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ACCURACY OF ENERGY ESTIMATION FOR SMALL WIND FARMS BASED ON MESOSCALE WIND DATAMengHan, Zhi January 2023 (has links)
As wind power is one of the main contributions to the energy transition, conducting the necessary production simulations during the development stage of a wind project can provide developers with an initial idea of its power generation potential. Existing wind farm production simulation studies have focused on data sources and time scales based on actual measurement wind data and annual production. This study analyses the accuracy of production simulations for two small wind farms using publicly available mesoscale wind data (NEWA, NORA3, CERRA) in WindPro software. A total of three simulations with different mesoscale data were performed for each wind farm. Annual energy production (AEP) and 12 monthly energy production (MEP) were compared to the actual data and AEP deviations and MEP root mean square error (RMSE) were calculated. Finally, the differences in accuracy between the three mesoscale data for the production simulations are discussed, as well as the consistency of the accuracy on the annual and monthly scales. The results show that the accuracy of all three mesoscale data for the Grollingbo wind farm is weak, with the AEP and MEP simulations from CERRA having the highest relative accuracy (+25.4%; 45.3). For the Räpplinge wind farm, NORA3 has the highest accuracy for both AEP and MEP simulations (+6.3%; 95.2).
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Hydrology and water quality analysis in the Big Black River watershed, MississippiShabbir, Moniba 10 December 2021 (has links) (PDF)
Evaluating hydrology and water quality for the Big Black River Watershed in Mississippi was accomplished by using the Better Assessment Science Integrating Point and Nonpoint Source (BASINS 4.5), Loading Simulation Program in C++ (LSPC), and Water Quality Analysis Simulation Program (WASP) models. The watershed model calibration was originally accomplished by using historical data collected from U.S. Geological Survey (USGS). The watershed model was calibrated using data from 2000 through 2018 in order to quantify stream flow and point source discharges under a variety of hydrologic conditions. The model predicted response of hydrology was consistent with the observed data range. The hydrology part of the model was integrated for water quality simulation. Nutrients levels in the river systems were closely examined, without the impacts from point source discharges. The calibrated model could be used as a planning tool to assess the water quality and to calculate total maximum daily load (TMDL) in the nation’s watersheds.
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Unraveling the Functions of Wiskott-Aldrich Syndrome Protein: Insights into RNA Splicing, Nucleolus Regulation, and ImmunosenescenceZhou, Xuan 08 1900 (has links)
The Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency characterized by microthrombocytopenia, eczema, recurrent infections, autoimmunity, and predisposition to malignancy. Mutations in the WAS gene lead to dysfunction of the Wiskott-Aldrich syndrome protein (WASP), a multifunctional regulator implicated in various hematopoietic and immune processes. While some disease phenotypes have been linked to classical WASP's actin nucleation function, recent advances have unveiled additional nuclear functions, such as involvement in R-loop formation, transcriptional regulation during T helper 1 cell differentiation, and homology-directed repair. However, a comprehensive understanding of WASP's multifaceted functions remains elusive.
We employ induced pluripotent stem cells (iPSCs) and Clustered Regularly Interspaced Palindromic Repeats (CRISPR) technology, specifically the CRISPR-Cas9 system, as powerful tools to investigate the mechanisms underlying WASP's functions. We first explore the consequences of WASP loss on RNA splicing. We reveal its critical role in RNA splicing. WASP-deficiency causes widespread alterations RNA splicing patterns and epigenetic activation of splicing factor gene promoters. Additionally, we uncover its involvement in liquid-liquid phase separation, forming phase-separated condensates to dynamically regulate the splicing machinery.
In the second part of this thesis, our investigation uncovers the presence of WASP within the nucleolus and its interactions with key nucleolar proteins. Intriguingly, depletion of WASP leads to significant reduction in nucleolar size, disrupted nucleolar morphology, and decreased ribosomal RNA transcription, unveiling its critical role in nucleolus structure and function. Furthermore, we successfully recapitulated nucleolus changes and ribosomal RNA profile in patient samples.
Lastly, we investigate immunosenescence, a crucial aspect of aging-related immune dysregulation, in the context of WAS. Through the use of WASP-deficient macrophage cells, our study revealed several distinctive features associated with immunosenescence in WASP-KO-iMPs. These include increased senescent cell proportions, heightened expression of senescence-associated secretory phenotype genes, nuclear deformation, loss of heterochromatin, and enhanced susceptibility to DNA damage. These preliminary findings offer valuable insights into our understanding of immunosenescence within the framework of WASP-deficient macrophages and its association with conditions related to WAS.
In conclusion, the mechanistic study of WASP has unveiled its novel roles in regulating RNA splicing, nucleolus structure and function, as well as its potential involvement in immunosenescence.
