scholarly journals Assessing temporal and spatial variability of phytoplankton composition in a large reservoir in the Brazilian northeastern region under intense drought conditions

2017 ◽  
Vol 77 (1) ◽  
Author(s):  
Hortência De Souza Barroso ◽  
Janaina A. Santos ◽  
Rozane V. Marins ◽  
Luiz Drude Lacerda
Keyword(s):  
Functional Groups ◽  
Rainy Season ◽  
Temporal Dynamics ◽  
The Other ◽  
Water Transparency ◽  
Phase Iii ◽  
Phytoplankton Composition ◽  
Large Reservoir ◽  
Reservoir Volume ◽  
Total Phytoplankton

The present study was carried out in Castanhão Reservoir, a large aquatic system in the Brazilian semi-arid region that serves multiples uses as water drinking supply and intensive fish-cage aquaculture site. In order to understand the effects of environmental conditions on the spatial and temporal variability of the phytoplankton functional groups (FG) and the main ‘characterizing taxa’, sub-superficial water samples were collected from March 2012 to August 2013, a period distinguished by the continuous drop in reservoir volume due to rainfall shortage. Eighteen functional groups and 102 total phytoplankton taxa were found in the Castanhão reservoir during the study. No significant differences were observed relative to spatial variation of total phytoplankton composition throughout the reservoir (PERMANOVA, P>0.05). On the other hand, according to cluster analysis results, three temporal phases have been identified (Similarity Profile, P<0.05), based on 102 phytoplankton taxa. The ‘characterizing taxa’ was found using the Similarity Percentage procedure (cut-off 90%), being thus defined as those taxa that contributed the most to the similarity within each temporal phase. Nineteen ‘characterizing taxa’ described the Castanhão reservoir, with predominance of those typical of mixing and turbidity conditions. Cyanobacteria dominated through the three temporal phases. According to the redundancy analysis, nutrient availability and water transparency were found to influence the phytoplankton temporal dynamics. The phase I (rainy season) was most represented by Planktolyngbya minor/Pl. limnetica (FG = S1), which reached best performance under strongly decreased phosphate-P concentrations and low water transparency. In phase II (dry season), Romeria victoriae (FG = ?) outcompeted other cyanobacteria probably due the increase in water transparency and decrease in ammonium-N. Finally, in phase III (rainy season) the decrease of water transparency triggered a recovery of shade-adapted cyanobacteria, but at this time mostly represented by Pseudanabaena limnetica (FG = S1). Phase III was also distinctive from the other ones by the highest Nitrate-N and phosphate-P concentrations related to thermocline disruption, which favored an increase in total phytoplankton biomass recorded by the augment of green algae density (FGs = X1, J and F). We concluded that the temporal dynamics of phytoplankton composition was associated to environmental changes in Castanhão Reservoir from 2012 to 2013, which were driven by seasonal climate variation from region (rainy/dry seasons), as well as, by the reduction in reservoir volume that resulted in the disruption of the thermocline, water mixing and an increase in inorganic P and N.

scholarly journals Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil)

2010 ◽  
Vol 70 (3) ◽  
pp. 551-557 ◽  
Author(s):  
AMA. Medeiros ◽  
JEL. Barbosa ◽  
PR. Medeiros ◽  
RM. Rocha ◽  
LF. Silva
Keyword(s):  
Species Richness ◽  
Rainy Season ◽  
Salinity Gradient ◽  
River Estuary ◽  
Positive Influence ◽  
Freshwater Discharge ◽  
The Other ◽  
Semiarid Region ◽  
Inverse Estuary ◽  
Species Richness And Abundance

The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.

scholarly journals Driving forces of the diel distribution of phytoplankton functional groups in a shallow tropical lake (Lake Monte Alegre, Southeast Brazil)

2009 ◽  
Vol 69 (1) ◽  
pp. 75-85 ◽  
Author(s):  
LM. Rangel ◽  
LHS. Silva ◽  
MS. Arcifa ◽  
A. Perticarrari
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Rainy Season ◽  
Phytoplankton Biomass ◽  
Driving Forces ◽  
Circulation Pattern ◽  
Dry Period ◽  
Phytoplankton Functional Groups ◽  
The Vertical Distribution ◽  
Cool Dry Season

