Understanding the spatial patterns of atmospheric ammonia trends in South Asia.

Ammonia (NH3) is the most abundant alkaline gas in the atmosphere, mainly emitted by agricultural activities. NH3 readily reacts with other atmospheric acidic pollutants, such as the oxidation products of sulfur dioxide (SO2) and nitrogen oxides (NOₓ), to create fine particulate matter, which has far-reaching effects on human health and ecosystems. Here, we investigated long-term atmospheric NH3 trends in South Asia (SA) using satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI). We analyzed 15 years (2008-2022) of IASI-NH3 retrievals against climate, biophysical, and chemical variables using an ensemble of multivariate statistical methods to identify the major factors driving the observed patterns in the region. Trend analysis of IASI-NH3 data reveals a significant rise in atmospheric NH3 over 51 % of SA plains, but a downward trend over 31 % of the region. Spatial correlation analysis reveals that biophysical factors, representing cropland expansion and agriculture intensification, have the highest positive correlation over 56 % of SA plains experiencing positive NH3 trends. However, our results reveal that the chemical conversion of NH3 to ammonium compounds, driven by the positive trends in NOₓ and SO2 pollution, is driving the apparently declining trend of NH3 in the other regions. Our results provide important insights into the NH3 trends detected by satellite data and can better inform the policy design aimed at reducing NH3 emissions and improving air quality for developing regions of the world.

Patterns of tropical forest understory temperatures.

Temperature is a fundamental driver of species distribution and ecosystem functioning. Yet, our knowledge of the microclimatic conditions experienced by organisms inside tropical forests remains limited. This is because ecological studies often rely on coarse-gridded temperature estimates representing the conditions at 2 m height in an open-air environment (i.e., macroclimate). In this study, we present a high-resolution pantropical estimate of near-ground (15 cm above the surface) temperatures inside forests. We quantify diurnal and seasonal variability, thus revealing both spatial and temporal microclimate patterns. We find that on average, understory near-ground temperatures are 1.6 °C cooler than the open-air temperatures. The diurnal temperature range is on average 1.7 °C lower inside the forests, in comparison to open-air conditions. More importantly, we demonstrate a substantial spatial variability in the microclimate characteristics of tropical forests. This variability is regulated by a combination of large-scale climate conditions, vegetation structure and topography, and hence could not be captured by existing macroclimate grids. Our results thus contribute to quantifying the actual thermal ranges experienced by organisms inside tropical forests and provide new insights into how these limits may be affected by climate change and ecosystem disturbances.

Posterior urethral polyp in a male child: a rare case report.

Urethral polyps are one of the rare deformities of the urethra. In most cases, the urethral polyps would not be considered in the differential diagnosis process by a huge number of physicians, mainly owing to the rarity of documented cases in the medical literature and because of the wide variety of unspecified symptoms the urethral polyp might demonstrate. Urethral polyps are more common in males than in females, and they are usually diagnosed at an early age. Treatment options include transurethral resection, endoscopic suprapubic approach and open surgery. The disease prognosis is excellent as it does not usually recur after being completely removed and the risk of malignant transformation is very low. We are going to report a case of a 3-month-old boy who presented with bilateral vesicoureteral reflux and hydronephrosis, which revealed the presence of a large posterior urethral polyp.

A new imaging technique for assessment of the effectiveness of long pulse Nd:YAG 532 nm laser in treatment of facial port wine stain.

BACKGROUND: PWS is a vascular malformation presented at birth and associated with a psychological problem to the patients. Many types of laser systems were used to solve this problem. AIM OF THE STUDY: To assess the efficacy of long-pulsed Nd:YAG 532-nm laser in the treatment of port wine stain both clinically and by imaging technique. PATIENTS AND METHODS: This is an interventional therapeutic clinical study for the treatment of facial port-twine stain with long-pulsed, 532-nm, Nd:YAG laser. The treatment sessions were done every 4 weeks for 12 sessions and follow-up after 3 months of the last session. The assessment of the response was done before and at the end of follow-up period, both objectively (percent of improvement, photo comparison by using PSNR) and subjectively (patient satisfaction). RESULTS: Sixteen patients completed all sessions of the treatment. The improvement score for the PWS were failure = 0%, mild = 6.25%, moderate = 12.5%, good = 31.25%, and excellent = 50%. The values of PSNR for all the patients have been recorded and were fewer than 25 which means that the response for the treated lesions was very good. CONCLUSION: The long-pulsed Nd:YAG laser 532 nm is an effective and safe method of treatment of facial PWSs without significant residue. The PSNR was a new, simple, cheap and noninvasive method for assessment of the response of PWSs to laser therapy.