Northeast-southwest Axis Research Articles

Spatial genetic structure and Ovis haplogroup as a tool for an adaptive conservation management of the endangered Cyprus mouflon

The mouflon (Ovis gmelini ophion) is the largest wild terrestrial mammal of Cyprus. Regarded as the local flagship species, its population range is limited to the mountainous Paphos Forest and adjacent areas including part of Troodos National Forest Park (> 700 Km2). This species, protected by both national and international legislation, is classified as Endangered by the IUCN, with livestock intrusion, poaching and habitat loss as the main threatening factors. We determined the spatial genetic structure by investigating sexes separately and shed further light on the Cyprus mouflon placement among Ovis haplogroups (HGs) to enforce its protection within an adaptive conservation framework. We genotyped 108 samples collected across the entire species’ range at both14 loci of the microsatellite DNA and the mitochondrial DNA Control Region (CR). Microsatellite genotyping indicated that the wild population retained low genetic variability, which, however, was not associated with a level of inbreeding raising particular concern (FIS = 0.12). An overall weak spatial genetic structure was disclosed, consistently with the limited extension of the mouflon range, the lack of significant physical barriers to dispersal and the intense gene flow mostly occurring along a northeast-southwest axis across the forest. Nevertheless, evidences of structure were found for females in compliance with their philopatric behaviour. The disclosure of unique features compared to Mediterranean and Near East conspecifics, such as the occurrence of a six-fold 76 bp-long repeated motif in the Cyprus mouflon CR, along with the outcome of a phylogenetic reconstruction (based on a far higher number of Ovis GenBank records and Cyprus haplotypes than in previous studies) inspired the proposal of a new haplogroup (HGC2) which included the Anatolian mouflon (O. g. anatolica, former HGX) as sister taxon. While both high habitat heterogeneity and low human disturbance were the main drivers in determining the overall spatial structure, future conservation efforts to preserve this valuable genetic resource should focus on avoiding possible introgressive hybridisation with co-grazing livestock to the edge of its range.

Spatio-temporal variations in fine particulate matter and evaluation of associated health risk over Pakistan.

Human health and the environment are adversely affected by fine particulate matter. By utilizing standard deviation ellipse and trend analyses, we studied the spatial patterns and temporal trends of PM2.5 over Pakistan from 1998 to 2016. The outcomes of these analyses indicated that PM2.5 concentrations were considerably amplified in Pakistan, particularly in the provinces of Punjab and Sindh. The areal extent of PM2.5 concentrations below 15 μg/m3 declined constantly, and the area with PM2.5 concentrations above 35 μg/m3 increased significantly. The highly affected cities were Lahore, Faisalabad, Multan, Southern Gujranwala, Dera Ghazi Khan, Bahawalpur, Sukkur, and Larkana. Overall, the northwest-southeast axis experienced more rapid variations in the spatial pattern of PM2.5 than the northeast-southwest axis; similarly, the east-north axis also experienced faster changes in the spatial distribution of this crucial pollutant than the west-south axis. To support nationwide air pollution control, a two-tier level was recommended for allocated regions in Pakistan depending on their PM2.5 concentrations. From 1998 to 2016, health risks expanded and increased in Pakistan, particularly in Lahore, Karachi, Multan, Gujranwala, Faisalabad, and Hyderabad; these are Pakistan's most populated cities. The outcomes of this study suggest that human health is continuously affected by PM2.5 in Pakistan, and that a plan of action to combat air pollution is immediately needed. Integr Environ Assess Manag 2021;17:1243-1254. © 2021 SETAC.

A weather surveillance radar view of Alaskan avian migration.