Phytoplankton vertical and diel dynamics in a small shallow lake (Lake Monte Alegre, Ribeirão Preto, state of São Paulo) were investigated in two climatological periods: July 2001 (cool-dry season) and March 2002 (warm-rainy season). Monte Alegre is a eutrophic reservoir, with a warm polymictic discontinuous circulation pattern. The lake was thermally stratified in both periods, although dissolved oxygen varied less in the cool-dry period. Phytoplankton biomass was higher in the warm-rainy season and the vertical distribution was stratified in both seasons. Flagellate groups (Lm, Y, W1 and W2) and functional groups typical of shallow eutrophic environments (J, X1 and Sn) were important throughout the study period. The lake's thermal pattern strongly influenced the vertical distribution of the phytoplankton community in both periods. Biomass, functional groups and size classes of phytoplankton also were determined by the presence of more efficient herbivores in the lake, especially during the cool-dry period when phytoplankton biomass decreased.

scholarly journals Biology of the Wild SilkmothAnaphe panda(Boisduval) in the Kakamega Forest of Western Kenya

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
N. Mbahin ◽  
S. K. Raina ◽  
E. N. Kioko ◽  
J. M. Mueke
Keyword(s):  
Life Cycle ◽  
Incubation Period ◽  
Rainy Season ◽  
Dry Season ◽  
Developmental Period ◽  
The Other ◽  
Western Kenya ◽  
Kakamega Forest ◽  
Pupal Period ◽  
Indigenous Forest

A study on the life cycle of the silkmothAnaphe panda(Boisduval) was conducted in two different habitats of the Kakamega Forest in western Kenya: Ikuywa, an indigenous forest, and Isecheno, a mixed indigenous forest. Eggs were laid in clusters, and the incubation period ranged from 40 to 45 days. Larvae fed onBridelia micrantha(Hochst) and passed through seven instars. The developmental period took between 83 to 86 days in the dry season and 112 to118 days in the rainy season. The pupal period ranged between 158 and 178 days in the rainy season and, on the other hand, between 107 and 138 days in the dry season. But the later caught up in development with those that formed earlier. Moths emerged from mid-October until mid-May. Longevity of adultAnaphe pandamoths took between 4 and 6 days, but generally females seemed to live longer than males. The moth also seems to have higher lifespan in the indigenous forest compared to the mixed indigenous forest.

scholarly journals Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil

2011 ◽  
Vol 83 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Giulliari A. S. T. Lira ◽  
Elcida L. Araújo ◽  
Maria Do Carmo Bittencourt-Oliveira ◽  
Ariadne N. Moura
Keyword(s):  
Rainy Season ◽  
Phytoplankton Community ◽  
Dry Season ◽  
Cylindrospermopsis Raciborskii ◽  
Phytoplankton Abundance ◽  
Vertical Variation ◽  
Total Phytoplankton ◽  
Physical And Chemical Variables ◽  
Different Depths ◽  
Physical And Chemical

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

scholarly journals Life Writing Trajectories in Post-1989 Eastern Europe

2013 ◽  
Vol 2 ◽  
pp. T1-T9 ◽  
Author(s):  
Ioana Luca ◽  
Leena Kurvet-Käosaar
Keyword(s):  
Eastern Europe ◽  
Sense Of Belonging ◽  
Temporal Dynamics ◽  
Life Writing ◽  
The Other ◽  
Writing Conference ◽  
Conceptual Frame ◽  
The One ◽  
Cultural Entity ◽  
Conference Papers

In May 2011, the second IABA Europe conference, entitled "Trajectories of(Be)longing: Europe in Life Writing", took place at Tallinn University, Estonia. The conference discussed questions regarding the possibility and productivity of specifically European modes and practices of life writing. Conference sessions focused on spatial mappings and sites of story-telling about Europe in life writing and their temporal dynamics with respectto major historical ruptures and transformations. The lines of inquiry focused, on the one hand, on how the modes and practices of auto/biographical representation were structured around a sense of belonging toor longing for Europe and, and on the other, on contestation, rejection and transgression of such modes of identification. Addressing the conceptual frame of Europe as a geographical, political, social and cultural entity, the conference papers explored the ways in which “life-mapping” constructs, confirms, contradicts, and erases borders within and in relation to Europe, also raising the question of Europe (and its possible Europeanness) within a larger and more fluid global framework.

