scholarly journals Mid-Cretaceous acanthomorph fishes with the description of a new species from the Turonian of Lac des Bois, Northwest Territories, Canada

2016 ◽  
Vol 1 ◽  
pp. 101 ◽  
Author(s):  
Alison M Murray
Keyword(s):  
Northwest Territories ◽  
Neural Spine ◽  
Single Specimen ◽  
Western Interior Seaway ◽  
Incertae Sedis ◽  
Comprehensive Survey ◽  
The Subject ◽  
Future Work ◽  
A New Species ◽  
Cretaceous Deposits

A single specimen of a new acanthomorph fish is described from a Turonian locality sampling the northern part of the Cretaceous Western Interior Seaway. This brings to three the number of acanthomorphs from Lac des Bois, Northwest Territories, Canada. The previously named acanthomorph, Boreiohydrias dayi (Boriohydriidae), was placed in the Polymixiiformes. The second, represented by a poorly preserved fish, was left unnamed and incertae sedis in Acanthomorpha. The new one described here, Cumbaaichthys oxyrhynchus gen. et sp. nov. cannot be easily placed in any previously described families. This fish is placed in the Polymixiiformes based on the caudal skeleton having 18 principal rays (16 branched), and having a full neural spine on the second preural centrum. Polymixiiform relationships are not well established but they are the subject of several current studies; therefore, the new acanthomorph is placed incertae sedis within this order but with the understanding that this placement may be refined with future work. Previous studies have suggested that acanthomorphs may have flourished with warming climates of the Cenomanian–Turonian. A comprehensive survey of named acanthomorphs from mid-Cretaceous deposits shows there are more species known from the Cenomanian rather than the Turonian, although this may be biased by the age of known fossiliferous deposits.

Anisotropic Elasticity

1996 ◽  
Author(s):  
T. T. C. Ting
Keyword(s):  
Composite Materials ◽  
Elastic Constants ◽  
Piezoelectric Materials ◽  
Anisotropic Materials ◽  
Anisotropic Elasticity ◽  
Stress Singularities ◽  
Comprehensive Survey ◽  
The Subject ◽  
Key Topics ◽  
First Time

Anisotropic Elasticity offers for the first time a comprehensive survey of the analysis of anisotropic materials that can have up to twenty-one elastic constants. Focusing on the mathematically elegant and technically powerful Stroh formalism as a means to understanding the subject, the author tackles a broad range of key topics, including antiplane deformations, Green's functions, stress singularities in composite materials, elliptic inclusions, cracks, thermo-elasticity, and piezoelectric materials, among many others. Well written, theoretically rigorous, and practically oriented, the book will be welcomed by students and researchers alike.

scholarly journals Sensorimotor impairment from a new analog of spaceflight-altered neurovestibular cues

2020 ◽  
Vol 123 (1) ◽  
pp. 209-223
Author(s):  
Jordan B. Dixon ◽  
Torin K. Clark
Keyword(s):  
Head Tilt ◽  
Semicircular Canals ◽  
Control Groups ◽  
Head Restraint ◽  
The Subject ◽  
Sensorimotor Impairment ◽  
Self Motion ◽  
Future Work ◽  
Extended Exposure ◽  
Sensorimotor Performance

Exposure to microgravity during spaceflight causes central reinterpretations of orientation sensory cues in astronauts, leading to sensorimotor impairment upon return to Earth. Currently there is no ground-based analog for the neurovestibular system relevant to spaceflight. We propose such an analog, which we term the “wheelchair head-immobilization paradigm” (WHIP). Subjects lie on their side on a bed fixed to a modified electric wheelchair, with their head restrained by a custom facemask. WHIP prevents any head tilt relative to gravity, which normally produces coupled stimulation to the otoliths and semicircular canals, but does not occur in microgravity. Decoupled stimulation is produced through translation and rotation on the wheelchair by the subject using a joystick. Following 12 h of WHIP exposure, subjects systematically felt illusory sensations of self-motion when making head tilts and had significant decrements in balance and locomotion function using tasks similar to those assessed in astronauts postspaceflight. These effects were not observed in our control groups without head restraint, suggesting the altered neurovestibular stimulation patterns experienced in WHIP lead to relevant central reinterpretations. We conclude by discussing the findings in light of postspaceflight sensorimotor impairment, WHIP’s uses beyond a spaceflight analog, limitations, and future work. NEW & NOTEWORTHY We propose, implement, and demonstrate the feasibility of a new analog for spaceflight-altered neurovestibular stimulation. Following extended exposure to the analog, we found subjects reported illusory self-motion perception. Furthermore, they demonstrated decrements in balance and locomotion, using tasks similar to those used to assess astronaut sensorimotor performance postspaceflight.

