What Practitioners Should Understand About Bovine Lymphosarcoma

Bovine lymphosarcoma (BLS) is a common neoplasm found in both dairy and beef cattle. It is important for veterinarians, dairy producers and beef producers to gain a thorough understanding of BLS. The \u27first step in understanding BLS is to define the disease. Bovine leukosis, bovine leukemia, bovine lymphoma, and malignant lymphoma are misnomers that add confusion and frustration in understanding the disease process of BLS. There are currently four distinct forms of BLS: calf form, thymic form, skin form, and adult or bovine leukemia virus (BLV) associated form. In understanding these forms of BLS it is important to know what clinical signs to look for, how to make the diagnosis, the treatment options and recommendations for prevention and control

The total ozone field separated into meteorological regimes ? Part II: Northern Hemisphere mid-latitude total ozone trends

International audiencePrevious studies have presented clear evidence that the Northern Hemisphere total ozone field can be separated into distinct regimes (tropical, midlatitude, polar, and arctic) the boundaries of which are associated with the subtropical and polar upper troposphere fronts, and in the winter, the polar vortex. This paper presents a study of total ozone variability within these regimes, from 1979?2003, using data from the TOMS instruments. The change in ozone within each regime for the period January 1979?May 1991, a period of rapid total ozone change, was studied in detail. Previous studies had observed a zonal linear trend of ?3.15% per decade for the latitude band 25°?60° N. When the ozone field is separated by regime, linear trends of ?1.4%, 2.3%, and 3.0%, per decade for the tropical, midlatitude, and polar regimes, respectively, are observed. The changes in the relative areas of the regimes were also derived from the ozone data. The relative area of the polar regime decreased by about 20%; the tropical regime increased by about 10% over this period. No significant change was detected for the midlatitude regime. From the trends in the relative area and total ozone it is deduced that 35% of the trend between 25° and 60° N, from January 1979?May 1991 is due to movement of the upper troposphere fronts. The changes in the relative areas can be associated with a change in the mean latitude of the subtropical and polar fronts within the latitude interval 25° to 60° N. Over the period from January 1979 to May 1991, both fronts moved northward by 1.1±0.2 degrees per decade. Over the entire period of the study, 1979?2003, the subtropical front moved northward at a rate of 1.1±0.1 degrees per decade, while the polar front moved by 0.5±0.1 degrees per decade

Resection of multifocal non–small cell lung cancer when the bronchioloalveolar subtype is involved

AbstractObjectiveBronchioloalveolar lung cancer is commonly multifocal and can also present with other non–small cell types. The staging and treatment of multifocal non–small cell cancer are controversial. We evaluated the current staging of multifocal bronchioloalveolar carcinoma and the therapeutic effectiveness of resection when this tumor type is involved.MethodsWe reviewed our experience between 1992 and 2000 with complete pulmonary resections for bronchioloalveolar carcinoma. Kaplan-Meier survival curves were calculated from the dates of pulmonary resection.ResultsAmong 73 patients with bronchioloalveolar carcinoma, 14 patients, 7 male and 7 female with a mean age of 65 years (51-87 years), had multifocal lesions without lymph node metastases. Follow-up was 100% for a median of 5 years (range 2.6-8.5 years). Tumor distribution was unilateral in 9 patients and bilateral in 5 patients. The multifocal nature of the disease was discovered intraoperatively in 4 patients. Nine patients had 2 lesions, 4 patients had 3 lesions, and 1 patient had innumerable discrete foci in a single lobe. Operative mortality was 0. Postoperatively, 10 patients were staged pIIIB or pIV on the basis of multiple foci of similar morphology; 4 patients had some differences in histology (implying multiple stage 1 primaries). The median survival time to death from cancer was 14 months (141 days–5.6 years). The overall 5-year survival after resection of multifocal bronchioloalveolar carcinoma was 64%. Unilateral or bilateral distribution had no impact on survival.ConclusionsThe current staging system is not prognostic for multifocal bronchioloalveolar carcinoma without lymph node metastases. Complete resection of multifocal non–small cell lung cancer when bronchioloalveolar carcinoma is a component may achieve survivals similar to that of stage I and II unifocal non–small cell lung cancer. When bronchioloalveolar carcinoma is believed to be one of the cell types in multifocal disease without lymph node metastases, consideration should be given to surgical resection

