Answer:
Amniocentesis is an invasive method that involves the aspiration of 10-20 ml of fetal water through the abdominal wall under ultrasound-guided control. In most cases, the procedure is performed around the 16th week of gestation. The fetal water sample contains fetal cells, mostly cells of fetal skin and the epithelium of the urinary tract.
Chorionic Villus Sampling (CVS) biopsy is performed between weeks 11 and 12 of gestation. During biopsy, with ultrasound guidance, the tissue of the chorionic fossa is aspirated mainly across the abdomen (transabdominal pathway). The biopsy specimen is of fetal origin and belongs to the outer layer of blastocyst cells or the trophoblast (outer layer of the placenta). Very often, the biopsy specimen contains tissue of the decidua (mucous membrane of the uterus) that is of maternal origin, and it is necessary to remove the maternal tissue before any treatment of the sample.
Explanation:
The amniocentesis procedure carries a risk of miscarriage of 0.5-1%. After aspiration of the fruit of the water, the sample is centrifuged to separate the cells from the amniotic fluid. Separate cells are seeded on a nutrient medium (cell culture) that stimulates cell growth. After about 14 days, the cell culture is further used for various genetic or biochemical analyzes such as karyotyping.
The advantage of chorionic biopsy is the amount of biological material, which is sufficient for the whole a number of different laboratory procedures. Also, a great advantage is the timing of the procedure as it allows diagnosis in the first trimester of pregnancy, but the chorionic biopsy procedure itself carries a risk of miscarriage of 1-2%.
Answer:
Explanation:
1. Visual design
Users can be distracted by the lack of visual design on a prototype because wireframes and other low-fidelity prototypes are very basic. This can cause users to comment on the lack of design and colour and distract both themselves and the researcher from the true goals of the project. The extent of this challenge depends on the level of detail within the prototype.
How to get around this: Ensure the user is aware at the start of a session that the website they are about to view is at an early stage of development and so does not look and feel like they may expect. The research may need to be explicit with some users and point out it is not the visual design that we are interested in for today.
2. Partial journeys
Prototypes often cover only partial user journeys, meaning that users may have to be dropped into a journey at a specific point and may lose the context of the overall task or what they would be coming on the site to do.
How to get around this: As well as creating tasks which set the context, consider including some time at the beginning of the session for users to explore the prototype as they would normally do on that website/app, without giving them long enough to discover the prototype journeys. Introductory questions can also be asked at the start of the session to position the user in the right frame of mind for what the prototype will allow them to do, therefore helping to provide some context alongside the task wording.
Answer:
<em>cellulose, starch and glycogen</em>
Explanation:
the three types of polysaccharides are cellulose, starch and glycogen
Answer:
One change to Earth's surface can result in changes to other Earth systems.
All of the spheres on the Earth are interconnected, and they constantly interact with each other. When there's a change in one of the spheres then the other ones have changed as well. This is the case with the hydrosphere and the atmosphere. The atmosphere is becoming hotter in the past few decades, and this is contributing to the increased temperature of the hydrosphere (in this case, the sea surface). With the increasing temperatures of the sea surface, the cyclone activity becomes bigger and stronger, and this contributes to lots of natural disasters. So we can easily see the interaction and changes in this case between the spheres;
* atmosphere gets hotter - temperature of the sea surface rises - bigger cyclone activity.
