Gravity inversion using seminorm minimization: Density modeling of Jasper Seamount

Geophysics ◽  
1991 ◽  
Vol 56 (1) ◽  
pp. 68-79 ◽  
Author(s):  
P. T. C. Hammer ◽  
J. A. Hildebrand ◽  
R. L. Parker
Keyword(s):  
Dense Body ◽  
Gravity Anomalies ◽  
Density Variation ◽  
Average Density ◽  
The Body ◽  
Gravity Inversion ◽  
Inversion Algorithm ◽  
Density Distributions ◽  
The Family ◽  
Uniform Model

A gravity inversion algorithm for modeling discrete bodies with nonuniform density distributions is presented. The algorithm selects the maximally uniform model from the family of models which fit the data, ensuring a conservative and unprejudiced estimate of the density variation within the body. The only inputs required by the inversion are the gravity anomaly field and the body shape. Tests using gravity anomalies generated from synthetic bodies confirm that seminorm minimizing inversions successfully represent mass distribution trends but do not reconstruct sharp discontinuities. We apply the algorithm to model the density structure of seamounts. Inversion of the seasurface gravity field observed over Jasper Seamount suggests the edifice has a low average density of [Formula: see text] and contains a dense body within its western flank. These results are consistent with seismic, magnetic, and petrologic studies of Jasper Seamount.

Topography of the crust–mantle interface under the Western Superior craton from gravity data

2003 ◽  
Vol 40 (10) ◽  
pp. 1307-1320 ◽  
Author(s):  
B Nitescu ◽  
A R Cruden ◽  
R C Bailey
Keyword(s):  
Gravity Data ◽  
Three Dimensional ◽  
Gravity Anomalies ◽  
Gravity Inversion ◽  
Constant Density ◽  
Inversion Algorithm ◽  
Data Set ◽  
Mantle Boundary ◽  
Refraction Seismic ◽  
Superior Craton

The Moho undulations beneath the western part of the Archean Superior Province have been investigated with a three-dimensional gravity inversion algorithm for a single interface of constant density contrast. Inversion of the complete gravity data set produces unreal effects in the solution due to the ambiguity in the possible sources of some crustal gravity anomalies. To avoid these effects a censored gravity data set was used instead. The inversion results are consistent with reflection and refraction seismic data from the region and, therefore, provide a basis for the lateral correlation of the Moho topography between parallel seismic lines. The results indicate the existence of a major linear east–west-trending rise of the Moho below the metasedimentary English River subprovince, which is paralleled by crustal roots below the granite–greenstone Uchi and Wabigoon subprovinces. This correlation between the subprovincial structure at the surface and deep Moho undulations suggests that the topography of the crust–mantle boundary is related to the tectonic evolution of the Western Superior belts. Although certain features of the crust–mantle boundary are likely inherited from the accretionary and collisional stages of the Western Superior craton, gravity-driven processes triggered by subsequent magmatism and crustal softening may have played a role in both the preservation of those features, as well as in the development of new ones.

Minimum-structure borehole gravity inversion for mineral exploration: A synthetic modeling study

Geophysics ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. G25-G39 ◽  
Author(s):  
Craig R. W. Mosher ◽  
Colin G. Farquharson
Keyword(s):  
Reference Model ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Synthetic Data ◽  
Density Variation ◽  
Gravity Inversion ◽  
Inversion Algorithm ◽  
Borehole Data ◽  
Text Type ◽  
The Impact

A borehole gravimeter for the diameters of holes typically used in mineral exploration has recently been developed. Investigating how the data from such instruments can contribute to the gravity interpretation procedures used in mineral exploration is therefore appropriate. Here, results are presented from a study in which synthetic data for 3D exploration-relevant earth models were inverted and the impact of borehole data assessed. The inversions were carried out using a minimum-structure procedure that is typical of those commonly used to invert surface gravity data. Examples involving data from a single borehole, from multiple boreholes, and combinations of borehole and surface data, are considered. Also, a range of options for the particulars of the inversion algorithm are investigated, including using a reference model and cell weights to incorporate along-borehole density information, and an [Formula: see text]-type measure of model structure. The selection of examples presented demonstrates what one can and cannot expect to determine about the density variation around and between boreholes when borehole gravity data are inverted using a minimum-structure approach. Specifically, the density variation along a borehole can be accurately determined, even without constraints in the inversion, but this capability decreases dramatically a few tens of meters from a borehole.

