Stock assessment and maximum sustainable yield of common kilka (Clupeonella cultriventris Borodin, 1904) in Iranian waters of the Caspian Sea

The main objectives of the present study were to estimate of biomass during 1997-2014 and maximum sustainable yield of common kilka Clupeonella cultriventris Borodin, 1904 in 2013 in Iranian waters of the Caspian Sea. This paper examines the maximum sustainable yield (MSY) and fishing intensity at MSY (fMSY) and then using fMSY, yield-per-recruit and spawning biomass-per-recruit under various harvest strategies of Fmax, F0.1 and F40%; the acceptable biological catch (ABC) was estimated. During 1997-2014, the biomass of common kilka was increased from 22000 in 1997 to 112000 t in 2009 then declined to 83300 in 2013. In the period, the instantaneous coefficient of fishing mortality varied between 0.246/yr to 1.640/yr and the exploration rates were 0.327 and 0.764. The reference points of common kilka at F0.1 and F40% were estimated 0.92 and 0.80 year−1 , respectively. According to Schafer model the MSY and fMSY were estimated 22670 t and 8690 vessel×nights (a unit of effort). During 2013, the ABC of common kilka was estimated 17500, 20060, 23500 and 18900 t in tiers 2, 3, 4 and 5, respectively. However, for the implementation of a precautionary management approach the lower and more accurate ABC-value, based on more information, should be selected and thus the catch should be restricted to 17500 t

Hygroscopic Expansion of Aesthetic Restorative Materials: One-Year Report

Objective: To measure the long-term linear hygroscopic expansion (LHE) of several materials using bulked and layered techniques.Materials and Methods: Seven materials were used; Fuji Cap II, Fuji II LC, Photac-Fil Aplicap, Vitremer, Dyract, Tetric and Z100. Ten specimens (6×4 mm) were made for each material using layered and bulked techniques (each group comprises five specimens). The specimens were stored in distilled water at 37°C. The length of each specimen was measured immediately after preparation, 24 hours, one week, one month, three months, six months, nine months and one year. This was used to calculate the percentage change in the length of materials. The mean LHE and standard deviation were calculated. Repeated measure analysis and paired sample t-test were used.Results: The type of material and time had a significant effect on LHE. Fuji Cap II and Fuji II LC exhibited no significant changes after one-year and one month, respectively.However, layered specimens of Photac-Fil Aplicap and Tetric showed constant expansionuntil six month, whereas bulked specimens reached the constant length at three months.Constant expansion was obtained for layered and bulked specimens of Dyract and Z100 at six month. Layered specimens of Vitremer showed no significant differences except between 24 hours and one year measurements. But in bulked specimens, the results at ninemonths and one year were significantly different from those obtained at three months and before.Conclusion: Fuji II showed no significant LHE and resin-modified glass ionomer cements (RMGICs) exhibited the highest LHE. Dyract maintained an intermediate LHE in comparison with RMGIC and composite resin

Aflatoxin contamination in wheat flour samples from Golestan province, Northeast of Iran

Background: Due to the high toxicity of aflatoxin and its effects on public health, determination of aflatoxin level in Wheat flour samples in the Golestan province, north of Iran was investigated. To examine the effect of seasonal changes, summer and winter sampling was performed with standard sampling methods. Methods: A total of 200 flour samples were collected from 25 factories. HPLC method with immunoaffinity chromatography was used to measure aflatoxin types (G2, G1, B2 and B1). Statistical analysis was performed by the Pearson correlation test, One-way ANOVA and multivariate regression analysis. Results: Mean total aflatoxin levels of samples were 0.82 and 1.99 ng/g in summer and winter, respectively. Aflatoxin B1 levels were detected in 3.1%, 7.4% over permissible limits by worldwide regulations in samples collected in summer and winter, respectively. Aflatoxins in winter were higher than summer. The highest frequency of aflatoxin contamination in winter was B2 (98%) and in summer G1 (51%). The relationship between humidity and rate of aflatoxin B1 and total aflatoxin was significant in winter. Results of multivariate regression were showed the strongest relationship with humidity and aflatoxin level. Despite the contamination of flour samples, there was no contamination higher than the standard limit of Iran Standard Institute. But it was significantly higher than similar studies from other regions. Conclusions: Therefore, with regard to negative impacts of aflatoxin on health, aflatoxin contamination should be considered in future programs. Decrease of aflatoxin contamination may be made practical through reducing wheat storage duration and controlling humidity

Environmental and strategic assessment of ecotourism potential in Anzali Wetland using SWOT analysis

