By examining continuous data from the Poker Flat Incoherent Scatter Radar (PFISR) in Poker Flat, Alaska, short-lived enhancements in the F-region ion temperature, or "Tᵢ spikes", were discovered in the evening while the radar was on the equatorward edge of the high latitude convection region. These enhancements were several hundred Kelvin above the background temperature, would last less than 15 minutes and were preceded by sharp depletions in plasma density (of roughly one half). Though they were mostly detected in the summer, 25 events throughout a whole year of data were identi ed in which the spike occurred within 1.5 hours of the density drop. By examining the location of PFISR at the time of the enhancements, as well as the conditions under which these spikes occurred, it was concluded that these enhancements were the result of electric elds increasing the frictional heating between ions and neutrals. By then examining geophysical data, it was found that these events were temporal and related to changes in magnetic indices. One possible explanation for the observations is that the electric eld is at its strongest near the plasmapause during substorms. Another more likely possibility is that during substorms the region of sunward ion convection expands into a region in the evening side where the neutral gas moves in a direction opposite to the ions, thereby enhancing the frictional heating rate.

Titel: Mellanchefens väg till arbetstillfredsställelse - En kvalitativ studie om hur arbetsdelegering, arbetsbeslutsgrad och arbetstillfredsställelse påverkar varandra sett från  mellanchefens perspektiv. Nivå: C-uppsats inom ämnet företagsekonomi Författare: Jacob Kjessler och Joakim Delking Handledare: Signe Jernberg och Kristina Mickelsson Datum: 2018 - maj Syfte: Inom företag finner vi mellanchefer, en anställd som befinner sig i mitten av organisationen med ledning och styrelse ovanför sig och anställda under sig. Krav ställs på dessa mellanchefer att arbeta effektivt med hög produktivitet där många beslut behöver fattas. Detta kan medföra att mellanchefer uppfattar en hög press i form av att arbeta hårt med brist på resursen tid och mellanchefer behöver arbeta effektivt för att klara av det dagliga arbetet vilket de kan göra genom deras höga arbetsbeslutsgrad. Denna höga press på effektivitet, produktivitet samt hög arbetstid kan medföra en minskning av mellanchefens arbetstillfredsställelse. För att hantera denna press med begränsade tidsresurs finns ledarskapsverktyget arbetsdelegering. Arbetsdelegering till underordnade gör att mellanchefer kan ge ifrån sig auktoritet och kontroll att utföra uppgifter, vilket har en effekt på att mellanchefens arbetstid frigörs. Med detta sagt finner vi tre begrepp, arbetstillfredsställelse, arbetsbeslutsgrad samt arbetsdelegering som är relaterade med varandra men vi vet inte hur de påverkar varandra. Hur dessa begrepp påverkar varandra kan bana väg för hur mellanchefer kan använda sig av dessa begrepp för att nå en hög arbetstillfredsställelse, inneha en välbalanserad arbetsbeslutsgrad samt arbeta effektivt med delegering. För att förstå detta ställer vi oss frågan; Hur påverkas arbetsbeslutsgraden när delegering av arbetsuppgifter till underordnade sker, påverkar även denna delegering mellanchefens arbetstillfredsställelse samt om fallet är så att delegering påverkar arbetsbeslutsgraden, kan arbetstillfredsställelsen påverkas också? Detta mynnar ut i ett syfte där denna studie vill skapa en fördjupad förståelse hur dessa begrepp påverkar varandra; Arbetstillfredsställelse Arbetsbeslutsgrad Arbetsdelegering till underordnade  Metod: För att göra denna studie möjlig har vi utfört 11 kvalitativa semistrukturerade intervjuer. Vi skapade ett urval med hjälp av strategiskt urval som grundar sig i vissa kriterier som vi tror våra respondenter behöver ha för att skapa ett resultat som hjälper oss att finna hur dessa begrepp påverkar varandra. Resultat och Slutsats: Vi fann hur arbetsdelegering och arbetsbeslutsgrad påverkar varandra, samtidigt som dessa två begreppet påverkar varandra fann vi att högre frekvent användning av arbetsdelegering positivt påverkar mellanchefens arbetstillfredsställelse. Då arbetsdelegering minskar arbetsbeslutsgrad fann vi även att den minskade arbetsbeslutsgraden även påverkar arbetstillfredsställelsen positivt. Uppsatsens bidrag: Mellanchefers arbetstillfredsställelse har tidigare inte behandlats inom företagsekonomin. Vi ger därför företagsekonomin en teoretisk insikt i hur arbetstillfredsställelse, arbetsbeslutsgrad samt arbetsdelegering påverkar varandra. Dock på grund av den begränsade forskningen inom detta område ger vi en första inblick sett från mellanchefers synsätt. Förslag på fortsatt forskning: Vi har sammanfattat fyra punkter som förslag till ytterligare forskning. Först anser vi att ytterligare studier behöver genomföras för att styrka vår slutsats, där studier som använder sig av fler respondenter är i fokus. Andra förslaget kretsar kring denna studies synsätt, då vi endast utgått från mellanchefers perspektiv behöver detta