scholarly journals Semi-automated counting of complex varves through image autocorrelation

2021 ◽  
pp. 1-12
Author(s):  
Maximillian Van Wyk de Vries ◽  
Emi Ito ◽  
Mark Shapley ◽  
Guido Brignone
Keyword(s):  
Sedimentation Rate ◽  
Sliding Window ◽  
Sedimentation Rates ◽  
Sedimentary Sequences ◽  
High Sedimentation ◽  
History Of ◽  
History Of Use ◽  
Sediment Layers ◽  
Annual Resolution ◽  
Varve Counting

Abstract Annual resolution sediment layers, known as varves, can provide continuous and high-resolution chronologies of sedimentary sequences. In addition, varve counting is not burdened with the high laboratory costs of geochronological analyses. Despite a more than 100-year history of use, many existing varve counting techniques are time consuming and difficult to reproduce. We present countMYvarves, a varve counting toolbox which uses sliding-window autocorrelation to count the number of repeated patterns in core scans or outcrop photos. The toolbox is used to build an annually-resolved record of sedimentation rates, which are depth-integrated to provide ages. We validate the model with repeated manual counts of a high sedimentation rate lake with biogenic varves (Herd Lake, USA) and a low sedimentation rate glacial lake (Lago Argentino, Argentina). In both cases, countMYvarves is consistent with manual counts and provides additional sedimentation rate data. The toolbox performs multiple simultaneous varve counts, enabling uncertainty to be quantified and propagated into the resulting age-depth model. The toolbox also includes modules to automatically exclude non-varved portions of sediment and interpolate over missing or disrupted sediment. CountMYvarves is open source, runs through a graphical user interface, and is available online for download for use on Windows, macOS or Linux at https://doi.org/10.5281/zenodo.4031811.

Use of Lacustrine Sedimentary Sequences as Indicators of Holocene Glacial History, Banff National Park, Alberta, Canada

1986 ◽  
Vol 26 (2) ◽  
pp. 218-231 ◽  
Author(s):  
Eric M. Leonard
Keyword(s):  
Sedimentation Rate ◽  
Lacustrine Sediments ◽  
Sedimentation Rates ◽  
Canadian Rocky Mountains ◽  
Glacial History ◽  
Climatic Forcing ◽  
Glacial Sediment ◽  
Sedimentary Sequences ◽  
Banff National Park ◽  
Glacial Chronology

Bottom sediments from three lakes in the Canadian Rocky Mountains were examined with the aim of evaluating the usefulness of downvalley sediment studies in reconstruction of Holocene glacial histories. Analyses of organic carbon and carbonate contents of core sediments provide information on changing sedimentation rate and changing relative importance of glacial and non-glacial sediment sources. Sedimentary histories of the three lakes are similar, suggesting that they record regional glacial/climatic forcing, rather than localized events, and thus that they may be useful in reconstructing Holocene glacial history. Lacustrine sediments indicate a period of high sedimentation rates and relatively large glacial sediment contribution prior to 7500-7000 yr B.P., with much reduced rates and decreased glacial sediment contribution between about 6000 and 4000 yr B.P., possibly interrupted by a brief period of increased glacial sediment output shortly after 5000 yr B.P. Sometime after 4000 yr B.P., sedimentation rates and glacial sediment output began to rise again, reaching approximately present levels by 2750-2650 yr B.P., and have not since returned to low mid-Holocene levels. In detail over the last 3000 yr there is some indication of a slight decrease in sedimentation rate for more than 1000 yr after about 2200 yr B.P. Sedimentation rates and glacial sediment input into all three lakes rose between about 900 and 750 yr B.P. and have remained very high since. If the lake sediments are interpreted as a proxy record of upvalley glacial activity, they allow the development of a glacial chronology which is at once generally consistent with, and more complete and easily datable than, the surficial glacial record.

scholarly journals Prediksi Laju Sedimentasi di Perairan Teluk Benoa Menggunakan Pemodelan Numerik

2018 ◽  
Vol 5 (1) ◽  
pp. 44 ◽  
Author(s):  
I Putu Ranu Fajar Maharta ◽  
I Gede Hendrawan ◽  
Yulianto Suteja
Keyword(s):  
Numerical Modeling ◽  
Sedimentation Rate ◽  
Mangrove Ecosystem ◽  
Scientific Study ◽  
Sedimentation Rates ◽  
Minimum Value ◽  
Shallow Estuary ◽  
High Sedimentation ◽  
Hydrodynamic Processes

