The onset of planet formation in brown dwarf disks

The onset of planet formation in protoplanetary disks is marked by the growth and crystallization of sub-micrometer-sized dust grains accompanied by dust settling toward the disk mid-plane. Here, we present infrared spectra of disks around brown dwarfs and brown dwarf candidates. We show that all three processes occur in such cool disks in a way similar or identical to that in disks around low- and intermediate-mass stars. These results indicate that the onset of planet formation extends to disks around brown dwarfs, suggesting that planet formation is a robust process occurring in most young circumstellar disks.     

Amending a loamy sand with three compost types: impact on soil quality

The objective of this study was to investigate the effects of the long‐term addition of three compost types (vegetable, fruit and yard waste compost – VFYW, garden waste compost – GW and spent mushroom compost – SM) on the physical properties of a sandy soil and to quantify any such effects using indicators of soil physical quality. Soil samples were taken from a field with annual compost applications of 30 m³/ha for 10 yr and various physico‐chemical analyses were undertaken. Results show a significant increase in soil organic carbon (21%) with the VFYW and GW compost types. With SM, soil organic carbon increased by 16%. Increased soil macroporosity and water content at saturation with a corresponding decrease in bulk density were observed for all compost types. However, quantification of these improvements using existing soil physical quality indicators such as the ‘S‐index’, soil air capacity and matrix porosity gave mixed results showing that these indices perform poorly when applied to sandy soils. It is concluded that the long‐term application of compost does not significantly improve the physical properties of sandy soils, but the absence of adverse effects suggests that these soils are a viable disposal option for these composts, but new indices of quality are needed for the proper characterization of sandy soils.     

Pathogenic characteristics of persistent feline enteric coronavirus infection in cats

Feline coronaviruses (FCoV) comprise two biotypes: feline enteric coronaviruses (FECV) and feline infectious peritonitis viruses (FIPV). FECV is associated with asymptomatic persistent enteric infections, while FIPV causes feline infectious peritonitis (FIP), a usually fatal systemic disease in domestic cats and some wild Felidae. FIPV arises from FECV by mutation. FCoV also occur in two serotypes, I and II, of which the serotype I viruses are by far the most prevalent in the field. Yet, most of our knowledge about FCoV infections relates to serotype II viruses, particularly about the FIPV, mainly because type I viruses grow poorly in cell culture. Hence, the aim of the present work was the detailed study of the epidemiologically most relevant viruses, the avirulent serotype I viruses. Kittens were inoculated oronasally with different doses of two independent FECV field strains, UCD and RM. Persistent infection could be reproducibly established. The patterns of clinical symptoms, faecal virus shedding and seroconversion were monitored for up to 10 weeks revealing subtle but reproducible differences between the two viruses. Faecal virus, i.e. genomic RNA, was detected during persistent FECV infection only in the large intestine, downstream of the appendix, and could occasionally be observed also in the blood. The implications of our results, particularly our insights into the persistently infected state, are discussed.     

Altrenogest and progesterone therapy during pregnancy in bottlenose dolphins (Tursiops truncatus) with progesterone insufficiency

Progesterone production is essential for growth and development of the conceptus during pregnancy. Abnormal development of the corpus luteum (CL) after conception can result in early embryonic loss or fetal abortion. Routine monitoring of bottlenose dolphin (Tursiops truncatus) pregnancy after artificial insemination or natural conception with ultrasonography and serum progesterone determination has allowed for the establishment of expected fetal growth rates and hormone concentrations. Using these monitoring techniques, we revealed four pregnant dolphins (12-24 yr old) with abnormally low progesterone production indicative of luteal insufficiency. Once diagnosed, animals were placed on altrenogest (0.044-0.088 mg/kg once daily) alone or with oral progesterone (50-200 mg twice daily). Doses of hormone were increased or decreased in each animal based on how fetal skull biparietal and thoracic growth rates compared with published normal values. Hormones were withdrawn starting from day 358 of gestation in animals 1 and 2, with labor occurring 6 and 7 days after withdrawal and at 376 and 373 days of gestation, respectively. Both deliveries were dystocic, with each calf requiring manual extraction and fetotomy for calf 1. The fetuses in animals 3 and 4 died at 348 and 390 days of gestation, respectively. Induction of labor was attempted in both animals, after fetal death, by using a combination of rapid progesterone withdrawal and steroid and prostaglandin F2alpha administration. The calf of animal 4 had to be removed with manual cervical dilation and fetotomy All adult females survived the procedures. These data provide the first in vivo evidence that the CL is the primary source of progesterone throughout pregnancy in the bottlenose dolphin. Until further characterization of hormones required during pregnancy and at parturition has been accomplished, the exogenous progestagen supplementation protocol described here cannot be recommended for treatment of progesterone insufficiency in bottlenose dolphins.     

A portable, contact animal fundus imaging system based on Rol's GRIN lenses

Objective To demonstrate a cost‐effective, portable, and simple‐to‐use fundus imaging system for laboratory animals. Animals Studied Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits. Procedure A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered. Results Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high‐quality images for each animal. Conclusions The portable, cost‐effective contact fundus imaging system was easy to use for fundus examination of laboratory animals.     

