Effects of water hardness and turbidity on growth and fecundity of freshwater Cladoceran, Moina macrocopa (Straus, 1820)

Water hardness and turbidity are important parameters in zooplankton culture, especially for Cladoceran affecting growth and reproductive parameters of the plankton. Effects of water hardness and turbidity on growth and fecundity of the Cladoceran, Moina macrocopa, was investigated by culturing and feeding them on green algae Scenedesmus quadricauda. Experimental treatments for hardness were 0, 20, 40 and 80mg/I as CaCO_3 and for turbidity were 0, 20, 40 and 80 NTU (Nephelometric Turbidity Unit). Experiments were carried out in 500m1 flasks with initial density of 15 individuals per flask in randomized complete block design with three replicates. After 10 days, we found that M macrocopa, had the maximum population density (370.5-365.0 individuals per flask), maximum specific growth rate (SGR) (0.35/day), and the shortest population doubling time (Dt) (1.98 days) at 0 and 20mg/1 CaCO_3, all with significant differences compared to other treatments (P<0.05). In contrast, we observed the maximum population density (296-325.5 individuals per flask) at turbidities of 0 and 20 NTU, maximum SGR (0.33/day) and the shortest Dt (2.10 days) at turbidity of 0 NTU, with significant differences compared to other treatments (P<0.05). The highest fecundity of Al macrocopa was obtained at 213mgil as CaCO_3 and turbidity of 0 NTU which significantly differed with other treatments (P<0.05). Overall, we showed that AI macrocopa in freshwater with hardness less than 20mg/l as CaCO3 and turbidity less than 20 NTU had better growth and fecundity performance. The species can be used to evaluate habitats where water hardness and turbidity is higher. Mass culture of the species based on its growth and reproduction under these optimal conditions could provide suitable zooplanktonic biomass for feeding of fish larvae

Relationships Between Working Memory, Theory Of Mind, And Verbal Ability Among Iranian Preschool Children

A corelational study was carried out to investigate the relationship between working memory (WM), theory of mind (ToM), and verbal ability (VA) among Iranian preschool children. Stratified random sampling method was utilized to identify respondents for the study. One hundred and sixty-three preschool children were selected as respondents in this study. Ninety eight (62%) children were bilingual and 65 (38%) were monolingual children. Data were collected by using a questionnaire and three standardized instruments which included Automated Working Memory Assessment (AWMA), false beliefs tasks and McCarthy Scales of children‟s ability and a questionnaire. The result revealed that the mean scores of bilingual children in working memory, verbal ability, and theory of mind were significantly higher than those of monolingual children. Pearson Product Moment Correlation statistically significant positive correlation were found between working memory and theory of mind (r = .436, p<.05), working memory and verbal ability (r = .426, p<.05) as well as theory of mind and verbal ability (r = .578, p<.05). The result supported a positive relationship between the working memory as well as verbal ability on children‟s theory of mind. Hierarchical regression analysis showed that controlling for age, verbal ability, and working memory, language status did not explain the variance in children‟s theory of mind. The findings suggest that it would be vital for the teachers in preschool age group and also school age to screen working memory capacity among children and apply the appropriate methods to enhance working memory regardless of the kind of language that the children are speaking with

Polycyclic Aromatic Hydrocarbons in Grilled Beef and Chicken and Their Reduction Through Various Treatments

