Serendipitous Discovery of An Infrared Bow Shock Near PSR J1549-4848 with Spitzer

We report on the discovery of an infrared cometary nebula around PSR J1549$-$4848 in our Spitzer survey of a few middle-aged radio pulsars. Following the discovery, multi-wavelength imaging and spectroscopic observations of the nebula were carried out. We detected the nebula in Spitzer IRAC 8.0, MIPS 24 and 70 $\mu$m imaging and in Spitzer IRS 7.5--14.4 $\mu$m spectroscopic observations, and also in the WISE all-sky survey at 12 and 22 $\mu$m.These data were analyzed in detail, and we find that the nebula can be described with a standard bow-shock shape, and that its spectrum contains polycyclic aromatic hydrocarbon and H$_2$ emission features. However, it is not certain which object drives the nebula. We analyze the field stars and conclude that none of them can be the associated object because stars with a strong wind or mass ejection that usually produce bow shocks are much brighter than the field stars. The pulsar is approximately 15\arcsec\ away from the region in which the associated object is expected to be located. In order to resolve the discrepancy, we suggest that a highly collimated wind could be emitted from the pulsar and produce the bow shock. X-ray imaging to detect the interaction of the wind with the ambient medium and high-spatial resolution radio imaging to determine the proper motion of the pulsar should be carried out, which will help verify the association of the pulsar with the bow shock nebula.Comment: 9 pages, 5 figures, accepted for publication in Ap

Ecological niche modeling to calculate ideal sites to introduce a natural enemy: the case of apanteles opuntiarum (hymenoptera: Braconidae) to control cactoblastis cactorum (lepidoptera: Pyralidae) in North America

The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), is an invasive species in North America where it threatens Opuntia native populations. The insect is expanding its distribution along the United States Gulf Coast. In the search for alternative strategies to reduce its impact, the introduction of a natural enemy, Apanteles opuntiarum Martínez and Berta (Hymenoptera: Braconidae), is being pursued as a biological control option. To identify promising areas to intentionally introduce A. opuntiarum for the control of C. cactorum, we estimated the overlap of fundamental ecological niches of the two species to predict their common geographic distributions using the BAM diagram. Models were based on native distributional data for both species, 19 bioclimatic variables, and the Maxent algorithm to calculate the environmental suitability of both species in North America. The environmental suitability of C. cactorum in North America was projected from Florida to Texas (United States) along the Gulf coastal areas, reaching Mexico in northern regions. Apanteles opuntiarum environmental suitability showed a substantial similarity with the calculations for C. cactorum in the United States. Intentional introductions of A. opuntiarum in the actual distribution areas of the cactus moth are predicted to be successful; A. opuntiarum will find its host in an environment conducive to its survival and dispersal.Fil: Pérez De la O, Nidia Bélgica. Universidad Autónoma de Chiapas. Facultad de Ciencias Agrícolas; MéxicoFil: Espinosa Zaragoza, Saúl. Universidad Autónoma de Chiapas. Facultad de Ciencias Agrícolas; MéxicoFil: López Martínez, Víctor. Universidad Autónoma del Estado de Morelos; MéxicoFil: Hight, Stephen D.. US Department of Agriculture. Agricultural Research Service; Estados UnidosFil: Varone, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para el Estudio de Especies Invasivas; Argentin

Actual and Potential Distribution of Five Regulated Avocado Pests Across Mexico, Using the Maximum Entropy Algorithm

Este trabajo representa un aporte al conocimiento de los insectos barrenadores de frutos y ramas del aguacate, considerados como plagas de tipo cuarentenario en México que limitan la comercialización de frutos de aguacate en el mercado exterior, principalmente NorteamericaMexican avocado producers face phytosanitary barriers that limit the ability to ship avocados to foreign markets due to concerns about invasion by unwanted pests. The principal regulated pests are the big avocado seed weevil, Heilipus lauri Boheman; the small avocado seed weevils Conotrachelus aguacatae Barber and C. perseae Barber; the branch borer weevil, Copturus aguacatae Kissinger (all Coleoptera: Curculionidae); and the avocado seed moth, Stenoma catenifer Walsingham (Lepidoptera: Elachistidae). In Mexico, distribution information of these pests is largely based on a slow integration of the geographic data. This study was conducted to determine the potential distribution of these 5 insect pests in Mexican avocadogrowing areas by using the maximum entropy algorithm. Distributional data of these insects were obtained from scientific literature, databases, and field collection, and incorporated into the MaxEnt model using 19 global climatic variables and elevation data. Distributional models for Mexico, and geographic interaction with avocado-growing areas of the country, were calculated. Conoctrachelus aguacatae, C. perseae, Copturus aguacatae, and H. lauri showed similar environmental suitability patterns in Mexico, with a potential distribution from central to southern Mexico. High suitability was projected principally in the Trans-Mexican Volcanic Belt and surrounding biogeographic provinces. Stenoma catenifer exhibited an irregular environmental suitability pattern, with preference for western Mexico. Altitude, isothermality, and seasonality of precipitation were the variables that most influenced potential distribution of analyzed species. Geographic interaction with avocado-growing areas ranged from wider (Conoctrachelus aguacatae, C. perseae, Copturus aguacatae, and S. catenifer) to narrow or irregular (H. lauri), but the last species has the potential to invade new geographic areas. For the first time, the geographic distribution of these 5 insect pests was determined based on environmental suitability and their geographic interaction with avocados. These data could support development of management strategies throughout the country, and help focusing surveys and control tactics