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Foraging ecology and sampling of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) and its host Halyomorpha halys (Stal) (Hemiptera: Pentatomidae) in wild host treesQuinn, Nicole Frances 27 November 2019 (has links)
The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive agricultural and nuisance pest in the United States and an increasing number of countries abroad. In the absence of other long-term solutions, biological control presents one of the most promising H. halys management options. An adventive population of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), one of the most effective egg parasitoids of H. halys in their shared native range in Asia, was discovered in the Maryland in 2014 and in Frederick County, VA in 2015. Adventive populations of T. japonicus have also been detected recently in several other states and show strong indications of ongoing range expansion. Despite their importance, the foraging ecology of H. halys and especially of T. japonicus in the USA need further study. Small pyramid traps baited with a low-dose H. halys aggregation pheromone lure and deployed as vertical transects in the canopy of female tree of heaven (Ailanthus altissima (Mill.) Swingle), male tree of heaven, or hackberry (Celtis occidentalis L.), captured significantly more H. halys adults and nymphs near the top of the canopy than at mid- or lower canopy, regardless of host plant. The majority of H. halys egg masses collected via destructive sampling of felled tree of heaven were from mid-canopy, and the majority of those parasitized by T. japonicus were also from mid-canopy, with no T. japonicus emergence from egg masses collected from the lower canopy. A comparison of sentinel H. halys egg masses and yellow sticky traps deployed as vertical transects in tree of heaven revealed that the majority of T. japonicus detections occurred at mid-canopy and that while both methods proved to be equally effective, yellow sticky traps were more efficient for this purpose. This led to the development of a novel T. japonicus sampling method in which a yellow sticky trap is deployed atop a bamboo pole in the mid-canopy of wild host trees. This method was employed to compare the effect of habitat type on T. japonicus captures in female tree of heaven growing in spatially isolated patches, thin windbreaks, and at the edge of contiguous woodlots. Consistent habitat effects on T. japonicus detections were not found between sampling years, but provided the first documentation of the seasonal activity of T. japonicus in the USA. A study of host plant effects on T. japonicus detection in mid-canopy yellow sticky traps did not reveal consistent host plant effects on captures. These data provide important insights into the foraging ecology of H. halys and T. japonicus in the USA, as well as efficient sampling methods for future studies of T. japonicus. / Doctor of Philosophy / The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive agricultural and nuisance pest from Asia that is widely distributed in the United States and is present in an increasing number of countries abroad. In the absence of other long-term management solutions, biological control via the actions of natural enemies presents a promising brown marmorated stink bug management option. Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), also known as the samurai wasp, is one of the most effective egg parasitoids of brown marmorated stink bug in Asia. Samurai wasp arrived in the USA without deliberate introduction and was first detected in Maryland in 2014 and subsequently in Frederick County, VA in 2015. It has continued to expand its range in the USA and was recently detected in several eastern and western states. Despite their importance, little is known of where brown marmorated stink bug eggs, nymphs, and adults are most likely to be found in wild trees. Even less is known about where samurai wasp is likely to occur within its new range. To address these issues, traps containing a lure to attract brown marmorated stink bug were placed in the upper, middle, and lower canopy of female tree of heaven (Ailanthus altissima (Mill.) Swingle), male tree of heaven, and hackberry (Celtis occidentalis L.). Significantly more brown marmorated stink bug adults and nymphs were caught in traps near the top of trees than in those at other canopy locations, with no effect of host plant species observed. The majority of brown marmorated stink bug egg masses collected from felled tree of heaven were from the middle of the canopy. The majority of samurai wasps emerged from egg masses collected from the mid-canopy, while none emerged from those collected from the lower canopy. In a comparison of sentinel brown marmorated stink bug egg masses and yellow sticky traps placed in the upper, middle, and lower canopy of tree of heaven, the majority of samurai wasp detections occurred at mid-canopy. Both methods were found to be effective, but yellow sticky traps required less time and effort to use. This led to the development of a new sampling method for samurai wasp, in which a yellow sticky trap was deployed atop a bamboo pole in the mid-canopy of wild host trees. Using this technique, the effect of habitat type on samurai wasp captures was examined, revealing no consistent effects on detections. However, this study provided the first documentation of when samurai wasps are present and most abundant during the spring and summer. A study of host plant effects on samurai wasp captures, also using yellow sticky traps placed in the mid-canopy of trees, did not reveal consistent host plant effects on captures. These data provide important insights into the interactions of brown marmorated stink bug, samurai wasp, and their environment in the Mid-Atlantic region of the USA, as well as an efficient tool with which to study the samurai wasp.