Monitoring avian migration within subarctic regions of the globe poses logistical challenges. Populations in these regions often encounter the most rapid effects of changing climates, and these seasonally productive areas are especially important in supporting bird populations-emphasizing the need for monitoring tools and strategies. To this end, we leverage the untapped potential of weather surveillance radar data to quantify active migration through the airspaces of Alaska. We use over 400 000 NEXRAD radar scans from seven stations across the state between 1995 and 2018 (86% of samples derived from 2013 to 2018) to measure spring and autumn migration intensity, phenology and directionality. A large bow-shaped terrestrial migratory system spanning the southern two-thirds of the state was identified, with birds generally moving along a northwest-southeast diagonal axis east of the 150th meridian, and along a northeast-southwest axis west of this meridian. Spring peak migration ranged from 3 May to 30 May and between, 18 August and 12 September during the autumn, with timing across stations predicted by longitude, rather than latitude. Across all stations, the intensity of migration was greatest during the autumn as compared to spring, highlighting the opportunity to measure seasonal indices of net breeding productivity for this important system as additional years of radar measurements are amassed.

Regional eco-efficiency evaluation and spatial pattern analysis of the Yangtze River Economic Zone

The environmental ecology of the Yangtze River Economic Zone (YREZ) faces ecological function decline, deterioration and degradation under intense human activities, long-term development and utilization and its economy has developed rapidly over recent decades. Eco-efficiency is considered as a measure of coordinated development of economy, resources, environment and ecology, and is currently considered a very important issue. In this paper, based on the slack-based measure and data envelope analysis model, we take 129 prefecture-level cities of the YREZ as the study unit and measure the eco-efficiency of the YREZ in 2000, 2005, 2010 and 2015, which considers undesired output. The evaluation of the status quo of the regional eco-efficiency development was carried out at provincial, prefectural and city scales. The spatial autocorrelation test model and standard deviation ellipse were used to analyze the spatially distributed characteristics and the evolutionary regularity of eco-efficiency. Our study suggested that the eco-efficiency value varied significantly at different spatiotemporal scales and the overall distribution presented an “N-shaped” pattern, the value is the largest downstream and the smallest upstream. Regional eco-efficiency presented certain volatility in growth and a clear spatial positive agglomeration trend from 2000 to 2015. The spatial distribution of each agglomeration area was also significantly different, forming some high-high agglomeration areas at the center of the shaft with Shanghai and surrounding cities, and some low-low agglomeration areas at the center with middle reaches and upstream cities. The low-high over-aggregation and high-low polarization clusters were fewer. At the same time, with the change of the research period, the degree of positive agglomeration became increasingly pronounced and the eco-efficiency gap of the neighborhood unit reduced. The regional eco-efficiency value of the YREZ presented a spatial distribution pattern in the northeast-southwest axis and the evolutionary pattern of the regional eco-efficiency similarly showed a northeast-southwest orientation.

Ectosymbionts alter spontaneous responses to the Earth\u2019s magnetic field in a crustacean

Magnetic sensing is used to structure every-day, non-migratory behaviours in many animals. We show that crayfish exhibit robust spontaneous magnetic alignment responses. These magnetic behaviours are altered by interactions with Branchiobdellidan worms, which are obligate ectosymbionts. Branchiobdellidan worms have previously been shown to have positive effects on host growth when present at moderate densities, and negative effects at relatively high densities. Here we show that crayfish with moderate densities of symbionts aligned bimodally along the magnetic northeast-southwest axis, similar to passive magnetic alignment responses observed across a range of stationary vertebrates. In contrast, crayfish with high symbiont densities failed to exhibit consistent alignment relative to the magnetic field. Crayfish without symbionts shifted exhibited quadramodal magnetic alignment and were more active. These behavioural changes suggest a change in the organization of spatial behaviour with increasing ectosymbiont densities. We propose that the increased activity and a switch to quadramodal magnetic alignment may be associated with the use of systematic search strategies. Such a strategy could increase contact-rates with conspecifics in order to replenish the beneficial ectosymbionts that only disperse between hosts during direct contact. Our results demonstrate that crayfish perceive and respond to magnetic fields, and that symbionts influence magnetically structured spatial behaviour of their hosts.

