Collisions and Mergers of Disk Galaxies: Hydrodynamics of Star Forming Gas

We summarize the results of numerical simulations of colliding gas-rich disk galaxies in which the impact velocity is set parallel to the spin axes of the two galaxies. The effects of varying the impact speed are studied with particular attention to the resulting gaseous structures and shockwave patterns, and the time needed to produce these structures. The simulations employ an N-body treatment of the stars and dark matter, together with an SPH treatment of the gas, in which all components of the models are gravitationally active. The results indicate that for such impact geometries, collisions can lead to the very rapid formation of a central, rapidly rotating, dense gas disk, and that in all cases extensive star formation is predicted by the very high gas densities and prevalence of shocks, both in the nucleus and out in the galactic disks. As the dense nucleus is forming, gas and stars are dispersed over very large volumes, and only fall back towards the nucleus over long times. In the case of low impact velocities, this takes an order of magnitude more time than that needed for the formation of a dense nucleus.Comment: To be published in Proceedings of 'The Evolution of Galaxies III- From simple approaches to self-consistent models,' held in Kiel, Germany, July 2002, Astrophysics and Space Science (Kluwer), vol. 284, p. 479, 200

Fertilty outcome in women after open abdominal myomectomy at the University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria

Background: Myomectomy is the surgical treatment of choice for uterine fibroids especially in women desirous of conception. There are controversies regarding fertility outcome following open abdominal myomectomy.Objective: To assess fertility outcome after open abdominal myomectomy in women with previous infertility.Design: A retrospective study.Setting: University of Port Harcourt Teaching Hospital (UPTH), Port Harcourt, Nigeria.Subjects: Women who wished to conceive after open abdominal myomectomy and had only subserous and/or intramural fibroids at surgery.Results: Over the five-year period under review, there were 301 abdominal myomectomies performed. One hundred and twenty case notes were retrieved giving a retrieval rate of 39.9%. Of these, 50 met the inclusion criteria. The mean age was 33.3 ± 3.2 years (range 27- 42 years). Pregnancy and miscarriage rates were 88% and 9.1% respectively. Live birth rate was 84.1%. Most (95.5%) of the patients conceived spontaneously after the procedure. Caesarean section was the common (84%) mode of delivery.Conclusion: Fertility and live birth rates improved after open abdominal myomectomy

Presynaptic control of transmission through group II muscle afferents in the midlumbar and sacral segments of the spinal cord is independent of corticospinal control.

Transmission of information from the terminals group II muscle afferents is subject to potent presynaptic modulation by both segmental group II and cutaneous afferents and by descending monoaminergic systems. Currently it is unknown whether descending corticospinal fibres affect this transmission. Here we have examined whether corticospinal tract activation modulates the size of monosynaptic focal synaptic potentials (FSPs) evoked by group II muscle afferents, and the excitability of intraspinal terminals of group II afferents, both of which are indices used to show presynaptic control. Conditioning stimulation of corticospinal pathways had no effects on the sizes of group II evoked FSPs in the midlumbar or sacral segments at either dorsal horn or intermediate zone locations. These stimuli also had no effect on the excitability of single group II afferent terminals in the dorsal horn of the midlumbar segments. As positive controls, we verified that the corticospinal conditioning stimuli used did effectively depress FSPs evoked from cutaneous afferents recorded at the same spinal locations as the group II field potentials in all experiments. Corticospinal tract conditioning stimuli did not consistently enhance or reduce the depression of group II FSPs that was evoked by stimulation of ipsilateral segmental group II or cutaneous afferents; in the large majority of cases there was no effect. The results reveal that the control of transmission of information from group II afferents in these regions of the spinal cord is independent of direct corticospinal control

Effects of weed control and cow dung manure on growth indices of quality protein maize

Field trials were conducted during the 2006, 2007 and 2008 rainy seasons at the Institute for Agricultural Research farm Samaru, in the Northern guinea savanna zone of Nigeria to evaluate the effects of weed control and cow dung manure treatments on growth of quality protein maize. Thetrials consisted of factorial combinations of eight weed control treatments which include application of proprietary mixtures of (Atrazine + Acetochlor + Terbuthylazine at a ratio of 1:1:1, Atrazine + Metolachlor at a ratio of 1:2 each at 3.0 and 4.0 kg a.i/ha, Atrazine at 4.0 and 5.0 kg a.i/ha, Hoe weeded at 3 and 6 weeks after sowing and a weedy check) with four cow dung manure levels at (0, 4, 8 and 12 t/ha and a recommended NPK mineral fertilizer check at the rate of 120 kg N, 26 kg P and 50 kg K/ha. The treatments were laid out in a split plot design with three replicates.Results indicated that application of Atrazine + Metolachlor at 4.0 kg a.i/ha and the two hoe weeded produced significantly (p>0.05) higher and similar values of 140.2 and 137.3 grams respectively for total dry matter with 11.1 and 11.8 g/m2/week respectively for crop growth rate. Plots treated with Atrazine + Metolachlor at 4.0 kg a.i/ha recorded significantly the highest values of 3.05 for leaf area index and 0.41 for harvest index. Application of Atrazine + Acetochlor + Terbuthylazine at 4.0 kg a.i/ha significantly recorded the highest shoot lodging count. The highest relative growth rate was by plots treated with Atrazine + Metolachlor at 3.0 kg a.i/ha. The weedy check consistently produced the least values for all parameters. Application of cow dung manure at 12 t/ha and the NPK mineral fertilizer check significantly produced the highest values for all parameters while the least were by the 0 fertilizer control. Based on the result of this study it canbe concluded that the application of Atrazine + Metolachlor at 4.0 kg a.i/ha and cow dung manure at 12 t/ha significantly increased growth indices of Quality Protein Maize.Keywords - Weed control, Cow dung manure, Growth indices, Quality protein maiz

