The biomass and species composition of zooplankton populations in Gorgon Bay

In order to estimate the species composition and biomass of the zooplankton in Gorgan Bay, more than 150 samples were collected from the surface and near the bottom (max. 5m) using 55 micrometer mesh sized net. Over 30 zooplankton species belonging to five phylum were identified, among which the biomass and the species composition of Copepoda were estimated. Copepods constituted nearly 70% of the zooplankton populations during the spring, followed by the Rotifers, which comprised almost 13.5% of the total biomass. Diversity and abundance of copepods and cladocera were more than the ether groups, and among the Copepods Acartia clausi had the highest biomass and abundance in each month and at all the stations. The seasonal changes and the life cycle of the zooplanktons in Gorgan Bay were in such a way that one or two peaks in the biomass occur during spring, summer and winter. In some months when we moved toward the littoral regions of the bay, due to the changes of the temperature, the density of tropical and semi-tropical organisms such as Medosa was increased. These organisms had the lowest density near the mouth of the bay. On the other Eland fresh water species were observed in the estuaries of Gara-Su and Gaz rivers

KINETIC AND KINEMATIC ANALYSIS OF RECURVE ARCHERY SHOOTING TECHNIQUE

The study investigated shooting techniques of the archers with kinetic and kinematic methods. Twenty-seven archers of different skill levels have been involved into the current study to investigate both muscular activation strategies of nine muscles and some kinematic data on drawing hand side. A statistical significant difference (p0.05) in the time-dependent exchange values of the angle of the joints, a difference was detected in the graphical sense. Elite archers use distal muscles less but proximal and axial muscles more, and mid-level and novice archers use distal muscles more to pull the bowstring. This was interpreted to be the most important factor affecting the horizontal oscillation (lateral diflection) of bowstring

Vision Screening of Ophthalmic Nursing Staff in a Tertiary Eye Care Hospital : Outcomes and ocular healthcare-seeking behaviours

Objectives: This study aimed to evaluate ocular healthcare-seeking behaviours and vision screening outcomes of nursing staff at a tertiary eye care hospital. Methods: This study was conducted between April and September 2016 among all 500 nurses employed at the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. Data were collected on age, gender, use of visual aids, the presence of diabetes, a history of refractive surgery and date of last ocular health check-up. Participants were tested using a handheld Spot™ Vision Screener (Welch Allyn Inc., Skaneateles Falls, New York, USA). Results: A total of 150 nurses participated in the study (response rate: 30.0%). The mean age was 41.2 ± 8.9 years old. Distance spectacles, reading spectacles and both types of spectacles were used by 37 (24.7%), 32 (21.3%) and 10 (6.7%) nurses, respectively. A total of 58 nurses (38.7%) failed the vision screening test. Visual defects were detected for the first time in 13 nurses (8.7%). With regards to regular eye checkups, 77 participants (51.3%) reported acceptable ocular healthcare-seeking behaviours; this factor was significantly associated with age and the use of visual aids (P <0.01 each). Conclusion: A high proportion of participants failed the vision screening tests and only half displayed good ocular healthcare-seeking behaviours. This is concerning as ophthalmic nurses are likely to face fewer barriers to eye care services than the general population

How Does Flow Alteration Propagate Across a Large, Highly Regulated Basin? Dam Attributes, Network Context, and Implications for Biodiversity

Large dams are a leading cause of river ecosystem degradation. Although dams have cumulative effects as water flows downstream in a river network, most flow alteration research has focused on local impacts of single dams. Here we examined the highly regulated Colorado River Basin (CRB) to understand how flow alteration propagates in river networks, as influenced by the location and characteristics of dams as well as the structure of the river network—including the presence of tributaries. We used a spatial Markov network model informed by 117 upstream-downstream pairs of monthly flow series (2003–2017) to estimate flow alteration from 84 intermediate-to-large dams representing \u3e83% of the total storage in the CRB. Using Least Absolute Shrinkage and Selection Operator regression, we then investigated how flow alteration was influenced by local dam properties (e.g., purpose, storage capacity) and network-level attributes (e.g., position, upstream cumulative storage). Flow alteration was highly variable across the network, but tended to accumulate downstream and remained high in the main stem. Dam impacts were explained by network-level attributes (63%) more than by local dam properties (37%), underscoring the need to consider network context when assessing dam impacts. High-impact dams were often located in sub-watersheds with high levels of native fish biodiversity, fish imperilment, or species requiring seasonal flows that are no longer present. These three biodiversity dimensions, as well as the amount of dam-free downstream habitat, indicate potential to restore river ecosystems via controlled flow releases. Our methods are transferrable and could guide screening for dam reoperation in other highly regulated basins

Nodular regenerative hyperplasia of the liver and portal thrombosis

Background: A 35-year-old female presented with upper gastrointestinal tract bleeding. Fifteen years ago, the diagnosis of esophageal varices caused by idiopathic portal venous thrombus was made. Follow-up examinations revealed mild elevation of bilirubin levels and normal alphafetoprotein level on blood tests. Splenectomy had been performed 6 years previously due to portal hypertension caused by portal venous thrombus

Effects of nonnative species on the stability of riverine fish communities

ResearchDespite the increasing ubiquity of biological invasions worldwide, little is known about the scale-dependent effects of nonnative species on real-world ecological dynamics. Here, using an extensive time series dataset of riverine fish communities across different biogeographic regions of the world, we assessed the effects of nonnative species on the temporal variability and synchrony in abundance at different organizational levels (population, metapopulation, community and metacommunity) and spatial scales (stream reach and river basin). At the reach scale, we found that populations of nonnative species were more variable over time than native species, and that this effect scaled up to the community level – significantly destabilizing the dynamics of riverine fish communities. Nonnative species not only contributed to reduced community stability, but also increased variability of native populations. By contrast, we found no effect of nonnative species dominance on local interspecific synchrony among native species. At the basin scale, nonnative metapopulations were again more variable than the native ones. However, neither native metapopulations nor metacommunities showed differences in temporal variability or synchrony as nonnative species dominance increased basin-wide. This suggests a ‘dilution effect’ where the contribution to regional stability of local native populations from sites displaying low levels of invasion reduced the destabilizing effects of nonnative species. Overall, our results indicate that accounting for the destabilizing effect of nonnative species is critical to understanding native species persistence and community stabilityinfo:eu-repo/semantics/publishedVersio