New olenelline trilobites from the Northwest Territories, Canada, and the phylogenetic placement of Judomia absita Fritz, 1973

Zootaxa ◽  
2011 ◽  
Vol 2918 (1) ◽  
pp. 15 ◽  
Author(s):  
I. WESLEY GAPP ◽  
BRUCE S. LIEBERMAN ◽  
MICHAEL C. POPE ◽  
KELLY A. DILLIARD
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Northwest Territories ◽  
Phylogenetic Analyses ◽  
Geographic Range ◽  
Early Cambrian ◽  
Phylogenetic Placement ◽  
The Subject ◽  
Three New Species ◽  
One New Species

The Early Cambrian olenelline trilobites are a diverse clade and have been the subject of several phylogenetic analyses. Here, three new species of Bradyfallotaspis Fritz, 1972 (B. coriae, B. nicolascagei, and B. sekwiensis) and one new species of Nevadia Walcott, 1910 (N. saupeae) are described from the Sekwi Formation of the Mackenzie Mountains, Northwest Territories, Canada. In addition, new specimens potentially referable to Nevadia ovalis McMenamin, 1987 were recovered that may expand that species’ geographic range, which was thought to be restricted to Sonora, Mexico. The results of a phylogenetic analysis incorporating several olenelline taxa, including Judomia absita Fritz, 1973 from the Sekwi Formation, are also presented herein. This species has been assigned to various olenelline genera, including Judomia Lermontova, 1951 and Paranevadella Palmer & Repina, 1993. Phylogenetic analysis suggests this species is closely related to Judomia tera Lazarenko, 1960 from Siberia. This phylogenetic relationship provides further support for the hypothesis that a close biogeographic relationship existed between Laurentia and Siberia during the Cambrian.

scholarly journals A Comparative Study of Target Tracking Approaches in Wireless Sensor Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Asmaa Ez-Zaidi ◽  
Said Rakrak
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Target Tracking ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Future Directions ◽  
Wide Range ◽  
Comprehensive Survey ◽  
The Subject ◽  
Intense Research

Wireless sensor networks have been the subject of intense research in recent years. Sensor nodes are used in wide range of applications such as security, military, and environmental monitoring. One of the most interesting applications in wireless sensor networks is target tracking, which mainly consists in detecting and monitoring the motion of mobile targets. In this paper, we present a comprehensive survey of target tracking approaches. We then analyze them according to several metrics. We also discuss some of the challenges that influence the performance of tracking schemes. In the end, we conduct detailed analysis and comparison between these algorithms and we conclude with some future directions.

Marine tube-dwelling diatoms of eastern Canada: descriptions, checklist, and illustrated key

1984 ◽  
Vol 62 (4) ◽  
pp. 778-794 ◽  
Author(s):  
Christopher S. Lobban
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Common Species ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
The Common ◽  
Living Material ◽  
St Lawrence Estuary ◽  
A New Species

From a study of living materials and specimens in several regional herbaria, a list has been drawn up of all the common and several of the rarer tube-dwelling diatoms of eastern Canada. Descriptions, illustrations of living material and acid-cleaned valves, and a key to the species are provided. Most specimens were from the Atlantic Provinces and the St. Lawrence estuary, but a few were from the Northwest Territories. By far the most common species is Berkeleya rutilans. Other species occurring commonly in the Quoddy Region of the Bay of Fundy, and sporadically in space and time elsewhere, arc Navicula delognei (two forms), Nav. pseudocomoides, Nav. smithii, Haslea crucigera, and a new species, Nav.rusticensis. Navicula ramosissima and Nav. mollis in eastern Canada are usually found as scattered cohabitants in tubes of other species. Nitzschia tubicola and Nz. fontifuga also occur sporadically as cohabitants.

Occella impi, a New Species of Sea Poacher from British Columbia with Notes on Related Species (Agonidae, Pisces)

1970 ◽  
Vol 27 (6) ◽  
pp. 1109-1114 ◽  
Author(s):  
C. G. Gruchy
Keyword(s):  
British Columbia ◽  
New Species ◽  
Related Species ◽  
Single Specimen ◽  
Queen Charlotte Islands ◽  
A New Species

Occella impi, a new species of sea poacher, is described from a single specimen captured in the Queen Charlotte Islands, British Columbia. Occella impi differs from other species of Occella in having spinous plates on the breast, the anus nearer the anal fin, and fewer anal rays; also, the numbers of bony body plates are distinctive. A key to the known species of Occella, based primarily on the numbers of bony body plates, is included. The size of the maxillary barbel and number of infralateral plates are shown to be characteristic of the genera Occella and Stellerina.

scholarly journals Gobiesox lanceolatus, a new species of clingfish (Teleostei:  Gobiesocidae) from Los Frailes submarine canyon, Gulf of California, Mexico

Zootaxa ◽  
2017 ◽  
Vol 4221 (3) ◽  
pp. 393 ◽  
Author(s):  
PHILIP A. HASTINGS ◽  
KEVIN W. CONWAY
Keyword(s):  
New Species ◽  
Posterior Margin ◽  
Gulf Of California ◽  
Baja California ◽  
Submarine Canyon ◽  
Single Specimen ◽  
Dorsal Fin ◽  
Fin Rays ◽  
A New Species ◽  
Pectoral Fin Rays

