Droop-Based Power Controller for Electronic Power Converters in Three-Phase Microgrids

openIn questa tesi, viene proposto un sistema di controllo di potenza basato sulla tecnica di controllo droop. Il controllo viene studiato considerando una generica rete trifase più neutro e, successivamente, analizzato ed esteso al caso di assenza della connessione del neutro (cioè, sistemi trifase a tre fili). La tecnica presenta la possibilità di controllare completamente la potenza attiva e reattiva su ogni singola fase e permette transizioni graduali verso il funzionamento in isola. In particolare, in questo lavoro, la tecnica viene proposta e analizzata per l'uso in reti a tre fili tenendo conto delle limitazioni dovute a questa particolare connessione. I risultati di simulazione e sperimentali sono riportati e discussi.In this thesis, a droop-based per-phase power controller is proposed. The control is studied considering a generic three-phase plus neutral network and, subsequently, analyzed and extended to the case of absence of the neutral connection (i.e., three-phase three-wire systems). The technique features the possibility to fully control per-phase active and reactive power and allows smooth transitions to the islanded operation. Specifically, in this work, the technique is proposed and analyzed for use in three-wire networks taking into account the limitations due to this particular connection. Simulation and experimental results are reported and discussed

Molecular analysis of petal development by X-ChIP and two-hybrid technology

Flowers of eudicots like Antirrhinum and Arabidopsis are composed of four concentric whorls, where four different kinds of organs develop: sepal and petals in the two outermost whorls and the sexual organs, stamens and carpels, in the centre of the flower. Organ development is determined by homeotic genes that interact according to the ABCDE model. The homeotic B class genes, represented by DEFICIENS (DEF) and GLOBOSA (GLO) in Antirrhinum and APETALA3 (AP3) and PISTILLATA (PI) in Arabidopsis, participate together with class A and E factors in regulating petals development and together with class C and E in stamens development. In the work here presented, class B target genes are investigated in Antirrhinum and Arabidopsis by Crosslinked Chromatin ImmunoPrecipitation (X-ChIP) experiments, to prove the direct protein-DNA interaction by an immunoprecipitation. In this study a new approach is presented and discussed for the X-ChIP data analysis that includes more controls with respect to the standard procedure reported in literature, and that allows the discrimination of false positive results. This new approach showed that the interaction of DEF protein with the promoter of the putative targets GLOBOSA, DEFICIENS and EXTENSIN is not demonstrable at these conditions and revealed its interaction with the promoter of DEFH125. Protein-protein and protein-DNA interactions that involve Class B factors have been studied in yeast: new interactors of AP3 and PI were isolated by a three-hybrid screening. Class B transcription factors determine the fate of petal primordia, but not their initiation, which is controlled by other genes, like ROXY1, which belongs to the plant glutaredoxin (GRX) family. roxy1 mutant phenotype presents a reduced number of petals and abnormalities during further petal development. GRXs are small proteins involved in posttranslational modifications of target proteins via redox reactions. In order to shed light on its activity, ROXY1 was used as bait in a two-hybrid screening. Among many isolated clones, the transcription factors TCP3, TCP4 and TCP21 were chosen for a further investigation. TCP proteins have been shown to participate in the control of cell proliferation and can be functionally linked to ROXY1 because, at early stages of roxy1 developing flower, misregulation of cell proliferation leads to phenotypic abnormalities. In order to support an in vivo interaction, in situ hybridizations were conducted, revealing that the expression domains of TCP3, TCP4 and TCP21 overlap with that of ROXY1 at early stages of floral development

On Epistemology of Construction Engineering and Management

In philosophy of science, there have been two different starting points for epistemology: Platonism and Aristotelianism. These two alternative starting points have played a major role also in the formation of fundamental ideas of engineering and management generally as well as in relation to construction. It is contended that an overly Platonic influence on engineering and management has created a number of problems. For solving these problems, beyond mere patching, a more balanced take on Platonism and Aristotelianism is needed

