A MECHANICAL MODEL TO ESTIMATE LEGS MUSCLE STIFFNESS COEFFICIENTS IN HORSE DURING JUMPING

The purpose of present study was to use a simple mechanical model to estimate horses’ legs muscles stiffness coefficients in jump height during jumping a spread fenceof 140 cm high. A digital camcoder was used (25 Hz) along with Ulead Studio program in order to obtain time, related distance, and various angles in horses’ legs data. The total jump distance and time of flight for each horse were measured with a precision of 10^-2 m and 10^-2 s respectively. Biomechanical formulae have been established in order to evaluate the muscles stiffness coefficients. Three groups of leg muscles; serratus ventralis, biceps brachii, and radial carpal extensor were considered in this study and their stiffness coefficients were successfully estimated

A NEW SIMPLE BIOMECHANICAL METHOD FOR INVESTIGATING HORSES JUMPING KINEMATICS

The purpose of present study was to use a simple mathematical model to investigate horses’ kinematical parameters such as initial CG angle and velocity components, horizontal distance to fence and to leading hind limb at take-off and jump height during jumping a spread fences of 100 and 140 cm high. A digital cam- coder was used (25 Hz) along with Ulead Studio program in order to get time and related distance data. The total jump distance and time of flight for each horse were measured to 10-2m and 10-2s respectively. Biomechanical formulae have been established in order to evaluate the kinematic parameters. The results obtained by this simple method agreed well with the results obtained by other researchers with sofisticated method. The simplicity of the method may permit the riders and trainers to to improve fast the jumping techniques for successful jumping

Space-Borne Retrieval of Solar-Induced Plant Fluorescence and its Relationship to Photosynthetic Parameters

Studies have shown that chlorophyll fluorescence is directly linked to the photosynthetic efficiency of plants. The excess absorbed energy by leaves which has not been used in photosynthesis is re-emitted to the environment, either as heat or fluorescence. Therefore, any potential stress in plants is technically visible through monitoring fluorescence and the Solar-Induced plant Fluorescence (SIF) can thus be monitored as an indicator for vegetation growth and health status. SIF is a broad band spectral feature exhibiting two maxima at about 680 and 740 nm respectively, also known as red and far-red SIF. In the recent decades, there have been several studies addressing SIF, its importance and approaches to measure its value over vegetated regions. Among several measurement approaches, satellite-based remote sensing of SIF is particularly valuable, since the covered (spatial) area can be explicitly larger than is the case with in-situ measurements. With current space-borne instruments, even a full global coverage is attainable within a few days. In the framework of this thesis, two novel methods have been developed, tested and utilized to retrieve SIF from hyper-spectral satellite measurements. In particular, the first developed method, makes use of the Fraunhofer absorption lines in the far-red spectral region (748.5 - 753 nm), to retrieve SIF via its in-filling effect on these absorption lines. However, the satellite-based remote sensing spectrometers, used in this work, typically exhibit an additive spectral feature, which is not fluorescence. This is often accompanying the actual SIF retrieval and can significantly deteriorate the results. To account for this effect, a correction method has been developed and is combined with the retrieval algorithm. The model-based sensitivity studies confirmed the feasibility of the method to disentangle SIF from this additive feature. Additionally, the potential influences of the atmospheric and measurement conditions on the retrieval results have been assessed. Finally, the method has been applied to ten years of SCIAMACHY data and the retrieved results have been mapped on seasonal base. On a global scale, the obtained values are between 0 to 4 mW ma 2 sra 1 nma 1 . In absence of large area ground based validation data, final judgment of the results obtained in the framework of this study, is not possible. Alternatively, comparison of the achieved results with those published by the US National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) has been performed. Despite some differences, the comparison also exhibited close results, both qualitatively and quantitatively. It should be noted that comparisons among the retrievals provided by other research groups (not only GSFC) over the same spatial region is also variable depending on the instruments and methods utilized (ranging on average from a few tenths to more than 4 mW ma 2 sra 1 nma 1 ). To further assess the reliability of retrieved SIF, monthly average values have been compared to ground-based flux-tower measurements of Absorbed Photosynthetically Active Radiation by plants (APAR) and Gross Primary Production (GPP), for a time span of several years. The agreement between the seasonal trends of SIF and these parameters was significant. Although the main focus of this PhD work was on retrieving SIF in the far-red wavelength region using a spectral micro-window, there are clear scientific benefits in having an estimation over the full spectral emission range of SIF. Therefore, the second retrieval method, developed in the framework of this work, was to obtain the full spectrum of the emitted SIF by retrieving the leaf and canopy parameters, utilizing a combination of two radiative transfer models. The model-based studies showed the feasibility of the method to retrieve SIF with high accuracy. Moreover, the first results of applying this approach on GOME-2 measurements demonstrated promising outcomes. Examples of the fit quality and retrieved SIF over two different vegetation coverage types have been presented in this thesis, showing clear applicability of the method to retrieve SIF over its full spectral emission range and the potential to derive other vegetation parameters (e.g. Chlorophyll content of the leaves and the so-called leaf area index)