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Toward optimized surveillance of adventive Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) based on aspects of its foraging ecologyDyer, Jared E. 02 February 2022 (has links)
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an invasive agricultural pest from Asia, has established in much of the USA, where it has had significant, deleterious impacts on the production of various specialty crops. Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) is the predominant egg parasitoid of H. halys in Asia and considered a potential agent for classical biological control. Adventive T. japonicus populations have been detected in 15 US states since 2014 and its continued spread is anticipated, creating the impetus for developing optimized sampling methods for it that are informed by its foraging ecology. Yellow sticky cards (YSC) deployed in the lower and mid-canopy of Ailanthus altissima (Mill.) Swingle trees in Virginia captured statistically equivalent numbers of T. japonicus. Season-long monitoring of T. japonicus and H. halys over two seasons resulted in significant correlations between captures of T. japonicus and H. halys adults, second instar nymphs, and all life stages combined, revealing spatiotemporal synchrony between the parasitoid and its host. Inspection of felled pheromone-baited and non-baited A. altissima showed no effect of baiting with the H. halys aggregation pheromone on H. halys egg mass abundance. Similarly, captures of T. japonicus in pheromone-baited and non-baited trees were not significantly different. Augmenting YSC with H. halys egg masses or n-tridecane did not improve T. japonicus captures. Together, these results should improve the efficiency of T. japonicus surveillance efforts and provide important guidance for future research toward enhancing the sensitivity of sampling tools for it and the interpretation of its impacts on H. halys. / Master of Science in Life Sciences / The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an invasive species from Asia, has become widely distributed throughout the United States as a serious pest of many important crops. Parasitic wasps that develop on eggs are often key natural enemies for reducing stink bug populations. The samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), is the primary parasitic wasp of BMSB in Asia and is under evaluation for potential use in biological control programs. Populations of samurai wasps have been detected in the United States since 2014 without intentional introduction. Its continued spread is anticipated, creating the need for effective sampling methods to track its establishment. Yellow sticky cards (YSC) deployed in the lower and mid-canopy of tree of heaven in Virginia captured similar numbers of samurai wasps. Season-long monitoring of samurai wasps and BMSB over two seasons resulted in significant correlations between captures of samurai wasps and BMSB adults, second instar nymphs, and all life stages combined, revealing spatiotemporal overlap between the wasp and its host. Inspection of felled pheromone-baited and non-baited tree of heaven showed no effect of baiting with the BMSB aggregation pheromone on numbers of BMSB egg masses. Similarly, captures of samurai wasps in pheromone-baited and non-baited trees were not significantly different. Combining YSC with BMSB egg masses or n-tridecane did not improve samurai wasp captures. Together, these results provide important guidance for future research toward enhancing the sensitivity of sampling tools for samurai wasps and the interpretation of its impacts on BMSB.
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Queens And Their Succerssors : The Story Of Power In The Primitively Eusocial Wasp Ropalidia MarginataBhadra, Anindita 11 1900 (has links)
Ropalidia marginata is characterized as a primitively eusocial wasp due to the absence of morphological differentiation between the queen and worker castes. Unlike other primitively eusocial wasps, however, the queen in this species is a docile individual, who does not use aggression to regulate worker reproduction, and does not act as the central pacemaker of her colony. However, if the queen dies or is experimentally removed, one of the workers steps up her aggression immensely within minutes, and if the queen is not replaced, she develops her ovaries, reduces aggression and takes over as the new queen of the colony. We call her the potential queen (PQ). When I started my work on R. marginata, two very intriguing questions were demanding to be answered, which had developed from work done by my immediate seniors in the lab. I decided to pursue both of these for my thesis. My work has been enriched by inputs from several collaborators and colleagues - I couldn’t have done all of it by myself. So, henceforth, I will be using the word “we”, instead of the first person singular to
describe the work that has gone into this thesis.
Question 1: Is there a designated successor to the queen in R. marginata?
My senior Sujata P. Kardile has shown in her thesis, that in R. cyathiformis, a primitively eusocial wasp very closely related to R. marginata, the queen is always
succeeded by the next most aggressive individual in the colony, and so the PQ is easily predictable in the presence of the queen. However, in R. marginata, the PQ appears to be an unspecialized individual, who cannot be predicted in the presence of the queen by using age, ovarian profile or behaviour as the yardsticks. However, the PQ
becomes evident within minutes after queen removal. The swiftness with which the PQ
is established led us to believe that perhaps the successor to the queen in R. marginata is known to the wasps, though we cannot identify her in the presence of the queen. We designed an experiment to check for the presence of such a ”cryptic successor” in R. marginata. Our experiments involved splitting a normal, queen-right nest into two halves separated by a wire mesh partition, so that the wasps could not move across the mesh. Earlier we had used this set-up to demonstrate that a PQ always establishes herself on the queen-less fragment of the nest. So, to test if there is a cryptic successor, we allowed a PQ to establish herself on the queen-less fragment, and then exchanged the queen and the PQ (designated as PQ1) between the two sides. There is a 50% probability that the cryptic successor, if present, would be on the queen-less side in the beginning. Then, upon exchange, she should be able to hold her position on the other side easily. On the other hand, if the cryptic successor is first on the queen-right side, then, upon exchange, she should take over as the PQ (PQ2), and PQ1 should not be able to hold her status. The cryptic successor hypothesis had two predictions: (i) the PQ1 would lose to a PQ2 in about half the cases, and (ii) there would never be a PQ3. We obtained a PQ2 in 5 out of 8 cases, and we never had a PQ3. So we could conclude that there is indeed one individual who is the designated successor to the queen in R. marginata. Since we could not identify her in the presence of the queen, we call her the
cryptic successor. The cryptic successor did not receive even a single act of aggression
from the PQ1, or from any other individual in the colony. Thus we conclude that she is acceptable to all the wasps in the colony.
