Some ecological indices of the Caspian Sea Amphipoda at different depths Guilan offshore

In the present study, some ecological factors were studied for Amphipoda at different depths. The Shannon, Margalef, and Hill indices were used to determine the species diversity, richness and evenness, respectively. In addition, the association and niche overlap values were estimated. Indices of species richness and diversity were highest at 50 and 100m depths, respectively. The ordination of depths shows that the highest dissimilarity was at 20m depth and the lowest dissimilarity at 100 meter. Results of interspecific association and specific overlap of species show that only a few species could have similar ecological requirements. Results show that Paraniphargoides derzhavini with Niphargoides grimmi and Stenogammarus compersus with Amathilina cristata had low associations. Corophium spinulosum with Corophium nobile and Stenogammarus compersus with Paraniphargoides derzhavini, however, had high associations

Metal bioaccumulation in representative organisms from different trophic levels of the Caspian Sea

The bioaccumulations of metals Cu, Cd, Ni, Cr, Co, Mn, Zn and Fe were measured in bivalves, Cerastoderma glaucum, and four species of fishes including Alburnus chalcoides, Liza aurata, Rutilus frisii and Sander lucioperca from various trophic levels of the Caspian food web. The concentrations of Cd, Cr, Co and Ni in most samples of fish were below the detection limits; while the concentrations were detected in most samples of bivalve C. glaucum. The stable nitrogen isotope ratios varied among the samples from C. glaucum (δ^15N=3.5 ‰) to S. lucioperca (δ^15N=13.1‰). Among the four fish species, while the highest concentrations of Mn, Ni and Fe were observed in L. aurata, the lowest concentrations of Mn and Fe were observed in S. lucioperca. These species also had the lowest and highest trophic levels with an average of 3.3 and 4.2, respectively. No accumulation of metals with increase in body size was observed in muscles of species from different trophic levels. The comparison of metal concentrations with the health guidelines for human consumption showed that those intakes were lower than the legislated limits. While there was a strong relationship between trophic levels and body size of A. chalcoides and R. frisii, no significant slopes were observed between the total lengths (TLs) and the Ln concentrations of metals. It is necessary to determine metal concentrations in food resources of fish species, particularly in R. frisii that has significantly different δ^15N in relation to body size

Investigating the Causes of Visual Impairment and Legal Blindness among Patients Coming to a Referral Hospital in Tehran, Iran

Purpose: To examine the causes of vision impairment and blindnessin a referral medical center in Tehran, Iran.Patients and Methods:  The present cross-sectional study was conducted on visually impaired and legally blind patients in optometricclinic of Rasoul-e-Akram hospital, Tehran, Iran, in 2015. We used the WHO criteria to evaluate visual impairment. The visual acuity of patients was recorded in a mono-eye fashion (right eye first then the left eye) using a 6-meter Snellen chart. The refractive error was evaluated and the best corrected visual acuity (BCVA) was recorded. Patients were then referred to ophthalmology department to diagnose the main cause of reduced vision.Results:  This study included 77 legally blind or visually impaired patients. After examining the underlying causes of visual impairment, we found that 41.17 % of visual impairment among patients was caused by cataracts and 29.41 % was caused by retinal diseases. Corneal pathology, glaucoma and other diseases were the rarer causes of low vision among subjects. The causes of legal blindness were different; retinal diseases were the main causes of legal blindness (46.51 %) followed by cataract (30.23 %) and corneal pathology (13.95 %).Conclusion:  Our results from a referral hospital in Tehran indicates that retinal pathology was the most common cause of legal blindness among our patients, while the most common cause of visual impairment was cataract. Due to the natural differences of epidemiologic findings gathered from a referral center and the community, multicenter studies are recommended to better evaluate the causes of visual impairment in our community.Keywords: Visual; Impairment; Legal; Blindness; Iran.

