Center for low-gravity fluid mechanics and transport phenomena

Research projects in several areas are discussed. Mass transport in vapor phase systems, droplet collisions and coalescence in microgravity, and rapid solidification of undercooled melts are discussed

The HH34 outflow as seen in [FeII]1.64um by LBT-LUCI

Dense atomic jets from young stars copiously emit in [FeII] IR lines, which can, therefore, be used to trace the immediate environments of embedded protostars. We want to investigate the morphology of the bright [FeII] 1.64um line in the jet of the source HH34 IRS and compare it with the most commonly used optical tracer [SII]. We analyse a 1.64um narrow-band filter image obtained with the Large Binocular Telescope (LBT) LUCI instrument, which covers the HH34 jet and counterjet. A Point Spread Function (PSF) deconvolution algorithm was applied to enhance spatial resolution and make the IR image directly comparable to a [SII] HST image of the same source. The [FeII] emission is detected from both the jet, the (weak) counter-jet, and from the HH34-S and HH34-N bow shocks. The deconvolved image allows us to resolve jet knots close to about 1\arcsec from the central source. The morphology of the [FeII] emission is remarkably similar to that of the [SII] emission, and the relative positions of [FeII] and [SII] peaks are shifted according to proper motion measurements, which were previously derived from HST images. An analysis of the [FeII]/[SII] emission ratio shows that Fe gas abundance is much lower than the solar value with up to 90% of Fe depletion in the inner jet knots. This confirms previous findings on dusty jets, where shocks are not efficient enough to remove refractory species from grains.Comment: 5 pages, 4 figures, note accepted by A&

Evaluation of the sleep modulating effects of methanolic extracts of Strychnos spinosa and Strychnos innocua fruits in mice

This study aimed to evaluate the sleep modulating properties of Strychnos spinosa and Strychnos innocua fruits in Swiss albino mice. The depressant effect of the extracts on the central nervous system was studied using a diazepam-induced sleep model in mice. The mice were divided into four groups of six mice each. The test groups received Strychnos spinosa and Strychnos innocua fruits extracts at the doses of 250, 500, and 1000 mg/kg body weight intraperitoneally. In contrast, the control group received distilled water at 10 ml/kg. Diazepam (Ranbaxy®, India) was used as a standard drug and administered 30 minutes after the initial treatment. The lethal doses (LD50) of the two extracts were estimated to be >5000 mg/kg. The results obtained from the onset of sleep of rats administered methanol extracts of Strychnos spinosa, and Strychnos innocua fruits showed that the extracts at 250, 500, and 1000 mg/kg, respectively, did not significantly (p >0.05) alter the onset of sleep when compared with the control. The onset of sleep in the groups treated with Strychnos spinosa fruit extracts indicated a dose-dependent decrease pattern. The study also revealed a prolonged duration of sleep in all the experimental groups treated with the two extracts compared to the control group. The treated groups of 250, 500 and 1000 mg/kg significantly (p <0.05) prolonged the duration of diazepam-induced sleep in a dose-dependent manner when compared to the control group. The group treated with 1000 mg/kg of Strychnos innocua fruit extract was significant (p <0.05) compared to the control group. In conclusion, the high LD50 observed in this study suggests that the two extracts are relatively safe and contain promising bioactive ingredients that cause sleep modulation in mice

Caldera collapse and tectonics along the Main Ethiopian Rift: Reviewing possible relationships

The Main Ethiopian Rift (MER) represents an area where volcanism and tectonics interact to create closely linked volcano-tectonic features. This linkage is paramount in the axial portion of the rift, where magmatic segments localize several large peralkaline eruptive centres. Many of them evolved into caldera collapse (the best preserved of which are younger than ${<}1~\mathrm{Ma}$) generating large ignimbrites and registering the interaction between magmatism and tectonics along the MER. In this work we review the structure of the main collapsed calderas along the axial portion of the MER, to summarize the relationships between volcanism and tectonics proposed in the literature explaining their structural evolution. By doing this, we infer that tectonics had a strong influence in controlling the elongation of the majority of examined calderas. This control was induced by reactivation of inherited crustal fabrics or by stretching of the magma reservoirs under the MER regional stress field