Dynamics of Within-, Inter-, and Cross-Modal Attentional Modulation

2011 ◽  
Vol 105 (2) ◽  
pp. 674-686 ◽  
Author(s):  
Tetsuo Kida ◽  
Koji Inui ◽  
Emi Tanaka ◽  
Ryusuke Kakigi
Keyword(s):  
Spatial Attention ◽  
Interstimulus Interval ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
The Other ◽  
Neural Representations ◽  
Tactile Stimuli ◽  
Sensory Modalities ◽  
The Right ◽  
Directing Attention

Numerous studies have demonstrated effects of spatial attention within single sensory modalities (within-modal spatial attention) and the effect of directing attention to one sense compared with the other senses (intermodal attention) on cortical neuronal activity. Furthermore, recent studies have been revealing that the effects of spatial attention directed to a certain location in a certain sense spread to the other senses at the same location in space (cross-modal spatial attention). The present study used magnetoencephalography to examine the temporal dynamics of the effects of within-modal and cross-modal spatial and intermodal attention on cortical processes responsive to visual stimuli. Visual or tactile stimuli were randomly presented on the left or right side at a random interstimulus interval and subjects directed attention to the left or right when vision or touch was a task-relevant modality. Sensor-space analysis showed that a response around the occipitotemporal region at around 150 ms after visual stimulation was significantly enhanced by within-modal, cross-modal spatial, and intermodal attention. A later response over the right frontal region at around 200 ms was enhanced by within-modal spatial and intermodal attention, but not by cross-modal spatial attention. These effects were estimated to originate from the occipitotemporal and lateral frontal areas, respectively. Thus the results suggest different spatiotemporal dynamics of neural representations of cross-modal attention and intermodal or within-modal attention.

Case Study of Condensate Dropout Effect in Unconventional Gas/Condensate Reservoirs with Hydraulically Fractured Wells

2022 ◽  
Author(s):  
Ali H. Alsultan ◽  
Josef R. Shaoul ◽  
Jason Park ◽  
Pacelli L. J. Zitha
Keyword(s):  
Gas Production ◽  
Gas Condensate ◽  
Dew Point ◽  
Productivity Index ◽  
Large Reservoir ◽  
Unconventional Gas ◽  
Gas Condensate Reservoirs ◽  
Liquid Saturation ◽  
Reservoir Volume ◽  
Fracture Performance

Abstract Condensate banking is a major issue in the production operations of gas condensate reservoirs. Increase in liquid saturation in the near-wellbore zone due to pressure decline below dew point, decreases well deliverability and the produced condensate-gas ratio (CGR). This paper investigates the effects of condensate banking on the deliverability of hydraulically fractured wells producing from ultralow permeability (0.001 to 0.1 mD) gas condensate reservoirs. Cases where condensate dropout occurs over a large volume of the reservoir, not only near the fracture face, were examined by a detailed numerical reservoir simulation. A commercial compositional simulator with local grid refinement (LGR) around the fracture was used to quantify condensate dropout as a result of reservoir pressure decline and its impact on well productivity index (PI). The effects of gas production rate and reservoir permeability were investigated. Numerical simulation results showed a significant change in fluid compositions and relative permeability to gas over a large reservoir volume due to pressure decline during reservoir depletion. Results further illustrated the complications in understanding the PI evolution of hydraulically fractured wells in "unconventional" gas condensate reservoirs and illustrate how to correctly evaluate fracture performance in such a situation. The findings of our study and novel approach help to more accurately predict post-fracture performance. They provide a better understanding of the hydrocarbon phase change not only near the wellbore and fracture, but also deep in the reservoir, which is critical in unconventional gas condensate reservoirs. The optimization of both fracture spacing in horizontal wells and well spacing for vertical well developments can be achieved by improving the ability of production engineers to generate more realistic predictions of gas and condensate production over time.