A three-decade outburst of the LMC luminous blue variable R127 draws to a close

The paradigmatic luminous blue variable R127 in the Large Magellanic Cloud has been found in the intermediate, peculiar early-B state, and substantially fainter in visual light, signaling the final decline from its major outburst that began between 1978 and 1980. This transformation was detected in 2008 January, but archival data show that it began between early 2005 and early 2007. In fact, significant changes from the maximum, peculiar A-type spectrum, which was maintained from 1986 through 1998, had already begun the following year, coinciding with a steep drop in visual light. We show detailed correspondences between the spectrum and light, in which the decline mimics the rise. Moreover, these trends are not monotonic but are characterized by multiple spikes and dips, which may provide constraints on the unknown outburst mechanism. Intensive photometric and spectroscopic monitoring of R127 should now resume, to follow the decline presumably back to the quiescent Ofpe/WN9 state, in order to fully document the remainder of this unique observational opportunity.Facultad de Ciencias Astronómicas y GeofísicasConsejo Nacional de Investigaciones Científicas y Técnica

A three-decade outburst of the LMC luminous blue variable R127 draws to a close

The paradigmatic luminous blue variable R127 in the Large Magellanic Cloud has been found in the intermediate, peculiar early-B state, and substantially fainter in visual light, signaling the final decline from its major outburst that began between 1978 and 1980. This transformation was detected in 2008 January, but archival data show that it began between early 2005 and early 2007. In fact, significant changes from the maximum, peculiar A-type spectrum, which was maintained from 1986 through 1998, had already begun the following year, coinciding with a steep drop in visual light. We show detailed correspondences between the spectrum and light, in which the decline mimics the rise. Moreover, these trends are not monotonic but are characterized by multiple spikes and dips, which may provide constraints on the unknown outburst mechanism. Intensive photometric and spectroscopic monitoring of R127 should now resume, to follow the decline presumably back to the quiescent Ofpe/WN9 state, in order to fully document the remainder of this unique observational opportunity.Facultad de Ciencias Astronómicas y GeofísicasConsejo Nacional de Investigaciones Científicas y Técnica

PREVALENCE OF NEOSPORA CANINUM IN SHEPHERD DOGS OF A LIVESTOCK FARM IN THE SOUTHERN HIGHLANDS OF PERU

La neosporosis es una parasitosis que afecta a una gama de mamíferos domésticos y silvestres; destacando, por su importancia, la especie bovina, al producir problemas reproductivos como el aborto; y la especie canina, al actuar como hospedador definitivo y como fuente de diseminación de la enfermedad. El objetivo del presente trabajo fue determinar la prevalencia de Neospora caninum en perros pastores procedentes de cinco zonas de producción de la empresa Rural Alianza ubicada en el departamento de Puno. Se evaluaron 122 muestras de suero canino, recolectadas en los meses de febrero y marzo de 2004 y evaluadas mediante la prueba de Inmunofluorescencia Indirecta (IFI), en una dilución de 1:50. Se encontró una prevalencia de 14.8 ± 6.3% (18/122). No se encontró diferencia estadística entre las variables procedencia (cinco sectores de la empresa), sexo y edad (<1, 1 a 7, >7 años), mediante la prueba de Chi Cuadrado. Este estudio demostró que los perros de la empresa Rural Alianza tuvieron contacto con Neospora caninum. Además, al comparar los valores hallados con estudios paralelos realizados en camélidos sudamericanos y bovinos de Puno, se evidenció una similitud en los valores de prevalencia entre los hospedadores intermediarios y definitivo.Neosporosis is a parasitic disease that affects several domestic and wild mammals. Among them, it is important in the bovine species because affect reproduction causing abortions, and in canine species as it is the definitive host and a dissemination source for the disease. The aim of the present study was to determine the prevalence of Neospora caninum in shepherd dogs from five production areas of the Rural Alianza enterprise located in the southern highlands, Puno. It was collected 122 samples of canine sera during February and March 2004, and they were analyzed using the Indirect Immunofluorescence assay (IFA), in a dilution of 1:50. A total prevalence of 14.8 ± 6.3% (18/122) was found. Statistical association between rearing area (five areas of the farm), sex, and age (<1, 1-7, > 7 years of age) through the chi square test was not found. This study showed that dogs from Rural Alianza showed a moderated prevalence for Neospora caninum. Besides, the prevalence reported is related to prevalence found for South American camelids and grazing cattle in Puno, which would indicate a close relationship between definitive and intermediate host, facilitating the horizontal transmission