Analisis Multi Raster SRTM, Radarsat dan Landsat untuk Karakterisisasi Morfo-struktur dari Geometri Sesar di Daerah Binuang, Kalimantan Selatan

The Binuang area and its surroundings are genetically structural landforms which characterized by cuesta ridge line with curve lineaments pattern on northeast-southwest direction. Geomorphological approach were carried out to determine structural geometry of geological surface using qualitative and quantitative approach on multiple map analysis of remote sensing data. The result of quantitative analysis on elevation data are used to classify heights, slope shape and steepness, lineaments, drainage, and slope aspect. Optical images were classified to determine lithological pattern and boundaries through analysis of band ratios, decorrelation stretch, principal component, and spatial enhancement. The research area are classified into eight class of structural landforms, depicting deformations that occured in western flank of Meratus Mountains. The surface pattern indicates the influence of compressional stress, shown by fold belt with longitudinal characteristic and fault-bounded anticlines on northeast-southwest axis. The formation of main structure pattern on research area was compared with that on strike-slip fault analog model. The resulting correlation factor, R=0.932, shows that both of them are highly correlated. In conclusion, surface structure can possibly form another variation of thrusted mountain belt, such as thrust-dominated restraining bends.Keywords: landsat, SRTM, morphostructure, morphometry, rhomboidal pattern, Meratus.

Analisis Multi Raster SRTM, Radarsat dan Landsat untuk Karakterisisasi Morfo-struktur dari Geometri Sesar di Daerah Binuang, Kalimantan Selatan

The Binuang area and its surroundings are genetically structural landforms which characterized by cuesta ridge line with curve lineaments pattern on northeast-southwest direction. Geomorphological approach were carried out to determine structural geometry of geological surface using qualitative and quantitative approach on multiple map analysis of remote sensing data. The result of quantitative analysis on elevation data are used to classify heights, slope shape and steepness, lineaments, drainage, and slope aspect. Optical images were classified to determine lithological pattern and boundaries through analysis of band ratios, decorrelation stretch, principal component, and spatial enhancement. The research area are classified into eight class of structural landforms, depicting deformations that occured in western flank of Meratus Mountains. The surface pattern indicates the influence of compressional stress, shown by fold belt with longitudinal characteristic and fault-bounded anticlines on northeast-southwest axis. The formation of main structure pattern on research area was compared with that on strike-slip fault analog model. The resulting correlation factor, R=0.932, shows that both of them are highly correlated. In conclusion, surface structure can possibly form another variation of thrusted mountain belt, such as thrust-dominated restraining bends.Keywords: landsat, SRTM, morphostructure, morphometry, rhomboidal pattern, Meratus.

Analisis Multi Raster SRTM, Radarsat dan Landsat untuk Karakterisisasi Morfo-struktur dari Geometri Sesar di Daerah Binuang, Kalimantan Selatan

The Binuang area and its surroundings are genetically structural landforms which characterized by cuesta ridge line with curve lineaments pattern on northeast-southwest direction. Geomorphological approach were carried out to determine structural geometry of geological surface using qualitative and quantitative approach on multiple map analysis of remote sensing data. The result of quantitative analysis on elevation data are used to classify heights, slope shape and steepness, lineaments, drainage, and slope aspect. Optical images were classified to determine lithological pattern and boundaries through analysis of band ratios, decorrelation stretch, principal component, and spatial enhancement. The research area are classified into eight class of structural landforms, depicting deformations that occured in western flank of Meratus Mountains. The surface pattern indicates the influence of compressional stress, shown by fold belt with longitudinal characteristic and fault-bounded anticlines on northeast-southwest axis. The formation of main structure pattern on research area was compared with that on strike-slip fault analog model. The resulting correlation factor, R=0.932, shows that both of them are highly correlated. In conclusion, surface structure can possibly form another variation of thrusted mountain belt, such as thrust-dominated restraining bends.Keywords: landsat, SRTM, morphostructure, morphometry, rhomboidal pattern, Meratus.