A Two-Day Virtual Workshop on the Micronutrient-Directed Nutrition-Focused Physical Exam for Ghanaian Nutrition Professionals: Examining Perceived Self-Efficacy and Innovation

Micronutrients are key components of various physiological processes. In Ghana, micronutrient deficiencies are common and medical resources are limited. Biochemical markers of nutrition status are costly and require specialized medical equipment. In the absence of available biochemical markers of nutrition status, the micronutrient-directed nutrition-focused physical exam is a viable tool. This mixed-methods research aimed to determine whether a two-day virtual workshop for Ghanaian nutrition professionals (N=131) would improve perceptions regarding the usefulness and self-efficacy of the micronutrient-directed nutrition-focused physical exam. Quantitative data were collected via a virtual pretest (immediately prior to the workshop) and a virtual posttest (immediately following the workshop). Qualitative data were gathered via focus groups, which were conducted in virtual breakout rooms on the second day of the workshop. Total posttest scores were significantly higher (M=70.15, SE= .703), t(130)= -7.357, p= M= 64.85, SE= .165), t(130)= -7.357, p

Characterizing Summer Roosts of Little Brown Myotis and Evaluating the Effects of Mountain Pine Beetle Disturbance

Mountain pine beetle (MPB, Dendroctonus ponderosae) outbreaks have resulted in large-scale changes in forest structure throughout the western United States. These changes can have large impacts on wildlife, but have not been studied in bats. Given that roosting sites may limit the distribution and abundance of bat populations, we aim to 1) quantify characteristics of roosts in forests during the summer and 2) evaluate how the availability of these characteristics changes with different intensities of MPB disturbance. During the summer of 2017, we mist-netted for bats in forests dominated by lodgepole pine (Pinus contorta) that exhibited varying degrees of tree mortality due to MPB. Three bat species comprised 76% of captures: hoary bat (Lasiurus cinereus, 12%), silver-haired bat (Lasionycteris noctivagans, 29%), and little brown myotis (Myotis lucifugus, 35%).Originally, we intended to tag lactating female little brown myotis to characterize maternity roosts. However, all 42 captures of little brown myotis were male. We attached radiotransmitters to 11 males and located at least 1 roost for 6 individuals (total roosts = 18). All roosts were in rock features, even though lodgepole snags were abundant and in close proximity to roosting sites. These preliminary results suggest that in lodgepole-dominated forests, male little brown myotis choose to roost in rock features over snags, regardless of the severity of MPB disturbance

Multimodality Imaging in the Diagnostic Work-Up of Endocarditis and Cardiac Implantable Electronic Device (CIED) Infection

Infective endocarditis (IE) is a serious cardiac condition, which includes a wide range of clinical presentations, with varying degrees of severity. The diagnosis is multifactorial and a proper characterization of disease requires the identification of the primary site of infection (usually the cardiac valve) and the search of secondary systemic complications. Early depiction of local complications or distant embolization has a great impact on patient management and prognosis, as it may induce to aggressive antibiotic treatment or, in more advanced cases, cardiac surgery. In this setting, the multimodality imaging has assumed a pivotal role in the clinical decision making and it requires the physician to be aware of the advantages and disadvantages of each imaging technique. Echocardiography is the first imaging test, but it has several limitations. Therefore, the integration with other imaging modalities (computed tomography, magnetic resonance imaging, nuclear imaging) becomes often necessary. Different strategies should be applied depending on whether the infection is suspected or already ascertained, whether located in native or prosthetic valves, in the left or right chambers, or if it involves an implanted cardiac device. In addition, detection of extracardiac IE-related lesions is crucial for a correct management and treatment. The aim of this review is to illustrate strengths and weaknesses of the various methods in the most common clinical scenarios

Knowledge on cognitive ageing, ageism and affective well-being in professionals working with older people

