A helium-burning white dwarf binary as a supersoft X-ray source.

Type Ia supernovae are cosmic distance indicators1,2, and the main source of iron in the Universe3,4, but their formation paths are still debated. Several dozen supersoft X-ray sources, in which a white dwarf accretes hydrogen-rich matter from a non-degenerate donor star, have been observed5 and suggested as Type Ia supernovae progenitors6-9. However, observational evidence for hydrogen, which is expected to be stripped off the donor star during the supernova explosion10, is lacking. Helium-accreting white dwarfs, which would circumvent this problem, have been predicted for more than 30 years (refs. 7,11,12), including their appearance as supersoft X-ray sources, but have so far escaped detection. Here we report a supersoft X-ray source with an accretion disk whose optical spectrum is completely dominated by helium, suggesting that the donor star is hydrogen-free. We interpret the luminous and supersoft X-rays as resulting from helium burning near the surface of the accreting white dwarf. The properties of our system provide evidence for extended pathways towards Chandrasekhar-mass explosions based on helium accretion, in particular for stable burning in white dwarfs at lower accretion rates than expected so far. This may allow us to recover the population of the sub-energetic so-called Type Iax supernovae, up to 30% of all Type Ia supernovae13, within this scenario.

Motivating landowners to recruit neighbors for private land conservation.

Encouraging motivated landowners to not only engage in conservation action on their own property but also to recruit others may enhance effectiveness of conservation on private lands. Landowners may only engage in such recruitment if they believe their neighbors care about the conservation issue, will positively respond to their conservation efforts, and are likely to take action for the conservation cause. We designed a series of microinterventions that can be added to community meetings to change these beliefs to encourage landowner engagement in recruitment of others. The microinterventions included neighbor discussion, public commitment making, collective goal setting, and increased observability of contributions to the conservation cause. In a field experiment, we tested whether adding microinterventions to traditional knowledge-transfer outreach meetings changed those beliefs so as to encourage landowners in Hawaii to recruit their neighbors for private lands conservation. We delivered a traditional outreach meeting about managing the invasive little fire ant (Wasmannia auropunctata) to 5 communities and a traditional outreach approach with added microinterventions to 5 other communities. Analysis of pre- and post-surveys of residents showed that compared with the traditional conservation outreach approach, the microinterventions altered a subset of beliefs that landowners had about others. These microinterventions motivated reputationally minded landowners to recruit and coordinate with other residents to control the invasive fire ant across property boundaries. Our results suggest integration of these microinterventions into existing outreach approaches will encourage some landowners to facilitate collective conservation action across property boundaries.

Motivaciones para que los Terratenientes Recluten a sus Vecinos para la Conservación Privada de Tierras Resumen Si se alienta a los propietarios motivados a no sólo participar con acciones de conservación en sus propiedades sino también a reclutar a otros, se podría mejorar la efectividad de la conservación en las propiedades privadas. Puede que los propietarios sólo se comprometan con el reclutamiento si consideran que a sus vecinos les importan los temas de conservación, si responderán positivamente a sus esfuerzos de conservación, y si tienen probabilidad de tomar acción por la causa de conservación. Diseñamos una serie de microintervenciones que pueden añadirse a las juntas comunitarias para cambiar estas creencias y así promover la participación de los propietarios en el reclutamiento de otros propietarios. Las microintervenciones incluyeron discusiones entre vecinos, firmas públicas de compromisos, el establecimiento de objetivos colectivos, y una observación incrementada de las contribuciones a la causa de la conservación. En un experimento de campo probamos si la suma de estas microintervenciones a las tradicionales juntas de participación con transferencia de conocimiento cambó dichas creencias de tal manera que alentara a los terratenientes en Hawái a reclutar a sus vecinos para la conservación de terrenos privados. Realizamos una junta tradicional de participación sobre el manejo de la hormiga de fuego (Wasmannia auropunctata), una especie invasora, para cinco comunidades y una estrategia tradicional de participación con la suma de microintervenciones para otras cinco comunidades. El análisis previo y posterior a las encuestas realizadas a los residentes mostró que, si se comparan con la estrategia tradicional de participación, las microintervenciones alteraron a un subconjunto de creencias que los propietarios tenían sobre los demás propietarios. Estas microintervenciones motivaron a los propietarios con una reputación de estar dispuestos a conservar a reclutar y coordinarse con otros residentes para controlar a la hormiga invasora atravesando los límites de las propiedades. Nuestros resultados sugieren que la integración de estas microintervenciones dentro de las estrategias existentes de participación alentará a algunos propietarios a facilitar las acciones de conservación colectiva a través de los límites de las propiedades.

