74 research outputs found
Revisiting the Glick-Rogoff Current Account Model: An Application to the Current Accounts of BRICS Countries
Understanding what drives the changes in current accounts is one of the most important macroeconomic issues for developing countries. Excessive surpluses in current accounts can trigger trade wars, and excessive deficits in current accounts can, on the other hand, induce currency crises. The Glick-Rogoff (1995, Journal of Monetary Economics) model, which emphasizes productivity shocks at home and in the world, fit well with developed economies in the 1970s and 1980s. However, the Glick-Rogoff model fits poorly when it is applied to fast-growing BRICS countries for the period including the global financial crisis. We conclude that different mechanisms of current accounts work for developed and developing countries
Chemical composition and antibacterial activity of essential oils from the medicinal plant Mentha cervina L. grown in Portugal
Mentha cervina is a medicinal plant traditionally
used in Portugal in folk medicine, in different gastric
disorders and inflammations of the respiratory tract. In
order to validate those traditional uses, M. cervina essential
oils (EOs) were characterized by GC and GC–MS and their
antimicrobial activity was tested against 23 bacterial strains
(including multiresistant strains). The EOs were dominated
by the monoterpenes pulegone (52–75%), isomenthone
(8–24%), limonene (4–6%), and menthone (1–2%). The
antibacterial activity of these EOs was compared to that of
the main components standards. The most effective antibacterial
activity was expressed by the EOs against the
Gram-negative bacteria, Escherichia coli and Acinetobacter
baumanni, with MIC values of 1 mg/ml. The EOs complex mixtures were more active than the individual
aromatic components supporting the hypothesis that the
EOs antibacterial activity is a function of the synergistic
effect of their different aromatic components. These results
show the potential role of M. cervina EOs as antibacterial
agents and validate the traditional use of this plant
Dental metric standards for sex estimation in archaeological populations from Iran
Sex estimation of skeletal remains is one of the major components of forensic
identification of unknown individuals. Teeth are a potential source of information on
sex and are often recovered in archaeological or forensic contexts due to their post-mortem
longevity. Currently there is limited data on dental sexual dimorphism of
archaeological populations from Iran. This dissertation represents the first study to
provide a dental sex estimation method for Iron Age populations.
The current study was conducted on the skeletal remains of 143 adults from two Iron
Age populations in close temporal and geographic proximity in the Solduz Valley
(West Azerbaijan Province of Iran). 2D and 3D cervical mesiodistal and buccolingual
and root volume measurements of maxillary and mandibular teeth were used to
investigate the degree of sexual dimorphism in permanent dentition and to assess their
applicability in sex estimation. In total 1327, 457, and 480 anterior and posterior teeth
were used to collect 2D cervical, 3D cervical, and root volume measurements
respectively. 2D cervical measurements were taken using Hillson-Fitzgerald dental
calliper and 3D measurements were collected using CT images provided by Open
Research Scan Archive (ORSA) - Penn Museum. 3D models of the teeth were created
using manual segmentation in the Amira 6.01 software package. Since tooth density
largely differs from crown to apex, root segmentation required two threshold levels:
the segmentation of the root from the jaw and the segmentation of the crown from the
root. Thresholds used for root segmentation were calculated using the half maximum
height protocol of Spoor et al. (1993) for each skull, and thresholds used for crown
segmentation were set visually for each tooth separately. Data was analysed using
discriminant function analysis and posterior probabilities were calculated for all
produced formulae where sex was previously assessed from morphological features of
pelvis and skull. Bootstrapping was used to account for small sample sizes in the
analysis. Statistical analysis was carried out using SPSS 23. The percentage of sexual
dimorphism was also used to quantify the amount of sexual dimorphism in the sample.
The results showed that incisors and canines were the most sexually dimorphic teeth,
providing percentages of correct sex classification between 80% and 100% depending
on the measurement used. Root volume measurement was shown to be the most
sexually dimorphic variable providing an accuracy of over 90% in all functions.
The present study provided the first dental metric standards for sex estimation using
odontometric data in Iranian archaeological populations. Dental measurements,
particularly root volume measurements, were found to be of value for sex assessment
and the method presented here could be a useful tool for establishing accurate
demographic data from skeletal remains of the Iron Age from Iran
Estimation of permeability and rock mechanical properties of limestone reservoir rocks under stress conditions by strain gauge
Petroleum engineering reservoir parameter calculations are generally performed in the absence of the overburden pressure effect. This leads to serious errors in further development of a hydrocarbon-bearing reservoir. Thus, measurements under stress conditions become important vitally. The objective is to correlate the overburden pressure and the permeability to see the overburden pressure effects on the permeability of Turkish southeastern limestone reservoir rock samples. Stress was applied to four representative limestone samples taken from southeast Turkey. In the laboratory tests, two identical core plugs from every sample were used for each application. This is why a Wheatstone Bridge with a full-bridge strain gauge method was used. A sample is inserted into a load frame and the axial load was increased. Internal friction angles and cohesion factors were determined. An exponential correlation was proposed between permeability and confining pressure. The experimental and correlated results match very accurately. The stress and permeability correlations may be useful with resistivity logs through which permeability may be measured and for stress-strain-related CBL (cement bond logs) which are used for the well bore stability during cementing applications
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