Thymectomy in the treatment of ocular myasthenia gravis

AbstractBackground: Thymectomy is an effective and accepted treatment for myasthenia gravis, but thymectomy for ocular myasthenia gravis (Osserman stage I) is controversial. Objective: To assess the efficacy and propriety of thymectomy for the treatment of ocular myasthenia gravis. Methods: We conducted a review and follow-up of all patients who had thymectomy for the treatment of ocular myasthenia gravis between 1970 and 1998 at the University of California, Davis, Medical Center, and the University of Rome, “La Sapienza,” Rome, Italy. Patient response to thymectomy was categorized as follows: cured, patients who became symptom-free and required no further medication; improved, patients who required less medication and whose symptoms were less severe; unchanged, patients whose symptoms and medications were the same; worse, patients who had more severe symptoms, needed more medication, or died. Results: Sixty-one patients (mean age 37 years; range 14–73 years) were followed up for a mean duration of 9 years (range 0.5–29 years). Ocular myasthenia gravis with mixed and cortical thymomas, stages I to IV, occurred in 12 patients, and ocular myasthenia without thymomas occurred in 49 patients. Transsternal thymectomy (n = 55) and transcervical thymectomy (n = 6) resulted in cure in 31 (51%) patients, improvement in 12 (20%) patients, no change in 16 (26%) patients, and worsening of symptoms (including 1 postoperative death) in 2 patients. Patient outcomes were statistically independent of the duration of preoperative symptoms (mean 9.5 months), patient age, or the presence or absence of thymoma. In patients with ocular myasthenia, 70% were cured or improved after thymectomy; in the subgroup of patients with ocular myasthenia and thymoma, 67% were cured or improved. Conclusion: Thymectomy is an effective and safe treatment for patients with ocular myasthenia gravis

Directly Imaged L-T Transition Exoplanets in the Mid-Infrared

Gas-giant planets emit a large fraction of their light in the mid-infrared ($\gtrsim$3$\mu$m), where photometry and spectroscopy are critical to our understanding of the bulk properties of extrasolar planets. Of particular importance are the L and M-band atmospheric windows (3-5$\mu$m), which are the longest wavelengths currently accessible to ground-based, high-contrast imagers. We present binocular LBT AO images of the HR 8799 planetary system in six narrow-band filters from 3-4$\mu$m, and a Magellan AO image of the 2M1207 planetary system in a broader 3.3$\mu$m band. These systems encompass the five known exoplanets with luminosities consistent with L$\rightarrow$T transition brown dwarfs. Our results show that the exoplanets are brighter and have shallower spectral slopes than equivalent temperature brown dwarfs in a wavelength range that contains the methane fundamental absorption feature (spanned by the narrowband filters and encompassed by the broader 3.3$\mu$m filter). For 2M1207 b, we find that thick clouds and non-equilibrium chemistry caused by vertical mixing can explain the object's appearance. For the HR 8799 planets, we present new models that suggest the atmospheres must have patchy clouds, along with non-equilibrium chemistry. Together, the presence of a heterogeneous surface and vertical mixing presents a picture of dynamic planetary atmospheres in which both horizontal and vertical motions influence the chemical and condensate profiles.Comment: Accepted to Ap

Accreting Protoplanets in the LkCa 15 Transition Disk

Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition discs, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition discs show evidence for the presence of young planets in the form of disc asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15. Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disc clearing. With accurate source positions over multiple epochs spanning 2009 - 2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect H{\alpha} emission from the innermost companion, LkCa 15 b, evincing hot (~10,000 K) gas falling deep into the potential well of an accreting protoplanet.Comment: 35 pages, 3 figures, 1 table, 9 extended data item

High-contrast imaging constraints on gas giant planet formation - The Herbig Ae/Be star opportunity