Istraživanja u području kognitivnog starenja sve više naglašavaju važnost ispitivanja stereotipa o starijim osobama, tzv. ageizam, kod stručnjaka u skrbi za starije. Prisutnost stereotipa i predrasuda kod stručnjaka u skrbi za starije, može dovesti do neprikladnog tretmana starijih osoba. Nedovoljno poznavanje procesa starenja može značajno doprinijeti stvaranju i razvoju ageizma. Također, nepoznavanje domene rada dovodi do smanjene percepcije dobrobiti na poslu, dok bolje poznavanje domene rada doprinosi smanjenju stresa na radnom mjestu. Ovim smo radom željeli ispitati razinu znanja o dobnim promjenama pamćenja, izražavanje ageizma, te afektivnu dobrobit na poslu kod stručnjaka u skrbi za starije osobe (N = 128), te međusoban odnos ispitivanih varijabli. U on-line ispitivanju sudionici su ispunili Upitnik znanja o dobnim promjenama pamćenja (KMAQ), Fraboni skalu ageizma (FSA) i Skalu afektivne dobrobiti na poslu (JAWS). Rezultati su analizirani s obzirom na specifične karakteristike sudionika (dob, zanimanje, skrb o starijem članu obitelji). Stručnjaci pokazuju umjereno znanje o dobnim promjenama pamćenja, izražavaju blago negativne stavove prema starijima i izvještavaju o prevladavajućim ugodnim emocijama u radu sa starijima. Liječnici pokazuju značajno više znanja o dobnim promjenama pamćenja u odnosu na ostale djelatnike obuhvaćene ispitivanjem, a stariji stručnjaci iskazuju značajno više razine izbjegavanja, kao aspekta ageizma, od ostalih sudionika. Također, stariji stručnjaci iskazuju višu razinu ugodnih i nižu razinu neugodnih emocija u odnosu na svoj radni kontekst. Izbjegavanje je pozitivno povezano s nižim znanjem o dobnim promjenama pamćenja, a stereotipi i diskriminacija s emocionalnom dobrobiti na radnom mjestu. Rezultati su interpretirani u skladu s hipotezom kontakta i teorijom upravljanja strahom.Cognitive aging research is ever more stressing the importance of examining ageist stereotypes in senior care professionals. Ageism in senior care professionals may lead to inappropriate treatment of the elderly. Inadequate knowledge of the aging process can significantly contribute to the creation and development of ageism. Also, lack of work-related knowledge might result in the reduction in perceived job-related well-being, while more knowledgeable professionals seem to experience higher satisfaction and less stress in their professional context. In this study, we examined the level of knowledge about memory aging, ageism and affective job-related well-being in professionals working with elderly (N = 128) and the relation between these variables. Using an on-line form, participants filled in the Knowledge of Memory Aging Questionnaire (KMAQ), Fraboni Ageism Scale (FSA) and Job-related Well-being Scale (JAWS). The results were analyzed with regard to the participants’ characteristics (age, occupation, care of the older family member). Professionals in this study show average knowledge of memory aging, express average levels of ageism, and mostly perceive the positive affect related to their job. Medical doctors show significantly higher levels of knowledge in comparison to other vocations. Older participants express higher levels of avoidance of the elderly, as an aspect of ageism. In terms of job-related affectivity, older participants express higher levels of positive and lower level of negative emotions. Avoidance is correlated with lower levels of memory aging knowledge, while stereotypes and discrimination are correlated with job-related affective well-being. The results are discussed in terms of contact hypothesis and terror management theory

Knowledge on cognitive ageing, ageism and affective well-being in professionals working with older people