Some biological aspects of Gammarus lacustris Sars, 1863 in Neur Lake Ardabeel province, Iran

A biological study was conducted to find out about reproduction and feeding of G. lacustris in Neur Lake from northwest mountains of Iran. Plankton diversity, hydro-chemical factors and substrate characteristic were recorded monthly. Findings showed that reproduction period of this species was short and limited to May and the mean brood size was 10.2 ± 5.3 eggs per female. The hydro-chemical analysis showed the eutrophic characteristic of Neur Lake in which the average of total organic matter was 3.7 ± 3.0 percent. The phyla representative Bacillariophyta, Chlorophyta and Cyanophyta were observed throughout the study and Chlorophyta was the dominant group. Three zooplankton phyla Rotatoria, Ciliophora and Copepoda were abundant respectively. Study on diet using gut content resulted in identification of 15 plankton genera with some resemblance to planktons of the lake

Investigation on meiofauna and substrate characteristic in the southern Caspian Sea (Guilan Province)

Meiofauna with a size of 100-1000µ having important rule in food webs. This study was carried out in autumn and winter 1992 along 30 transects at depths of 10, 20, 50 and 100m. The sediment samples were collected by grab (0.1 m2 area). In addition to identification of meiofauna, the sediments were examined to determine T.O.M. and grain size parameters. The results showed that bivalvia, foraminifera, nematoda, ostracoda and copepoda were dominant taxa among 12 identified fauna groups, in which foraminifera and bivalvia were the most abundant. The nonparametric Kroscall-walis test showed significant difference among abundance of meiofauna in different depths. The depth of 20m had the most abundance and with increasing depth (5O and 100m), the abundance had a descending trend. The maximum and minimum mean abundance of meiofauna varied from 29315±37248 and 825±498 ind/10 em2 for depth of 10 and 100m, respectively. The substrate characteristics indicated that the depth of 50 and 10m included the most and the least organic matter. Also all depths indicated the same grain size and sediment composition was mostly silt. Most of meiofauna were found in substrates with 4 to 8 % organic matter

Characterization of the Mixed Radiation Fields for BNCT

Mixed radiation fields are normally encountered in the treatment of tumors with ionizing radiations in Boron Neutron Capture Therapy (BNCT). The present thesis describes the characterization and the application of the Bonner sphere spectrometer of university of Pisa (BSS-UNIPI), based on 6LiI (Eu), as neutron spectrometer in investigating neutron beam in mixed fields, as found in BNCT. The shadow cone technique was optimized and applied for the evaluation of the scattered neutrons. The BSS set and shadow cones were used to characterize the 9Be (p, xn) reaction with 5 MeV proton beam, in the framework of TRASCO-BNCT project at the INFN-LNL. Different angles of neutron emission (0°, 40°, 80°, and 120°) were considered. Evaluation of the response matrix for the BSS was carried out by using a Monte Carlo code in the neutron energy range from 1E -8 to 100 MeV. The neutron spectrum was obtained by a proper unfolding code applying to the experimental BSS data and the response function matrix. The BSS-UNIPI was coupled with the shadow cone technique. The result showed satisfactory agreement with other authors. BSS-UNIPI coupled with the shadow cone technique can be used for determination of neutron spectra in BNCT facility and other mixed fields

The mammals of Anzali Wetland in the Southern Caspian Sea

Anzali Wetland as a listed habitat in Montreux Record, was investigated for the mammal fauna during Jan. 2015 - Jan. 2016. About 165 km of water bodies and 200 km around Anzali Wetland were patrolled, respectively. By applying different methods, such as direct observation, different signs recording, using different sampling traps,nets and camera traps, twenty mammal species were identified from 5 orders and 13 families. While Wild boar,Golden Jackal and Common otter were widely distributed, Common badger, Asiatic wildcat and Jungle cat were observed in some parts of this wetland. Six rodent species were recognized in different parts of the wetland. Among four identified bat species, Nathusius’s pipistrelle has been reported only from this region in Iran. The most commonly recorded bat species was the Soprano pipistrelle, a species hereto recorded only from two Iranian localities. Two recognized species from order Eulipotyphla; Caspian shrew and a mysterious mole are important due to their narrow geographical distribution range as well as their taxonomic situation. Although there was no quantitative or qualitative data from the past, our results show that the situation of many mammal species are not suitable, and some of them are being increasingly threatened

