scholarly journals HARBOR STUDY FOR SAN NICOLAS BAY, PERU

1970 ◽  
Vol 1 (12) ◽  
pp. 133
Author(s):  
James M. Keith ◽  
Emmett J. Murphy
Keyword(s):  
Particle Velocity ◽  
Time Lapse ◽  
Wave Action ◽  
Ship Motion ◽  
Long Period ◽  
Wave Property ◽  
Directional Wave ◽  
Detailed Interpretation ◽  
Wave Phenomena ◽  
Insight Into

A pair of ducted impeller current meters, one mounted vertically and the other horizontally, were used to measure wave action at San Nicolas Harbor, Peru The horizontal water velocity records are superior to conventional wave records because they measure directly the wave property which induces adverse horizontal ship motion, and provide directional wave data Spectral analysis methods proved well-suited to detailed interpretation of the particle velocity records, while considerable insight into the wave phenomena was gained by simple, rational inspections and interpretations of the records Time-lapse movies of a moored ship, when correlated with simultaneous water particle velocity records, provided an exceptionally clear picture of ship response to wave action, and led to the rather surprising observation that long-period ship motion is not necessarily caused by long-period waves The foregoing ship response was duplicated in hydrau1ic model tests.

Parameterization of Directional Spectra and Its Influence on Ship Motion Predictions

1993 ◽  
Vol 37 (02) ◽  
pp. 138-147
Author(s):  
Ross Graham ◽  
Barbara-Ann Juszko
Keyword(s):  
Spectral Data ◽  
Field Data ◽  
Ship Motion ◽  
Flight Operations ◽  
Modeling Accuracy ◽  
Directional Wave ◽  
Made In

An approach to parameterizing directional spectra proposed by Hogben & Cobb based on a combination of the Ochi & Hubble 6-parameter spectrum and the Longuet-Higgins et al cos2p model is adopted for a study of directional parameterizations and their influence on ship motion predictions. Two schemes for evaluating the directional spreading parameters are assessed in terms of their ability to reproduce highly resolved measured directional spectra, and the best approach, termed the 10-parameter spectrum, is adopted. The applicability of the 10-parameter spectrum to hindcast spectra is investigated, and acceptable fits obtained for 93% of the spectra considered. An evaluation of the ability of the hindcast model to reproduce the measured spectral data is also made. In general, it is found that the differences between the hindcast spectra and associated 10-parameter fits are significantly smaller than the differences between the hindcast spectra and the field data, and it is concluded that the 10-parameter spectrum is a suitable basis for developing statistical descriptions of directional wave climates. The effects of directional parameterization on ship motion predictions are investigated by computing the ship responses as a function of heading for sample hindcast spectra, and the associated 10-parameter and Bretschneider 2-parameter spectra. The responses calculated using the 10-parameter spectrum are found to be in better agreement with the hindcast results than those obtained with the Bretschneider 2-parameter spectrum, with a significant improvement in modeling accuracy in the case of bi-modal spectra. The potential advantages of incorporating the 10-parameter spectrum in future operability analyses of flight operations is examined by comparing the head-to-wind roll response computed using hindcast spectra with that predicted using 10-parameter and Bretschneider spectra.

scholarly journals A family of T6SS antibacterial effectors related to L,D-transpeptidases targets the Peptidoglycan

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Stephanie Sibinelli de Sousa ◽  
Julia Takuno Hespanhol ◽  
Bruno Matsuyama ◽  
Stephane Mesnage ◽  
Gianlucca Nicastro ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Point Mutations ◽  
Time Lapse ◽  
Secretion Systems ◽  
Bacterial Antagonism ◽  
New Family ◽  
Type Vi Secretion ◽  
Altered Cell ◽  
Bacterial Effectors ◽  
Insight Into