Analysis of population vulnerability to environmental technological risks in the urban area of the city of Manaus-AM

Este trabalho procura identificar e caracterizar a situação de vulnerabilidade populacional aos riscos tecnológicos ambientais nos bairros da área urbana de Manaus-AM, Brasil. As fontes geradoras desses riscos, identificadas e caracterizadas como ameaças que tenham potencial de causar algum dano foram: termelétricas, indústrias que utilizam solventes e/ou gases, áreas portuárias, áreas de disposição de resíduos, áreas aeroportuárias e depósito de combustíveis. A elaboração da base de dados foi realizada por meio do levantamento de informações disponibilizadas pelos órgãos locais, federais e agências nacionais; trabalho de campo, a fim de certificar a operação das fontes geradoras de risco; e uso de Sistema de Informação Geográfica. Os bairros da cidade de Manaus foram classificados em cinco categorias de vulnerabilidade, resultantes da combinação de três dimensões: densidade populacional; Índice de Desenvolvimento Humano Municipal – Dimensão Renda; e ocorrência de fatores geradores de risco. Os resultados apontam que os fatores de risco tecnológico estão concentrados na região sul da cidade, embora os bairros que apresentam maior ocorrência de fatores de risco estejam situados nas zonas norte e leste, zonas que também apresentam os piores IDH. A distribuição da população concentra-se no eixo nordeste–sudoeste, com destaque para os bairros a sudoeste, onde localizam-se os bairros mais antigos e o centro histórico da capital. Os níveis mais elevados de vulnerabilidade encontram-se na região nordeste, onde estão localizados bairros de condições socioeconômicas precárias e muito povoados. Este trabalho, nesse sentido, ao identificar e caracterizar as áreas críticas de vulnerabilidade e de concentração de fatores de risco tecnológico, traz subsídios relevantes para o planejamento de políticas públicas e desenvolvimento de estratégias para a prevenção de riscos e danos à saúde da população. Os resultados expõem cenários que devem ser alvos de políticas direcionadas à redução das problemáticas, podendo e devendo ser o planejamento urbano uma ferramenta para atenuar esses níveis.

Analysis of Environment-Marker Associations in American Chestnut

American chestnut (Castanea dentata Borkh.) was a dominant tree species in its native range in eastern North America until the accidentally introduced fungus Cryphonectria parasitica (Murr.) Barr, that causes chestnut blight, led to a collapse of the species. Different approaches (e.g., genetic engineering or conventional breeding) are being used to fight against chestnut blight and to reintroduce the species with resistant planting stock. Because of large climatic differences within the distribution area of American chestnut, successful reintroduction of the species requires knowledge and consideration of local adaptation to the prevailing environmental conditions. Previous studies revealed clear patterns of genetic diversity along the northeast-southwest axis of the Appalachian Mountains, but less is known about the distribution of potentially adaptive genetic variation within the distribution area of this species. In this study, we investigated neutral and potentially adaptive genetic variation in nine American chestnut populations collected from sites with different environmental conditions. In total, 272 individuals were genotyped with 24 microsatellite (i.e., simple sequence repeat (SSR)) markers (seven genomic SSRs and 17 EST-SSRs). An FST-outlier analysis revealed five outlier loci. The same loci, as well as five additional ones, were significantly associated with environmental variables of the population sites in an environmental association analysis. Four of these loci are of particular interest, since they were significant in both methods, and they were associated with environmental variation, but not with geographic variation. Hence, these loci might be involved in (temperature-related) adaptive processes in American chestnut. This work aims to help understanding the genetic basis of adaptation in C. dentata, and therefore the selection of suitable provenances for further breeding efforts.

The Co-evolution of Disks and Stars in Embedded Stages: The Case of the Very-low-mass Protostar IRAS 15398–3359

