284 research outputs found

    Fasciculate kleopatrinid corals from the Bashkirian (Late Carboniferous) of Sardar Formation (Ozbak-Kuh mountains, East-central Iran)

    Get PDF
    In the East-Central Iran, the Sardar Formation (upper Visean–Moscovian) consists of shallow-water limestone with intercalations of shale containing rugose corals, tabulate corals and brachiopods. Ten sections were sampled in the Ozbak-kuh Mountains, from north to south. Among the rugose corals, an assemblage of fasciculate Kleopatrinidae has been collected. The latter contains the species: Paraheritschioides antoni antoni, P. antoni minor, P. gracilis and two new species for the genera Fomichevella and Heintzella. Heintzella is described from Iran for the first time. However, its age, as determined by conodonts and foraminifers, is early to middle Bashkirian (early late Carboniferous). The most similar, time-equivalent faunal associations are that of the Ellesmere Island, Sverdrup Basin in Arctic Canada, Alexander terrane and Brooks Range in southeastern Alaska and eastern Klamath terrane in northern California, where similar tropical warm water conditions have been identified during the Bashkirian in the northern hemisphere. During these times central Iran block and Northern provinces, characterized by a dominant carbonate facies and more diversified colonial coral faunas

    Additive main effects and multiplicative interactions (AMMI) analysis of dry leaf yield in tobacco hybrids across environments

    Get PDF
    To determine the yield stability, adaptability and analyze the genotype×environment of Virginia tobacco, 15 hybrids of tobacco including 10 Iranian and 5 international hybrids were evaluated in two different experiments (water stress and normal irrigation) using a randomized completely block design (RCBD) with three replications at two locations including Rasht and Tirtash Tobacco Research Centers, during the growing season of 2006 and 2007 (eight environments). Additive main effects and multiplicative interactions (AMMI) analysis indicated that the dry leaf yield of genotypes were under the major environmental effects of genotype by environmental interactions. The first two principal component axes (PCA 1 and 2) were significant (p £ 0.01) and cumulatively contributed to 94.12% of the total genotype by environment interaction. The biplot technique was used to identify appropriate genotype to special locations. Results showed that hybrids PVH03, K394/NC89 and Coker254/NC89 with the lowest interaction, and hybrids ULT109, NC291, Coker254/Coker347 and VE1/Coker347 with the highest interaction were the most stable and unstable hybrids, respectively. Furthermore, hybrids Coker254/K394, NC291 and CC27 were more suitable for Tirtash in non drought stress condition and hybrids NC89/Coker347, K394/Coker347, Coker254/VE1 and ULT109 were more suitable for Rasht in drought stress condition.Key words: Additive main effects and multiplicative interactions (AMMI), biplot, stability analysis, tobacco

    Parallel Implementation of a Recursive Least Squares Neural Network Training Method on the Intel IPSC/2

    Get PDF
    An algorithm based on the Marquardt-Levenberg least-square optimization method has been shown by S. Kollias and D. Anastassiou (IEEE Trans. on Circuits Syst. vol.36, no.8, p.1092-101, Aug. 1989) to be a much more efficient training method than gradient descent, when applied to some small feedforward neural networks. Yet, for many applications, the increase in computational complexity of the method outweighs any gain in learning rate obtained over current training methods. However, the least-squares method can be more efficiently implemented on parallel architectures than standard methods. This is demonstrated by comparing computation times and learning rates for the least-squares method implemented on 1, 2, 4, 8, and 16 processors on an Intel iPSC/2 multicomputer. Two applications which demonstrate the faster real-time learning rate of the last-squares method over than of gradient descent are give

    First report of Quaternary mammals from the Qalehjough area, Lut Desert, Eastern Iran

    Get PDF
    Taxonomic study of Quaternary mammal remains from the Qalehjough fossil site, eastern Iran, has resulted in the identification of two mammal orders, Artiodactyla and Perissodactyla, with four families and six taxa. Of particular note was the recovery of Stephanorhinus and a caballoid horse. These remains have provided the first opportunity to examine Late Quaternary faunal assemblages in the northern parts of the Lut Desert, eastern Iran. The Qalehjough faunal assemblage documents some zoogeographic characteristics of the eastern Iranian Plateau, and suggests that palaeoenvironments in this part of Iran during the Pleistocene were more humid and wooded than today. The disappearance of rhinoceroses and caballoid horses from this region is most likely a result of climate change and concomitant habitat loss

    A floristic study of the Sorkhankol Wildlife Refuge, Guilan province, Iran

    Get PDF
    Sorkhankol Wildlife Refuge with an area of 1209 ha is located in the central part of Anzali Wetland. In total, 81 species belonging to 35 families and 68 genera were surveyed and identified on the basis of a floristic study from July 2013 through June 2014. The largest families are Poaceae (11 taxa), Asteraceae (8 taxa) Apiaceae, Brassicaceae and Cyperacae (5 taxa). The dominant life forms were cryptophyte (43.21%), followed by the therophytes (39.51%), hemicryptophytes (13.58%) and phanerophytes (3.7%). From the chorological point of view, the largest proportion of the flora belongs to the pluriregional elements (44.44%). A comparison between our study and other parts of the Anzali Wetland showed that Sorkhankol was not particularly species-rich. Currently, the major threats to the research area include eutrophication, pressure from boating and fishing activities, invasion of exotic species and other human induced disturbances