Early clinical predictors and correlates of long-term morbidity in bipolar disorder

OBJECTIVES: Identifying factors predictive of long-term morbidity should improve clinical planning limiting disability and mortality associated with bipolar disorder (BD). METHODS: We analyzed factors associated with total, depressive and mania-related long-term morbidity and their ratio D/M, as %-time ill between a first-lifetime major affective episode and last follow-up of 207 BD subjects. Bivariate comparisons were followed by multivariable linear regression modeling. RESULTS: Total % of months ill during follow-up was greater in 96 BD-II (40.2%) than 111 BD-I subjects (28.4%; P=0.001). Time in depression averaged 26.1% in BD-II and 14.3% in BD-I, whereas mania-related morbidity was similar in both, averaging 13.9%. Their ratio D/M was 3.7-fold greater in BD-II than BD-I (5.74 vs. 1.96; P<0.0001). Predictive factors independently associated with total %-time ill were: [a] BD-II diagnosis, [b] longer prodrome from antecedents to first affective episode, and [c] any psychiatric comorbidity. Associated with %-time depressed were: [a] BD-II diagnosis, [b] any antecedent psychiatric syndrome, [c] psychiatric comorbidity, and [d] agitated/psychotic depressive first affective episode. Associated with %-time in mania-like illness were: [a] fewer years ill and [b] (hypo)manic first affective episode. The long-term D/M morbidity ratio was associated with: [a] anxious temperament, [b] depressive first episode, and [c] BD-II diagnosis. CONCLUSIONS: Long-term depressive greatly exceeded mania-like morbidity in BD patients. BD-II subjects spent 42% more time ill overall, with a 3.7-times greater D/M morbidity ratio, than BD-I. More time depressed was predicted by agitated/psychotic initial depressive episodes, psychiatric comorbidity, and BD-II diagnosis. Longer prodrome and any antecedent psychiatric syndrome were respectively associated with total and depressive morbidity

In vitro anticoccidial activity of ethanolic leaf extract of Citrus aurantium L. against Eimeria tenella oocysts

This study was carried out to examine the anticoccidial effect of Citrus aurantium L ethanol leaf extract against the oocysts of Eimeria tenella isolated from broiler chickens. The fresh leaves of C. aurantium were collected from Emirate Garden, Katsina, authenticated, air-dried at room temperature, pulverised by milling and subjected to extraction. Sporulation inhibition bioassay was employed to examine the activity of C. aurantium ethanol extract on the sporulation of E. tenella oocysts. In this assay, deep well petri dishes containing 100 unsporulated oocysts were subjected to 2 ml of five different concentrations of the extract (2.5, 5, 10, 20 and 30 mg/ml) in triplicates while oocysts sporulated in 2.5% potassium dichromate solution (K2Cr2O7) and phenol served as control groups. The content of the Petri dishes was stirred to ensure adequate oxygenation. The experimental set-up was incubated at room temperature and examined after 24 and 48 hours for sporulation inhibition. The sporulated and unsporulated oocysts were determined by counting using the Mcmaster apparatus. Phytochemical screening of C. aurantium revealed the presence of alkaloids, saponins, carbohydrates, steroids and tannins. The result showed that ethanolic leaf extract of C. aurantium to possess anticoccidial activity against unsporulated oocysts of E. tenella in a concentration-dependent manner. There was significant difference (p &lt; 0.05) in the sporulation inhibition activity, with the highest (97 ± 0.8%) at 30 mg/ml and the lowest activity (8 ± 1.0%) at 2.5 mg/ml concentration of the extract after 48 hours of incubation. There was a general trend of sporulation inhibition with an increase in the concentration of the plant extract. The findings from this study showed ethanol leaf extract of C. aurantium possesses a remarkable In vitro anticoccidial effect that may be further scientifically explicated