Epidemiology chapter.

This chapter outlines the epidemiology of brucellosis in the Russian Federation and in five countries bordering Russia. Since the Soviet Union's dissolution, Russia and the newly formed independent republics have failed to maintain policies to control brucellosis and other zoonotic diseases. Many of these republics, due to weak animal control and prevention systems and dangerous food preparation practices, are still burdened with the human cost of brucellosis. The final summary of this section provides an example of the successful transboundary cooperative efforts between Arizona and Mexico, which could be applied to the situation between Russia and the bordering independent republics.

Effect of circumcostal gastropexy on gastric myoelectric and motor activity in dogs.

Gastric electrical and contractile activities were assessed in healthy adult dogs on the eighth day after circumcostal gastropexy surgery, using serosal electrodes and strain gauge force transducers. Recordings were analysed to determine gastric slow wave frequency, presence of gastric slow wave dysrhythmias, gastric slow wave propagation velocity, coupling of gastric contractions to slow waves, a gastric motility index based on relative contractile amplitudes, and onset of gastric contractions after a standardised meal. Overall, gastric electrical and contractile activities were relatively unaffected by circumcostal gastropexy.

Passive drainage versus primary closure after total ear canal ablation-lateral bulla osteotomy in dogs: 59 dogs (1985-1995).

OBJECTIVE: Compare passive wound drainage to primary closure of total ear canal ablation-lateral bulla osteotomy (TECA-LBO) in dogs. STUDY DESIGN: Retrospective analysis of medical records. SAMPLE POPULATION: Fifty-nine dogs with end-stage otitis externa or neoplasia of the external and middle ear. METHODS: Medical records of dogs with TECA-LBO were reviewed. Dogs were divided into postoperative drain and primary closure groups. Statistical analyses were performed to identify differences in data for signalment, preoperative treatment, duration of hospitalization, immediate complications, and long-term complications between groups. RESULTS: No significant differences were detected in signalment, diagnosis, and duration of medical management between groups (P > .05). Duration of hospitalization was greater for dogs in the drain group (P < .05). Immediate postoperative complications occurred in 26 of 59 dogs and included ipsilateral facial palsy, incision swelling, vestibular signs, premature drain removal, and one dog died of aspiration pneumonia. Long-term (> 6 months) complications were identified in 12 of 50 dogs and included dermatitis of the medial aspect of the pinna, chronic fistula formation, and permanent facial paralysis. No association between immediate or long term complications and method of closure was identified. CONCLUSIONS: Primary closure is an acceptable alternative in dogs undergoing TECA-LBO when surgical wound dead space can be managed with meticulous hemostasis, complete debridement of devitalized tissue, and accurate apposition of tissue planes.

Gross and histologic evaluation of hepatogastric ligaments in clinically normal dogs and dogs with gastric dilatation-volvulus.