Three new species, two new genera, and new family Biphragmosagittidae (Сhaetognatha) from Southwest Pacific Ocean

2011 ◽  
Vol 20 (1) ◽  
pp. 161-173
Author(s):  
A.P. Kassatkina
Keyword(s):  
New Species ◽  
Type Species ◽  
Morphological Characters ◽  
The Body ◽  
New Order ◽  
New Genera ◽  
New Family ◽  
The Family ◽  
Three New Species

Resuming published and own data, a revision of classification of Chaetognatha is presented. The family Sagittidae Claus & Grobben, 1905 is given a rank of subclass, Sagittiones, characterised, in particular, by the presence of two pairs of sac-like gelatinous structures or two pairs of fins. Besides the order Aphragmophora Tokioka, 1965, it contains the new order Biphragmosagittiformes ord. nov., which is a unique group of Chaetognatha with an unusual combination of morphological characters: the transverse muscles present in both the trunk and the tail sections of the body; the seminal vesicles simple, without internal complex compartments; the presence of two pairs of lateral fins. The only family assigned to the new order, Biphragmosagittidae fam. nov., contains two genera. Diagnoses of the two new genera, Biphragmosagitta gen. nov. (type species B. tarasovi sp. nov. and B. angusticephala sp. nov.) and Biphragmofastigata gen. nov. (type species B. fastigata sp. nov.), detailed descriptions and pictures of the three new species are presented.

scholarly journals “It’s Always Been a Second Class Cancer”: An Exploration of the Experiences and Journeys of Bereaved Family Carers of People with Sarcoma

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2670
Author(s):  
Moira O’Connor ◽  
Greta Smith ◽  
Ashleigh Pantaleo ◽  
Darren Haywood ◽  
Rhys Weaver ◽  
...  
Keyword(s):  
Palliative Care ◽  
Family Member ◽  
The Body ◽  
Social Constructionist ◽  
Family Carers ◽  
Writing Therapy ◽  
The Family ◽  
Qualitative Descriptive ◽  
Bereaved Family ◽  
Delays In Diagnosis

Sarcomas are a group of rare and aggressive cancers, which develop in bones and connective tissue throughout the body. Sarcomas account for only 1–2% of all cancers worldwide; however, mortality rates for sarcoma are high with approximately two in four sarcoma patients dying following a diagnosis. Delays in diagnosis, poor management of symptoms, patients’ high symptom loads and high carer burden are all associated with carer distress, which may lead to complications after bereavement. The experience of having a family member referred for palliative care is also distressing for carers, with the realisation that their family member is dying. This study aimed to explore the experiences of bereaved family carers of people diagnosed with sarcoma. A qualitative descriptive design using a social constructionist framework was adopted. Interviews were conducted with sixteen participants, and thematic analysis was used to identify patterns in the data. Four overarching themes emerged: beginning the journey; moving through treatment; transitioning to palliative care; and experiencing bereavement. The narratives were coherent and potent, and people reflected on their journeys. Interventions and supports for bereaved carers could include opportunities for counselling to support reflections, supports for developing a narrative such as writing therapy, and preparation for the death of the family member.

scholarly journals Primary Congenital Lymphedema with More Than 10 Years of Treatment Using the Godoy Method Through to Adolescence