Effects of Weed Control and Cow Dung Manure on Growth Performance of Quality Protein Maize in Samaru, Zaria, Nigeria

Field trials were conducted during the 2006, 2007 and 2008 rainy seasons at the Institute for Agricultural Research Samaru, in the Northern guinea savanna zone of Nigeria to evaluate the effects of weed control and cow dung manure treatments on growth of Quality Protein Maize. The trial consisted of factorial combinations of eight weed control treatments which include application of (Atrazine + Acetochlor + Terbuthylazine at a ratio of 1:1:1, Atrazine + Metolachlor at a ratio of 1:2 each at 3.0 and 4.0kg a.i/ha, Atrazine at 4.0 and 5.0kg a.i/ha, Hoe weeding at 3 and 6 weeks after sowing and a weedy check) with four cow dung manure levels at (0, 4, 8 and 12t/ha and a recommended NPK mineral fertilizer check at the rate of 120kg N, 26kg P and 50kg K/ha). The treatments were laid out in a split plot design with three replicates. In the mean data, application of Atrazine + Metolachlor at 4.0kg a.i/ha and the two hoe weedings produced significantly (P < 0.05) higher and similar values for total dry matter and crop growth rate, whereas Atrazine + Metolachlor at 4.0kg a.i/ha onlyproduced significantly (P<0.05) the higher values for leaf area index and harvest index. Application of Atrazine + Acetochlor + Terbuthylazine at 4.0kg a.i/ha had statistically (P<0.05) the higher lodging count. The highest Relative growth rate was by Atrazine + Metolachlor at 3.0kg a.i/ha (P<0.05). The weedy check consistently produced the least values for all parameters. Application of cow dung manure at 12t/ha and the NPK mineral fertilizer check produced significantly the highest values for all parameters (P<0.05) while 0 fertilizer control had the least. Based on the result of this study it can be deduced that the application of Atrazine + Metolachlor at 4.0 kg a.i/ha and cow dung manure at 12t/ha increased growth of Quality Protein Maize.Keywords - Weed control, Cow dung manure, Growth indices, Quality protein maiz

The effect of exercise training interventions in adult kidney transplant recipients: a systematic review and meta-analysis of randomised control trials

Background: Kidney transplant recipients (KTRs) are characterised by adverse changes in physical fitness and body composition. Post-transplant management involves being physically active, although evidence for the effect of exercise is limited. Objective: To assess the effects of exercise training interventions in KTRs. Methods: NCBI PubMed (MEDLINE) and CENTRAL (EMBASE, WHO ICTRP) databases were searched up to March 2021 to identify eligible randomized controlled trials (RCTs) that studied exercise training in adult KTRs. Outcomes included exercise capacity, strength, blood pressure, body composition, heart rate, markers of dyslipidaemia and renal function, and health-related quality of life (QoL). Results: Sixteen RCTs, containing 827 KTRs, were included. The median intervention length was 14-weeks with participants exercising between 2–7x/week. Most studies used a mixture of aerobic and resistance exercise. Significant improvements were observed in cardiorespiratory function (VO2peak) (3.21 ml/kg/min, p = 0.003), 6MWT (76.3 meters, p = 0.009), physical function (STS-60, 4.8 repetitions, p = 0.04), and high-density lipoprotein (HDL) (0.13 mg/dL, p = 0.03). A moderate increase in maximum heart rate was seen (p = 0.06). A moderate reduction in creatinine was also observed (0.14 mg/dl, p = 0.05). Isolated studies reported improvements in strength, bone health, lean mass, and QoL. Overall, studies had high risk of bias suggestive of publication bias. Conclusions: Exercise training may confer several benefits in adult KTRs, particularly by increasing cardiorespiratory function and exercise capacity, strength, HDL levels, maximum heart rate, and improving QoL. Additional long-term large sampled RCTs, incorporating complex interventions requiring both exercise and dietary behaviour change, are needed to fully understand the effects of exercise in KTRs