Evaluation of tubotympanic angle of Eustachian tube and its relationship with Eustachian tube function in patients with chronic middle ear infection

Background: chronic otitis media is characterized by the accumulation of fluid in the middle ear and behind the tympanic membrane without signs of acute infection. The association between a middle ear infection and anatomical and physiological disorders of the Eustachian tube has been reported in several studies and its malfunction is one of the main causes of middle ear infection.  Aim: We aim to find the relation of tubotympanic angle of Eustachian tube and chromic otitis media.  Methods: In this study, 100 patients with chronic unilateral middle ear infections were included. To determine the tubotympanic angle of the Eustachian tube, a temporal bone CT scan was used in the radiology department of Loghman Hospital. Eustachian tube angle and ear function were recorded. Results: Among the 100 patients in the study, 42 were men and 58 were women. The mean age of patients in the study was 39.64±12.64 years. The angle was 3.79 ± 34.27 in the healthy ear and 2.43 ± 31.06 in the diseased ear, which showed a statistically significant difference between the two groups  Conclusion: Eustachian tube angles in adults may play an important role in the cause of chronic otitis media. In this study, it was found that the horizontalization of the Eustachian tube is associated with chronic otitis media. Besides, determining the angle of the Eustachian tube can help determine the susceptibility to otitis media.&nbsp

Satellite remote sensing of regional and seasonal Arctic cooling showing a multi-decadal trend towards brighter and more liquid clouds

Two decades of measurements of spectral reflectance of solar radiation at the top of the atmosphere and a complementary record of cloud properties from satellite passive remote sensing have been analyzed for their pan-Arctic, regional, and seasonal changes. The pan-Arctic loss of brightness, which is explained by the retreat of sea ice during the current warming period, is not compensated by a corresponding increase in cloud cover. A systematic change in the thermodynamic phase of clouds has taken place, shifting towards the liquid phase at the expense of the ice phase. Without significantly changing the total cloud optical thickness or the mass of condensed water in the atmosphere, liquid water content has increased, resulting in positive trends in liquid cloud optical thickness and albedo. This leads to a cooling trend by clouds being superimposed on top of the pan-Arctic amplified warming, induced by the anthropogenic release of greenhouse gases, the ice–albedo feedback, and related effects. Except over the permanent and parts of the marginal sea ice zone around the Arctic Circle, the rate of surface cooling by clouds has increased, both in spring (−32 % in total radiative forcing for the whole Arctic) and in summer (−14 %). The magnitude of this effect depends on both the underlying surface type and changes in the regional Arctic climate

The Arctic Ocean in CMIP6 Models: Biases and Projected Changes in Temperature and Salinity

We examine the historical evolution and projected changes in the hydrography of the deep basin of the Arctic Ocean in 23 climate models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6). The comparison between historical simulations and observational climatology shows that the simulated Atlantic Water (AW) layer is too deep and thick in the majority of models, including the multi-model mean (MMM). Moreover, the halocline is too fresh in the MMM. Overall our findings indicate that there is no obvious improvement in the representation of the Arctic hydrography in CMIP6 compared to CMIP5. The climate change projections reveal that the sub-Arctic seas are outstanding warming hotspots, causing a strong warming trend in the Arctic AW layer. The MMM temperature increase averaged over the upper 700 m at the end of the 21st century is about 40% and 60% higher in the Arctic Ocean than the global mean in the SSP245 and SSP585 scenarios, respectively. Salinity in the upper few hundred meters is projected to decrease in the Arctic deep basin in the MMM. However, the spread in projected salinity changes is large and the tendency toward stronger halocline in the MMM is not simulated by all the models. The identified biases and projection uncertainties call for a concerted effort for major improvements of coupled climate models

