"a nurse notes that an infant with a diagnosis of failure to thrive who has been receiving tube feedings for 3 days has very dry skin and mucous membranes. the nurse verifies that all feedings have been retained, but the daily urine output is consistently 250 ml, and the infant has lost weight. what does the nurse conclude

The infant is suffering from dehydration most probably from esophageal atresia (non-development of the distal side of the esophagus, forming a closed tube) or partial/complete gut obstruction. With a urine output of 250 mL constantly, the patient will be dehydrated. The infant is diagnosed with failure to thrive and is most probably malnourished (most common cause of failure to thrive in infants is preterm birth). In the presence of esophageal atresia, along with retained feedings, the patient will also present with vomiting. In the presence of partial/complete gut obstruction, the patient will also present with distension of the abdomen. 

Mantle convection  is the slow  creepingmotion of earth's solid silicate  mantle  caused by  convection  currents carrying  heat from the interior  to the planet's surface.[1][2]  the earth's surface  lithosphere, which rides atop the  asthenosphere  (the two components of the  upper mantle), is divided into a number of  plates  that are continuously being created and consumed at their opposite  plate boundaries. accretion occurs as mantle is added to the growing edges of a plate, associated with  seafloor spreading. this hot added material cools down by  conduction  and  convection  of heat. at the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of  subduction  usually at an  ocean trench.[3]this subducted material sinks through the earth's interior. some subducted material appears to reach the lower mantle,[4]  while in other regions, this material is impeded from sinking further, possibly due to a phase transition from  spinel  to  silicate perovskiteand  magnesiowustite, an  endothermic reaction.[5]the subducted oceanic crust triggers  volcanism, although the basic mechanisms are varied. volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease in density of the partial melt.secondary forms of convection that may result in surface volcanism are postulated to occur as a consequence of intraplate extension[6]  and  mantle plumes.[7]it is because the mantle can convect that the  tectonic plates  are able to move around the earth's surface.[8]mantle convection seems to have been much more active during the  hadean  period, resulting in gravitational sorting of heavier molten  iron, and  nickel  elements and  sulphides  in the core, and lighter  silicate minerals  in the  mantle.