ABSTRACT
G351.16+0.70 is a relatively well-studied high-mass star-forming region with at least two main bipolar outflow structures originating from an OB-embedded star and multiple IR sources. Using ...high-resolution and large-bandwidth SMA observations, we studied its molecular content to probe the emission of iCOMs, which could be related to the bipolar outflows or their jets. We analysed the emission spectra in the 1 mm band within 8 GHz bandwidth coverage, finding that the observed emission spectra could be explained by 11 iCOMs and 5 molecular isotopologues. Additionally, we analysed the unusually broad iCOM emission lines by using integrated and velocity field maps, searching for extended emission and velocity gradients related to molecular outflows. Ro-vibrational transitions of CH3OH and CH3OCHO present evidence of extended emission that does not fit with spherical morphology and that follows the extension of the low-velocity 13CO outflow. The multiple outflows in the system are revealed also by the CO (2–1) and SiO (5–4) emission, but in particular we have discovered an extremely high-velocity outflow (|VMax − VLSR| ∼ 60 km s−1). Finally, we provide the complete catalogue of iCOMs produced by the protostellar core within the 8 GHz bandwidth of our observations, along with a compilation of iCOM abundances studied in interferometric works from the literature and a comparison with single-dish results.
LMT/AzTEC observations of Vega Marshall, J P; Chavez-Dagostino, M; Sanchez-Arguelles, D ...
Monthly notices of the Royal Astronomical Society,
06/2022, Letnik:
514, Številka:
3
Journal Article
Recenzirano
ABSTRACT
Vega is the prototypical debris disc system. Its architecture has been extensively studied at optical to millimetre wavelengths, revealing a near face-on, broad, and smooth disc with ...multiple distinct components. Recent millimetre-wavelength observations from ALMA spatially resolved the inner edge of the outer, cold planetesimal belt from the star for the first time. Here we present early science imaging observations of the Vega system with the AzTEC instrument on the 32-m LMT, tracing extended emission from the disc out to 150 au from the star. We compare the observations to three models of the planetesimal belt architecture to better determine the profile of the outer belt. A comparison of these potential architectures for the disc does not significantly differentiate between them with the modelling results being similar in many respects to the previous ALMA analysis, but differing in the slope of the outer region of the disc. The measured flux densities are consistent between the LMT (single dish) and ALMA (interferometric) observations after accounting for the differences in wavelength of observation. The LMT observations suggest the outer slope of the planetesimal belt is steeper than was suggested in the ALMA analysis. This would be consistent with the interferometric observations being mostly blind to structure at the disc outer edges, but the overall low signal to noise of the LMT observations does not definitively resolve the structure of the outer planetesimal belt.
Abstract
The interstellar medium contains dust and gas, in which molecules can proliferate at high densities and in cold conditions. Interstellar complex organic molecules (iCOMs) are C-bearing ...species that contain at least six atoms. As they are detected in young stellar objects, iCOMs are expected to inhabit early stages of star formation evolution. In this study, we try to determine which iCOMs are present in the outflow component of massive protostars. To do this, we analyzed the morphological extension of blue- and redshifted iCOM emission in a sample of 11 massive protostars employing mapping observations at 1 mm within a ∼1 GHz bandwidth for both the IRAM-30 m and APEX telescopes. We modeled the iCOM emission of the central pointing spectra of our objects using the XCLASS local thermal equilibrium radiative transfer code. We detected the presence of several iCOMs such as CH
3
OH,
13
CH
3
OH, CH
3
OCHO, C
2
H
5
C
15
N, and (
c
-C
3
H
2
)CH
2
. In G034.41+0.24, G327.29-0.58, G328.81+0.63, G333.13-0.43, G340.97-1.02, G351.45+0.66, and G351.77-0.54, the iCOM lines show a faint broad-line profile. Due to the offset peak positions of the blue- and redshifted emission, covering from ∼0.1 to 0.5 pc, these wings are possibly related to movements external to the compact core, such as large-scale low-velocity outflows. We have also established a correlation between the parent iCOM molecule CH
3
OH and the shock tracer SiO, reinforcing the hypothesis that shock environments provide the conditions to boost the formation of iCOMs via gas-phase reactions.
ABSTRACT Fishing is an important economic activity in the world that produces food and generates employment. Although cooperatives have been strengthened as a successful business model, in Mexico ...they face diverse problems. The use of sustainability indicators is useful to identify areas of opportunity. One of these is the ecological footprint from which the corporate ecological footprint was derived, which measures the environmental impact in surface units. The objective of this work is to identify areas of opportunity for environmental improvement of a fishing cooperative through the evaluation and analysis of the footprint, to generate strategies. The calculation was made through the Composite Method in Financial Accounts. A gross ecological footprint of 299.24 gha was found, as well as 688.96 t of CO2. Opportunity areas are the consumption reduction in the categories of materials, land use of forest resources, and the forest ecosystem, the latter two with greater impact on the footprint. It is recommended that annual monitoring of the footprint be implemented in the future to evaluate its reduction over time.
This paper reports upon data obtained from tourist perception research project related to whale-watching tourists during the 2010–2011 season near the Marietas Islands, off Puerto Vallarta, Mexico. ...In particular, questions about climate change and about the feasibility of compensation by the purchase of carbon bonds were asked. A total of 136 on-site tourist surveys were conducted to evaluate the perception of tourists about climate change. These were analyzed using SPSS statistical software. The perception of tourists is that they recognize that their actions negatively affect the marine ecosystem because of the greenhouse gas emissions produced during their touristic activities. It was acknowledged that this is especially the case for tourists who came from developed countries. It was also found that the studied tourists claim to be willing to change their lifestyle, in order to continue to have the opportunity to engage in activities such as whale watching. Addition- ally, they would support the purchase of carbon bonds in order to help conserve resources, mitigate, and adapt to climate change.
