Orbital period change of Dimorphos due to the DART kinetic impact.

The Double Asteroid Redirection Test (DART) spacecraft successfully performed the first test of a kinetic impactor for asteroid deflection by impacting Dimorphos, the secondary of near-Earth binary asteroid (65803) Didymos, and changing the orbital period of Dimorphos. A change in orbital period of approximately 7 min was expected if the incident momentum from the DART spacecraft was directly transferred to the asteroid target in a perfectly inelastic collision1, but studies of the probable impact conditions and asteroid properties indicated that a considerable momentum enhancement (ß) was possible2,3. In the years before impact, we used lightcurve observations to accurately determine the pre-impact orbit parameters of Dimorphos with respect to Didymos4-6. Here we report the change in the orbital period of Dimorphos as a result of the DART kinetic impact to be -33.0 ± 1.0 (3σ) min. Using new Earth-based lightcurve and radar observations, two independent approaches determined identical values for the change in the orbital period. This large orbit period change suggests that ejecta contributed a substantial amount of momentum to the asteroid beyond what the DART spacecraft carried.

Surgical management of duodenal web in an adult presenting with melaena; Case report and literature review.

INTRODUCTION: Duodenal web is a rare pathology presenting infrequently in adults. Diagnosis is challenging and definitive management is commonly delayed. We present a case of a patient with a late diagnosis of duodenal web, who underwent laparotomy, intraoperative gastroscopy and surgical removal of the web performed by two general surgeons. CASE PRESENTATION: A 32-year-old woman with a previous diagnosis of irritable bowel syndrome presented with a three day history of abdominal pain, nausea and anorexia, and a one day history of melaena and haematemesis. Investigations including a magnetic resonance enterography, barium swallow study and gastroscopy revealed the diagnosis. The patient underwent laparotomy and excision of duodenal web. Intraoperative gastroscopy assisted with identification of the web's anatomical location. A longitudinal duodenotomy was performed and this was closed in a transverse fashion using the Heineke-Mikulicz technique. DISCUSSION: This case reports successful application of intraoperative gastroscopy during laparotomy and duodenotomy. Longitudinal duodenotomy with excision of the web and transverse closure of the duodenum appears to be the best approach. There are no previous publications detailing gastroscopy at the time of laparotomy with duodenal web. This technique may be utilised in appropriate situations to improve operative accuracy. CONCLUSION: Duodenal web is a rare entity in adults, and delayed diagnosis may lead to significant patient morbidity. Incorporating intraoperative endoscopy ensures accurate anatomical visualisation. This technique avoids duodenectomy, organ damage, bypass, or an unnecessarily large incision.