scholarly journals RESULTS OF OBSERVATIONS OF MAXIMA OF PULSATING STARS

2021 ◽  
Vol 57 (1) ◽  
pp. 241-246
Author(s):  
J. H. Peña ◽  
H. Huepa ◽  
D. S. Piña ◽  
J. Guillén ◽  
A. Rentería ◽  
...  

The systematic study of some HADS stars, recognized as variables for decades, has allowed us to provide data on their secular variations through O-C analysis. However, some of the data have large gaps without observations. This is our motivation for continuously observing these stars as part of the research carried out by the “Grupo de Astronomía Observacional del Observatorio de Tonantzintla” (GAOOT). This article is our third compilation of times of maxima for pulsating stars. These observations have been carried out at the Observatorio Astronómico Nacional de Tonantzintla (TNT) and San Pedro Mártir (SPM), México and for the first time we also present data from the Complejo Astronómico de Cota Cota, Bolivia (Universidad Mayor de San Andrés) and the Observatorio Astronómico Centroamericano de Suyapa, Honduras (Universidad Nacional Autónoma de Honduras).

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 85603-85611 ◽  
Author(s):  
Jinyang Wang ◽  
Wei Gao ◽  
Haimin Zhong ◽  
Canjian Liang ◽  
Xiaojuan Chen ◽  
...  

Intradiffusion coefficients ofN,N-dimethylformamide (DDMF) and water (DW) in their mixtures were measured as a function of temperature, pressure and composition for the first time using the PGSE-NMR technique.


2012 ◽  
Vol 13 (1) ◽  
pp. 89 ◽  
Author(s):  
L.M. FERRERO-VICENTE ◽  
A. LOYA-FERNANDEZ ◽  
C. MARCO-MENDEZ ◽  
E. MARTINEZ-GARCIA ◽  
J.I. SAIZ-SALINAS ◽  
...  

Specimens of the sipunculan worm Phascolion (Phascolion) caupo Hendrix, 1975 have been collected for the first time in the Mediterranean Sea, thus increasing the number of known sipunculan species of up to 36 in this area. They were encountered on soft bottoms from the coast of San Pedro del Pinatar (Western Mediterranean). Thirty specimens were collected at a depth ranging from 32.6 to 37.2 m, mainly in sandy substrata with high load of silt and clays. 80% of the individuals were found inhabiting empty shells of gastropods or empty tubes of serpulid polychaetes.


2020 ◽  
Vol 115 ◽  
pp. 175-245
Author(s):  
Vassilis L. Aravantinos ◽  
Ioannis Fappas ◽  
Yannis Galanakis

Questions were raised in the past regarding the use of Mycenaean tiles as ‘roof tiles’ on the basis of the small numbers of them recovered in excavations and their overall scarcity in Mycenaean domestic contexts. The investigation of the Theodorou plot in 2008 in the southern part of the Kadmeia hill at Thebes yielded the single and, so far, largest known assemblage per square metre of Mycenaean tiles from a well-documented excavation. This material allows, for the first time convincingly, to identify the existence of a Mycenaean tiled roof. This paper presents the results of our work on the Theodorou tiles, placing emphasis on their construction, form and modes of production, offering the most systematic study of Mycenaean tiles to date. It also revisits contexts of discovery of similar material from excavations across Thebes. Popular as tiles might have been in Boeotia, and despite their spatially widespread attestation, their use in Aegean Late Bronze Age architecture appears, on the whole, irregular with central Greece and the north-east Peloponnese being the regions with the most sites known to have yielded such objects. Mycenaean roof tiles date mostly from the mid- and late fourteenth century bc to the twelfth century bc. A study of their construction, form, production and contexts suggests that their role, apart from adding extra insulation, might have been one of signposting certain buildings in the landscape. We also present the idea that Mycenaean tile-making was guided by a particular conventional knowledge which was largely influenced by ceramic-related technologies (pottery- and drain-making). While production of roof tiles might have been palace-instigated to begin with, it does not appear to have been strictly controlled. This approach to Mycenaean tile-making may also help explain their uneven (in terms of intensity of use) yet widespread distribution.


Author(s):  
Susana Camarillo-Coop ◽  
César A. Salinas-Zavala ◽  
Marlenne Manzano-Sarabia ◽  
Eugenio Alberto Aragón-Noriega

The jumbo squid Dosidicus gigas is the only ommastrephid commercially caught in Mexico. Despite the economic and ecological importance of this species, little is known about its early life stages. The relationship between the presence of paralarvae and mesoscale oceanic features was investigated for the first time in the central Gulf of California, Mexico in February, April, June and September of 2008. A total of 86 paralarvae were found only in June and September (summer season), in the well-stratified column water where the thermocline was evident and warm sea surface waters (27.7° to 29.4°C) dominated. The greatest abundance of D. gigas paralarvae was observed within 2.23 to 3.48 km of the main front. The mantle length of the smallest paralarvae corresponded with the mantle length at hatching. The San Pedro Mártir Island–Santa Rosalia transect and Santa Rosalia–Guaymas transect were determined as the main hatching localities in June and September respectively. The number of paralarvae found in this study contrast with the potential fecundity of mature females which are found throughout the year.