kompletteras med fler perspektiv från underordnade och överordnade. Tredje förslaget inkluderar ett mönster vi såg under intervjuerna, teorin menar att mer erfarenhet också kommer resultera i att mellanchefer använder sig utav arbetsdelegering mer frekvent. Detta vad dock inget vi kunde se under våra intervjuer, därför anser vi att fortsatt forskning inom området hur erfarenheten hos mellanchefer påverkar deras sätt att se på arbetsdelegering. Sista och fjärde förslaget innebär vad kontroll och auktoritet över en uppgiften egentligen är? Nyckelord: Arbetsbeslutsgrad, arbetsbelastning, arbetstillfredsställelse, mellanchefer, arbetsdelegering. / Title: The Middle level managers road to job satisfaction - A qualitative study of how job delegation, job decision latitude and job satisfaction affect eachother, from a middle level managers perspective. Level: Final assignment for Bachelor Degree in Business Administration Author: Jacob Kjessler and Joakim Delking Supervisor: Signe Jernberg and Kristina Mickelsson Date: 2018– May Aim: Within companies we find the middle level managers, located in the middle of the organization with managers above them, as well as employees underneath. Requirements are made on these middle level managers to work efficiently with high productivity, where many decisions need to be made. This may cause middle managers to perceive high pressure in terms of working hard with lack of resource time, middle managers need to work effectively to cope with daily work, which can be summed up as high levels of job decision latitude. This high pressure on efficiency, productivity and high working hours can lead to a reduction of the mid-career's job satisfaction. To manage this press with limited time resources, the leadership tool delegation could be an option. Subordination of work to subordinates allows middle level managers to give authority and control to perform tasks, which has the effect of releasing the mid-term working hours. Having said that, we find three concepts, job satisfaction, job decision latitude, and job delegation that seem to coincide with each other, but we do not know how they affect each other. How these concepts affect each other can pave the way for middle level managers to use these concepts to achieve high job satisfaction, maintain a well-balanced job decision latitude, and see benefits of job delegation. In order to understand this, we ask ourselves the question; How does job decision latitude affect when delegation of duties to subordinates takes place, does this delegation affect the middle level managers job satisfaction, and if the case is such that delegation affects the level of job decision latitude, can job satisfaction also be affected? This opens up for a aim in which this study wants to create an in-depth understanding of how these concepts affect each other; Job satisfaction Employment Decisions Degree Work delegation to subordinates Method: In order to make this study possible we have conducted 11 qualitative semistructured interviews. We created a selection using strategic selection based on certain criteria that we believe our respondents need to create a result that helps us find out how these concepts affect each other. Result & Conclusions: We found how job delegation and job decision latitude affect each other. While these two concepts affect each other, we found that higher frequent use of job delegation positively affects the middle level managers job satisfaction. As labor delegation reduces the level of workability we also found that the reduced job decision latitude also has a positive impact on job satisfaction. Contribution of the thesis: Middle level managers job satisfaction has previously not been addressed in the business administration. We therefore give the business economics a theoretical insight into how job satisfaction, job decision latitude and work delegation affect each other. However, due to the limited research in this area, we provide a first insight from the middle level managers approach. Suggestions for future research: We have summarized three points as suggestions for further research. First, we consider that further studies need to be conducted to reinforce our conclusion, where studies that use more respondents are in focus. The second proposal focuses on this study approach, since we only started from the middle managers perspective, we ask further studies to include more perspectives from subordinates and superiors. The third suggestion includes a pattern we saw during the interviews, the theory means that more work experience will also affect how much middle managers uses job delegation as a management tool. This, however was nothing we could see during our interviews, we therefore believe that further research in the field should be made of how the experience of middle managers affects their way of looking at work delegation. The last and fourth proposals mean what control and authority over a task really is? Key words: Job Decision Latitude, Job Demands, Job Satisfaction, Middle level manager, Job Delegation.