The International Agency for research on cancer (IARC) and the Environmental Protection Agency (EPA) have classified some polycyclic aromatic hydrocarbons (PAHs) are probably and possibly carcinogenic to humans. This research has been conducted to test for availability of three of PAHs in grilled beef and chicken and assess their levels, and to evaluate the potential for reducing their levels, if any, through different treatments. The specific objectives are i) to validate the method of extraction of the PAHs (fluoranthene, benzo(b)fluoranthene and benzo(a)pyrene) from meat matrix, ii) to examine the effects of different grilling methods on generation of PAHs in meat, iii) to assess the effects of different marinating procedures on the generation of PAHs in meat, iv) to explore the effects of meat preheating and wrapping on generation of PAHs in meat, and v) to evaluate the sensory properties of treated (marinated, preheated and wrapped) grilled meat. Tandem solid-phase extraction (SPE), were validated for sample preparation and clean up. A high performance liquid chromatography (HPLC) with fluorescence detector was used for PAHs analysis. For achievement of the second objective, nine types of Malaysian grilled meat dishes were analyzed for PAHs. The highest total concentration of the three PAHs, 103.32 ng/g, was found in the charcoal-grilled beef satay. For fulfillment of the second objective, the charcoal, gas and oven grilling methods were compared. The total concentrations of PAHs produced in the meat were significantly (p<0.05) different between the three grilling methods and were 132.64 ng/g, 15.00 ng/g, and 7.14ng/g in the charcoal-, gas-, and oven-grilled dishes, respectively. Since the highest total concentrations of PAHs were detected in beef and chicken satay, these dishes were chosen for the next objectives. For third objective, seven marinade treatments at four time intervals (0, 4, 8 and 12 hr) were applied on meat samples before charcoal grilling. The study showed that the highest reductions in PAH generation were achieved by the acidic marinade treatments for the chicken (81%) and beef (70%) satay samples. Acidic marinating using lemon juice at a concentration of 1.2% for 4 hr marinating time affected significantly (p<0.05) lower total PAHs generation. Therefore, this marinade treatment was applied on the meat samples in order to study the effects of preheating methods, steam and microwave heating, on reducing the duration of charcoal-grilling and PAHs generation. The results demonstrated that steam-heating lead to reductions in PAH generation ranging from 46 to 100% and from 51 to 100% respectively in the beef and chicken samples. On the other side, microwave-heating resulted in reductions in PAH generation in the beef and chicken samples ranging from 34 to 100% and from 60 to 100%, respectively. The effects of wrapping using aluminum foil and banana leaf during charcoal-grilling on the levels of PAHs produced, Showed the reductions of PAH generation in the beef and chicken samples fell within the ranges of 39-100% and 72-100%, respectively, when aluminum foil was used as the wrapping material. However, reductions fell within the ranges of 32-100% and 81-100%, respectively, upon use of banana leaves as the wrapping material. The results of sensory evaluation confirmed that the preheating, wrapping and acidic marinating treatments were successful methods for reducing food contamination with the studied PAHs

From Microarrays to Behavior: Genes Controlled by Feeding State in Mosquitoes and Flies

Across many species, animals carefully regulate their food intake according to their energy needs. They are able to do so through the ability to sense hunger or satiety cues. In vertebrates, these signals are released by the gastrointestinal tract and by adipose tissue, and reach feeding centers in the brain, where they stimulate the release of peptides that modulate feeding behavior (Benarroch, 2010; Berthoud, 2008). Although many of these neuronal populations have been identified in rodent models, the neural circuitry behind behavioral modification of food intake remains largely unknown. Insects like the blowfly and the locust have classically been used to describe basic features of feeding behavior (Bernays and Chapman, 1974; Dethier, 1976). These animals, as well as vinegar flies and mosquitoes have been shown to modify their feeding behavior according to their internal nutritional status (Edgecomb et al., 1994; Takken et al., 2001). Thus they are good models for examining the question of how this modulation of behavior occurs. Moreover, Drosophila melanogaster has been used to study mechanisms of complex behaviors to great effect, and there are ample genetic tools available to study feeding behavior in this organism (Vosshall, 2007). We set out to identify genes that regulate feeding behavior according to nutritional status. Anopheles gambiae mosquitoes were previously shown to display reduced host-seeking behavior for forty-eight hours after taking a bloodmeal (Takken et al., 2001). We used whole genome microarrays to look for genes that are regulated in olfactory tissue by blood-feeding, and that therefore might function to modify olfactory driven host-seeking behavior according to nutritional state. We found that two odorant receptor genes are significantly regulated by blood-feeding. These are therefore candidate receptors for ligands that are important for host-seeking. We then extended our studies to Drosophila with the goal of identifying novel regulators of post-fasting feeding behavior. First we defined two stereotypical post-fasting behaviors in flies: increased attraction to food odor, and increased consumption of liquid food. We then looked for candidate genes that regulate these behaviors by looking for transcripts that are regulated by fasting and found that 247 genes in the head are significantly regulated by nutritional status. Finally, we carried out a targeted genetic screen using RNA interference against these candidate genes. We looked for flies that show a defective post fasting food intake response, and found eleven genes that cause such a behavioral disruption. These genes may represent novel regulators of hunger and satiety in insects, laying the groundwork for future studies of modification of feeding behavior

Associations between Iranian University-Level EFL Learners’ Perceptions of Their Language Learning Environment and Their Motivation and Self-regulation

