acetochlor concentration decreased with an increase in the depth of seawater. Both the spatial distributions and the vertical concentrations in water, SPS, and sediment proved that these two herbicides had different responses during transportation from the estuary to the bay. Despite the significant difference in concentration of the two herbicides in the water and sediment, their spatially averaged value in SPS was very close, indicating that the particles had saturated sorption capability. The organic carbon normalized partition coefficient (LogKoc) was used to explain the partitioning of the herbicides between water and sediment. The LogKoc difference between herbicides demonstrated that acetochlor was strongly phase partitioned in the coastal and the bay areas, thereby causing similar distributions of acetochlor in the three matrices. Atrazine had a higher LogKoc value in the estuary, which explained its higher concentration in the estuary SPS. The correlation and redundancy analyses both demonstrated that the concentrations of the herbicides in water were sensitive to dissolved organic carbon and dissolved oxygen. The current tides and bathymetry were the critical factors in determining the spatial distribution of herbicides in the water and sediment, resulting in a low herbicide load in the river mouth area.

Slavery, Freedom and Contract: Blurred Lines and Historical Resistance

Hendrik Hartog’s The Trouble with Minna complicates the binary between freedom and unfreedom in American history by probing the mixture of slavery and contract in antebellum New Jersey’s regime of gradual emancipation. This Essay argues that if Hartog’s narrative is read for more general patterns—in addition to everyday lived experiences which Hartog emphasizes—it also reveals resistance to such line-blurring, and historical efforts to construct conceptual boundaries that would separate slave relations from capitalist ones. That resistance should assume a more central conceptual place within the current tide of historiographical emphasis toward blurred lines.

Unraveling InSAR Observed Antarctic Ice-Shelf Flexure Using 2-D Elastic and Viscoelastic Modeling

Ice-shelf grounding zones link the Antarctic ice-sheets to the ocean. Differential interferometric synthetic aperture radar (DInSAR) is commonly used to monitor grounding-line locations, but also contains information on grounding-zone ice thickness, ice properties and tidal conditions beneath the ice shelf. Here, we combine in-situ data with numerical modelling of ice-shelf flexure to investigate 2-D controls on the tidal bending pattern on the Southern McMurdo Ice Shelf. We validate our results with 9 double-differential TerraSAR-X interferograms. It is necessary to make adjustments to the tidal forcing to directly compare observations with model output and we find that when these adjustments are small (< 1.5 cm) a viscoelastic model matches better, while an elastic model is more robust overall. Within landward embayments, where lateral stresses from surrounding protrusions damp the flexural response, a 2-D model captures behaviour that is missed in simple 1-D models. We conclude that improvements in current tide models are required to allow for the full exploitation of DInSAR in grounding-zone glaciology.

A Survey On Marine Fish Species In River of Mahakam East Kalimantan, Indonesia

A first survey on a community marine species in river of Mahakam East Kalimantan was performed in December 2015 and May 2016. Fish samplings were carried out from two locations the lower and the middle part of Mahakam. Whilst hydrometric observation of current velocity, water depth and tide was measured not only at the locations but also along the river from 2013 to 2017, tide was only observed in the lower part of Mahakam. However, marine fish species were recognized to reach up the middle part of Mahakam, 230 km from coastline. To describe a community fish structure and its dissimilarity of the two surveyed locations, diversity and bray Curtis index were applied. Almost 15 marine fish species identified in river of Mahakam was demersal fish and index of the similarity of marine fish community between the locations only 0.106.

Repression and Resistance in Asia: Introduction

Pankaj Mishra’s phrase “age of anger” captures the current zeitgeist, not just in the United States and Europe but also many other parts of the world, including the East and Southeast Asian countries that are the focus of this section. Anger can be good for progressive causes. One thing that this collection of dispatches on misrule and discontent show clearly is the need to think of the current illiberal tide wreaking havoc at both ends of Eurasia, as well as to consider what happened before votes were cast over Brexit in May and in the U.S. election in November. The following pieces highlight just how widespread the disturbing trends associated with our age of anger are. But progressives will also find rays of hope in these accounts of repression in Asia, which are also full of examples of brave efforts to push back against authoritarian regimes.

Effects of moisture release and radiation properties in pulverized fuel combustion: A CFD modelling study

Pulverized fuels (PF) prepared and fired in utility boilers always contain some moisture. For some fuels with high moisture contents (e.g., brown coals), the share of the evaporation enthalpy is quite significant compared to the heat released during combustion, which often needs to be reclaimed to improve the plant efficiency and is also expected to affect the combustion process. Thermal radiation is the principal mode of heat transfer in combustion. In PF furnaces, radiation consists of contribution from both participating gases and solid particles, in which gas and particle radiation properties play an important role. There are different methods or models in the literature to address fuel moisture release and radiation properties, some of which may be inappropriate and can produce misleading results. This paper compares the different methods and models and demonstrates their implementation and impacts via a computational fluid dynamics (CFD) study of a 609MWe pulverized coal-fired utility boiler. Overall speaking, it is suggested to add the free moisture in the fuel to the primary air stream while lump the bound moisture with volatiles in PF combustion modelling, although different methods for fuel moisture release may not induce distinct difference in combustion of PF with relatively low moisture content. For radiation, it has to be emphasized that particle radiation largely overwhelms gas radiation in PF combustion. The current tide of radiation research that over-focuses on gas radiation while over-simplifies particle radiation or even neglects particle radiation needs to be turned. For gaseous fuel combustion in which particle radiation is negligible, more generic model for gas radiative properties that can naturally and correctly accommodate the changes in combustion condition (e.g., oxy-fuel or air–fuel), account for the variations in CO2 and H2O concentrations in a flame, and include the impacts of other participating gases (e.g., CO and hydrocarbons) needs to be derived for combustion CFD community.

Locke on the Ontology of Persons

AbstractThe importance of John Locke's discussion of persons is undeniable. Locke never explicitly tells us whether he thinks persons are substances or modes, however. We are thus left in the dark about a fundamental aspect of Locke's view. Many commentators have recently claimed that Lockean persons are modes. In this paper I swim against the current tide in the secondary literature and argue that Lockean persons are substances. Specifically I argue that what Locke says about substance, power, and agency commits him to the claim that persons are substances. I consider the passages mode interpreters cite and show why these passages do not imply that Lockean persons are modes. I also respond to two objections anyone who thinks Lockean persons are substances must address. I show that a substance reading of Locke on persons can be sympathetic and viable. I contend that with a clearer understanding of the ontological status of Lockean persons we can gain a firmer grasp of what Locke's picture of persons looks like. Finally, once we are armed with a better understanding of Locke on substance, mode, and personhood, we can pave the way toward a more nuanced description of the early modern debate over personal identity.

Applying evolutionary anthropology.

Evolutionary anthropology provides a powerful theoretical framework for understanding how both current environments and legacies of past selection shape human behavioral diversity. This integrative and pluralistic field, combining ethnographic, demographic, and sociological methods, has provided new insights into the ultimate forces and proximate pathways that guide human adaptation and variation. Here, we present the argument that evolutionary anthropological studies of human behavior also hold great, largely untapped, potential to guide the design, implementation, and evaluation of social and public health policy. Focusing on the key anthropological themes of reproduction, production, and distribution we highlight classic and recent research demonstrating the value of an evolutionary perspective to improving human well-being. The challenge now comes in transforming relevance into action and, for that, evolutionary behavioral anthropologists will need to forge deeper connections with other applied social scientists and policy-makers. We are hopeful that these developments are underway and that, with the current tide of enthusiasm for evidence-based approaches to policy, evolutionary anthropology is well positioned to make a strong contribution.