Comparisons between countries around the globe reported since 1999 reveal that nations’ wealth consistently increases with distance from the Equator. Is Peru’s territory exempt from this trend? This study used GPS coordinates, questionnaire data, climate files, and census information from the 2000 Peru Demographic and Health Survey, Climate Wizard, and G-Econ data sets toreconcile the contradictory national evidence and understand the role of certain geophysical and social variables. Household assets increase from north to south in the Brack ecological regionswith latitudinal orientation which were studied (Desert, Puna, Yunga, Amazon), especially in rural settings, and as does women’s education, except in the Amazon. Neither temperature nor fourteen other geophysical and social variables account for such effects, though women’s domestic power explains them in the Yunga ecoregion. The findings can be understood through two theoretical perspectives: one, according to the evolutionary theses of Lynn, Rushton, and Kanazawa, suggests the genetic fixation of differential intellectual levels caused by an ancestral adaptation of Peruvian to various conditions of climate and altitude. The other, combining what is known about ultraviolet radiation, vitamin D, and production of sexual hormones with Zajon’sconfluence theory, is defined by fertility rate and the consequent intellectual home environment for the child. Both predict the increment of IQ and educational PISA scores from north to south Peru, but one points toward education and the other to family planning as human development strategies. / Resultados de comparaciones reportadas entre países alrededor del globo desde 1999 indican quela riqueza de las naciones crece consistentemente con la distancia a la línea ecuatorial. ¿Está el territorio peruano exento de esta tendencia? Para reconciliar la contradictoria evidencia nacional y entender el rol de ciertos factores geofísicos y sociales, este estudio utilizó coordenadas GPS, datos de cuestionarios, archivos de clima, e información censal existentes en varias bases de datos(Encuesta Demográfica y de Salud Perú 2000, Climate Wizard, G-Econ). Los activos del hogar crecen de norte a sur en las regiones ecológicas de Brack de orientación latitudinal estudiadas (desierto, puna, yunga, Amazonía), especialmente en ámbitos rurales, y la educación de la mujer lo hace en las tres primeras. Ni la temperatura ni otras 14 variables geofísicas y sociales dan cuenta de los efectos, aunque el poder doméstico de la mujer los explica en la ecoregión Yunga. Los resultados pueden entenderse en dos perspectivas teóricas. Una, acorde con las tesis evolucionistas de Lynn, Rushton y Kanazawa, sugiere la fijación genética de niveles intelectuales diferenciales producidos por una adaptación ancestral de los peruanos a distintas condicionesde clima y altura. La otra, combinando lo que se conoce sobre radiación ultravioleta, vitamina D, y producción de hormonas sexuales con la teoría de la confluencia de Zajonc, se define por la tasa de fertilidad y consecuente ambiente intelectual hogareño para el niño. Ambas predicen el incremento del cociente intelectual y los puntajes educativos PISA del norte al sur peruanos, pero de una se desprende la educación y de la otra la planificación familiar como estrategias promotoras de desarrollo humano.

Suicide is a serious public health problem around the world. Each year, approximately 800.000 people complete suicide and it is estimated that for each suicide committed, there must be another 20 attempts. Differences have been reported between individuals who attempted suicide and those who committed suicide. These tend to be male, older, less impulsive, using more lethal methods, leave suicidal note and are more depressed. The attempters tend to be female and use a non-violent method, such as poisoning. Despite these differences, a seasonal pattern has been described with peak in the spring / summer, but there are divergences in suicide attempts. This lack of consensus allowed us to evaluate through a systematic review if these attempts occur more frequently in the spring / summer as already described for cases of suicide. A seasonal profile similar to the occurrences of suicide was also found for suicide attempts. This seasonal behavior suggests the influence of an environmental modulator, and since light is the main synchronizing agent of the endogenous rhythm with the environment through the light-dark cycle, it is also likely to be an important agent of the circannual / seasonal rhythms. As Brazil is a country with great territorial extension, crossing the Equator line (latitude 0º) and the Tropic of Capricorn (latitude S24°14’), we investigated the influence of latitude and photoperiod in the seasonality of suicides in all Brazilian cities in the period from 2010 to 2015. A seasonal variation of suicides were find with peak in late spring / early summer and nadir in winter. This seasonal profile is better observed as latitude decreases. The further away from latitude 0 °, the higher the suicide rate and amplitude (Peak / Trough ratio), and the in-phase correlation between the seasonality of suicide occurrences and the photoperiod. As several diseases have been associated with disturbances in circadian rhythm, this environmental modulation of the circadian rhythm may play a relevant role in the formation of seasonal suicidal behavior in individuals with vulnerability. In animals, the manipulation of the photoperiod, simulating seasons, results in changes in the gene expression and behavioral profile. We studied, in C57BL / 6J mice, the effect of the photoperiod gradual variation, a simulation from winter to summer, to observe the molecular effect in brain structures related to human suicide and behavioral changes. A significant decrease in circadian gene expression and loss of rhythmicity were found, in addition to an antidepressant-like behavior in the forced swimming test. The photoperiodic influence observed in animal models associated with seasonal suicide reports only in countries distant from 0º latitude, where there are significant alterations in the photoperiod, reinforce the participation of light as an important modulator of the seasonality of suicidal behavior. / O suicídio é um grave problema de saúde pública em todo o mundo. A cada ano, aproximadamente 800.000 pessoas cometem suicídio e estima-se que para cada suicídio cometido, deve haver outras 20 tentativas. Foram relatadas diferenças entre indivíduos que tentaram suicídio e aqueles que consumaram o suicídio. Estes que consumaram tendem a ser do sexo masculino, mais velhos, menos impulsivos, usando métodos mais letais, deixam nota de suicídio e são mais deprimidos. Aqueles que tentam e não efetivam o suicídio, tendem a ser do sexo feminino e utilizam método não-violento, como o envenenamento. Apesar dessas diferenças, um padrão sazonal tem sido descrito com pico na primavera/verão, mas há divergências nas tentativas de suicídio. Esta ausência de consenso nos permitiu avaliar através de uma revisão sistemática, se essas tentativas ocorrem com maior frequência na primavera/verão assim como já descrito para os casos de suicídio. Um perfil sazonal semelhante às ocorrências de suicídio foi encontrado também para tentativas de suicídio. Este comportamento sazonal sugere a influência de um modulador ambiental, e como a luz é o principal agente sincronizador do ritmo endógeno com o ambiente através do ciclo claro-escuro, é provável que também seja um importante agente dos ritmos circanuais/sazonais. Como o Brasil é um país com grande extensão territorial, atravessando a linha do Equador (latitude 0º) e o Trópico de Capricórnio (latitude S24°14’), investigamos a influência da latitude e fotoperíodo na sazonalidade dos suicídios em todas as cidades brasileiras no período de 2010 a 2015. A variação sazonal dos suicídios teve pico no final da primavera/início do verão e nadir no inverno. Este perfil sazonal é melhor observado à medida que decresce a latitude. Quanto mais distante da latitude 0º, maiores as taxas de suicídio e amplitude (razão pico/vale), além de correlação em fase entre a sazonalidade das ocorrências de suicídio e o fotoperíodo. Assim como várias doenças têm sido associadas a perturbações no ritmo circadiano, esta modulação ambiental do ritmo circadiano pode ter papel relevante na formação do comportamento suicida sazonal em indivíduos com vulnerabilidade. Em animais, a manipulação do fotoperíodo, simulando estações do ano, resulta em alterações no perfil de expressão gênica e comportamental. Estudamos em camundongos C57BL/6J, o efeito da variação gradual do fotoperíodo, simulando do inverno ao verão em curto tempo, para observar o efeito molecular em estruturas cerebrais relacionadas ao suicídio em humanos e alterações comportamentais. Uma redução importante e perda de ritmicidade em genes circadianos foi encontrada, além de um efeito tipo antidepressivo no teste do nado forçado. A influência fotoperiódica observada em modelos animais associada a relatos de sazonalidade do suicídio apenas em países distantes da latitude 0º, onde há alterações significativas no fotoperíodo, reforçam a participação da luz como um importante modulador da sazonalidade do comportamento suicida.