2021 ◽  
Vol 13 (1) ◽  
pp. 91-94
Author(s):  
Ana Carolina Pereira de Godoy ◽  
Jose Maria Pereira de Godoy ◽  
Maria de Fatima Guerreiro Godoy
Keyword(s):  
Treatment Period ◽  
Clinical Diagnosis ◽  
Treatment Option ◽  
Therapeutic Option ◽  
The Body ◽  
The Family ◽  
Cervical Stimulation

Introduction: Lymphedema is a specific type of edema that affects regions of the body in a chronic, progressive manner. Aim: The aim of the present study was to describe the therapeutic evolution of more than ten years of treatment for primary congenital lymphedema using the Godoy and Godoy method. Method: Ten children with primary congenital lymphedema with more than ten years of treatment at the Godoy Clinic were evaluated. Children with a clinical diagnosis of primary congenital lymphedema in treatment for more than 10 years with the Godoy Method. Cervical stimulation is the first treatment option of the method and is performed as monotherapy. The patients were reevaluated with weekly, bi-weekly and monthly frequencies and then every three months or when the family was able to return to the clinic. Results: For cases in which cervical stimulation was not possible, grosgrain stockings as monotherapy was the second therapeutic option. Conclusion: The Godoy and Godoy Method is effective at reducing edema in cases of primary congenital lymphedema, with the maintenance of the results throughout the treatment period.

Assessing Model Uncertainty for the Scaling Function Inversion of Potential Fields

Geophysics ◽  
2021 ◽  
pp. 1-39
Author(s):  
Mahak Singh Chauhan ◽  
Ivano Pierri ◽  
Mrinal K. Sen ◽  
Maurizio FEDI
Keyword(s):  
Simulated Annealing Algorithm ◽  
Scaling Function ◽  
Vertical Section ◽  
Gravity Data ◽  
Geometric Model ◽  
Salt Dome ◽  
The Body ◽  
Gravity Inversion ◽  
Geometrical Parameters ◽  
The Scaling Function

We use the very fast simulated annealing algorithm to invert the scaling function along selected ridges, lying in a vertical section formed by upward continuing gravity data to a set of altitudes. The scaling function is formed by the ratio of the field derivative by the field itself and it is evaluated along the lines formed by the zeroes of the horizontal field derivative at a set of altitudes. We also use the same algorithm to invert gravity anomalies only at the measurement altitude. Our goal is analyzing the different models obtained through the two different inversions and evaluating the relative uncertainties. One main difference is that the scaling function inversion is independent on density and the unknowns are the geometrical parameters of the source. The gravity data are instead inverted for the source geometry and the density simultaneously. A priori information used for both the inversions is that the source has a known depth to the top. We examine the results over the synthetic examples of a salt dome structure generated by Talwani’s approach and real gravity datasets over the Mors salt dome and the Decorah (USA) basin. For all these cases, the scaling function inversion yielded models with a better sensitivity to specific features of the sources, such as the tilt of the body, and reduced uncertainty. We finally analyzed the density, which is one of the unknowns for the gravity inversion and it is estimated from the geometric model for the scaling function inversion. The histograms over the density estimated at many iterations show a very concentrated distribution for the scaling function, while the density contrast retrieved by the gravity inversion, according to the fundamental ambiguity density/volume, is widely dispersed, this making difficult to assess its best estimate.

scholarly journals A new species of Characidium (Characiformes: Crenuchidae) from small coastal drainages in northeastern Brazil, with remarks on the pseudotympanum of some species of the genus

2014 ◽  
Vol 12 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Angela M. Zanata ◽  
Priscila Camelier
Keyword(s):  
New Species ◽  
Lateral Line ◽  
The Body ◽  
Northeastern Brazil ◽  
Horizontal Scale ◽  
Caudal Peduncle ◽  
Transversal Line ◽  
Lateral Band ◽  
The Family ◽  
A New Species