We next used the more sophisticated and rigorous method of network analysis to check if the PQ could be predicted due to some unique position she might be holding in the social network on her colony. Since this was a first study in a primitively eusocial insect using network tools, we began by characterizing the social networks of queen-right and queen-less colonies of R. marginata, and compared them with the R. cyathiformis networks to see how different the R. marginata society is from a typical primitively eusocial one. The R. marginata social networks based on dominant-subordinate interactions were low in their centrality measure as compared to the R. cyathiformis networks. However, in both the species, the queen-less networks were highly centralized, star-shaped networks with the PQs at the centre. Neither the queens, nor the PQs were key individuals in the queen-right colonies, but it is interesting
to note that the removal of an insignificant node, the queen, resulted in a major change in the network architecture, converting the de-centralized queen-right network into a highly centralized one. Such centralized star-shaped networks are unique, and
to our knowledge, the first ever described, in any social system. When we removed the queen from the data set (in silico removal), the resulting network was similar in centrality to the queen-right networks. We then did a comparative analysis of the positional importance of the PQs of the two species, and tried to see if we could use this as a tool to predict the PQ in the queen-right network. In R. cyathiformis, the PQs had consistently high ranks (mostly rank 2) in the network based on the degree index,
while the PQs in R. marginata had random ranks in the hierarchy. However, since the
PQs are known not to have unique ranks in the dominance hierarchies, we repeated the analysis using data on all interactions from the Q-PQ exchange experiments described above. Neither the cryptic successors nor the losers occupied any unique ranks in the all interactions networks. Thus the successors in R. marginata are truly cryptic,
even in their social networks. Since R. marginata is known to be more evolved than
typical primitively eusocial species, it is likely that the queen’s successor is identified by the wasps through some subtle cue like smell, and so we cannot identify her using the methods that are adequate for the identification of the PQ in a typical primitively eusocial species like R. cyathiformis.
Question 2: How does the queen signal her presence and reproductive status to her workers or, how do the workers perceive the presence of their queen?
The fact that in spite of her docility, the queen in R. marginata manages to maintain complete reproductive monopoly in her colony, gives rise to the obvious question of how she suppresses worker reproduction. The most attractive hypothesis is that she uses a pheromone like queens of highly eusocial species. My senior A. Sumana
had shown that the queen pheromone, if present, is not a volatile substance. She
also showed that the queen interacts at a very low rate with her workers, and so they
cannot possibly perceive her by means of direct interactions. Since the PQ steps up her aggression within minutes of queen removal, we used her as a proxy to know how soon the queen’s absence is felt in the colony. We built a model to delineate the relationship between the decay time of the pheromone (td), the average age of the queen’s signal present with the PQ (ta), and the average realization time (tr); where tr = td − ta. Using Dijkstra’s algorithm, we showed that the queen could interact faster with the PQ by using relay interactions. Then using experimental data from 50 colonies, we obtained a ta of 102.9 minutes. The td was 340 minutes, and so we obtained a tr of 237.1 minutes; which meant that the PQ should not perceive the queen’s absence
within 237 minutes of queen removal, if the queen pheromone is transmitted by a relay
mechanism. However, from our experimental data, we had obtained a tr of 30 minutes.
So we concluded that physical interactions, both direct and indirect were inadequate
for the workers to perceive their queen.
As we had ruled out physical interactions, we then wanted to check if it is possible that the queen applies her pheromone to the nest material, from where it is perceived by the workers when they walk or sit on the nest, or antennate the nest surface. The “rub abdomen behaviour (RA)” has been observed to be quite typical of R. marginata queens, and is not very common in the workers of the species. RA involves rubbing the ventral side of the tip of the abdomen or dragging it on the nest surface while walking. We thought that the queen might be using this behaviour to apply her pheromone on the nest material. So we characterized this behaviour using focal behaviour sampling, and found that the queen rubs her abdomen on the nest once in every 23 minutes. Since the observed tr is 30 minutes, it is quite likely that the queen
uses the rub abdomen behaviour to apply her pheromone on the nest. The next step was to check for the source of the queen pheromone. We looked for glands that open near the base of the sting, and the Dufour’s gland was a good choice, as it is known to be involved in the recognition of egg-laying workers in the honeybees. We performed a bioassay in the blind using the crude extract of the Dufour’s gland (prepared in Ringer’s solution) from the queen. The Dufour’s gland extract of a randomly chosen worker and the solvent were used as controls. We found that the PQ responds to the queen’s Dufour’s gland extract by lowering her aggression to 65% of what she was showing on queen removal and before the application of the extract. However, the PQ did not change her behaviour significantly when the worker’s extract or Ringer’s solution was applied. The PQ’s reduction of aggression on application of the queen’s extract mimicked the reaction of PQ’s when the queen is re-introduced on the nest some time after removal. So we hypothesize that the Dufour’s gland is the source of the queen pheromone (signal) in R. marginata.