Samhället utmanas idag av många svårlösta problem som bland annat hur vi ska klara vård och omsorg samt den arbetslöshet som gör det svårt för ungdomar att etablera sig på arbetsmarknaden. Ansvaret för insatser på välfärdsområdet vilar på landsting och kommuner. De barn och ungdomar som har svårigheter med att klara målen i skolan riskerar att hamna i utanförskap som vuxna. Syftet med studien var att undersöka hur specialpedagogers och speciallärares handlingsutrymme ser ut i arbetet med elever som riskerar att hamna i utanförskap. Den kvalitativa studien genomfördes med semistrukturerade intervjuer. Materialet till studien, baserades på specialpedagogers och speciallärares erfarenheter, svaren utvärderades med tematisk analys. Det analyserade materialet kopplades till tidigare forskning, handlingsteorin och den ekologiska utvecklingsteorin. Vår slutsats blev att handlingsutrymmet påverkas av såväl kreativitet och kunskap som tid och ekonomi men viktigaste faktorn är ledningens vilja och engagemang, det är de som har makten. / The society today is challenged with many difficult issues, such as how to manage health and social care, and the unemployment that makes it difficult for young people to establish themselves in the labor market. The responsibility for welfare initiatives rests on county councils and municipalities. The children and adolecents who are having difficulty in achieving the goals in school are likely to end up in alienation. The purpose with this study was to investigate the latitude of special educateors and special teachers in their work with pupils at risk of alienation. The qualitative study was conducted with semistructured interviews. The material for the study was based on the experiences of special educators and special teachers, the answers was evaluated with thematic analysis. The analyzed material was linked to previous research, action theory and the ecological systems theory. Our conclusion was that the latitude is affected by creativity and knowledge as well as time and finances, but the most crucial factor is the will and commitment of management, those who have the power.

Abstract Deciduous shrubs form the tallest type of vegetation in arctic-alpine areas and are important for ecosystem function. In the southern part of the Eurasian tundra zone, willows (Salix spp.) are the most common species in the shrub layer. In the alpine areas of Northern Fennoscandia, willow shrubs are characteristic to areas between tree line and treeless tundra heaths. Vertical structure and composition of willow-characterized tundra vegetation is affected by a variety of ecological factors including climate and herbivory. In turn, the abundance of the willow canopy affects understory species in several ways that still remain inadequately understood. In this PhD work I describe compositional differentiation of willow-characterized vegetation by using a large data set spanning from north-western Fennoscandia to the Yamal Peninsula in north-western Siberia. I studied environmental factors affecting willow-characterized vegetation and willow growth by using correlative analyses. The factors under investigation were latitude, distance from the sea, depth of thaw, position in the slope, industrial disturbance and reindeer grazing. In addition, I examined the relationships between the shrub biomass estimate and composition and species richness of understory vegetation. The effects of reindeer grazing on vegetation in an alpine forest-tundra ecotone were studied experimentally using reindeer-proof exclosures. I found that willow-characterized vegetation is floristically variable and comprises at least eight vegetation types. The most abundant willow thickets typically have a forb-rich understory. The growth of willow increased along with increasing summer temperatures. However the height of willow was more determined by distance from the sea, thaw depth and slope position. Reindeer grazing decreased the abundance of willow and changed the composition of understory vegetation. In addition, industrial activities were detected to have destructed shrub vegetation and turned it into graminoid-dominated vegetation. Shrub canopies facilitated forbs but decreased the cover of all the other groups including dwarf shrubs, bryophytes and lichens. The species richness of vegetation decreased along with increasing shrub abundance. My study shows that arctic-alpine willow vegetation is more diverse than previously thought. There is a predictable relationship between summer temperatures and willow growth. However, the results also show that there are many factors, both physical and anthropogenic, that are likely to complicate this pattern. Most important of these counteracting effects are industrial activities and reindeer grazing. In the areas where shrubs grow in abundance, the species richness of understory vegetation is likely to decrease and forbs are likely to replace other tundra species.

The objective of the diploma thesis is to design a device for positioning of mobile devices using GPS satellites. When coordinates are acquired they can be sent via the GSM network to a user's cell phone or to an SQL server. A web interface has been designed to access the stored data and to show the current device position and the history. This position datalogging system can be used for monitoring vehicles as well as a security system for cars.