Investigation of Mnemiopsis leidyi feeding from the Caspian Sea zooplanktons

Mnemiopsis leidyi was sampled from December 2003 to March 2005 in 11 stations located along four regions Anzali, Khazarabad, Tourkman and Gorgan Bay using METU net in the Iranian coasts of the Caspian Sea. Study of stomach contents of M. leidyi showed that Acartia sp. belonging to Copepoda and Lamellibranchia sp. had the highest frequency comprising 66% and 13% of food items taken by the organism respectively and the least food items taken were Balanus nauplii, Rotatoria, Tintinnopsis and Podon polyphemoides. The maximum mean abundance of food item was Acartia sp. which was shown to be present in stomach content of M. leidyi caught in different depths, seasons and regions in the Iranian coasts of the Caspian Sea. For the M. leidyi larvae, the highest amount of food item was Acartia sp. and Lamellibranchia sp. with an average of 44% and 32% and the maximum abundance of food item for juvenile and mature M. leidyi was also Acartia sp. with an average of 67.5% and 66%. The results showed that the main food item for M. leidyi is Acartia sp. of the Copepoda. Hence, M. leidyi feeding has an important effect in declining zooplankton populations

Is corneal sensitivity sex dependent?

Purpose: To determine whether corneal sensitivity is different between the two genders. Methods: Corneal sensitivity of 130 normal volunteers, including 77 women and 53 men aged 20-35 years, with no history of previous ocular surgery was measured using the Cochet-Bonnet esthesiometer. Measurements were done on five corneal regions: central, nasal, inferior, temporal and superior. The findings were compared between men and women using the non-parametric Mann-Whitney U test. Results: Mean age of male subjects was 28.0 years and that of female participants was 26.8 years (P = 0.063). There was a significant difference in corneal sensitivity between men and women in the superior (P = 0.013), temporal (P = 0.020) and inferior (P = 0.046) regions. There was no significant difference in corneal sensitivity in the central (P = 0.862) and nasal (P = 0.273) regions. Conclusion: Except for the central and nasal regions, corneal sensitivity is significantly higher in men as compared to women. The reason for this difference is not yet evident. © 2015 Journal of Ophthalmic and Vision Research

The Prevalence of Accommodative Insufficiency among Students of an Iranian Medical School

Purpose: To evaluate the prevalence of accommodative insufficiency in a student population from Iran.Patients and Methods: This cross-sectional study was performed on 596 eyes from 298 participants (157 males, 141 females) in age range of 18 to 29 years among students from Iran University of Medical Sciences, Tehran, Iran, between 2014 and 2015. The amplitude of accommodation among volunteers in this study was evaluated using the Donder's push up method. Then, the minimum normal amplitude of accommodation for a given age was estimated by Hofstetter formula (15 - 0.25 * age in years), and then the prevalence of accommodative insufficiency among the study population was determined according to this calculations. Results: We found the prevalence of accommodative insufficiency to be 7.2% in the study population. The prevalence of accommodative insufficiency was 4.1% and 7.25% among males and females respectively (P < 0.001). Conclusion: The prevalence of accommodative insufficiency in our study population was less than previous studies among children, which might be explained by the role of natural selection (people with accommodative disorders might have less chance of excelling in education and entering higher education institutes than patients without this disorder). We also found a statistically significant higher prevalence of accommodative insufficiency among female college aged students compared to male students.Keywords: Accommodation, insufficiency, prevalence, eye, Iran