Gaseous carbonation of cementitious backfill for geological disposal of radioactive waste: Nirex Reference Vault Backfill

The ability of Nirex Reference Vault Backfill (NRVB), a cement backfill material, to capture carbon dioxide from Intermediate Level Radioactive waste packages after repository backfilling, has been assessed. Large-scale trials assessed the physical and chemical reaction of carbon dioxide with the hardened backfill grout. A carbonation front, radial in nature, was observed extending into the grout and three distinct regions were identified in the hardened grouts. A carbonated region, a carbonation front, and a partially carbonated zone were discerned. Potassium, and to a lesser extent sodium, were concentrated in the carbonated region just behind of the main reaction front. The area just ahead of the carbonation front was enriched in both sulphur and aluminium, while sulphur was found to be depleted from the carbonated material behind the main reaction front. Within the main carbonated region, virtually all of the hydrated cement phases were found to be carbonated, and carbonation extended throughout the grout, even within material indicated by phenolphthalein solution to be uncarbonated. Importantly, carbonation was observed to impact both the mineral assemblage and porosity of the cement backfill; it is therefore important to understand these characteristics in terms of the long term evolution of NRVB and its groundwater buffering safety function within the geological disposal facility near-field

Seasonal variation in collective mood via Twitter content and medical purchases

The analysis of sentiment contained in vast amounts of Twitter messages has reliably shown seasonal patterns of variation in multiple studies, a finding that can have great importance in the understanding of seasonal affective disorders, particularly if related with known seasonal variations in certain hormones. An important question, however, is that of directly linking the signals coming from Twitter with other sources of evidence about average mood changes. Specifically we compare Twitter signals relative to anxiety, sadness, anger, and fatigue with purchase of items related to anxiety, stress and fatigue at a major UK Health and Beauty retailer. Results show that all of these signals are highly correlated and strongly seasonal, being under-expressed in the summer and over-expressed in the other seasons, with interesting differences and similarities across them. Anxiety signals, extracted from both Twitter and from Health product purchases, peak in spring and autumn, and correlate also with the purchase of stress remedies, while Twitter sadness has a peak in the Winter, along with Twitter anger and remedies for fatigue. Surprisingly, purchase of remedies for fatigue do not match the Twitter fatigue, suggesting that perhaps the names we give to these indicators are only approximate indications of what they actually measure. This study contributes both to the clarification of the mood signals contained in social media, and more generally to our understanding of seasonal cycles in collective mood

Climate change promotes parasitism in a coral symbiosis.

Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals' sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodinium phylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change

Hypertension artérielle pulmonaire au cours de la sclérodermie: à propos de 12 cas

Introduction: La survenue de l’hypertension artérielle pulmonaire (HTAP) est un tournant dans l’évolution de la sclérodermie. L’objectif de cette étude est de décrire les aspects épidémiologiques et évolutifs de l’HTAP au cours de la sclérodermie systémique.Méthodes: Nous avons réalisé une étude descriptive concernant des patients suivis pour sclérodermie systémique, au service de Dermatologie de l’hôpital Aristide Le Dantec entre Janvier 2000 et Août 2009. Ces patients étaient inclus dans l’étude après exploration cardio-vasculaire (ECG, échocardiographie-Doppler). Nous avons étudié les paramètres épidémiologiques, cliniques, paracliniques et évolutifs des patients. Résultats: Nous avons enregistré 12 cas d’hypertension artérielle pulmonaire parmi les 83 patients atteints de sclérodermie systémique soit une prévalence de 14,45%. L’âge moyen des patients était de 43,58 ans ± 12,5 ans et le sex-ratio (H/F) de 0,33. Sur le plan clinique, la dyspnée était quasi constante (75%) et la douleur thoracique présente dans 25% des cas. Le syndrome de Raynaud était observé chez 8 patients soit 66,67% de nos patients. L’électrocardiogramme montrait des signes de surcharge droite chez 4 malades (33,33%) et la radiographie thoracique en faveur d’une fibrose pulmonaire chez 4 patients. L’échocardiographie-Doppler notait une insuffisance tricuspide importante dans 58, 33% des cas (7 patients), une pression artérielle pulmonaire systolique (PAPs) en moyenne de 66,25 ± 29,3 mmHg, une dilatation des cavités cardiaques droites dans 5 cas et un mouvement paradoxal du septum interventriculaire chez 3 malades (33,33%). Il était également noté 3 cas (25%) d’épanchement péricardique. Nous avons déploré 4 décès (33,33%).Conclusion: L’hypertension artérielle pulmonaire est une complication fréquente et grave de la sclérodermie. Son dépistage, grâce à l’échocardiographie- Doppler systématique, constitue une étape fondamentale de la prise en charge