Emergence and Migration of a Nearshore Bar: Sediment Flux and Morphological Change on a Multi-Barred Beach in the Great Lakes

Burley Beach (southeastern Lake Huron) exhibits a multi-barred shoreface, the long-term equilibrium morphology characteristic of many low angle, sandy beaches in the Canadian Great Lakes. During a single major storm, a new bar emerged 50-60 m offshore as an irregular trough-crest form, through differential erosion of an existing shore terrace. Emergence, bar growth and offshore migration were associated with: (a) an overall negative sediment balance in the inner surf zone initially (‑2.30 m3>/m beach width), but with a large positive sediment balance (+5.10 m3/m) subsequent to the storm peak and during the storm decay; (b) progradation of the beach step to produce a new shore terrace; and (c) offshore migration of the two outer bars to provide the accommodation space necessary for the new bar. The primary transport mechanisms accounting for emergence of the new bar, its growth and migration were: (a) the mean cross-shore currents (undertow), which always transported suspended sediment offshore; and (b) the onshore transport of suspended sediment by incident gravity wave frequencies early in the storm and subsequently by infragravity waves (at the storm peak and the decay period). The longshore transport of sediment was significant in terms of the gross transport, although the net result was only a small transport to the south-west (historic littoral transport direction). It did not cause bar initiation, but it may have supplied some of the sediment for bar growth. The primary mechanism for bar initiation and growth was the cross-shore displacement of sediment by wave-driven (oscillatory) transport and cross-shore mean currents (undertow).Émersion et migration d’une barre côtière : bilan sédimentaire et changements morphologiques d’une plage à barres multiples des Grands Lacs. La plage de Burley (sud-est du lac Huron) présente une avant-côte à barres multiples, état morphologique caractéristique de l’équilibre à long terme des plages sableuses à pente faible. Au cours d’un seul orage majeur, une nouvelle barre s’est développée à 50-60 m au large de la côte en forme de creux et crête irrégulière, suite à l’érosion d’une terrasse côtière. L’émersion, la croissance et la migration de la barre est attribuable à (a) un bilan sédimentaire négatif dans la zone interne du ressac (‑2,30 m3/m), mais à un bilan sédimentaire positif (+5,10 m3/m) durant l’apogée et la dissipation de l’orage, (b) l’exondation du gradin de plage pour générer une nouvelle terrasse côtière et (c) la migration de deux barres distales au large de la côte, laissant assez d’espace pour la mise en place d’une nouvelle barre. Les mécanismes de l’émersion, de la croissance et de la migration sont : (a) les contre-courants qui transportent les sédiments en suspension au large de la côte et (b) le transport vers la côte via la fréquence des vagues de gravité générées au début de l’orage et par les vagues d’infragravité subséquentes (au maximum de l’orage et durant sa dissipation). Le transport brut des sédiments est important, mais le résultat net correspond seulement à un léger transport vers le sud-ouest (direction historique du transit littoral). Ceci ne cause pas la création de la barre, mais peut contribuer aux apports sédimentaires nécessaires à sa croissance. Le mécanisme responsable de l’évolution des barres est le transport des sédiments par les vagues oscillatoires et les contre-courants

Caracterização morfológica de sementes de variedades locais de feijoeiro comum (Phaseolus vulgaris) do Ace.

O feijoeiro comum é cultivado no Acre exclusivamente por agricultores familiares e representa grande importância agronômica, econômica, social e cultural. A abertura de novas estradas no Estado constitui-se em uma ameaça a perda da variabilidade e de espécies locais necessitando que essas seja estudadas para usos futuros. Este trabalho teve como objetivo caracterizar sementes de dez variedades locais de feijoeiro comum. Avaliaram-se 10 variedades. As sementes foram coletados em feiras e mercados públicos de municípios do Acre. Os trabalhos de campo e laboratório foram realizados no primeiro semestre de 2012. Foram avaliadas as seguintes características; cor do tegumento, presença e cor do halo, brilho, forma e grau de achatamento da semente e o peso de 100 sementes. Detectou-se a ocorrência de variabilidade para todos os descritores de sementes avaliados, com destaque para a diversidade de cores, brilho e forma bem como para a amplitude do caráter peso de 100 sementes

Obtention of plant peroxidase and its potential for the decolorization of the reactive dye Remazol Turquoise G 133%