Istraživanja u području kognitivnog starenja sve više naglašavaju važnost ispitivanja stereotipa o starijim osobama, tzv. ageizam, kod stručnjaka u skrbi za starije. Prisutnost stereotipa i predrasuda kod stručnjaka u skrbi za starije, može dovesti do neprikladnog tretmana starijih osoba. Nedovoljno poznavanje procesa starenja može značajno doprinijeti stvaranju i razvoju ageizma. Također, nepoznavanje domene rada dovodi do smanjene percepcije dobrobiti na poslu, dok bolje poznavanje domene rada doprinosi smanjenju stresa na radnom mjestu. Ovim smo radom željeli ispitati razinu znanja o dobnim promjenama pamćenja, izražavanje ageizma, te afektivnu dobrobit na poslu kod stručnjaka u skrbi za starije osobe (N = 128), te međusoban odnos ispitivanih varijabli. U on-line ispitivanju sudionici su ispunili Upitnik znanja o dobnim promjenama pamćenja (KMAQ), Fraboni skalu ageizma (FSA) i Skalu afektivne dobrobiti na poslu (JAWS). Rezultati su analizirani s obzirom na specifične karakteristike sudionika (dob, zanimanje, skrb o starijem članu obitelji). Stručnjaci pokazuju umjereno znanje o dobnim promjenama pamćenja, izražavaju blago negativne stavove prema starijima i izvještavaju o prevladavajućim ugodnim emocijama u radu sa starijima. Liječnici pokazuju značajno više znanja o dobnim promjenama pamćenja u odnosu na ostale djelatnike obuhvaćene ispitivanjem, a stariji stručnjaci iskazuju značajno više razine izbjegavanja, kao aspekta ageizma, od ostalih sudionika. Također, stariji stručnjaci iskazuju višu razinu ugodnih i nižu razinu neugodnih emocija u odnosu na svoj radni kontekst. Izbjegavanje je pozitivno povezano s nižim znanjem o dobnim promjenama pamćenja, a stereotipi i diskriminacija s emocionalnom dobrobiti na radnom mjestu. Rezultati su interpretirani u skladu s hipotezom kontakta i teorijom upravljanja strahom.Cognitive aging research is ever more stressing the importance of examining ageist stereotypes in senior care professionals. Ageism in senior care professionals may lead to inappropriate treatment of the elderly. Inadequate knowledge of the aging process can significantly contribute to the creation and development of ageism. Also, lack of work-related knowledge might result in the reduction in perceived job-related well-being, while more knowledgeable professionals seem to experience higher satisfaction and less stress in their professional context. In this study, we examined the level of knowledge about memory aging, ageism and affective job-related well-being in professionals working with elderly (N = 128) and the relation between these variables. Using an on-line form, participants filled in the Knowledge of Memory Aging Questionnaire (KMAQ), Fraboni Ageism Scale (FSA) and Job-related Well-being Scale (JAWS). The results were analyzed with regard to the participants’ characteristics (age, occupation, care of the older family member). Professionals in this study show average knowledge of memory aging, express average levels of ageism, and mostly perceive the positive affect related to their job. Medical doctors show significantly higher levels of knowledge in comparison to other vocations. Older participants express higher levels of avoidance of the elderly, as an aspect of ageism. In terms of job-related affectivity, older participants express higher levels of positive and lower level of negative emotions. Avoidance is correlated with lower levels of memory aging knowledge, while stereotypes and discrimination are correlated with job-related affective well-being. The results are discussed in terms of contact hypothesis and terror management theory

Stronger response of farmland birds than farmers to climate change leads to the emergence of an ecological trap

Climate change is triggering adaptation by people and wildlife. The speed and magnitude of these responses may disrupt ecological equilibria and potentially cause further biodiversity losses, but this has rarely been studied. Species inhabiting human-dominated landscapes may be particularly negatively affected by human adaptations to climate change. This could be, for example, the case of ground-nesting farmland birds, a group of highly vulnerable species that may be impacted by shifts in the timing of mechanical farming operations in response to climate change. Here we aim to explore whether trends in phenology of breeding ground-nesting birds differ from those of farming practices, and whether differences lead to the emergence of phenological mistiming with detrimental consequences to the birds. To achieve our objective, we tan linear mixed effects models using a 38 year dataset on onset of farming practices (i.e. sowing dates) and laying date of two endangered ground-nesting farmland birds (Northern lapwing and Eurasian curlew) in Finland. We found that timing of farming practices advanced slower than birds nesting phenology, with birds progressively starting nesting before fields are sown. These nests are at high risk of destruction from incoming sowing operations. The results highlight the importance of considering human adaptation responses, in addition to those of wildlife, for implementing species conservation in managed landscapes under climate change.Peer reviewe