OBJECTIVE--To investigate any potential structural differences in hepatogastric ligaments between clinically normal dogs and dogs with gastric dilatation-volvulus (GDV). DESIGN--Case-control study. ANIMALS--Hepatogastric ligaments were examined in 13 large-breed control dogs and in 13 large-breed dogs referred for surgical treatment of GDV. PROCEDURE--Measurements and biopsies of hepatogastric ligaments were performed at the time of surgery, circumcostal gastropexy, for correction of GDV. Serial sections from each ligament were stained with H&E, Masson's trichrome, and elastin stains to assess morphology, including smooth muscle, collagen, and elastic fiber contents. RESULTS--There were no differences observed by light microscopy in incidence or degree of histopathologic alterations between the 2 groups of dogs. The lengths of hepatogastric ligaments in GDV-affected dogs, however, were significantly longer than those of control dogs (GDV-affected dogs, 7.0 [5.0 to 9.5] cm median [range]; control dogs, 5.0 [3.0 to 7.5] cm median [range]; P = 0.01). CONCLUSIONS--Causality can not be inferred from this study. It is not known whether the ligaments were lengthened as a result of GDV or whether the lengthened ligaments predisposed dogs to GDV. CLINICAL RELEVANCE--This finding may reflect increased laxity of the supporting hepatogastric ligament in the right quadrant of the abdomen. An elongated ligament may permit increased stomach mobility and predispose dogs to partial or complete gastric volvulus.

Gastric emptying of nondigestible radiopaque markers after circumcostal gastropexy in clinically normal dogs and dogs with gastric dilatation-volvulus.

Using radiopaque particles mixed with food, gastric emptying was assessed in healthy dogs not subjected to surgery, in healthy dogs 9 to 35 days after circumcostal gastropexy, and, in dogs 1 to 54 months after surgical treatment and recovery from gastric dilatation-volvulus (GDV). Circumcostal gastropexy surgery did not alter the 90% gastric emptying time for radiopaque particles in healthy dogs. However, 90% gastric emptying time was significantly (P less than 0.05) increased after circumcostal gastropexy in dogs with GDV, compared with healthy dogs after the same surgical procedure and recovery period. These results imply that dogs with GDV have delayed gastric emptying of solid particles. Whether delayed gastric emptying of markers detected in affected dogs after surgical treatment and recovery was the result or the cause of GDV was not determined. Results indicate that circumcostal gastropexy could be recommended as a prophylactic procedure for GDV in large breeds with deep thorax, because delayed gastric emptying of markers secondary to the surgical procedure is unlikely.

Partial carpal arthrodesis for third degree carpal sprains. A review of 45 carpi.

The efficacy of partial carpal arthrodesis was evaluated retrospectively in 39 dogs (45 carpi) with severe sprains of the middle carpal joints, the carpometacarpal joints, or both. The carpometacarpal joint was the most frequently injured joint. Jumping or falling from heights was the cause of injury in 49% of these animals. Of the 25 owners who responded to a mailed questionnaire (mean follow-up, 32 months), all stated their animal had improved or greatly improved after partial carpal arthrodesis and all were pleased or very pleased with the final surgical result. Hyperextension persisted in 11% of the cases and degenerative joint disease of the antebrachiocarpal joint was present in 15.5% of the cases. No dogs with partial carpal arthrodesis required panarthrodesis at a later date.

Urinary bladder neoplasia in the dog and cat.

Neoplasms of the canine and feline urinary bladder are diagnostic and therapeutic challenges to the veterinary clinician. The diagnosis of a urinary bladder neoplasm is generally delayed because of a lack of overt clinical signs or a partial response to empirical treatment. Surgical resection by partial (segmental) resection is the treatment of choice; however, due to delays in diagnosis, tumor location or extent (stage), this form of treatment may be precluded. More information is needed concerning the efficacy of adjuvant (nonsurgical) treatment modalities. The prognosis of dogs and cats with urinary bladder neoplasms is based on tumor type, location, depth of bladder wall invasion, and presence of regional or distant metastases.

Current status of direct gold in teaching and licensure.

A questionnaire on the teaching of direct gold was mailed to each dental school in the United States, and a telephone survey of direct gold requirements on all state and regional licensure examining boards was conducted. While the vast majority of schools still teach direct gold in some form, there is a definite trend toward deemphasis of this material both in dental education and in licensing examinations. Cited as major reasons for this decline are (1) the observation that relatively few practicing dentists offer direct gold as a treatment alternative, (2) the decline in faculty motivation and dedication in teaching the techniques, and (3) the shifting of available curriculum time away from direct gold to other areas of restorative dentistry.