Phenylalanine induces Burkholderia cenocepacia phenylacetic acid catabolism through degradation to phenylacetyl-CoA in synthetic cystic fibrosis sputum medium

a b s t r a c t Synthetic cystic fibrosis sputum medium (SCFM) is rich in amino acids and supports robust growth of Burkholderia cenocepacia, a member of the Burkholderia cepacia complex (Bcc). Previous work demonstrated that B. cenocepacia phenylacetic acid (PA) catabolic genes are up-regulated during growth in SCFM and are required for full virulence in a Caenorhabditis elegans host model. In this work, we investigated the role of phenylalanine, one of the aromatic amino acids present in SCFM, as an inducer of the PA catabolic pathway. Phenylalanine degradation intermediates were used as sole carbon sources for growth and gene reporter experiments. In addition to phenylalanine and PA, phenylethylamine, phenylpyruvate, and 2-phenylacetamide were usable as sole carbon sources by wild type B. cenocepacia K56-2, but not by a PA catabolism-defective mutant. EMSA analysis showed that the binding of PaaR, the negative regulator protein of B. cenocepacia PA catabolism, to PA regulatory DNA could only be relieved by phenylacetyl-Coenzyme A (PA-CoA), but not by any of the putative phenylalanine degradation intermediates. Taken together, our results show that in B. cenocepacia, phenylalanine is catabolized to PA and induces PA catabolism through PA activation to PA-CoA. Thus, PaaR shares the same inducer with PaaX, the regulator of PA catabolism in Escherichia coli, despite belonging to a different protein family

Effects of weight on osmoregulatory ability of Salmo trutta caspius juveniles

Salmo trutta caspius is a commercial migratory fish species in the Caspian Sea. Over fishing and deterioration of natural spawning grounds of the species are two major causes depressing stocks of the fish in the Sea. Thus, artificial breeding and release of salmon juveniles into the Caspian Sea is now considered an urgent need towards the rehabilitation of the stocks of the fish. This study was conducted in early 2004 to determine the ideal weight for the release of salmon fry in order to increase fishery return coefficients in the species. For this research, we used facilities of the Marine Fisheries Breeding and Research Center in Ghazian, along the coastal areas of the Bandar Anzali. Salmon juveniles used in this study belonged to the same generation. Fishes belongirig to different weight classes (5, 10, 15 and 20g) were selected in a random design and stocked in two groups of sea water at 7% salinity and freshwater. Osmosis was studied using blood samples collected at 0, 3, 6, 12, 24, 72, 168 and 240 hours. Heparin tubes were used for sampling blood which was centrifuged to separate blood plasma. Osmotic pressure was determined using osmometer. Statistical analysis of the results on variations in osmotic pressure showed that after 10 days of stocking fish in seawater (7%), fishes in all weight classes were capable of osmoregulation. Also fishes in weight classes 10, 15 and 20g were capable of osmore-gulation in the Caspian Sea water

Scale of population synchrony confirms macroecological estimates of minimum viable range size

Global ecosystems are facing a deepening biodiversity crisis, necessitating robust approaches to quantifying species extinction risk. The lower limit of the macroecological relationship between species range and body size has long been hypothesized as an estimate of the relationship between the minimum viable range size (MVRS) needed for species persistence and the organismal traits that affect space and resource requirements. Here, we perform the first explicit test of this assumption by confronting the MVRS predicted by the range-body size relationship with an independent estimate based on the scale of synchrony in abundance among spatially separated populations of riverine fish. We provide clear evidence of a positive relationship between the scale of synchrony and species body size, and strong support for the MVRS set by the lower limit of the range-body size macroecological relationship. This MVRS may help prioritize first evaluations for unassessed or data-deficient taxa in global conservation assessments

Climatic aridity increases temporal nestedness of invertebrate communities in naturally drying rivers

Climate change is altering the water cycle globally, increasing the frequency and magnitude of floods and droughts. An outstanding question is whether biodiversity responses to hydrological disturbance depend on background climatic context – and if so, which contexts increase vulnerability to disturbance. Answering this question requires comparison of organismal responses across environmental gradients. However, opportunities to track disturbed communities against an undisturbed baseline remain rare. Here we gathered a global dataset capturing responses of aquatic invertebrate communities to river drying, which includes 112 sites spanning a gradient of climatic aridity. We measured the effects of river drying on taxonomic richness and temporal β‐diversity (turnover and nestedness components). We also measured the relative abundance of aquatic invertebrates with strategies that confer resilience (or resistance) to drying. Contrary to our expectations, we found that taxonomic richness recovered from drying similarly across the aridity gradient. The turnover component of β‐diversity (i.e. species replacements over time) largely accounted for differences in community composition before versus after drying. However, increasing aridity was associated with greater nestedness‐driven compositional changes at intermittent sites – that is, after drying communities became subsets of those before drying. These results show that climatic context can explain variation in community responses to the same hydrological disturbance (drying), and suggest that increased aridity will constrain biodiversity responses at regional scales. Further consideration of the climatic context in hydroecological research may help improve predictions of the local impacts of hydrological disturbance by identifying climate regions where communities are more (or less) sensitive to extremes, including river drying events