Benoa Bay is one of the unique ecosystems on the island of Bali because it is a shallow estuary area and has an ecosystem that is important for the waters of the mangrove ecosystem and seagrass. In recent years, Benoa Bay has been reported to have undergone siltation due to sedimentation. However, there has not been much scientific study of the sedimentation rate occurring in Benoa Bay. The study of sedimentation will provide an overview of the rate of sedimetation in the study area. Numerical modeling is one of the most commonly used methods to describe hydrodynamic processes in waters, which are the main drivers of the process of movement of pollutants in waters such as waste, sediment, and others. Thus, the study of sedimentation rate, either spatially or temporally, needs to be done in the waters of Benoa Bay using numerical modeling. The results of this study show that sedimentation rates in Benoa Bay have a minimum value of 1.08x10-6 and a maximum of 24.88 kg/m2/day with an average of 0.57 kg/m2/day. High sedimentation rates occur in the western part of the bay, on the river route, and in the northern part of the bay, between Serangan Island and Mertasari beach. Areas that potentially experience silting in Benoa Bay include the southern port of Benoa Harbor which reaches 0.23 m/year, the waters north of Serangan Island reaching 0.008 m/year, and the area close to the estuary which reaches 0.35 m/year.

Varve Studies at Hector Lake, Alberta, Canada, and the Relationship Between Glacial Activity and Sedimentation

1986 ◽  
Vol 25 (2) ◽  
pp. 199-214 ◽  
Author(s):  
Eric M. Leonard
Keyword(s):  
Sedimentation Rate ◽  
General Pattern ◽  
Sedimentation Rates ◽  
Sedimentary Records ◽  
Banff National Park ◽  
High Sedimentation ◽  
Lake Bottom ◽  
Lake Bottom Sediments ◽  
The Relationship ◽  
Very High

Glacial lake sedimentary records from Hector Lake in Banff National Park, Alberta, are examined with the aim of clarifying the relationship between glacial activity and outwash sedimentation. Rhythmic couplets in lake bottom sediments provide a method for accurate documentation and dating of recent sedimentation chronology, as analysis of 137Cs content indicates that the couplets are of annual periodicity (i.e., varves). A comparison of sedimentation rate records with recent regional glacial history indicates that high sedimentation rates of one to a few decades duration occur either during and immediately following periods of moraine deposition (ie, maximum ice stands) or during periods of rapid ice recession. Comparison of sedimentary records with somewhat longer term glacial and vegetation records indicates that sedimentation rate variations of several centuries duration closely parallel changes in upvalley ice extent. Over this time scale, high sedimentation rates occur during periods of relatively increased ice extent, low rates during periods of reduced ice extent. Within this general pattern, however, sedimentation rates may remain very high for nearly a century following maximum ice stands, due to the exposure of unstable glaciogenic deposits to fluvial reworking during ice recession.

scholarly journals Jojoba Oil: An Updated Comprehensive Review on Chemistry, Pharmaceutical Uses, and Toxicity

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1711
Author(s):  
Heba A. Gad ◽  
Autumn Roberts ◽  
Samirah H. Hamzi ◽  
Haidy A. Gad ◽  
Ilham Touiss ◽  
...  
Keyword(s):  
Industrial Applications ◽  
Literature Survey ◽  
Jojoba Oil ◽  
Pharmacological Activities ◽  
Wide Range ◽  
Liver Functions ◽  
History Of ◽  
History Of Use ◽  
Pharmaceutical Uses ◽  
Obesity And Cancer

Jojoba is a widely used medicinal plant that is cultivated worldwide. Its seeds and oil have a long history of use in folklore to treat various ailments, such as skin and scalp disorders, superficial wounds, sore throat, obesity, and cancer; for improvement of liver functions, enhancement of immunity, and promotion of hair growth. Extensive studies on Jojoba oil showed a wide range of pharmacological applications, including antioxidant, anti-acne and antipsoriasis, anti-inflammatory, antifungal, antipyretic, analgesic, antimicrobial, and anti-hyperglycemia activities. In addition, Jojoba oil is widely used in the pharmaceutical industry, especially in cosmetics for topical, transdermal, and parenteral preparations. Jojoba oil also holds value in the industry as an anti-rodent, insecticides, lubricant, surfactant, and a source for the production of bioenergy. Jojoba oil is considered among the top-ranked oils due to its wax, which constitutes about 98% (mainly wax esters, few free fatty acids, alcohols, and hydrocarbons). In addition, sterols and vitamins with few triglyceride esters, flavonoids, phenolic and cyanogenic compounds are also present. The present review represents an updated literature survey about the chemical composition of jojoba oil, its physical properties, pharmacological activities, pharmaceutical and industrial applications, and toxicity.