Abstract We have observed the CCH (N = 3–2, J = 7/2–5/2, F = 4–3 and 3–2) and SO (67–56) emission at a 0.″2 angular resolution toward the low-mass Class 0 protostellar source IRAS 15398–3359 with ALMA. The CCH emission traces the infalling-rotating envelope near the protostar with the outflow cavity extended along the northeast–southwest axis. On the other hand, the SO emission has a compact distribution around the protostar. The CCH emission is relatively weak at the continuum peak position, while the SO emission has a sharp peak there. Although the maximum velocity shift of the CCH emission is about 1 km s−1 from the systemic velocity, a velocity shift higher than 2 km s−1 is seen for the SO emission. This high-velocity component is most likely associated with the Keplerian rotation around the protostar. The protostellar mass is estimated to be from the velocity profile of the SO emission. With this protostellar mass, the velocity structure of the CCH emission can be explained by the model of the infalling-rotating envelope, where the radius of the centrifugal barrier is estimated to be 40 au from the comparison with the model. The disk mass evaluated from the dust continuum emission by assuming the dust temperature of 20–100 K is 0.1–0.9 times the stellar mass, resulting in the Toomre Q parameter of 0.4–5. Hence, the disk structure may be partly unstable. All these results suggest that a rotationally supported disk can form in the earliest stages of the protostellar evolution.

VLBA imaging of the 3 mm SiO maser emission in the disk-wind from the massive protostellar system Orion Source I

We present the first images of the 28SiO v=1, J=2-1 maser emission around the closest known massive young stellar object Orion Source I observed at 86 GHz (3mm) with the VLBA. These images have high spatial (~0.3 mas) and spectral (~0.054 km/s) resolutions. We find that the 3mm masers lie in an X-shaped locus consisting of four arms, with blue-shifted emission in the south and east arms and red-shifted emission in the north and west arms. Comparisons with previous images of the 28SiO v=1,2, J=1-0 transitions at 7mm (observed in 2001-2002) show that the bulk of the J=2-1 transition emission follows the streamlines of the J=1-0 emission and exhibits an overall velocity gradient consistent with the gradient at 7mm. While there is spatial overlap between the 3mm and 7mm transitions, the 3mm emission, on average, lies at larger projected distances from Source I (~44 AU compared with ~35 AU for 7mm). The spatial overlap between the v=1, J=1-0 and J=2-1 transitions is suggestive of a range of temperatures and densities where physical conditions are favorable for both transitions of a same vibrational state. However, the observed spatial offset between the bulk of emission at 3mm and 7mm possibly indicates different ranges of temperatures and densities for optimal excitation of the masers. We discuss different maser pumping models that may explain the observed offset. We interpret the 3mm and 7mm masers as being part of a single wide-angle outflow arising from the surface of an edge-on disk rotating about a northeast-southwest axis, with a continuous velocity gradient indicative of differential rotation consistent with a Keplerian profile in a high-mass proto-binary.

Dynamics of Abell 3266 – I. An optical view of a complex merging cluster

We present spectroscopy of 880 galaxies within a 2-degree field around the massive, merging cluster Abell 3266. This sample, which includes 704 new measurements, was combined with the existing redshifts measurements to generate a sample of over 1300 spectroscopic redshifts; the largest spectroscopic sample in the vicinity of A3266 to date. We define a cluster sub-sample of 790 redshifts which lie within a velocity range of 14,000 to 22,000 kms$^{-1}$ and within 1 degree of the cluster centre. A detailed structural analysis finds A3266 to have a complex dynamical structure containing six groups and filaments to the north of the cluster as well as a cluster core which can be decomposed into two components split along a northeast-southwest axis, consistent with previous X-ray observations. The mean redshift of the cluster core is found to be $0.0594 \pm 0.0005$ and the core velocity dispersion is given as $1462^{+99}_{-99}$ kms$^{-1}$. The overall velocity dispersion and redshift of the entire cluster and related structures are $1337^{+67}_{-67}$ kms$^{-1}$ and $0.0596 \pm 0.0002$, respectively, though the high velocity dispersion does not represent virialised motions but rather is due to relative motions of the cluster components. We posit A3266 is seen following a merger along the northeast southwest axis, however, the rich substructure in the rest of the cluster suggests that the dynamical history is more complex than just a simple merger with a range of continuous dynamical interactions taking place. It is thus likely that turbulence in A3266 is very high, even for a merging cluster.