The present study attempted to examine Iranian university level EFL students’ perceptions of their language learning environment regarding two fundamental components of language learning engagement and achievement; that is, motivation and self-regulation. The study involved the administration of modified versions of the Engagement in English Language Learning and Self-Regulation (EELLS) questionnaire to assess participants’ motivation and self-regulation in English language learning, and the School, Physical and Campus Environment Survey (SPACES) questionnaire to assess students’ perceptions of their physical language learning environment. Statistical measures of variance, Eigenvalue, alpha Cronbach value, and component correlation matrix ensured the reliability and validity of the two questionnaires. Furthermore, the results of simple and multiple correlation analyses as well as standardized regression analysis revealed a strong and significant association between students’ perceptions of their language learning environment and their motivation and self-regulation. The findings suggest that EFL stakeholders should carefully examine language learning environments that they are creating in terms of architectural, spatial, visual, ambient, and aesthetics features

Seasonal changes in the abundance and biomass of zooplankton from shallow mudflat river-estuarine system in Persian Gulf

The present study was designed to investigate the seasonal changes in the abundance and biomass of zooplankton and their relationships with water quality parameters in mudflat shallow estuary, Helleh River, Persian Gulf (Iran). The zooplankton consisted of Acartia sp., Euterpina sp., Oithona spp., Oncaea sp., Paracalanus sp., Corycaeus sp., Labidocera sp., Macrosetella sp., Microsetella sp., Temora sp., copepod copepodid, copepod nauplii, Barnacle, Polychaeta, Conchoecia sp. (Ostracoda), Hyperid, Decapoda (zoea and megalopa), Actinula, Echinopluteus, Mollusca, Tintinnopsis sp., Ctenophora (Boliopsis sp.), Protozoa (Discorbis sp.), cumacea (Diastylis sp.), Cnidaria (Siphonophora and Phialidium), Nematoda (Pratylenchus spp.), Urocordata (Oikopleura spp.), fish eggs and fish larvae. The maximum biomass was estimated at estuary mouth in all seasons, the highest values in autumn (97.8-255.6 mg/m3) and the lowest in winter (5.5-68.2 mg/m3). The seasonal abundance (density) of zooplankton was 21237±2419, 45739±6053, 5242±648, and 12905±1867 ind./m3 in summer, autumn, winter and spring, respectively. There was a significant correlation (P<0.01) between zooplankton abundance as well as biomass with salinity, dissolved oxygen and chlorophyll a. Based on PCA (Principal Component Analysis), the most important factors in mudflat shallow river–estuarine system that could describe most changes of biomass and abundance of zooplankton were salinity, chlorophyll a, temperature and pH,  respectively.The present study was designed to investigate the seasonal changes in the abundance and biomass of zooplankton and their relationships with water quality parameters in mudflat shallow estuary, Helleh River, Persian Gulf (Iran). The zooplankton consisted of Acartia sp., Euterpina sp., Oithona spp., Oncaea sp., Paracalanus sp., Corycaeus sp., Labidocera sp., Macrosetella sp., Microsetella sp., Temora sp., copepod copepodid, copepod nauplii, Barnacle, Polychaeta, Conchoecia sp. (Ostracoda), Hyperid, Decapoda (zoea and megalopa), Actinula, Echinopluteus, Mollusca, Tintinnopsis sp., Ctenophora (Boliopsis sp.), Protozoa (Discorbis sp.), cumacea (Diastylis sp.), Cnidaria (Siphonophora and Phialidium), Nematoda (Pratylenchus spp.), Urocordata (Oikopleura spp.), fish eggs and fish larvae. The maximum biomass was estimated at estuary mouth in all seasons, the highest values in autumn (97.8-255.6 mg/m3) and the lowest in winter (5.5-68.2 mg/m3). The seasonal abundance (density) of zooplankton was 21237±2419, 45739±6053, 5242±648, and 12905±1867 ind./m3 in summer, autumn, winter and spring, respectively. There was a significant correlation (P<0.01) between zooplankton abundance as well as biomass with salinity, dissolved oxygen and chlorophyll a. Based on PCA (Principal Component Analysis), the most important factors in mudflat shallow river–estuarine system that could describe most changes of biomass and abundance of zooplankton were salinity, chlorophyll a, temperature and pH,  respectively

Being Prime is not necessary for Goldbach Conjecture

Here, we have generalized the Goldbach Conjecture to any subset of natural numbers whose distribution is similar to the prime numbers. Consequently, being prime is not a necessary condition for the conjecture to hold. We have built several new sets whose distribution in the natural numbers are similar to the prime numbers by randomly addition of +1 and -1 to the prime numbers and checked the Goldbach conjecture for every even integer less than $2 \times 10^8$ by computer. As it was expected, the Goldbach conjecture holds true for these new reconstructed sets, as well