Phytolith‐rich biochar increases cotton biomass and silicon‐mineralomass in a highly weathered soil

Non‐essential silicon (Si) is beneficial to plants. It increases the biomass of Si‐accumulator plants by improving photosynthetic activity and alleviating stresses. Desilication, however, takes place because of natural soil weathering and removal of harvested biomass. Pyrolysis transforms Si‐rich biomass into biochar that can be used to supply bioavailable Si. Here, we applied two biochar materials differing in Si content on soils differing in weathering stage: a young Cambisol and a highly weathered Nitisol. We studied the impact of biochar supply on the bioavailability of Si, cotton biomass, and Si mineralomass. The biochar materials derived from, respectively: Miscanthus × giganteus (Mi; 34.6 g Si kg^?1 in biochar) and soft woody material (SW; 0.9 g Si kg^?1 in biochar). They were compared to conventional Si fertilizer wollastonite (Wo; CaSiO₃). Amendments were incorporated in soils at the rate of 3% (w/w). The content of bioavailable Si in soil was determined through 0.01 M CaCl₂ extraction. In the Cambisol, the proportion (CaCl₂ extractable Si: total Si content) was significantly smaller for Mi (0.9%) than for Wo (5.2%). In the Nitisol, this proportion was much larger for Mi (1.4%) than for Wo (0.7%). Mi‐biochar significantly increased Si‐mineralomass relatively to SW‐biochar in both soils. This increase was, however, much larger in the Nitisol (5.9‐fold) than in the Cambisol (2.2‐fold). Mi biochar is thus an alternative Si fertilizer to Wo to supply bioavailable Si, increase plant biomass, and promote the biological cycle of Si in the soil‐plant system in the Nitisol. Besides, it increased soil fertility and soil organic carbon content.     

Soil management effects on runoff and soil loss from field rainfall simulation

Soil erosion from agricultural lands is a serious problem on the Chinese Loess Plateau. In total, 28 field rainfall simulations were carried on loamy soils under different management practices, namely conventional tillage (CT), no till with mulch (NTM), reduced tillage (RT), subsoiling with mulch (SSM), subsoiling without mulch (SS), and two crops per year (TC), to investigate (i) the effects of different soil management practices on runoff sediment and (ii) the temporal change of runoff discharge rate and sediment concentration under different initial soil moisture conditions (i.e. initially dry soil surface, and wet surface) and rainfall intensity (85 and 170 mm h^− 1) in the Chinese Loess Plateau. NTM was the best alternative in terms of soil erosion control. SSM reduced soil loss by more than 85% in 2002 compared to CT, and its effects on runoff reduction became more pronounced after 4 years consecutive implementation. SS also reduced considerably the runoff and soil loss, but not as pronounced as SSM. TC resulted in a significant runoff reduction (more than 92%) compared to CT in the initial ‘dry’ soil, but this effect was strongly reduced in the initial ‘wet’ soil. Temporal change of runoff discharge rate and sediment concentration showed a large variation between the different treatments. In conclusion, NTM is the most favorable tillage practices in terms of soil and water conservation in the Chinese Loess Plateau. SSM can be regarded as a promising measure to improve soil and water conservation considering its beneficial effect on winter wheat yield.     

Impact of deposition on the enrichment of organic carbon in eroded sediment

A substantial part of eroded material can be deposited along the runoff pathway. This deposition process may alter the composition of the transported material. Topography- and vegetation-induced deposition processes were examined under laboratory conditions and at the hillslope and watershed scale. The laboratory experiments showed that the enrichment ratio of the specific surface area, ER_SSA, of the transported sediment followed an exponential increase with decreasing sediment delivery ratio, SDR, regardless of the type of deposition process. However, the increase in ER_SSA with decreasing SDR values was lower than expected. The upper limit of the ER_SSA was estimated to be 1.66, which is much lower than the calculated theoretical upper limit of 5.22. This difference can be attributed to the transport of the eroded material in micro-aggregated form. It was also found that the specific surface area, SSA, is a good predictor of organic carbon, OC. The observations on field plots confirmed the results of the laboratory experiments. Measurements at the watershed level indicated that the intensity of the erosion process had a more important influence on sediment enrichment, while the impact of deposition tended to be rather limited. However, sediment monitoring over a longer period is required to reveal the importance of the different erosion processes with regard to OC losses at the field and watershed level.     

Coughing,mucus accumulation,airway obstruction,and airway inflammation in control horses and horses affected with recurrent airway obstruction

OBJECTIVE: To investigate relationships between cough frequency and mucus accumulation, airway obstruction, and airway inflammation and to determine effects of dexamethasone on coughing and mucus score. ANIMALS: 13 horses with recurrent airway obstruction (RAO) and 6 control horses. PROCEDURE: 6 RAO-affected and 6 control horses were stabled for 3 days. Coughing was counted for 4 hours before and on each day horses were stabled. Before and on day 3 of stabling, tracheal mucus accumulation was scored, airway obstruction was assessed via maximal change in pleural pressure (deltaPpl(max)), and airway inflammation was evaluated by use of cytologic examination of bronchoalveolar lavage fluid (BALF). Effects of dexamethasone (0.1 mg/kg, IV, q 24 h for 7 days) were determined in 12 RAO-affected horses. RESULTS: To assess frequency, coughing had to be counted for 1 hour. In RAO-affected horses, stabling was associated with increases in cough frequency, mucus score, and deltaPpl(max). Control horses coughed transiently when first stabled. In RAO-affected horses, coughing was correlated with deltaPpl(max), mucus score, and airway inflammation and was a sensitive and specific indicator of deltaPpl(max) > 6 cm H2O, mucus score > 1.0, and > 100 neutrophils/microL and > 20% neutrophils in BALF Dexamethasone reduced cough frequency, mucus score, and deltaPpl(max), but BALF neutrophil count remained increased. CONCLUSIONS AND CLINICAL RELEVANCE: Because of its sporadic nature, coughing cannot be assessed accurately by counting during brief periods. In RAO-affected horses, coughing is an indicator of airway inflammation and obstruction. Corticosteroid treatment reduces cough frequency concurrently with reductions in deltaPpl(max) and mucus accumulation in RAO-affected horses.