Peroxidases can be used in the decolorization process. There is a growing interest for new sources of this enzyme and for obtaining economically viable processes. In this work, a low-cost vegetable peroxidase extraction process is proposed; the resulting enzyme is characterized to determine its optimum pH, temperature, and stability conditions, and it is then applied in the decolorization of reactive dye Remazol Turquoise G 133%. The turnip peroxidase (TP) was utilized as an enzymatic source. This enzyme exhibited maximum activity at pH 7.0, and it was active in the temperature range of 30 to 50 °C, which favors its use in industrial processes. Acetone was the most efficient solvent to induce precipitation. The removal of Remazol Turquoise G 133% was 56.0% complete after 50 min, while 41.0% of the same dye was removed with the commercial horseradish peroxidase enzyme in 50 min. TP presents potential as a viable alternative in the decolorization of textile wastewaters

Associations among ancestry, geography and breast cancer incidence, mortality, and survival in Trinidad and Tobago

Breast cancer (BC) is the most common newly diagnosed cancer among women in Trinidad and Tobago (TT) and BC mortality rates are among the highest in the world. Globally, racial/ethnic trends in BC incidence, mortality and survival have been reported. However, such investigations have not been conducted in TT, which has been noted for its rich diversity. In this study, we investigated associations among ancestry, geography and BC incidence, mortality and survival in TT. Data on 3767 incident BC cases, reported to the National Cancer Registry of TT, from 1995 to 2007, were analyzed in this study. Women of African ancestry had significantly higher BC incidence and mortality rates (Incidence: 66.96; Mortality: 30.82 per 100,000) compared to women of East Indian (Incidence: 41.04, Mortality: 14.19 per 100,000) or mixed ancestry (Incidence: 36.72, Mortality: 13.80 per 100,000). Geographically, women residing in the North West Regional Health Authority (RHA) catchment area followed by the North Central RHA exhibited the highest incidence and mortality rates. Notable ancestral differences in survival were also observed. Women of East Indian and mixed ancestry experienced significantly longer survival than those of African ancestry. Differences in survival by geography were not observed. In TT, ancestry and geographical residence seem to be strong predictors of BC incidence and mortality rates. Additionally, disparities in survival by ancestry were found. These data should be considered in the design and implementation of strategies to reduce BC incidence and mortality rates in TT

POTs: Protective Optimization Technologies

Algorithmic fairness aims to address the economic, moral, social, and political impact that digital systems have on populations through solutions that can be applied by service providers. Fairness frameworks do so, in part, by mapping these problems to a narrow definition and assuming the service providers can be trusted to deploy countermeasures. Not surprisingly, these decisions limit fairness frameworks' ability to capture a variety of harms caused by systems. We characterize fairness limitations using concepts from requirements engineering and from social sciences. We show that the focus on algorithms' inputs and outputs misses harms that arise from systems interacting with the world; that the focus on bias and discrimination omits broader harms on populations and their environments; and that relying on service providers excludes scenarios where they are not cooperative or intentionally adversarial. We propose Protective Optimization Technologies (POTs). POTs provide means for affected parties to address the negative impacts of systems in the environment, expanding avenues for political contestation. POTs intervene from outside the system, do not require service providers to cooperate, and can serve to correct, shift, or expose harms that systems impose on populations and their environments. We illustrate the potential and limitations of POTs in two case studies: countering road congestion caused by traffic-beating applications, and recalibrating credit scoring for loan applicants.Comment: Appears in Conference on Fairness, Accountability, and Transparency (FAT* 2020). Bogdan Kulynych and Rebekah Overdorf contributed equally to this work. Version v1/v2 by Seda G\"urses, Rebekah Overdorf, and Ero Balsa was presented at HotPETS 2018 and at PiMLAI 201

The National Eye Survey of Trinidad and Tobago (NESTT): Rationale, objectives and methodology