This thesis has opened up newer questions pertaining to the power of the queen and the intricacies of the succession to power in R. marginata. For example, we need to pursue chemical analyses of the Dufour’s gland extract of R. marginata to have conclusive proof of it’s being the source of the queen pheromone. But that is perhaps suitable topic for my juniors in the lab, who can continue the tradition of beginning with questions opened up by their seniors!
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The Role of Nursery Size and Plant Phenology on the Reproduction of and Relationships within a Fig-fig Wasp Nursery Pollination SystemKrishnan, Anusha January 2014 (has links) (PDF)
Obligate nursery pollination mutualisms such as the fig–fig wasp system, with their central plant–pollinator mutualism associated with non-pollinating satellite wasp species, can function as closed system microcosms representative of tritrophic communities. In this system, enclosed inflorescences (syconia) function as sites of seed production, as well as brood-sites for the progeny of herbivorous mutualistic pollinators, non-pollinating gallers and parasitoids of the two. Plant reproductive traits such as inflorescence size (syconium volume) and within-plant phenology (within-tree asynchrony) as can affect inter-species relationships among the three trophic levels in such plant–herbivore–parasitoid systems. Induced or natural variations in such plant traits could influence various direct and indirect effects among the organisms in the community and could even lead to the formation of feedback cycles. Furthermore, changes in the abiotic environment could have major impacts on the biotic associations in the system either by affecting the community members directly, or through their effects on plant reproductive traits. Ficus racemosa with its fig wasp community comprised of a single herbivorous pollinator mutualist, three non-pollinating parasitic gallers and three non-pollinating parasitoids was used as a model to investigate: (1) the role of mutualistic and parasitic fig wasps in affecting within-tree phenology; (2) direct and indirect biotic associations between various groups of fig wasps (pollinators, gallers and parasitoids) and the influence of inflorescence size and within-tree phenology on them; and (3) variations in the reproduction of and the biotic associations between the organisms of the community under variable abiotic climatic conditions.
Patterns of plant reproductive phenology are usually considered evolved responses directed at optimizing resource use, pollen receipt/donation schedules and seed dispersal for plant individuals. Within-plant reproductive synchrony or asynchrony can arise due to variation in floral initiation patterns, as well as from localised proximate mechanistic responses to interactants such as pollinators, parasites and herbivores which could affect floral longevity or fruit development time. The investigation was begun by exploring the role of a mutualistic pollinator, and for the first time in a brood-site mutualism, that of parasitic herbivores (gallers) and parasitoids in influencing within-plant reproductive phenology. Since a syconium functions as an inflorescence which develops into a fruit after pollination, investigations were carried out on the impact on syconium synchrony of fig wasps that began their development within the brood site syconium at pre-pollination, pollination, and post-pollination stages via their effects on the development time of individual syconia in Ficus racemosa. We found that syconium initiation patterns were not the only proximate mechanism for within-tree reproductive asynchrony, and that individual syconia (even within a tree) had highly plastic development times dependent on their sizes, pollination time and the species of wasp progeny developing within them. Syconium volume, pollination early in the pollen-receptive phase and presence of early-ovipositing galler progeny reduced syconium development time, whereas the presence of late-ovipositing parasitoid progeny or pollination late in the pollen-receptive phase increased syconium development time. These results suggest an ongoing tug-of-war between syconium inhabitants to modify syconium development times. Parasitic fig wasps pull in different directions to suit their own needs, such that final syconium development times are likely to be a compromise between conflicting demands from developing seeds and from different wasp species.
Inter-species relationships among the three trophic levels in plant–herbivore–parasitoid systems can potentially include various direct and indirect effects possibly mediated by induced or natural variations in plant traits. Analysing the seed and fig wasp compositions of microcosm replicates, i.e. individual syconia, shows that besides direct competition for resources and predator–prey interactions, the F. racemosa community also displays exploitative or apparent competition and trait-mediated indirect interactions. Syconium volume and within-tree asynchrony were reproductive plant traits that not only affected plant–herbivore and plant–parasitoid associations, but also possibly modified herbivore–herbivore and herbivore–parasitoid interactions. Our results also indicated that the reciprocal effects of higher trophic level fauna on plant traits (and vice versa) within this system drive a positive feedback cycle between syconium inhabitants and within-tree reproductive asynchrony.
In the F. racemosa system, abiotic environmental factors could affect the reproduction of mutualistic pollinators, non-mutualistic parasites and seed production via seasonal changes in plant reproductive traits such as syconium volume within-tree asynchrony. Temperature, relative humidity and rainfall defined four seasons: winter; hot days, cold nights; summer and wet seasons. Syconium volumes were highest in winter and lowest in summer, and affected syconium contents positively across all seasons. Greater transpiration from the nurseries was possibly responsible for smaller syconia in summer. The 3–5°C increase in mean temperatures between the cooler seasons and summer reduced fig wasp reproduction and increased seed production nearly two-fold. Yet, seed and pollinator progeny production were never negatively related in any season confirming the mutualistic fig–pollinator association across seasons. Parasites affected seed production negatively in some seasons, but had a surprisingly positive relationship with pollinators in most seasons. While within-tree reproductive phenology did not vary across seasons, its effect on syconium inhabitants varied with season. In all seasons, within-tree reproductive asynchrony affected parasite reproduction negatively, whereas it had a positive effect on pollinator reproduction in winter and a negative effect in summer. Seasonally variable syconium volumes probably caused the differential effect of within-tree reproductive phenology on pollinator reproduction. Within-tree reproductive asynchrony itself was positively affected by intra-tree variation in syconium contents and volume, creating a unique feedback loop which varied across seasons. Therefore, nursery size affected fig wasp reproduction, seed production and within-tree reproductive phenology via the feedback cycle in this system. Climatic factors affecting plant reproductive traits can cause biotic relationships between plants, mutualists and parasites to vary seasonally and must be accorded greater attention, especially in the context of climate change.