scholarly journals The Botanical, Chemical and Ethnobotanical Diversity of Southern African Lamiaceae

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3712
Author(s):  
Ryan D. Rattray ◽  
Ben-Erik Van Wyk
Keyword(s):  
Southern Africa ◽  
Folk Medicine ◽  
Taxonomic Diversity ◽  
Volatile Oils ◽  
Edible Plant ◽  
Flora Of Southern Africa ◽  
Traditional Uses ◽  
History Of ◽  
Pharmaceutical Industries ◽  
History Of Use

The Lamiaceae is undoubtedly an important plant family, having a rich history of use that spans the globe with many species being used in folk medicine and modern industries alike. Their ability to produce aromatic volatile oils has made them valuable sources of materials in the cosmetic, culinary, and pharmaceutical industries. A thorough account of the taxonomic diversity, chemistry and ethnobotany is lacking for southern African Lamiaceae, which feature some of the region’s most notable medicinal and edible plant species. We provide a comprehensive insight into the Lamiaceae flora of southern Africa, comprising 297 species in 42 genera, 105 of which are endemic to the subcontinent. We further explore the medicinal and traditional uses, where all genera with documented uses are covered for the region. A broad review of the chemistry of southern African Lamiaceae is presented, noting that only 101 species (34%) have been investigated chemically (either their volatile oils or phytochemical characterization of secondary metabolites), thus presenting many and varied opportunities for further studies. The main aim of our study was therefore to present an up-to-date account of the botany, chemistry and traditional uses of the family in southern Africa, and to identify obvious knowledge gaps.

scholarly journals Nanomedicine Reformulation of Chloroquine and Hydroxychloroquine

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 175
Author(s):  
David M. Stevens ◽  
Rachael M. Crist ◽  
Stephan T. Stern
Keyword(s):  
Safety Evaluation ◽  
Therapeutic Index ◽  
Short Term ◽  
Tissue Concentrations ◽  
History Of ◽  
History Of Use ◽  
Novel Applications ◽  
Therapeutic Doses ◽  
Extensive Clinical Experience ◽  
Higher Doses

The chloroquine family of antimalarials has a long history of use, spanning many decades. Despite this extensive clinical experience, novel applications, including use in autoimmune disorders, infectious disease, and cancer, have only recently been identified. While short term use of chloroquine or hydroxychloroquine is safe at traditional therapeutic doses in patients without predisposing conditions, administration of higher doses and for longer durations are associated with toxicity, including retinotoxicity. Additional liabilities of these medications include pharmacokinetic profiles that require extended dosing to achieve therapeutic tissue concentrations. To improve chloroquine therapy, researchers have turned toward nanomedicine reformulation of chloroquine and hydroxychloroquine to increase exposure of target tissues relative to off-target tissues, thereby improving the therapeutic index. This review highlights these reformulation efforts to date, identifying issues in experimental designs leading to ambiguity regarding the nanoformulation improvements and lack of thorough pharmacokinetics and safety evaluation. Gaps in our current understanding of these formulations, as well as recommendations for future formulation efforts, are presented.

New Devonian microconchids (Tentaculita) from the Holy Cross Mountains, Poland

2011 ◽  
Vol 85 (4) ◽  
pp. 757-769 ◽  
Author(s):  
Michał Zatoń ◽  
Wojciech Krawczyński
Keyword(s):  
Sedimentation Rate ◽  
Distal Portion ◽  
Taxonomic Composition ◽  
Soft Bottom ◽  
Holy Cross Mountains ◽  
Competition For Space ◽  
High Sedimentation ◽  
New Material ◽  
Three New Species ◽  
Hard Substrates

Tentaculitoid microconchid tubeworms from Devonian (uppermost Emsian-upper Givetian) deposits of the Holy Cross Mountains, Poland, include three new species from stratigraphically well-constrained lithological units:Polonoconchus skalensisn. gen. n. sp.,Palaeoconchus sanctacrucensisn. sp. andMicroconchus vinnin. sp. The microconchids inhabited fully marine environments during transgressive pulses, as is evidenced from facies and associated fossils.Polonoconchus skalensisn. gen. n. sp. andPalaeoconchus sanctacrucensisn. sp. inhabited secondary firm- to hard-substrates in deeper-water, soft-bottom environments. They developed planispiral, completely substrate-cemented tubes and planispiral tubes with elevated apertures, which is indicative of environments where sedimentation rate is low but competition for space (by overgrowth) may be high.Microconchus vinnin. sp., on the other hand, developed a helically coiled distal portion of the tube as a response to a high sedimentation rate. As the taxonomic composition of Devonian microconchids is poorly recognized at both regional and global scales, this new material contributes significantly to our understanding of the diversity of these extinct tube-dwelling encrusters.