Purpose: This paper describes the rationale, study design and procedures of the National Eye Survey of Trinidad and Tobago (NESTT). The main objective of this survey is to obtain prevalence estimates of vision impairment and blindness for planning and policy development. Methods: A population-based, cross-sectional survey was undertaken using random multistage cluster sampling, with probability-proportionate-to-size methods. Eligible participants aged 5 years and older were sampled from the non-institutional population in each of 120 cluster segments. Presenting distance and near visual acuity were screened in their communities. People aged 40 years and older, and selected younger people, were invited for comprehensive clinic assessment. The interview included information on potential risk factors for vision loss, associated costs and quality of life. The examination included measurement of anthropometrics, blood glucose, refraction, ocular biometry, corneal hysteresis, and detailed assessment of the anterior and posterior segments, with photography and optical coherence tomography imaging. Adult participants were invited to donate saliva samples for DNA extraction and storage. Results: The fieldwork was conducted over 13 months in 2013–2014. A representative sample of 10,651 individuals in 3410 households within 120 cluster segments identified 9913 people who were eligible for recruitment. Conclusion: The study methodology was robust and adequate to provide the first population-based estimates of the prevalence and causes of visual impairment and blindness in Trinidad and Tobago. Information was also gathered on risk factors, costs and quality of life associated with vision loss, and on normal ocular parameters for the population aged 40 years and older

Ischemia Induces P-Selectin-Mediated Selective Progenitor Cell Engraftment in the Isolated-Perfused Heart

Clinical trials infusing Bone Marrow Cells (BMCs) into injured hearts have produced measureable improvements in cardiac performance, but were insufficient to improve patient outcomes. Low engraftment rates are cited as probable contributor to limited improvements. To understand the mechanisms that control myocardial engraftment of BMCs following ischemia-reperfusion injury, in isolated–perfused mouse hearts, stop-flow ischemia was followed by variable-duration reperfusion (0–60 min) before addition of labeled syngenic BMCs to the perfusate. After a buffer-only wash, the heart was disaggregated. Retained BMCs (digest) and infused BMCs (aliquot) were compared by flow cytometry for c-kit and CD45 expression to determine the proportion of cell subtypes engrafted versus delivered (selectivity ratio). In these studies, a time-dependent selective retention of c-kit+ cells was apparent starting at 30 min of reperfusion, at which time c-kit+/CD45+ BMCs showed a selectivity ratio of 18 ± 2 (versus 2 ± 1 in sham-ischemic controls). To study the underlying mechanism for this selective retention, neutralizing antibodies for P-selectin or L-selectin were infused into the heart preparation and incubated with BMCs prior to BMC infusion. Blocking P-selectin in ischemic hearts ablated selectivity for c-kit+/CD45+ BMCs at 30 min reperfusion (selectivity ratio of 3 ± 1) while selectivity persisted in the presence of L-selectin neutralization (selectivity ratio of 17 ± 2). To corroborate this finding, a parallel plate flow chamber was used to study capture and rolling dynamics of purified c-kit+ versus c-kit- BMCs on various selectin molecules. C-kit+ BMCs interacted weakly with L-selectin substrates (0.03 ± 0.01% adhered) but adhered strongly to P-selectin (0.28 ± 0.04% adhered). C-kit- BMCs showed intermediate binding regardless of substrate (0.18 ± 0.04% adhered on L-selectin versus 0.17 ± 0.04% adhered on P-selectin). Myocardial ischemia–reperfusion stress induces selective engraftment of c-kit+ bone marrow progenitor cells via P-selectin activation

Bimetallic reduced graphene oxide/zeolitic imidazolate framework hybrid aerogels for efficient heavy metals removal

Graphene oxide is a promising adsorption material. However, it has been difficult to recycle and separate graphene oxide in the solution. To alleviate this problem, graphene oxide was thermally reduced to produce porous hydrogel which was then functionalized with polydopamine. The functional groups act as not only adsorption sites but also nucleation sites for in situ crystallization of cobalt-doped zeolitic-imidazolate-framework-8 nano-adsorbents. The effects of cobalt-doping contents on the physicochemical and adsorption properties of the resulting aerogel were also evaluated by varying the cobalt concentration. For instance, the reduced graphene oxide-polydopamine/50cobalt-zeolitic-imidazolate-framework-8 aerogel exhibited a high surface area of 900 m2·g−1 and maintained the structure in water after ten days. The assynthesized aerogels showed an ultrahigh adsorption capacity of 1217 ± 24.35 mg·g−1 with a removal efficiency of &gt; 99% of lead, as well as excellent adsorption performance toward other heavy metals, such as copper and cadmium with adsorption capacity of 1163 ± 34.91 and 1059 ± 31.77 mg·g−1, respectively. More importantly, the lead adsorption stabilized at 1023 ± 20.5 mg·g−1 with a removal efficiency of &gt; 80% after seven cycles, indicating their potential in heavy metal removal from industrial wastewater.</p