A SUBSTELLAR-MASS PROTOSTAR AND ITS OUTFLOW OF IRAS 15398–3359 REVEALED BY SUBARCSECOND-RESOLUTION OBSERVATIONS of H2CO AND CCH

Sub-arcsecond ($0.^{\prime\prime}5$) images of H$_2$CO and CCH line emission have been obtained in the $0.8$ mm band toward the low-mass protostar IRAS 15398-3359 in the Lupus 1 cloud as one of the Cycle 0 projects of the Atacama Large Millimeter/Submillimeter Array. We have detected a compact component concentrated in the vicinity of the protostar and a well-collimated outflow cavity extending along the northeast-southwest axis. The inclination angle of the outflow is found to be about $20^\circ$, or almost edge-on, based on the kinematic structure of the outflow cavity. This is in contrast to previous suggestions of a more pole-on geometry. The centrally concentrated component is interpreted by use of a model of the infalling rotating envelope with the estimated inclination angle, and the mass of the protostar is estimated to be less than $0.09\ M_\odot$. Higher spatial resolution data are needed to infer the presence of a rotationally supported disk for this source, hinted at by a weak high-velocity H$_2$CO emission associated with the protostar.

Diffuse light in the young cluster of galaxies CL J1449+0856 atz= 2.07

Cluster properties do not seem to be changing significantly during their mature evolution phase, for example they do not seem to show strong dynamical evolution at least up to z~0.5, their galaxy red sequence is already in place at least up to z$\sim$1.2, and their diffuse light content remains stable up to z~0.8. The question is now to know if cluster properties can evolve more significantly at redshifts notably higher than 1. We propose here to see how the properties of the intracluster light (ICL) evolve with redshift by detecting and analysing the ICL in the X-ray cluster CL J1449+0856 at z=2.07 (discovered by Gobat et al. 2011), based on deep HST NICMOS H band exposures.We used the same wavelet-based method as that applied to 10 clusters between z=0.4 and 0.8 by Guennou et al. (2012). We detect three diffuse light sources with respective total magnitudes of H=24.8, 25.5, and 25.9, plus a more compact object with a magnitude H=25.3. We discuss the significance of our detections and show that they are robust. The three sources of diffuse light indicate an elongation along a north-east south-west axis, similar to that of the distribution of the central galaxies and to the X-ray elongation. This strongly suggests a history of merging events along this direction. While Guennou et al. (2012) found a roughly constant amount of diffuse light for clusters between z~0 and 0.8, we put in evidence at least a 1.5 magnitude increase between z~0.8 and 2. If we assume that the amount of diffuse light is directly linked to the infall activity on the cluster, this implies that CL J1449+0856 is still undergoing strong merging events.

ALMA OBSERVATIONS OF THE OUTFLOW FROM SOURCE I IN THE ORION-KL REGION

In this {\it Letter}, we present sensitive millimeter SiO (J=5-4; $\nu$=0) line observations of the outflow arising from the enigmatic object Orion Source I made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The observations reveal that at scales of a few thousand AU, the outflow has a marked "butterfly" morphology along a northeast-southwest axis. However, contrary to what is found in the SiO and H$_2$O maser observations at scales of tens of AU, the blueshifted radial velocities of the moving gas are found to the northwest, while the redshifted velocities are in the southeast. The ALMA observations are complemented with SiO (J=8-7; $\nu$=0) maps (with a similar spatial resolution) obtained with the Submillimeter Array (SMA). These observations also show a similar morphology and velocity structure in this outflow. We discuss some possibilities to explain these differences at small and large scales across the flow.

IMAGING THE TIME EVOLUTION OF ETA CARINAE'S COLLIDING WINDS WITH HST

We report new HST/STIS observations that map the high-ionization forbidden line emission in the inner arcsecond of Eta Car, the first that fully image the extended wind-wind interaction region of the massive colliding wind binary. These observations were obtained after the 2009.0 periastron at orbital phases 0.084, 0.163, and 0.323 of the 5.54-year spectroscopic cycle. We analyze the variations in brightness and morphology of the emission, and find that blue-shifted emission (-400 to -200 km s-1) is symmetric and elongated along the northeast-southwest axis, while the red-shifted emission (+100 to +200 km s-1) is asymmetric and extends to the north- northwest. Comparison to synthetic images generated from a 3-D dynamical model strengthens the 3-D orbital orientation found by Madura et al. (2011), with an inclination i \approx 138\degree, argument of periapsis {\omega} \approx 270\degree, and an orbital axis that is aligned at the same PA on the sky as the symmetry axis of the Homunculus, 312\degree. We discuss the potential that these and future mappings have for constraining the stellar parameters of the companion star and the long-term variability of the system.