Gobiesox lanceolatus is described from a single specimen collected from 300 meters depth in the Los Frailes submarine canyon in the southwestern Gulf of California. The "Canyon Clingfish" is unique within Gobiesox in having a lanceolate caudal fin, with the central rays longer than those above and below them. It is also distinguished by 14 dorsal-fin rays (first tiny and unsegmented), 11 anal-fin rays, 28 pectoral-fin rays, anus slightly closer to anal-fin origin than to posterior margin of pelvic disc, and dorsal-fin origin in front of vertical from anus. It is most similar to Gobiesox eugrammus, known from Isla Guadelupe, the coast of outer Baja California and southern California. This is the deepest record for a species of Gobiesox and only four other species of clingfishes are known from greater depths. 

scholarly journals The first fossil wedge-shaped beetle (Coleoptera, Ripiphoridae) from the middle Jurassic of China

2017 ◽  
Author(s):  
Yun Hsiao ◽  
Yali Yu ◽  
Congshuang Deng ◽  
Hong Pang
Keyword(s):  
New Species ◽  
Middle Jurassic ◽  
Inner Mongolia ◽  
Host Preference ◽  
Potential Host ◽  
Incertae Sedis ◽  
Jiulongshan Formation ◽  
Wood Boring ◽  
A New Species

A new species of Ripiphoridae Gemminger & Harold, 1870, Archaeoripiphorus nuwa gen. et sp. nov., is described and illustrated from a well-preserved impression fossil from the Middle Jurassic Jiulongshan Formation collected at Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China, representing the oldest documented occurrence of the Ripiphoridae described from the Mesozoic era. It shares several characters belonging to two basal ripiphorid subfamilies (Pelecotominae and Ptilophorinae), but it cannot be attributed to either of them and is herein placed as Subfamily incertae sedis. An overall similarity between Archaeoripiphorus gen. nov. and Recent Pelecotominae and the occurrence of wood-boring beetles in the same Formation implies a similar parasitoid host preference in xylophagous beetles for A. nuwa gen. et sp. nov., putting a spotlight on a potential host-parasitoid relationship in the Mesozoic.

scholarly journals Biodiversity of bulbous and tuberous geophytes from the El Kala National Park (North-Eastern Algeria): checklist, vulnerability and conservation

2019 ◽  
pp. 25-38
Author(s):  
Besma Dechir ◽  
Atef Chouikh ◽  
Tarek Hamel ◽  
Nawel Nadia Azizi ◽  
Nawel Ganaoui ◽  
...  
Keyword(s):  
New Species ◽  
Environmental Variables ◽  
National Park ◽  
Multivariate Analyses ◽  
North Eastern ◽  
Floristic Analysis ◽  
The Subject ◽  
Eastern Algeria ◽  
A New Species

Treinta estaciones en el Parque Nacional El Kala (Noreste de Argelia) fueron objeto de un inventario florístico que se centró en el estudio de la ecología de geófitos bulbosos y tuberosos. La flora se caracteriza por una alta proporción de taxones raros y/o endémicos, entre ellos, 6 especies son endemismos algero-tunecinos pertenecientes a la familia Orchidaceae. En este trabajo, se da a conocer la presencia de una nueva especie para la flora argelina, Ophrys fusca subsp. lupercalis. Los análisis multivariantes revelaron, ciertas variables ambientales que determinan la distribución de los geófitos. Los lugares de interés son particularmente sensibles a las amenazas, particularmente las de origen antrópico. Thirty stations at the El Kala National Park (North Eastern Algeria) were the subject of a floristic focused on the study of the ecology of bulbous and tuberous geophytes. The floristic analysis was used to draw up a checklist of 67 species belonging to 36 genera and 14 families, among of which 19 species a high proportion of rare and/or endemic taxa; among them six signed taxa are endemic to algerian-tunisian mainly represented by family of Orchidaceae. In this work, we recorded the presence of a new species for the Algerian flora which is Ophrys fusca subsp. lupercalis. Multivariate analyses revealed certain environmental variables determining the distribution of geophytes. The visited sites show an alarming vulnerability and subject to threats, particularly anthropogenic ones.

A Program for an Investigation of the Rudder-Torque Problem

1965 ◽  
Vol 2 (03) ◽  
pp. 282-298
Author(s):  
Karl E. Schoenherr
Keyword(s):  
Research Program ◽  
Current Knowledge ◽  
Lateral Force ◽  
The Status ◽  
The Subject ◽  
Future Work ◽  
Marine Engineers

Panel H-10 (Controllability) of The Society of Naval Architects and Marine Engineers Technical and Research Program was requested to undertake an investigation of existing uncertainties in pre-calculating rudder torque and lateral force. In order to become quickly familiar with the subject and prospects therein, the Panel commissioned the author of this paper to survey the status of current knowledge of the subject and prepare a report of the findings. In particular, this report was to identify the most promising approaches for future work leading to an ultimate solution of the problem and to include technical descriptions of proposed programs for an exhaustive investigation, all of which are discussed in this paper.

Sign in / Sign up

Export Citation Format

Share Document