Cytogentic analysis of human dermal fibroblasts (HDFs) in early and late passages using both karyotyping and comet assay techniques

Human dermal fibroblasts (HDFs) are a potential source of somatic cells for genetic manipulation and tissue engineering. Confirmation of cytogenetic stability of these cells is an essential step for cell nuclear transfer and generation of a suitable and functional induced pluripotent stem cells line. HDF cells were isolated and cultured from human foreskin samples. Cytogenetic stability of these cells was evaluated in early (3-4) and late (10-15) passages using karyotype test and alkaline comet assay techniques. HDF cells in early and late passages showed normal karyotype but by comet assay abnormality and DNA damages in late passages of HDFs were observed. Also, the parameters of alkaline comet assay in early passages of HDFs compared with late passages and positive control groups more significantly were different (p < 0.05). These findings indicate that single-strand breaks or DNA damage after many passages may have occurred in HDF cells. Our results demonstrate that only early passages of HDF cells maintain cytogenetic stability and are good candidates for gene reprogramming. In conclusion, karyotype testing alone can not be used for detection of all signs of cytogenetic abnormality and DNA damages of cells. So, for precise evaluation of DNA damage and cytogenetic instability of fibroblast cells comet assay and karyotype techniques could complement each other

Depression Symptoms and Sleep Quality during COVID-19 Outbreak in Iran: A National Cross-Sectional Study

Background: Coronavirus 2019 is a new infectious disease that has been declared by the World Health Organization as a global pandemic. This pandemic may have psychological effects on populations. Objectives: This study aimed to investigate the quality of sleep and depression in the Iranian community during COVID-19 pandemic. Methods: This nationwide cross-sectional web-based study was conducted from April 19 to May 12, 2020 in Iran. The data collection tools were the Pittsburgh Sleep Quality Index and Depression Center for Epidemiologic Studies' Depression Scale questionnaires. Each province in Iran was assumed as a cluster, and generalized estimating equations models were used to determine the demographic variables that were related to depression symptoms and sleep quality during COVID-19 outbreak. Results: In this study, 73.5% and 41.4% of the participants had poor sleep quality and had depression symptoms, respectively. Perceived income, hours spent outdoors, the number of people with COVID-19 that were acquainted with, and a history of depression significantly were related to sleep quality. Also, gender, age, having a child, education level, economic status, and a history of depression were significantly associated with having depression symptoms. Conclusions: Most participants had poor sleep quality, and less than half had depressionsymptomsduring the COVID-19 pandemic. These problems can disturb daily routines, cut social ties, and increase worries and fears of the future. Interventions are necessary to reduce psychological problems in Iran

Knowledge, Attitudes, and Practices Towards COVID-19 in Iran: A Population-Based Study

Abstract Background and aims: The novel coronavirus (COVID-19) epidemic has far been the biggest global health threat of the 21st century. Protective measures are still one of the most effective methods for controlling COVID-19. Practicing hygiene and control measures are largely influenced by knowledge and attitude towards COVID-19. This study aimed to investigate the knowledge, attitude, and practice of Iranians towards COVID-19 as well as the demographic factors related to it in April and May, 2020. Methods: The study population in this cross-sectional, descriptive-analytical, and web-based study included 3736 Iranian individuals who were collected via convenience sampling method. A validated Iranian knowledge, attitude, and practices (KAP) Questionnaire about COVID-19 was used for collecting the required data. Ordinal multivariate generalized estimating equations (GEEs) were applied to analyze data. Results: The majority of participants (88.1%) had considerable knowledge, the right attitude (91%), and good practices (90.3%). In the multivariate models, factors related to greater knowledge were age>20 years (P<0.001), living in the urban area (P=0.030), holding a master’s or doctoral degree (P=0.044), and a moderate financial status (P=0.001). Females displayed mor positive attitude (P=0.035). Variables related to more favorable practices were age>20 years (P<0.001), and having a good (P=0.003) or moderate (P=0.038) financial status. Conclusion: It was concluded that the participants had good knowledge and a positive attitude, as well as adopted sound practices regarding COVID-19. However, this conclusion might not have been generalizable to entire Iranian community; therefore, it was recommended that preventive measures against COVID-19 should receive continued monitoring and emphasis. Keywords: Attitudes, COVID-19, Knowledge, Practice