USING REMOTE SENSING AND GIS TO IDENTIFY TREND OF EXPANSION OF URBAN AREA IN HOCHIMINH CITY

Studying on the trend of spatial expansion of urban in Hohiminh city, which used remote sensing and spatial analysis of GIS, has revealed changes of spatial urban over times.. Analysis of spectral response for main land cover types had been done on Landsat data from 1975 to 2005 in order to discriminate urban type with the others. Based on this spectral analysis, the expansion of urban area over times has been identified. Spatial statistics analysis was applied to estimate trends of urban area of Hochiminh city. Tthe results showed a wide spreading out from 1975 to 2008, the urban area has been extended two times in radius and three times in area. The trends of spatial expansion is anisotropic. There is a spatial expansion trend in the north east-south west axis.

MASER EMISSION FROM SiO ISOTOPOLOGUES TRACES THE INNERMOST 100 AU AROUND RADIO SOURCE I IN ORION BECKLIN–NEUGEBAUER/KLEINMANN-LOW

We have used the Very Large Array (VLA) at 7 mm wavelength to image five rotational transitions (J=1-0) from three SiO isotopologues towards Orion BN/KL: 28SiO v=0,1,2; and 29SiO and 30SiO v=0. For the first time, we have mapped the 29SiO and 30SiO J=1-0 emission, established the maser nature of the emission, and confirmed association with the deeply embedded high-mass young stellar object commonly denoted radio Source I. The 28SiO v=0 maser emission shows a bipolar structure that extends over ~700 AU along a northeast-southwest axis, and we propose that it traces a bipolar outflow driven by Source I. The high-brightness isotopic SiO maser emission imaged with a ~0.2 arcsec resolution has a more compact distribution, generally similar to that of the 28SiO v=1,2 emission, and it probably traces bulk gas flows in a region of diameter <100 AU centered on Source I. On small scales of <10 AU, however, compact 29SiO/30SiO v=0 and 28SiO v=1,2 emission features may be offset from one another in position and line-of-sight velocity. From a radiative transfer analysis based on a large velocity gradient (LVG) pumping model, we derive similar temperatures and densities for the optimum excitation of both 29SiO/30SiO v=0 and 28SiO v=1,2 masers, significantly higher than required for 28SiO v=0 maser excitation. In order to account for the small-scale differences among the isotopologues (v=0) and the main species (v=1,2), follow-up radiative transfer modeling that incorporates non-local line overlap among transitions of all SiO isotopic species may be required.

First records of lesser black-backed gullsLarus fuscuscrossing the Sahara non-stop

Lesser black-backed gulls Larus fuscus migrate regularly along coastlines or the Nile to their wintering grounds in sub-Saharan Africa. They usually avoid the interior of the Sahara, but occur occasionally far inland when moving upstream along rivers. We discovered several flocks of lesser black-backed gulls crossing the western Sahara about 500 km east of the Atlantic coast. Their concentrated flight directions along a northeast-southwest axis indicate that the gulls were on an intended migratory flight and not incidentally drifted inland. Ground speed of 8 flocks of gulls averaged 20 m/s and was considerably larger than the mean air speed (12 m/s) demonstrating that the gulls were strongly assisted by tailwinds. Highest ground speed was 26 m/s. Warmest temperature encountered when crossing the study site was 13° C due to relative high flight altitudes of 3,500 m above sea level. Thus, lesser black-backed gulls migrated under favourable conditions with respect to energy and water consumption. Our observations strongly suggest that the gulls performed long non-stop flights between the eastern Atlantic coast of sub-Saharan Africa and the Mediterranean Sea.