Broad Balmer Wings in BA Hyper/Supergiants Distorted by Diffuse Interstellar Bands: Five Examples in the 30 Doradus Region from the VLT-FLAMES Tarantula Survey

Extremely broad emission wings at Hβ and Hα have been found in VLT-FLAMES Tarantula Survey data for five very luminous BA supergiants in or near 30 Doradus in the Large Magellanic Cloud. The profiles of both lines are extremely asymmetrical, which we have found to be caused by very broad diffuse interstellar bands (DIBs) in the longward wing of Hβ and the shortward wing of Hα. These DIBs are well known to interstellar but not to many stellar specialists, so that the asymmetries may be mistaken for intrinsic features. The broad emission wings are generally ascribed to electron scattering, although we note difficulties for that interpretation in some objects. Such profiles are known in some Galactic hyper/supergiants and are also seen in both active and quiescent Luminous Blue Variables (LBVs). No prior or current LBV activity is known in these 30 Dor stars, although a generic relationship to LBVs is not excluded; subject to further observational and theoretical investigation, it is possible that these very luminous supergiants are approaching the LBV stage for the first time. Their locations in the HRD and presumed evolutionary tracks are consistent with that possibility. The available evidence for spectroscopic variations of these objects is reviewed, while recent photometric monitoring does not reveal variability. A search for circumstellar nebulae has been conducted, with an indeterminate result for one of them

Agroecological coverings for the sustainable production of Rambutan (Nephelium lappaceum L.)

Objective: To evaluate the influence of living and dead covers on the yield and quality of rambutan fruits (Nephelium lappaceum L.) in Soconusco, Chiapas, Mexico. Design / methodology / approach: Five treatments were evaluated, two live covers, two dead covers and an always clean control without covers. The following were evaluated: plant height, crown volume, fruit quality, fruit yield (t ha-1). The data were analyzed under a randomized block experimental design. Results: All the agroecological modalities of hedging evaluated produced fruits with the quality required for national and international commercialization. Study limitations / implications: The morphological and physiological response of the crop can change with the age of the tree. Findings / conclusions: An agroecological management strategy is presented to develop rambutan cultivation in Soconusco region

The periodicity of the η Carinae events

Extensive spectral observations of η Carinae over the last cycle, and particularly around the 2003.5 low-excitation event, have been obtained. The variability of both narrow and broad lines, when combined with data taken from two earlier cycles, reveal a common and well-defined period. We have combined the cycle lengths derived from the many lines in the optical spectrum with those from broad-band X-rays, optical and near-infrared observations, and obtained a period length of Ppres = 2022.7 ± 1.3 d. Spectroscopic data collected during the last 60 yr yield an average period of Pavg = 2020 ± 4 d, consistent with the present-day period. The period cannot have changed by more than ΔP/P = 0.0007 since 1948. This confirms the previous claims of a true, stable periodicity, and gives strong support to the binary scenario. We have used the disappearance of the narrow component of He I 6678 to define the epoch of the Cycle 11 minimum, T0 = JD 245 2819.8. The next event is predicted to occur on 2009 January 11 (±2 d). The dates for the start of the minimum in other spectral features and broad-bands are very close to this date, and have well-determined time-delays from the He I epoch.Facultad de Ciencias Astronómicas y Geofísica

The periodicity of the η Carinae events

Extensive spectral observations of η Carinae over the last cycle, and particularly around the 2003.5 low-excitation event, have been obtained. The variability of both narrow and broad lines, when combined with data taken from two earlier cycles, reveal a common and well-defined period. We have combined the cycle lengths derived from the many lines in the optical spectrum with those from broad-band X-rays, optical and near-infrared observations, and obtained a period length of Ppres = 2022.7 ± 1.3 d. Spectroscopic data collected during the last 60 yr yield an average period of Pavg = 2020 ± 4 d, consistent with the present-day period. The period cannot have changed by more than ΔP/P = 0.0007 since 1948. This confirms the previous claims of a true, stable periodicity, and gives strong support to the binary scenario. We have used the disappearance of the narrow component of He I 6678 to define the epoch of the Cycle 11 minimum, T0 = JD 245 2819.8. The next event is predicted to occur on 2009 January 11 (±2 d). The dates for the start of the minimum in other spectral features and broad-bands are very close to this date, and have well-determined time-delays from the He I epoch.Facultad de Ciencias Astronómicas y Geofísica