Data collected in two-dimensional projections give planar images of object at each projection angle. To obtain information along the depth of the object, tomographic images are reconstructed using these projections. There are basically two approaches to solve the problem of reconstruction: analytical and iterative, each one presenting its own advantages and limitations. This paper provides a detailed introduction and comparison to four analytical image reconstruction methods including Fourier transformation, simple back-projection, back-projection filtering and filtered back-projection.
Lake Uluabat, having an international significance
and subject to the Ramsar Convention, is fed by the basin of Mustafakemalpasa
Stream which runs through fertile lands utilized for livestock breeding and
agriculture. In this study, total amount of nitrogen (TN) and phosphorus (TP)
loads of non-point pollutants (agriculture, livestock breeding, vegetation,
surface runoff and small settlements) was calculated. It was found out that
most intensive pollution load stemmed from livestock breeding which causes
dispersion of 13653.57 tons·year-1 of TN and
3224.45 tons·year-1 of TP into the Lake Uluabat. Additionally,
seasonal changes in concentration of TN and TP were observed during the period
of 2008-2009 in Lake Uluabat. It was concluded that the rise of agricultural
activities in summer months was the reason underlying the increase in pollution
during the months in question.
AIDS is one of the medical professional’s or young person ventures in third world countries like Iran. The growth of AIDS victims in the recent years has made a lot of global worries about cure process and other related issues to HIV problems in these countries. One of the effective groups in the study of AIDS patients is nurses who are in direct contact with patients. Our investigation led to study two variables “consciousness” and “vision” of nurses working in Imam Khomeini hospital of Tehran University of Medical Sciences. Based on the results we achieved that nurses have a low medium degree in the variables studied which is as a result of poor and low effective trainings. In addition to this as a consequence of wrong culture in Iran about AIDS patients or even people in contact with them, nurses have been in a great pressure as they might be in danger of disease transmission. This negative trend has caused a great anxiety about the real condition of AID patients in Iran and their cure process.