Tourism is a major economic activity with significant social, political and environmental repercussions that affect people and places in virtually every corner of the contemporary world. This study ...focuses on tourism development in Puerto Vallarta (PV), Jalisco, Mexico. The region has been almost completely transformed by this industry in a relatively short period of time since the development of the first major hotel in 1948. The article begins by discussing the development of PV as a place, as a coastal tourist resort and also as a set of quite different cultural landscapes. Building on this we specifically identify, describe and discuss some of the major cultural imprints of tourism upon PV, including hotels, restaurants, the gay community, art galleries and Internet cafes as well as ecological imprints of
Les empreintes du tourisme sur Puerto Vallarta, Jalisco, Mexique
Le tourisme est un secteur d'activitééconomique de première importance générant des retombées notables sur les plans social, politique et environnemental qui touchent les populations et les lieux dans presque tous les coins du monde contemporain. Cette étude porte principalement sur le développement du tourisme à Puerto Vallarta, ville de l'état de Jalisco au Mexique. Le tourisme a presque entièrement transformé cette région au cours d'une période de temps relativement courte, soit depuis la construction du premier hôtel d'envergure en 1948. Cet article traite du développement de Puerto Vallarta en tant que lieu, station balnéaire touristique, et comme un ensemble de paysages culturels
tourism (using ecological footprint analysis). The conclusions provide a commentary on the potential for and challenges of continued tourism development in PV, as a place that is likely to face serious questions regarding sustainability as the new millennium unfolds.
particuliers. De manière plus spécifique, nous identifions, décrivons et discutons certaines des plus importantes empreintes du tourisme laissées sur Puerto Vallarta, comprenant notamment les hôtels, les restaurants, la communauté gaie, les galeries d'art et les cafés internet, en plus des empreintes écologiques du tourisme (étudiées à l'aide d'une analyse de l'empreinte écologique). Des observations sont présentées en conclusion sur les possibilités et les défis inhérents au développement du tourisme à Puerto Vallarta, qui est un lieu susceptible d'être confronté, un jour ou l'autre, à de graves enjeux de durabilité au cours du nouveau millénaire.
•Fishers catch primarily Family Lutjanidae, although rural fishers report a greater variety of species.•Rural fishers were more likely to report needing a second form of income.•Both urban and rural ...fishers are concerned for the sustainability of fish populations.•Urban and rural fishers want the government to do their job in enforcing fishing regulations.•Urban fishers generally possessed a greater ecocentric view of humanity and nature.
Artisanal fishing is a very important activity for the subsistence of coastal inhabitants in Latin American countries. Increasingly, what has traditionally been a rural activity is being enveloped by urban expansion, resulting in urban-based artisanal fishers. We administered 98 questionnaires to artisanal fishers along the Jalisco coast of the Bahia de Banderas, on the Pacific Coast of Mexico. Approximately half of the participants belonged to each of urban (Puerto Vallarta) or rural collectives. The aim of the study was to understand the differences and similarities between urban and rural fishers with respect to demographics, fishing behaviors, assessments of past, current, and future fishing resources, attitudes towards fisheries management, and perceptions of human-environment relationships. The respondents represented an aging demographic with a low level of education. They reported catching 27 different species of fish, primarily of the Family Lutjanidae, although rural fishers reported a greater variety of species captured. Half of the respondents supplement fishing with a second form of income, a trend that is more prevalent in rural fishers. Fishers indicated that fishing was better in the past and predicted it will be poorer in the future; rural fishers were more negative about fishing conditions. Almost all fishers were concerned about the health of fish populations and three-quarters of them felt that fish populations are disappearing. Specific fishing practices were the highest cited problems facing fishing and making changes to these problems was identified to improve fishing. Half the respondents felt that there is conflict between artisanal and commercial sport fishers, but this is more prevalent in urban fishers. Respondents indicated that fishery managers need to do their job (e.g. resource monitoring, enforcement) and apply fisheries laws in order to help improve regional fisheries. Overall, concerns for a future sustainable fishery are reflected in an ecocentric view of humanity and nature by both groups, although it is often statistically greater in urban fishers. These results provide an insight into differences between urban and rural fishers that can be useful for local fisheries collectives, regional and federal fisheries management agencies, as well as global approaches to small-scale fisheries.
Whale watching has become a globally important ecotourism activity due to its economic and conservation potential. The predictable presence of humpback whales (Megaptera novaeangliae) and consequent ...popularity of whale watching in Bahía de Banderas, near Puerto Vallarta on the Pacific coast of Mexico, throughout the winter months has resulted in a successful private and community-based whale-watching industry in. While private whale watching companies are operated as commercial, larger scale businesses, community-based whale watching operates with less financial resources and experience in tourism affairs. How do these two different approaches meet the needs of tourists and contribute to conservation? This paper compares whale watching tourists’ satisfaction between private and community-based platforms. During 2013–2014, a questionnaire survey was administered to whale watching tourists aboard private (n=246) and community-based vessels (n=101) using the intercept method. Whale watchers from both types of companies reported high satisfaction in environmental education. There appeared to be a different demand for the two types of companies, as a greater pro- portion of Mexican nationals and those who had been whale watching previously chose to go whale watching on community-based vessels.
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