SWOT analysis is used extensively as an assessment and planning method, particularly in tourism planning. However, there are little documentations on application of SWOT analysis in ecotourism. An assessment on systematic use of SWOT analysis was carried out in the present study to highlight the applicability of the SWOT technique in detailed investigations. In this study, based on field surveys and questionnaires (on Anzali Wetland and the local population), matrix of internal and external factors (threats, opportunities, weaknesses and strength) influencing tourism development in Anzali Wetland were evaluated within the framework of SWOT analysis and SO, WO, ST and WT strategies were identified. Based on the obtained results, the total score of 3.22 in IFE matrix suggests good condition of the system and high internal strength of the tourism development related to internal factors and the final score of 2.93 in the EFE matrix represents poor condition related to the external factors which means external factors have not been utilized properly; Thus appropriate planning and organizational management practices are required to deal with these factors. The study further proposes solutions, operational priorities and strategic planning according to environmental and local conditions of Anzali Wetland. Since the tourism industry in Iran is still in its early stages, particularly in Anzali Wetland region, the findings could help decision makers to estimate better the weaknesses, strengths, threats and opportunities, and to develop tourism industry in the region

Controlador híbrido robusto basado en red neuronal fuzzy de intervalo tipo 2 y modo deslizante de alto orden para robots manipuladores

Industrial arms should be able to perform their duties in environments where unpredictable conditions and perturbations are present. In this paper, controlling a robotic manipulator is intended under significant external perturbations and parametric uncertainties. Type-2 fuzzy logic is an appropriate choice in the face of uncertain environments, for various reasons, including utilizing fuzzy membership functions. Also, using the neural network (NN) can increase robustness of the controller. Although neural network does not basically need to build its type-2 fuzzy rules, the initial rules based on sliding surface of higher order sliding mode controller (HOSMC) can improve the system's performance. In addition, self-regulation feature of the controller, which is based on the existence of the neural network in the central type-2 fuzzy controller block, increases the robustness of the method even more. Effective performance of the proposed controller (IT2FNN-HOSMC) is shown under various perturbations in numerical simulations.Los brazos industriale deben poder realizar sus tareas en entornos donde existen condiciones y perturbaciones impredecibles. En este artículo, el control de un manipulador robótico está bajo perturbaciones externas significativas e incertidumbres paramétricas. La lógica difusa de tipo 2 es una opción adecuada frente a entornos inciertos, por varias razones, incluida la utilización de funciones de membresía difusas. Además, el uso de la red neuronal (NN) puede aumentar la robustez del controlador. Aunque la red neuronal no necesita básicamente construir sus reglas difusas tipo 2, las reglas iniciales basadas en la superficie deslizante del controlador de modo deslizante de orden superior (HOSMC) pueden mejorar el rendimiento del sistema. Además, la función de autorregulación del controlador, que se basa en la existencia de la red neuronal en el bloque central del controlador difuso tipo 2, aumenta aún más la robustez del método. El rendimiento efectivo del controlador propuesto (IT2FNN-HOSMC) se muestra bajo varias perturbaciones en simulaciones numéricas

Dietary administration of vitamin C and Lactobacillus rhamnosus in combination enhanced the growth and innate immune response of the rainbow trout, Oncorhynchus mykiss

The effects of dietary vitamin C and Lactobacillus rhamnosus on immunity and growth performance were investigated in Oncorhynchus mykiss. For this purpose, 480 rainbow trout (68±5g) were obtained from a local farm and acclimated to laboratory conditions for 10 days and then divided into four groups in three replicates. During 30 days, juvenile rainbow trout were fed diets supplemented with vitamin C (1g/kg) and L. rhamnosus (at 5 × 107 CFU/g) or a control diet. Biometry was done at day -30 and blood samples were taken by caudal vein after fish anesthesia with clove powder at day 0, 15, 30 and 45. Serum lysozyme activity, alternative complement activity and total plasma immunoglobulin level were assayed as innate immune response of rainbow trout. Results showed fish fed with vitamin c and L. rhamnosus (group 3) statistically could improve fish growth performance. Also lysozyme activity and alternative complement activity of serum significantly were higher in group three than other groups, but total plasma level of immunoglobulin only was higher than all groups at day 30. In conclusion dietary administration of vitamin C and L. rhamnosus in rainbow trout diet could enhance the growth and innate immune response, but these properties need further studies on the field applications

Shape memory nanocomposite of poly(L-lactic acid)/graphene nanoplatelets triggered by infrared light and thermal heating

In this study, the effect of graphene nanoplatelets (GNPs) on the shape memory properties of poly(L-lactic acid) (PLLA) was studied. In addition to thermal activation, the possibility of infrared actuating of thermo-responsive shape memory PLLA/GNPs nanocomposite was investigated. The incorporated GNPs were expected to absorb infrared wave’s energy and activate shape memory PLLA/GNPs. Different techniques such as differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), field emission gun scanning electron microscope (FEG-SEM) and dynamic mechanical thermal analysis (DMTA) were used to characterize samples. DSC and WAXD results indicated that GNPs augmented crystallinity due to nucleating effect of graphene particles. GNPs improved both thermal and infrared activating shape memory properties along with faster response. Pure shape memory PLLA was slightly responsive to infrared light and its infrared actuated shape recovery ratio was 86% which increased to more than 95% with loading of GNPs. Drastic improvement in the crystallinity was obtained in nanocomposites with lower GNPs contents (0.5 and 1 wt%) due to finer dispersion of graphene which resulted in more prominent mechanical and shape memory properties enhancement. Infrared activated shape memory PLLA/GNPs nanocomposites can be developed for wireless remote shape control of smart medical and bio-systems