Formulation and Evaluation of Benzoyl Peroxide Injection

2021 ◽  
pp. 198-200
Author(s):  
Ajay Bedadurge ◽  
Mahesh Kadare ◽  
Vinod Matole ◽  
Parikshit Shirure ◽  
Sainath Suryawanshi ◽  
...  
Keyword(s):  
Benzoyl Peroxide ◽  
Functional Groups ◽  
The Other ◽  
Test Results ◽  
Methyl Paraben ◽  
Propyl Paraben ◽  
Sterility Test ◽  
Leakage Test ◽  
Drug Content ◽  
Clear Solution

Objective: The present research has been undertaken for the formulation and evaluation of Benzoyl Peroxide Injection. It is used for Antiacne activity. Methods: Benzoyl peroxide is used as Antiacne. Methyl paraben, Propyl paraben and benzalkoniumchloride were used as preservatives. Water for injection is used as a vehicle. The following parameters were evaluated such as clarity test, leakage test, chearity test, assay and Sterility test. Results: The clearity test shows clear solution. Drug chearity test shows no chear in the vials. Leakage test shows no leakage in the vials. pH and drug content show the F1 batch was better the other batches. IR confirmed that all functional groups are same as benzoyl Peroxide. Conclusion: It was concluded that F1 batch is the good than the other batches. So F1 batch is good for the Parenteral use.

Sterilization of Chitosan Membranes for Use as Biomaterial

2014 ◽  
Vol 805 ◽  
pp. 35-40 ◽  
Author(s):  
Imarally V.S.R. Nascimento ◽  
Rita de Cássia A. Leal ◽  
Marcus Vinícius Lia Fook ◽  
Roberta Costa Meira
Keyword(s):  
Ethylene Oxide ◽  
Ultraviolet Radiation ◽  
Physicochemical Properties ◽  
Functional Groups ◽  
Medical Devices ◽  
The Other ◽  
Complete Destruction ◽  
Chitosan Membranes

Sterilization is a procedure which promotes complete destruction or elimination of all forms of microorganisms. It is a fundamental stage in the processing of biomaterials, and functionality of any sterilization system must be determined by its effectiveness in exterminating microorganisms without harming or adversely affect the properties of medical devices. Some sterilization techniques can react with functional groups of the polymer leading to changes in the properties, affecting the biomaterial. This study aimed to develop chitosan membranes sterilize them by following methods: an autoclave, ethylene oxide, glutaraldehyde and ultraviolet radiation and characterized by FTIR, XRD and SEM. Based on the results of this study it can be concluded that the method of sterilization indicated for the membranes of chitosan is ethylene oxide because the other altered physicochemical properties thereof.

Dispersal and survival of Anopheles funestus and A. gambiae s.l. (Diptera: Culicidae) during the rainy season in southeast Tanzania

1998 ◽  
Vol 88 (5) ◽  
pp. 561-566 ◽  
Author(s):  
W. Takken ◽  
J.D. Charlwood ◽  
P.F. Billingsley ◽  
G. Gort
Keyword(s):  
Rainy Season ◽  
Light Trap ◽  
Survival Rates ◽  
Anopheles Funestus ◽  
The Other ◽  
Movement Rates ◽  
Fluorescent Powder ◽  
Local Topography ◽  
Release Area ◽  
Species Specific

AbstractIn a rural area of southeastern Tanzania, studies were undertaken on the dispersal and survival of Anopheles funestus Giles and A. gambiae Giles s.l. during the rainy season. Blood fed, resting mosquitoes were collected indoors, marked with fluorescent powder and released on the same day from two different sites in the study area. For two weeks indoor resting mosquitoes were collected from 11 houses in the release area. Additional collections were made with a light trap from a sentinel house in the centre of the study area. Anopheles funestus was more abundant than A. gambiae s.l. Of 4262 A. funestus and 645 A. gambiae s.l. released, 4.3% and 7.4%, respectively, were recaptured. Dispersal of mosquitoes was not random: one of three areas was favoured significantly more than the other areas, as shown by the recapture and movement rates of marked mosquitoes. Based on the regression of the recapture rate, estimated daily survival rates of A. funestus and A. gambiae s.l. were 0.63 and 0.78, respectively. These were significantly different. The differences in dispersal and survival rates between the two species are discussed in view of local topography and species-specific characteristics.

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