Planet formation studies are often focused on solar-type stars, implicitly considering our Sun as reference point. This approach overlooks, however, that Herbig Ae/Be stars are in some sense much better targets to study planet formation processes empirically, with their disks generally being larger, brighter and simply easier to observe across a large wavelength range. In addition, massive gas giant planets have been found on wide orbits around early type stars, triggering the question if these objects did indeed form there and, if so, by what process. In the following I briefly review what we currently know about the occurrence rate of planets around intermediate mass stars, before discussing recent results from Herbig Ae/Be stars in the context of planet formation. The main emphasis is put on spatially resolved polarized light images of potentially planet forming disks and how these images - in combination with other data - can be used to empirically constrain (parts of) the planet formation process. Of particular interest are two objects, HD100546 and HD169142, where, in addition to intriguing morphological structures in the disks, direct observational evidence for (very) young planets has been reported. I conclude with an outlook, what further progress we can expect in the very near future with the next generation of high-contrast imagers at 8-m class telescopes and their synergies with ALMA.Comment: Accepted by Astrophysics and Space Science as invited short review in special issue about Herbig Ae/Be stars; 12 pages incl. 5 figures, 2 tables and reference

The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging

We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8 from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about 1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE \about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at \ks band, but not at \lprime . The surface brightness at \ks band declines inside 1\asec (\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The \ks - \lprime disk color, after removal of the stellar color, is mostly grey for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 \microns -sized grains on the east side and 1-10 \microns dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.Comment: Apj-accepted March 27 2012; minor correction

Accreting protoplanets: Spectral signatures and magnitude of gas and dust extinction at H α

Context. Accreting planetary-mass objects have been detected at H α, but targeted searches have mainly resulted in non-detections. Accretion tracers in the planetary-mass regime could originate from the shock itself, making them particularly susceptible to extinction by the accreting material. High-resolution (R > 50 000) spectrographs operating at H α should soon enable one to study how the incoming material shapes the line profile. Aims. We calculate how much the gas and dust accreting onto a planet reduce the H α flux from the shock at the planetary surface and how they affect the line shape. We also study the absorption-modified relationship between the H α luminosity and accretion rate. Methods. We computed the high-resolution radiative transfer of the H α line using a one-dimensional velocity–density–temperature structure for the inflowing matter in three representative accretion geometries: spherical symmetry, polar inflow, and magnetospheric accretion. For each, we explored the wide relevant ranges of the accretion rate and planet mass. We used detailed gas opacities and carefully estimated possible dust opacities. Results. At accretion rates of Ṁ ≲ 3 × 10−6 MJ yr−1, gas extinction is negligible for spherical or polar inflow and at most AH α ≲ 0.5 mag for magnetospheric accretion. Up to Ṁ ≈ 3 × 10−4 MJ yr−1, the gas contributes AH α ≲ 4 mag. This contribution decreases with mass. We estimate realistic dust opacities at H α to be κ ~ 0.01–10 cm2 g−1, which is 10–104 times lower than in the interstellar medium. Extinction flattens the LH α –Ṁ relationship, which becomes non-monotonic with a maximum luminosity LH α ~ 10−4 L⊙ towards Ṁ ≈ 10−4 MJ yr−1 for a planet mass ~10 MJ. In magnetospheric accretion, the gas can introduce features in the line profile, while the velocity gradient smears them out in other geometries. Conclusions. For a wide part of parameter space, extinction by the accreting matter should be negligible, simplifying the interpretation of observations, especially for planets in gaps. At high Ṁ, strong absorption reduces the H α flux, and some measurements can be interpreted as two Ṁ values. Highly resolved line profiles (R ~ 105) can provide (complex) constraints on the thermal and dynamical structure of the accretion flow

First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs

As the only directly imaged multiple planet system, HR 8799 provides a unique opportunity to study the physical properties of several planets in parallel. In this paper, we image all four of the HR 8799 planets at H-band and 3.3 microns with the new LBT adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3$ micron photometry of the innermost planet (for the first time) and put strong upper-limits on the presence of a hypothetical fifth companion. We find that all four planets are unexpectedly bright at 3.3 microns compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 microns due to CH4 opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres, but find that removing CH4 to fit the 3.3 micron photometry increases the predicted L' (3.8 microns) flux enough that it is inconsistent with observations. In an effort to fit the SED of the HR 8799 planets, we construct mixtures of cloudy atmospheres, which are intended to represent planets covered by clouds of varying opacity. In this scenario, regions with low opacity look hot and bright, while regions with high opacity look faint, similar to the patchy cloud structures on Jupiter and L/T transition brown-dwarfs. Our mixed cloud models reproduce all of the available data, but self-consistent models are still necessary to demonstrate their viability.Comment: Accepted to Ap