Hydroflux-Controlled Growth of Magnetic K-Cu-Te-O(H) Phases

Innovative synthetic approaches can yield new phases containing novel structural and magnetic motifs. In this work, we show the synthesis and magnetic characterization of three new and one previously reported layered phase in the K-Cu-Te-O(H) phase space using a tunable hydroflux technique. The hydroflux, with a roughly equal molar ratio of water and alkali hydroxide, is a highly oxidizing, low melting solvent which can be used to isolate metastable phases unattainable through traditional solid state or flux techniques. The newly synthesized phases, K$_{2}$Cu$_{2}$TeO$_{6}$, K$_{2}$Cu$_{2}$TeO$_{6}$ $\cdot$ H$_{2}$O, and K$_{6}$Cu$_{9}$Te$_{4}$O$_{24}$ $\cdot$ 2 H$_{2}$O, contain Cu$^{2+}$ within CuO$_{4}$ square planar plaquettes and TeO$_{6}$ octahedra ordering to form structural honeycomb layers isolated by interlayer K$^{+}$ ions and H$_{2}$O molecules. We find the synthesized structures display varying tilt sequences of the CuO$_{4}$ plaquettes, leading to distinct Cu$^{2+}$ magnetic motifs on the structural honeycomb lattice and a range of effective magnetic dimensionalities. We find that K$_{2}$Cu$_{2}$TeO$_{6}$ $\cdot$ H$_{2}$O does not order and displays alternating chain Heisenberg antiferromagnetic (AFM) behavior, while K$_{2}$Cu$_{2}$TeO$_{6}$ and K$_{6}$Cu$_{9}$Te$_{4}$O$_{24}$ $\cdot$ 2 H$_{2}$O order antiferromagnetically (T$_{N}$ = 100 K and T$_{N}$ = 6.5 K respectively). The previously known phase, K$_{2}$CuTeO$_{4}$(OH)$_{2}$ $\cdot$ H$_{2}$O, we find contains structurally and magnetically one-dimensional CuO$_{4}$ plaquettes leading to uniform chain Heisenberg AFM behavior and shows no magnetic order down to T = 0.4 K. We discuss and highlight the usefulness of the hydroflux technique in novel syntheses and the interesting magnetic motifs that arise in these particular phases

Photocatalytic self-cleaning graphene oxide/ZnO hybrid membrane for ultrafast cyclic small organic molecule separation

Graphene oxide (GO) based membranes have attracted tremendous interest owing to their unique lamellar structure resulting in excellent molecular filtration. However, the expansion of interlayer spacing of GO nanoflakes in liquid solutions, particularly in aqueous solution, and the adsorption of foulants in the layered nanoconfinement as well as on the surface adversely affects the long-term performance of the membranes. In this work, one-dimensional zinc oxide (ZnO) nanorods were integrated with graphene oxide via in-situ crystallization. A fast thermal treatment was applied to partially reduce the graphene oxide nanoflakes and chemically ‘lock’ the newly formed ZnO nanorods during the final step of hybrid membrane fabrication. It was found that the partially reduced graphene oxide (rGO) provided excellent mechanical stability between the nanolayers and also very stable and efficient molecular sieving properties. Interestingly, the ZnO nanorods not only served as a space holder between neighbouring reduced graphene-oxide nanoflakes but also endowed the hybrid membrane with responsive photocatalytic self-cleaning properties, which has been considered one of the most promising approaches for energy-efficient environmental remediation. In water permeation tests, these graphene oxide-zinc oxides (P-rGO/ZnO) membranes exhibited ultrahigh permeance of 400 ± 21 L m−2 h−1 bar−1, more than an order of magnitude higher than the conventional rGO membranes. In the meantime, these membranes exhibited excellent small organic molecule separation efficiencies with &gt;98.8 ± 1.2% rejections toward direct red 80, rose bengal, reactive black 5, and trypan blue. More importantly, under ultraviolet–visible light irradiation, the membrane demonstrated highly efficient self-cleaning behaviour for fast organic dye decomposition, enabling excellent cyclic removal of pre-adsorbed dye molecules. Therefore, this intelligent self-cleaning hybrid membrane has great potential in wastewater purification, particularly for ultrafast small organic molecule removal.</p