Type VI secretion systems (T6SSs) are contractile nanomachines widely used by bacteria to intoxicate competitors. Salmonella Typhimurium encodes a T6SS within the Salmonella pathogenicity island 6 (SPI-6) that is used during competition against species of the gut microbiota. We characterized a new SPI-6 T6SS antibacterial effector named Tlde1 (type VI L,D-transpeptidase effector 1). Tlde1 is toxic in target-cell periplasm and its toxicity is neutralized by co-expression with immunity protein Tldi1 (type VI L,D-transpeptidase immunity 1). Time-lapse microscopy revealed that intoxicated cells display altered cell division and lose cell envelope integrity. Bioinformatics analysis showed that Tlde1 is evolutionarily related to L,D-transpeptidases. Point mutations on conserved histidine121 and cysteine131 residues eliminated toxicity. Co-incubation of purified recombinant Tlde1 and peptidoglycan tetrapeptides showed that Tlde1 displays both L,D-carboxypeptidase activity by cleaving GM-tetrapeptides between meso-diaminopimelic acid3 and D-alanine4, and L,D-transpeptidase exchange activity by replacing D-alanine4 for a non-canonical D-amino acid. Tlde1 constitutes a new family of T6SS effectors widespread in Proteobacteria. This work increases our knowledge about the bacterial effectors used in interbacterial competitions and provides molecular insight into a new mechanism of bacterial antagonism.

Von Malachit zu Kupfer

2017 ◽  
Vol 144 (1) ◽  
Author(s):  
Rainer Nutz
Keyword(s):  
Research Paper ◽  
Long Period ◽  
Air Supply ◽  
Pertinent Data ◽  
Insight Into

SummaryPetrie describes in „Researches in Sinai“ an expedition into Serabit el-Khadim to extract minerals. Newer excavations in Ayn Soukhna allow insight into the reduction of malachite to copper. Reducing malachite to copper proves to be a very energy-intensive process. To obtain the necessary temperatures over a sufficiently long period of time a surprisingly high amount of charcoal has to be mixed with small-grained mineral under constant air supply. In dry climate wood grows comparatively slowly which translates into requirements of larger wooded areas to provide enough wood for the production of charcoal. This research paper aims at collecting pertinent data to improve the transparency of these processes. But only additional parameters will allow better models and help to paint a clearer picture.

Cell behaviour in a polygonal cell sheet*

Development ◽  
1984 ◽  
Vol 83 (Supplement) ◽  
pp. 313-327
Author(s):  
H. Honda ◽  
R. Kodama ◽  
T. Takeuchi ◽  
H. Yamanaka ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Cell Sheet ◽  
Cell Monolayer ◽  
Time Lapse ◽  
Geometrical Method ◽  
Cell Behaviour ◽  
Cell Monolayers ◽  
Polygonal Cell ◽  
Computer Based ◽  
Insight Into

Cell monolayers on culture dishes were divided into two groups: tensile monolayers and non-tensile ones. In the development of an epithelium, a non-tensile cell monolayer turns into a tightly bound tensile one. Detection of these states was carried out by using the boundary shortening procedure, a computer-based geometrical method to show how much the polygonal cell boundary contracts. Non-tensile monolayers were divided further into two groups according to their motility: a fluctuating monolayer in which cells move laterally, and a stable monolayer in which cells are immobilized. Quantitative determination of cell motility was performed by analysing time-lapse cellular patterns. These computer-based geometrical analyses enabled us to divide monolayers into three groups: tensile stable monolayers, non-tensile stable monolayers and fluctuating monolayers, and this study therefore gives an insight into the way in which changing conformations of cells may be assayed.

APPLICATION OF SEMI-AUTOMATED AND INTERACTIVE MAGNETIC INTERPRETATION TECHNIQUES IN PETROLEUM EXPLORATION

1977 ◽  
Vol 17 (1) ◽  
pp. 85
Author(s):  
Robert J. Whiteley ◽  
Barry F. Long ◽  
David A. Pratt
Keyword(s):  
Sedimentary Basin ◽  
Sedimentary Basins ◽  
Magnetic Anomalies ◽  
Petroleum Exploration ◽  
Magnetic Data ◽  
Magnetic Method ◽  
Magnetic Interpretation ◽  
Geological Information ◽  
Detailed Interpretation ◽  
Insight Into

The magnetic method is used at many stages of a modern petroleum exploration program. Effective interpretation techniques are required to extract maximum geological information from magnetic data. Those techniques which provide the greatest flexibility and make full use of the talents of experienced interpreters are generally of a semi-automated and interactive nature.There are several practical methods for semi-automated quantitative magnetic interpretation in sedimentary basins. Initial interpretation can be achieved by automatic calculation of characteristic anomaly parameters continuously along original or processed magnetic data profiles. Detailed interpretation of more subtle magnetic features can then follow by theoretical anomaly comparison with field anomalies using interactive portfolio modelling or by direct computation.Examples of the use of these semi-automated techniques in the interpretation of basement and intra-sedimentary magnetic anomalies show that combined magnetic and seismic interpretations can provide considerable insight into the structural processes which have operated in a sedimentary basin.