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Utvärdering av dataprogram för vindresursberäkningar : En jämförelse av vindresursberäkningar i kuperad skogsterräng med programmet WAsP (linjär modellering) och CFD-programmet WindSim / An evaluation of wind energy software : A comparison of wind resource calculations made with the software WAsP (linear model) and the CFD software WindSim over a hilly forested areaJohansson, Eric January 2013 (has links)
Vindkraft för generering av el har under de senaste åren vuxit kraftigt i Sverige och utbyggnaden väntas fortsätta. Ett viktigt steg när nya vindkraftsparker skall byggas är att göra en vindanalys för det aktuella området. Vindanalysen är ett viktigt underlag för att avgöra om en investering i vindkraftverk kommer vara ekonomiskt lönsamt på den aktuella platsen. Som underlag till vindanalysen sätts vanligen mätutrustning upp i området och vindförhållandena på platsen mäts upp. Att installera och underhålla mätmaster är kostsamt och därför mäts vindarna på ett begränsat antal platser i det intressanta området. Sedan används olika beräkningsprogram för att extrapolera de uppmätta vindresurserna till positioner där mätningar saknas. För närvarande används programmet WAsP som standard av många vindkraftsprojektörer. WAsP:s beräkningsmodell är relativt enkel och tar till exempel inte hänsyn till turbulens som uppkommer då terrängen är kuperad. Som ett alternativ till WAsP har olika CFD-program introducerats på marknaden under senare år. Dessa programs modeller är mer avancerade och de kräver därför längre beräkningstid jämfört med WAsP, men förhoppningen är att de skall ge mer tillförlitliga modelleringsresultat. I denna studie har vindmodelleringar i det linjära modelleringsprogrammet WAsP jämförts med modelleringar i CFD-programmet WindSim. Syftet har varit att undersöka om WAsP ger tillförlitliga modelleringsresultat i svenskt kuperat skogslandskap och om WindSims CFD-beräkningar kan ge en ökad noggrannhet i jämförelse. Prestandan hos respektive program har utvärderats genom att jämföra extrapolerade medelvindar med faktiska mätningar. Vindmätningar har funnits att tillgå från en period av 12 månader från två mätmaster med givare på 60, 80 och 100 meters höjd. Avståndet mellan masterna är cirka 10 kilometer. Resultaten från studien tyder på att WindSim kan ge en något ökad noggrannhet jämfört med WAsP, men resultaten visar samtidigt att en CFD-modellering inte med automatik ger mer tillförlitliga modelleringsresultat. Studien har visat att resultatet från WindSim är starkt beroende av hur modellen sätts upp och det kan därför vara enklare att göra fel i WindSim jämfört med WAsP. Det blev också tydligt att en modell där den simulerad vindskjuvning (variation av vindhastigheten i höjdled) stämde bra överens med den uppmätta inte behöver betyda att WindSim-modellen gör bra extrapolationer av vindförhållandena från den ena masten till den andra. Vidare visade sig WAsP missbedöma effekter från topografin något och om vindmätningar görs på utmärkande höjder är det sannolikt att WAsP överskattar vindförhållandena i de lågt belägna delarna av terrängen. I WindSim undersöktes två olika modelluppsättningar, en med WindSims skogsmodul där skogen simuleras som 3D objekt och en modell där skogen hanteras med på samma sätt som i WAsP med råhetslängd och nollplansförskjutning. När skogsmodulen användes var det inte möjligt att erhålla en modellerad vindskjuvning som stämde överens med den uppmätta i en neutral atmosfär, vilket är WindSims standardinställning för atmosfärsstabiliteten. I en neutral atmosfär med skogsmodulen överskattades vindhastigheten på låga höjder. Om atmosfären simulerades som stabil i medeltal var det möjligt att få den simulerad vindskjuvning att stämma överens med den uppmätta, men extrapolationerna i horisontalled blev inte bra med denna modell. Om atmosfären skall simuleras som stabil i WindSim tyder resultaten från studien på att vindmätningarna måste delas in efter rådande atmosfärstabilitet för den aktuella tidpunkten för mätningen. Det fungerade inte tillfredställande att använda alla vindmätningar i samma modell och försöka hitta ett passande medelvärde för stabiliteten. Om vindmätningarna skall delas upp efter rådande stabilitet kommer varje stabilitet kräva en egen modellering vilket betyder att beräkningstiden kommer öka markant. Att simulera skogen i WindSim med en råhetslängd och en nollplansförskjutning visade sig fungera bra. En modellerad vindskjuvning som stämde bra överens med den uppmätta kunde erhållas i en neutral atmosfär och denna modell presterade sammantaget bäst av alla undersökta modeller i den här studien. Det studerade området består övervägande av skog och vindmätningarna som använts är utförda inom skogsområdet. WindSim skogsmodul kan tänkas vara mer användbar och viktig om skog förekommer i begränsade partier och då tänkta vindturbiner inte placeras direkt inom skogsområdet. En förhoppning på CFD-program är att vindmätningar utförda på låg höjd skall kunna användas för att förutse vinden på högre höjder med större noggrannhet jämfört