Characidium samurai, a species of the family Crenuchidae apparently endemic to rio das Almas and rio Vermelho basins, Bahia, Brazil, is described. The new species is readily distinguishable from its congeners, except C. lanei, by having a dark lateral band along the head and body that is particularly broad from the rear of the head to the end of the caudal peduncle (1.5 or 2 scales wide) and by the absence of dark bars or blotches on the ventral half of the body. Characidium samurai differs from C. laneiby having the lateral band with straight borders overall (vs.lateral band with somewhat irregular borders due to blotches extending dorsally or ventrally), anal fin ii,7-8 (vs. ii,6), and 4 horizontal scale rows above the lateral line and 4 below (vs. 5/3). It further differs from congeners by a series of features, including isthmus completely covered by scales, lateral line complete with 34-37 perforated scales, 9 scales on the transversal line, 14 scale rows around the caudal peduncle, anal fin ii,7-8, and the absence of dark bars or spots on the fins, except by a faded dorsal-fin bar. The presence of pseudotympanum in four species of Characidium is discussed.

scholarly journals Morphology of lateral line canals in Neotropical freshwater stingrays (Chondrichthyes: Potamotrygonidae) from Negro River, Brazilian Amazon

2010 ◽  
Vol 8 (4) ◽  
pp. 867-876 ◽  
Author(s):  
Akemi Shibuya ◽  
Jansen Zuanon ◽  
Maria Lúcia G. de Araújo ◽  
Sho Tanaka
Keyword(s):  
Lateral Line ◽  
The Body ◽  
Mechanical Stimuli ◽  
High Concentration ◽  
Ventral Region ◽  
Negro River ◽  
Accurate Localization ◽  
Posterior Lateral Line ◽  
The Family ◽  
The Relationship

The relationship between the distribution of the lateral line canals and their functionality has not been well examined in elasmobranchs, especially among Neotropical freshwater stingrays of the family Potamotrygonidae. The spatial distribution of the canals and their tubules and the quantification of the neuromasts were analyzed in preserved specimens of Potamotrygon motoro, P. orbignyi, Potamotrygon sp. "cururu", and Paratrygon aiereba from the middle Negro River, Amazonas, Brazil. The hyomandibular, infraorbital, posterior lateral line, mandibular, nasal and supraorbital canals were characterized and their pores and neuromasts quantified. The ventral canals are known to facilitate the accurate localization of prey items under the body, and our results indicate that the dorsal canals may be employed in identifying the presence of predators or potential prey positioned above the stingray's body. The presence of non-pored canals in the ventral region may be compensated by the high concentration of neuromasts found in the same area, which possibly allow the accurate detection of mechanical stimuli. The concentration of non-pored canals near the mouth indicates their importance in locating and capturing prey buried in the bottom substrate, possibly aided by the presence of vesicles of Savi.

Philometra barbata n. sp. (Nematoda: Philometridae) from the red mullet Mullus barbatus (Perciformes, Mullidae) off Tunisia

2018 ◽  
Vol 63 (4) ◽  
pp. 766-771 ◽  
Author(s):  
Nessrine Ghanmi ◽  
David González-Solís ◽  
Lamia Gargouri
Keyword(s):  
New Species ◽  
Mediterranean Sea ◽  
Body Length ◽  
Nematode Species ◽  
The Body ◽  
Nominal Species ◽  
Congeneric Species ◽  
Red Mullet ◽  
Mullus Barbatus ◽  
The Family

Abstract Helminthological examinations of the red mullet Mullus barbatus (Linnaeus) (Mullidae) from the Gulf of Hammamet, off Tunisia, revealed the presence of one undescribed gonad-infecting nematode species, Philometra barbata n. sp. (Philometridae). The new species as other congeneric species is mainly characterized by the shape of the caudal mound, the distribution of the caudal papillae and the shape of the gubernaculum with the presence of a dorsal protuberance consisting of two dorsolateral lamellar parts separated from each other by a smooth median field in the male. The new species differs from its gonadinfecting congeners in the body length of male, the length of spicules and gubernaculum. This is the second nominal species of Philometra reported from fishes of the family Mullidae and the 14th from the Mediterranean Sea.

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