Real-Time Estimation of Directional Wave Spectra Using Non-Stationary Ship Motion Data

2009 ◽  
Author(s):  
Toshio Iseki
Keyword(s):  
Stochastic Processes ◽  
Real Time ◽  
Time Estimation ◽  
Ship Motion ◽  
Wave Spectra ◽  
Time Step ◽  
Motion Data ◽  
Stationary Stochastic Processes ◽  
Real Time Estimation ◽  
Directional Wave

The Bayesian modeling procedure is modified for real-time estimation of directional wave spectra using non-stationary ship motion data. The assumption of stationary stochastic processes is applied to the seaway, but not to ship response because it also depends on ship maneuvers. Ship response is strongly affected by changes in the encounter angle and frequency of waves. Therefore, it is need to be a real-time algorithm that can deal with non-stationary stochastic processes and estimate the directional wave spectra. In the proposed algorithm, the iterative calculations of the non-linear equations were optimized and the convergence was not achieved at every time step, but was achieved gradually over several time steps. In order to examine the reliability of the proposed method, real-time estimation was conducted by using the data of onboard experiments. Comparisons between the results of the proposed algorithm and a wave monitoring radar system show good agreements.

scholarly journals Plasmid segregation: spatial awareness at the molecular level

2007 ◽  
Vol 179 (5) ◽  
pp. 813-815 ◽  
Author(s):  
Jakob Møller-Jensen ◽  
Kenn Gerdes
Keyword(s):  
Molecular Level ◽  
Time Lapse ◽  
Spatial Awareness ◽  
Division Plane ◽  
Plasmid Partition ◽  
Plasmid Segregation ◽  
Low Copy Number ◽  
Coli Plasmid ◽  
Cell Division Plane ◽  
Insight Into

In bacteria, low-copy number plasmids ensure their stable inheritance by partition loci (par), which actively distribute plasmid replicates to each side of the cell division plane. Using time-lapse fluorescence microscopic tracking of segregating plasmid molecules, a new study provides novel insight into the workings of the par system from Escherichia coli plasmid R1. Despite its relative simplicity, the plasmid partition spindle shares characteristics with the mitotic machinery of eukaryotic cells.

scholarly journals Timing of meristem initiation and maintenance determines the morphology of fern gametophytes

2021 ◽  
Author(s):  
Xiao Wu ◽  
An Yan ◽  
Scott McAdam ◽  
Jo Ann Banks ◽  
Shaoling Zhang ◽  
...  
Keyword(s):  
Vascular Plants ◽  
Plant Architecture ◽  
Time Lapse ◽  
Seed Plants ◽  
Cellular Mechanisms ◽  
Free Living ◽  
Meristem Development ◽  
Insight Into ◽  
Fern Gametophytes ◽  
Alternation Of Generations

The alternation of generations in land plants occurs between the sporophyte phase and the gametophyte phase. The sporophytes of seed plants develop self-maintained, multicellular meristems, and these meristems determine plant architecture. The gametophytes of seed plants lack meristems and are heterotrophic. In contrast, the gametophytes of seed-free vascular plants, including ferns, are autotrophic and free-living, developing meristems to sustain their independent growth and proliferation. Compared to meristems in the sporophytes of seed plants, the cellular mechanisms underlying meristem development in fern gametophytes remain largely unknown. Here, using confocal time-lapse live imaging and computational segmentation and quantification, we determined different patterns of cell divisions associated with the initiation and proliferation of two distinct types of meristems in fern gametophytes. Our results reveal how the simple timing of a switch between two meristems has considerable consequences for the divergent gametophyte morphologies of two closely related ferns from Pteridaceae (Pteris and Ceratopteris). Our result provides evolutionary insight into the function and regulation of gametophyte meristems in seed-free vascular plants.

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