Greenhouse gas (GHG) emissions from human activities escalate the greenhouse effect, causing climate change. Confronting climate change requires accurate measurements of GHG emissions.

This work aims to optimize a ground-based, integrated path, differential absorption (IPDA) light detection device for GHG (CO2 and CH4) detection and monitoring that already has been developed and tested. The laser beam of the IPDA device was modulated using a rotating optical chopper that produces fluctuations in the recorded signal. By processing them with a Lock-In amplifier the signal to noise ratio (SNR) is reduced. In this work, the mechanical chopper was replaced by the laser beam modulation by changing the current of the laser controller.

In that case, rapid changes in the laser current produce undesirable changes in the laser wavelength. To investigate this effect, the optimum parameters of the laser driver for laser modulation were defined using a cell filled with GHG. Finally, the upgraded system was used to measure the background concentrations of CO₂ and CH₄ in the atmosphere. These measurements were used to determine the accuracy and reliability of the system.

Crocidura zimmermanni and Crocidura suaveolens are insectivorous mammals belonging to the extant shrew fauna of Crete. In particular, the C. zimmermanni has probably been present since the early Pleistocene. C. suaveolens, a species recently (i.e. in historical times) introduced to Crete, has constrained C. zimmermanni to the higher altitudes of the island. The lack of clear external morphological characters has caused a long history of confusion between the two. Within the framework of this thesis, we will employ high-resolution Computed Tomography (CT) imaging, aiming at finding distinctive characters between the two shrews through the acquisition of morphological information from skull bones and teeth. The recorded 3D reconstructions of the skull will provide precise assessments of the molar length, the jaw width as measured between the first and second molar, and the condylomaxillary length between the canine and the third molar. Furthermore, we are planning to determine the height of the cingulum above the end of the teeth in the investigated mammals. Each of the characters mentioned, or their combination, may allow for a safe distinction between the two species. The rapid and inexpensive morphological examination through CT is expected to provide additional evidence as regards the reliable classification of the animals, complementing the state-of-the-art molecular analysis methods.