Author(s):  
Alan G. Haddow ◽  
Steven W. Shaw

Abstract This paper presents results from tests completed on a rotor system fitted with pendulum-type torsional vibration absorbers. A review of the associated theoretical background is also given and the experimental and theoretical results are compared and contrasted. An overview of the test apparatus is provided and its unique features are discussed. To the best knowledge of the authors, this is the first time that a systematic study of the dynamic behavior of torsional vibration absorbers has been undertaken in a controlled environment.


2019 ◽  
Vol 17 (17) ◽  
pp. 4342-4349 ◽  
Author(s):  
Valeriia Hutskalova ◽  
Pavel K. Mykhailiuk

A systematic study on the directed Pd-catalyzed (hetero)arylation of 26 substituted cyclic α-amino acids at the C(3)-atom was performed. For the first time, the 7- and 8-membered cyclic amino acids were introduced to C–H activation. 8–Aminoquinoline was used as a directing group.


2014 ◽  
Vol 9 (S310) ◽  
pp. 101-103
Author(s):  
D. Ricci ◽  
M. Reyes-Ruiz ◽  
R. Michel ◽  
C. Ayala-Loera ◽  
G. Ramón-Fox ◽  
...  

AbstractExoplanetary transit observations were carried out for the first time with all the three telescopes at the San Pedro Mártir National Astronomical Observatory in Baja California, Mexico.We present preliminary results on WASP-39 and WASP-43, two Hot Jupiters known for the presence of a highly-inflated radius. Using the defocused photometry technique, we observed these systems, achieving photometric precision of ± 3–5mmag peak-to-valley. The preliminary fit of their lightcurves shows physical and orbital parameters consistent with published results.


1963 ◽  
Vol 11 (1) ◽  
pp. 35 ◽  
Author(s):  
FHS Roberts

A systematic study has been made of the species of Haemaphysalis occurring in Australia. Six species were recognized in the material examined, namely H. humerosa, H. ratti, H. bremneri, H. lagostrophi, H. bispinosa, and H. bancrofti. Two of these, H. lagostrophi and H. bremneri, are new species, and H. ratti is recorded from Australia for the first time. H. novaeguineae recorded by Nuttall and Warburton (1915) from Queensland and the Northern Territory was not seen. A detailed description with appropriate figures is given for the known stages in the life cycle of each species, together with data on host range and geographical distribution. Keys are presented for the males, females, and nymphs and a classified host list has been included.


2015 ◽  
Vol 20 (3) ◽  
pp. 221-224
Author(s):  
Mateo LÓPEZ-VICTORIA ◽  
Juan Manuel DAZA

<p><em>Aristelliger georgeensis</em>, previously known to occur in the Yucatan peninsula (Mexico), the coasts and islands from Belize and Honduras, and the oceanic islands of Colombia in the Caribbean (San Andres, Providence and Saint Catalina) was registered for the first time in Roncador Cay, a flat and small island of coralline origin, located in the southwest of the Caribbean. Being considered as an endangered species at the national level, the new locality for this gecko constitutes an opportunity for its conservation. Some topics regarding the possible origins of this new population are discussed. This new locality represents the eastern most documented record of this species so far.</p><p><strong>La especie amenazada <em>A</em><em>ristelliger georgeensis</em> (Squamata: Sphaerodactylidae) en el Cayo Roncador, Caribe colombiano</strong></p><p><em>Aristelliger georgeensis</em>, previamente conocido de la península de Yucatán (México), las costas e islas de Belice y Honduras y de las islas oceánicas de Colombia en el Caribe (San Andrés, Providencia y Santa Catalina), fue registrado por primera vez en el Cayo Roncador, una isla plana y pequeña de origen coralino, ubicada en el suroccidente del Caribe. Siendo considerada como una especie amenazada a nivel nacional, la nueva localidad para este geco constituye una oportunidad para su conservación. Se discuten algunos tópicos relacionados con el posible origen de esta nueva población. Esta nueva localidad representa el registro documentado más al Este para la especie. </p>


Zootaxa ◽  
2021 ◽  
Vol 4975 (1) ◽  
pp. 176-186
Author(s):  
BLANCA HUERTAS ◽  
CARLOS PRIETO ◽  
FREDY MONTERO ◽  
MIKE ADAMS ◽  
JEAN FRANÇOIS LE CROM ◽  
...  

Catasticta lycurgus is a striking endemic butterfly, restricted to high elevation habitats in the Sierra Nevada de Santa Marta, an isolated mountain range separate from the Andes in the north of Colombia. The type, which for almost a hundred years was the only known specimen, was collected in 1878 by Frederick Simons in the vicinity of Atánquez and was sent to the UK to be described by renowned naturalists Godman and Salvin in 1880. In 1972, explorers Adams and Bernard collected a second specimen of C. lycurgus in the locality of San Pedro at 2,900m of elevation in the Sierra Nevada de Santa Marta. These two specimens were the only known ones for many decades until recently, when Colombian entomologists found the species again in San Pedro de la Sierra and later, when a female was discovered in 2013. Here, we report the rediscovery of this rare and charismatic species, with new specimens collected near the type locality, which have not been reported previously. The female of C. lycurgus is described and illustrated for the first time as well the male genitalia of this species. We combine all information available to provide some insights on the systematic relationships of this species within the genus Catasticta Butler, discuss its distribution and provide a preliminary conservation assessment. Despite the newly collected specimens, the species remains very rare in the field and in collections. 


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