    The Effect of Paraspinal Fatty Muscle Infiltration and Cumulative Lumbar Spine Degeneration on the Outcome of Patients with Lumbar Spinal Canal Stenosis: Analysis of the Lumbar Stenosis Outcome Study (LSOS) Data

    Full text link
    STUDY DESIGN - Prospective. OBJECTIVE To investigate the influence of paraspinal fatty muscle infiltration (FMI) and cumulative lumbar spine degeneration as assessed by magnetic resonance imaging (MRI) on long-term clinical outcome measures in patients with lumbar spinal canal stenosis (LSCS) of the Lumbar Stenosis Outcome Study (LSOS) cohort. SUMMARY OF BACKGROUND DATA Past studies have tried to establish correlations of morphologic imaging findings in LSCS with clinical endpoints. However, the impact of FMI and overall lumbar spinal degeneration load has not been examined yet. METHODS Patients from the LSOS cohort with moderate to severe LSCS were included. Two radiologists assessed the degree of LSCS as well as cumulative degeneration of the lumbar spine. FMI was graded using the Goutallier scoring system. Spinal Stenosis Measure (SSM) was used to measure the severity level of symptoms and disability. European Quality of Life 5 Dimensions 3 Level Version (EQ-5D-3L) was used to measure health-related quality of life. RESULTS The non-surgically treated group consisted of 116 patients (age 74.8±8.5 y), whereas the surgically treated group included 300 patients (age 72.3±8.2 y). Paraspinal FMI was significantly different between the groups (54.3% vs. 32.0% for Goutallier grade ≥2; P0.05). CONCLUSION FMI is associated with higher disability and worse health-related quality of life of LSCS patients in the LSOS cohort. There was no significant association between total cumulative lumbar spine degeneration and the outcome of either surgically or non-surgically treated patients. LEVEL OF EVIDENCE - Level 3

    Cytomegalovirus and toxoplasma gondii: Common causes of profound sensori neural hearing loss in children with cochlear implant surgery in a highly immune population: Tehran; Iran

    Get PDF
    Background: Iranian population is highly immune from T.Gondii and CMV infection. Objective: To determine the immunity to T.Gondii and CMV in children with the cochlear implant surgery accompanied with the profound Idiopathic type of SNHL Methods and Materials: We studied 45 cases with the cochlear implant surgery (Idiopathic profound SNHL) and 30 controls with the normal OAEs in a cross-sectional study in Rasoul Akram Hospital in Tehran (2010-2012). Blood samples (2 ml) were centrifuged and were kept frozen at-20°C. Sera searched for the specific antibodies against CMV and T.Gondii. The enzyme-linked immunosorbent assay (ELISA; BioChem Immune System) was calculated qualitatively. (P value< 0.05) Results: Range of age in cases with profound SNHL (<95 dB) was 6 months-to-14 years; mean=3.4+3.16 y; Idiopathic type of SNHL children diagnosed in 45 cases were younger than cases with non-Idiopathic SNHL (mean age=20 months; PV=0.05). Positive T.Gondii-IgM was found in 8 /45 (17.7) and also one of these cases (2.2) had positive T.Gondii �IgG test. Positive CMV-IgM & IgG were determined in 23 and 51 of cases, respectively. Positive T.Gondii �IgG was observed in 60 (18/30) of controls but none of them had positive T.Gondii � IgM. Positive CMV-IgM & IgG in controls was 3.3 and 90, respectively. Conclusion: CMV infection is one of the most common infections found in profound idiopathic SNHL children especially in younger cases (< 2 years) even in highly immune Iranian populations. Probably, T.Gondii infection has a relative role in younger cases with profound SNHL but a higher role in mild to moderate SNHL in our pediatric population. Most of the T.Gondii infected SNHL cases never require cochlear implant surgery. In future, a cohort study for prenatal diagnosis of the intrauterine infection and the role of infection in producing SNHLwould be very helpful. It has been recommended to search the specific antibodies against these two common infections in all types of SNHL in pediatric groups which are treatable especially in younger cases (<2 year). © 2019 Noorbakhsh et al

    High-resolution stratigraphy of the Changhsingian (Late Permian) successions of NW Iran and the Transcaucasus based on lithological features, conodonts and ammonoids

    Get PDF
    The Permian–Triassic boundary sections in north-western Iran belong to the most complete successions, in which the largest mass extinction event in the history of the Earth can be studied. We investigated the Changhsingian stage in six sections in the area of Julfa (Aras Valley) for their lithology, conodonts and ammonoids. Revision of the biostratigraphy led to the separation of 10 conodont zones (from bottom to top Clarkina orientalis–C. subcarinata interval zone, C. subcarinata, C. changxingensis, C. bachmanni, C. nodosa, C. yini, C. abadehensis, C. hauschkei, Hindeodus praeparvus–H. changxingensis and Merrilina ultima–Stepanovites ?mostleri zones) and 8 ammonoid zones (from bottom to top Iranites transcaucasius–Phisonites triangulus, Dzhulfites nodosus, Shevyrevites shevyrevi, Paratirolites trapezoidalis, P. waageni, Stoyanowites dieneri, Abichites stoyanowi and Arasella minuta zones). The new ammonoid genera Stoyanowites and Arasella are described
    corecore