The determination of sedimentation rates in Lake Ontario using the 210Pb dating method

1978 ◽  
Vol 15 (3) ◽  
pp. 431-437 ◽  
Author(s):  
John G. Farmer
Keyword(s):  
Sedimentation Rate ◽  
Lake Ontario ◽  
Sedimentary Basins ◽  
210Pb Dating ◽  
Sedimentation Rates ◽  
Surface Mixing ◽  
Dating Method ◽  
210Pb Dating Method

The 210Pb dating method has been applied successfully to the determination of recent sedimentation rates at four sites distributed among the three major sedimentary basins (Niagara, Mississauga and Rochester) of Lake Ontario. Following correction for effects due to compaction of the sediments, mean sedimentation rates ranging from 0.02 cm/year at the periphery of the Mississauga basin to 0.11 cm/year in the Niagara and Rochester basins were determined. Allowance for compaction reduced the non-compaction-corrected sedimentation rates by 20–35%. Neither 210Pb nor fallout 137Cs profiles indicated surface mixing of sediment sufficient to noticeably affect the calculated sedimentation rates. At all four sites, the sedimentation rate seems to have remained constant during the last 100–150 years.

scholarly journals Aquaculture Production of the Brown Seaweeds Laminaria digitata and Macrocystis pyrifera: Applications in Food and Pharmaceuticals

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1306
Author(s):  
Diane Purcell-Meyerink ◽  
Michael A. Packer ◽  
Thomas T. Wheeler ◽  
Maria Hayes
Keyword(s):  
Dietary Supplements ◽  
Functional Foods ◽  
Folk Medicine ◽  
Macrocystis Pyrifera ◽  
Fish Feed ◽  
Laminaria Digitata ◽  
Brown Seaweeds ◽  
Commercial Potential ◽  
History Of ◽  
History Of Use

Seaweeds have a long history of use as food, as flavouring agents, and find use in traditional folk medicine. Seaweed products range from food, feed, and dietary supplements to pharmaceuticals, and from bioenergy intermediates to materials. At present, 98% of the seaweed required by the seaweed industry is provided by five genera and only ten species. The two brown kelp seaweeds Laminaria digitata, a native Irish species, and Macrocystis pyrifera, a native New Zealand species, are not included in these eleven species, although they have been used as dietary supplements and as animal and fish feed. The properties associated with the polysaccharides and proteins from these two species have resulted in increased interest in them, enabling their use as functional foods. Improvements and optimisations in aquaculture methods and bioproduct extractions are essential to realise the commercial potential of these seaweeds. Recent advances in optimising these processes are outlined in this review, as well as potential future applications of L. digitata and, to a greater extent, M. pyrifera which, to date, has been predominately only wild-harvested. These include bio-refinery processing to produce ingredients for nutricosmetics, functional foods, cosmeceuticals, and bioplastics. Areas that currently limit the commercial potential of these two species are highlighted.

A Holocene Marine Climate Record in Mollusc Shells from the Southwest African Coast

1992 ◽  
Vol 38 (3) ◽  
pp. 379-385 ◽  
Author(s):  
Anne L. Cohen ◽  
John E. Parkington ◽  
Geoff B. Brundrit ◽  
Nikolaas J. van der Merwe
Keyword(s):  
Late Quaternary ◽  
Climatic Variability ◽  
Temperature Changes ◽  
Climate Record ◽  
Benguela Upwelling ◽  
Isotope Record ◽  
History Of ◽  
Glacial Expansion ◽  
Sediment Layers ◽  
Marine Climate

AbstractDetails of short-term climatic variability are often lost from marine sediments through bioturbation in the upper, aerobic sediment layers. Alternatively, a high-resolution and dated record of climatic events may be obtained using material preserved in archaeological deposits. The Holocene history of the southern Benguela upwelling regime has been constructed from the oxygen isotope and mineral analysis of midden shells. Three discrete episodes of significant isotope enrichment corresponded to periods of glacial expansion in the northern hemisphere. Significant changes in shell mineralogy, which is a response to sea-surface temperatures, were also recorded. The timing and duration of these changes approximated those in the isotope record and may provide a link between events affecting the subcontinent and global temperature changes of the late Quaternary.

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