med WAsP. Resultat från den här studien visar dock att det kan vara svårt att uppnå en bra modellerad vindskjuvning i WindSim. Även i WindSim är således viktigt att ha vindmätningar från flera olika höjder för att kunna verifiera modellen mot innan programmet kan förväntas förutse vinden på högre höjder korrekt. Sammanfattningsvis förefaller en bra inställd WindSim-modell kunna ge en något ökad noggrannhet av extrapolerade vindförhållanden jämfört med WAsP, men om extrapolationer skall göras mellan liknade områden i terrängen, till exempel från en kulle till en annan kulle, är det tveksamt om den lilla ökade noggrannheten ger skäl för den ökade beräkningstiden i WindSim. / An evaluation of wind energy software: a comparison of wind resource calculations made with the software WAsP (linear model) and the CFD software WindSim over a hilly forested area. Results produced from the wind modeling linear program WAsP were compared with modeling results produced by the CFD program WindSim. The aim was to investigate whether WAsP achieves accurate calculation results over a hilly forested area in Sweden, and if the CFD modeling in WindSim provides more accurate results than WAsP. The performance of each program was evaluated by comparing extrapolated average wind speed data to actual measurements. The study shows that WindSim may achieve an increased accuracy of extrapolated wind conditions compared to WAsP, as well as indicates that a CFD calculation does not automatically provide more reliable extrapolations than linear modeling in WAsP. The accuracy of the WindSim extrapolations was highly dependent on how the model was set up, and hence it may be easier to make errors with WindSim compared to WAsP. A model in WindSim with accurate simulated wind shear did not necessarily mean that the model made good extrapolations of wind conditions horizontally. Furthermore, WAsP was shown to slightly misjudge orographic effects, and when wind measurements are made over hilltops, WAsP most likely overestimates the average wind speed in the lower parts of the terrain. When a good model was established, WindSim provided slightly more accurate results than WAsP, but if extrapolations are to be made between similar areas in the terrain, for example from one hill to another hill, it is doubtful that the small increase in accuracy gives enough reason for the increased time in calculation required by WindSim.
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Mapeamento eólico do estado de Alagoas utilizando ferramentas computacionais e dados observados / Wind power mapping of the state of Alagoas using observed data and computer toolsRamos, Diogo Nunes da Silva 24 January 2011 (has links)
With the growing energy demand and the opportunity for exploitation of renewable energy (wind energy), this paper performs the mapping of wind potential in Alagoas. This study is based on the use of anemometer measurements between August/2007 to July/2008, as also computational tools: mesoscale atmospheric model (WRF); numerical model of microscale (WAsP®); data from Geographic Information Systems (GIS). The stations with anemometers were geographically distributed in three mesoregions of the State: Backwoods Sertão (Água Branca), Rural Agreste (Girau do Ponciano and Palmeira dos Índios) and Coast Litoral (Feliz Deserto, Maragogi and Roteiro). WRF simulations have validated by time series (daily average, monthly average and diurnal cycles), statistical analysis and Weibull distributions. It was also evaluated using WAsP as a tool for calculating the spatial wind speed in microscale. The input data in WAsP, in addition to the WRF model simulations and the preparation of various maps, were all treated and developed in the ArcGIS® software. The results showed greater efficiency in the WRF simulation of wind speed for sites to the interior of Alagoas, with bias less than 1 m.s-1. These estimates were more accurate during the summer season (bias less than 0.5 m.s-1) and more disparate in winter, with average error of up to 3 m.s-1. For the Coast, these values were overestimated by more than 3 m.s-1, except in Maragogi. The wind direction from WRF was calculated with accuracy in all sites, being dominant in the east coast, east to northeast in Rural, and southeast in Água Branca. The annual wind map for WRF for Alagoas showed areas with good potential energy, the magnitude of the wind varies between 7-9 m.s-1 at 50 meters high. Application of the WAsP in the microscale showed good resemblance to the maps obtained in the Wind Atlas of the State of Alagoas - AEEA. The models achieved satisfactory results, but still need to be improved in some respects. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Com a crescente demanda energética e a oportunidade de exploração de energia renovável (eólica), este trabalho realiza o mapeamento do potencial eólico em Alagoas. Este trabalho é baseado no uso de medições anemométricas entre agosto/2007 a julho/2008, além de ferramentas computacionais: modelo atmosférico de mesoescala (WRF); modelo numérico de microescala (WAsP®); dados de sistemas de informações geográficas (SIG). As estações anemométricas foram distribuídas geograficamente nas três mesorregiões do Estado: Sertão (Água Branca), Agreste (Girau do Ponciano e Palmeira dos Índios) e Litoral (Feliz Deserto, Maragogi e Roteiro). As simulações do WRF foram validadas através de séries temporais (médias diárias, mensais, ciclos diurnos), análises estatísticas e Distribuições de Weibull. Avaliaram-se ainda o uso do WAsP como ferramenta para cálculo espacial da velocidade do vento em microescala. Os dados de entrada no WAsP, além das simulações do modelo WRF e da elaboração de diversos mapas, foram todos tratados e desenvolvidos no software ArcGIS®. Os resultados mostraram que houve maior eficiência do WRF nas simulações da velocidade do vento para sítios do interior alagoano, com bias inferior a 1 m.s-1. Estas estimativas foram mais precisas durante a estação do verão (bias menor que 0,5 m.s-1) e mais discrepantes no inverno, com erro médio de até 3 m.s-1. Para o litoral, estes valores foram superestimados em mais de 3 m.s-1, exceto em Maragogi. A direção do vento do WRF foi calculada com acerto em todos os sítios, sendo dominante de leste no litoral, leste a nordeste no agreste, e sudeste em Água Branca. O mapa eólico anual do WRF para Alagoas apresentou áreas com bom potencial energético, cuja magnitude do vento varia entre 7 a 9 m.s-1 em 50 metros de altura. A aplicação do WAsP na microescala mostrou boa semelhança aos mapas obtidos no Atlas Eólico do Estado de Alagoas AEEA. Os modelos atingiram resultados satisfatórios, porém ainda precisam ser aperfeiçoados em alguns aspectos.
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Reflected Light of Exoplanets : a case study of WASP-43b using the Hubble Space TelescopeGupta, Prashansa 12 1900 (has links)
Avec près de 4000 exoplanètes connues, le domaine est passé de simplement détecter des exoplanètes à étudier leurs propriétés atmosphériques. Cependant, les spectres en lumières réfléchies de ces objets sont encore mal compris. Les exoplanètes réfléchissent une partie de la lumière qu’elles reçoivent de leur étoile, selon les propriétés de l’atmosphère, ce qui affecte le budget énergétique de la planète. Les Jupiters chaudes, c’est-à-dire des planètes de types Jupiter avec des périodes orbitales très courtes, sont les cibles les plus faciles à observer par spectroscopie des éclipses. L’albédo est une mesure directe de la lumière réfléchie qui peut être mesurée pendant que la planète passe derrière l’étoile hôte. Dans leur cas spécifique, une incohérence apparente, appelée le problème d’albédo des Jupiters chaudes, reste non résolu. Alors que les géantes gazeuses du système solaire ont des albédos de Bond inférieurs aux albédos géométriques, les mesures dans le visible et l’infrarouges pour HD 189733b et HD 209458b indiquent le contraire. Ceci pourrait être expliqué par des albédos géométriques plus élevés à des longueurs d’onde UV/visibles hors de la bande passante de Kepler, mais très peu de mesures existent pour corroborer cela. Ce mémoire présente le spectre de réflexion complet de WASP-43b, incluant 3 mesures d’éclipse obtenues par le HST (290-570 nm) ainsi que 28 obtenues par la mission TESS (600-1000 nm). Lorsque combinées avec les observations Spitzer ou les observations d’éclipse du JWST à venir, ces mesures répondront à des questions-clés concernant la structure et composition atmosphérique de la planète, le budget énergétique global et sa circulation. / With nearly 4000 exoplanets known, the field has evolved from merely detecting exoplanets to actually probing atmospheric properties. However, reflected light spectra from these objects are still not fully understood. Exoplanets reflect a portion of the light that they receive from the star, the amount of which depends on the properties of the atmosphere and in turn affects the energy budget of the planet. Hot Jupiters, i.e. Jupiter-like planets giants with very short orbital periods are the easiest targets amenable to eclipse spectroscopy. Albedo is a direct measure of reflected light that can be measured while the planet eclipses behind the host star. In the specific case of these intriguing planets, an apparent inconsistency, termed as the hot Jupiter Albedo Problem, remains unsolved. While Solar System gas giants show Bond albedos lower than geometric albedos, the measurements from optical and infrared instruments for HD 189733b and HD 209458b show the opposite. This phenomenon has the potential to be explained by higher geometric albedos at UV/optical wavelengths outside the Kepler bandpass, but very few measurements exist to corroborate this. This thesis presents WASP-43b’s full reflection spectrum, including 3 eclipse measurements obtained by the HST (290-570 nm) along with 28 obtained by the TESS mission (600-1000 nm). When combined with the Spitzer or the upcoming JWST’s eclipse observations, these measurements will answer key questions about the planet’s atmospheric composition and structure, global energy budget and circulation.
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