The terrestrial carbon cycle is a part of the global carbon cycle, where one important component is the terrestrial vegetation. Terrestrial vegetation largely controls the land surface carbon exchanges and leverage the atmospheric greenhouse gas concentrations, significantly affecting the trajectory of global warming. It is therefore important to improve the understanding of vegetation response to different climatic factors, in particular for those linked to large-scale climate variability, which is still less studied so far. Vegetation greenness is suggested to be a useful tool in order to understand vegetation response. Looking at Europe, the climate factors that affect vegetation the most are linked to the large-scale atmospheric circulation over the North Atlantic, like the jet stream, which varies in speed and latitude, and the North Atlantic Oscillation (NAO). Here, I compute monthly indices representing the variability of these atmospheric features, and correlate them with monthly vegetation greenness data (NDVI) anomalies over a period of five years. This is done both for regionally-averaged NDVI and the months April-July and as a geographical point-by-point analysis for the month of May. The results show a significant correlation between Scandinavian NDVI and the NAO as well as jet speed at multiple time lags, up until 2 months. The jet latitude, instead, showed significant correlation for three regions in mid/southwestern Europe at longer time lags of 3-4 months. This means that the position of the jet in winter can affect the spring vegetation growth in this area. The jet speed and NAO, however, works mostly at shorter timespans. / Den jordbunda kolcykeln, som är en del av den globala kolcykeln, består av olika komponenter där en viktig del är vegetation. Växtlighet på land kontrollerar till stor del utbytet av kol vid jordytan och har därigenom inflytande på atmosfäriska växthusgaskoncentrationer, vilket medför stor påverkan på global uppvärmning. Det är därför viktigt att förbättra förståelsen för hur vegetation reagerar på olika klimatologiska faktorer, särskilt de som är kopplade till storskalig klimatvariabilitet då dessa kopplingar har studerats i mindre utsträckling hittils. Ett bra sätt att mäta den jordbunda kolcyklen på är med grönhet av vegatation. Om vi beaktar Europa så är det främst storskaliga atmosfäriska cirkulatoiner över norra Atlanten av de klimatologiska faktorerna som påverkar vegetation. En av dessa faktorer är jetströmmen, vilken varierar i fart och latitud, samt Nordatlantiska Oscillationen(NAO). I detta arbete beräknar jag index som representerar variationen i dessa i form av månadsgenomsnitt och korrelerar dem med månatlig data över avvikelser i vegetationsgrönhet (NDVI) över en femårsperiod. Det här gjordes för både regionala medelvärden och månaderna april-juli samt en geografisk punkt till punkt analys utförd för maj. Resultatet visar att det finns en signifikant korrelation mellan NDVI i Skandinavien och NAO samt jetfarten vid flera tidsfördröjningar, upp till 2 månader. Jetlatituden visade däremot signifikant korrelation för tre regioner i centrala/sydvästa Europa vid längre tidsfördröjningar på 3-4 månader. Detta innebär att positionen på jetströmmen under vintern kan påverka vegetationstillväxten under våren i detta område. Jetfarten och NAO påverkar däremot mest vid kortare tidsspan.

Department of Ecology an Resource Management / MENVSC

Detailed study of the spatial correlations of day-to-day ionospheric TEC variations on a global scale was performed for four 30-day-long periods in 2004 (January, March/April, June/July, September/October) using observations from more than 1000 ground-based GPS receivers. In order to obtain the spatial correlations, initially, the day-to-day variability was calculated by first mapping the observed slant TEC values for each 5-minute GPS ground receiver-satellite pair to the vertical and then differencing it with its corresponding value from the previous day. This resulted in more than 150 million values of day-to-day change in TEC (delta TEC). Next, statistics were performed on the delta TEC values. The study indicates strong correlationsbetween geomagnetic conjugate points, and these correlations are larger at low latitudes than at middle latitudes. Typical correlation lengths, defined as the angular separation at which the correlation coefficient drops to 0.7, were found to be larger at middle latitudes than at low latitudes. The correlation lengths are larger during daytime than during nighttime. The results indicate that the spatial correlation is largely independent of season. These spatial correlations are important for understanding the physical mechanisms that cause ionospheric weather variability and are also relevant to data assimilation. In an effort to better understand the effects of neutral wind and electric field on the TEC variability, a physics-based numerical Ionosphere/Plasmasphere Model (IPM) was used. The model solves the transport equations for the six ions, O+, NO+, O2+, N2+, H+, and He+, on convecting flux tubes that realistically follow the geomagnetic field. Two of the inputs required by the IPM are the thermospheric neutral wind and the low-latitude electric field, which can be given by existing empirical model or externally specified by the user. To study the relative importance of the neutral wind and the electric field for the TEC variations, these two model inputs were externally modified and the resulting variations in TEC were compared. Neutral wind and electric field modifications were introduced at three different local times in order to investigate the effect of different start times of the imposed perturbations on TEC. This study focused on modeled low- and middlelatitude TEC variations in the afternoon and post-sunset at three different longitude sectors for medium solar activity and low geomagnetic activity. The largest changes in TEC were found predominantly in the equatorial anomaly, and a significant longitudinal dependence was observed. The results indicate that the perturbation effect on the TEC at 2100 LT varied nonlinearly with the elapsed time after the imposed neutral wind and electric field perturbations. An important outcome of this study is that daytime neutral wind and/or electric field modifications will lead to essentially identical TEC changes in the 2100 local time sector.