L'objectif est d'évaluer sur le plan agro-climatique les options de réalisation d'une culture de printemps dans les hautes vallées du Nord du Vietnam. A partir d'hypothèses sur les contraintes agro-climatiques s'exerçant sur ces options, un modèle de simulation et le dispositif expérimental permettant de le caler et de l'évaluer ont été élaborés. Une expérimentation virtuelle replaçant les cultures de printemps envisagées (riz, riz « aérobie », maïs et soja) dans le climat de trois régions contrastées sur ce plan a ensuite été réalisée, le long d'un gradient d'altitude, et sous différentes modalités techniques, notamment de dates de semis. Cette démarche a été appliquée successivement aux deux grands cas de figure rencontrés dans les montagnes : irrigation des parcelles dès le printemps, et conduite en régime pluvial (irrigation praticable seulement pour le cycle estival). Elle a conduit à identifier, pour chacun de ces cas de figure et chacune des régions et cultures étudiées des fenêtres de semis favorables, intervalles de dates de semis pour lesquelles la culture de printemps présente peu de risques. La taille de cette fenêtre constitue ainsi un indicateur synthétique de la contrainte climatique pour une culture donnée dans un lieu donné : plus cette fenêtre est étroite, plus on peut s'attendre à ce qu'il soit délicat pour les producteurs de pratiquer la culture. Les résultats confirment clairement que même lorsque l'eau d'irrigation est abondante, le climat des montagnes du Vietnam ne permet pas partout de pratiquer une culture de printemps. Les risques identifiés sont la destruction par le froid pendant les stades précoces de la croissance végétative, l'allongement du cycle au-delà de la date où le riz irrigué d'été doit être installé selon la pratique actuelle, l'obtention de rendements nettement abaissés du fait de la faiblesse du rayonnement global et des températures pendant la première partie de la saison. Pour ce contexte irrigué, la culture qui échappe le mieux à ces contraintes dans les simulations est le soja, suivie du maïs et du riz conduit en semis en plein champ. Le riz semé en pépinière et repiqué est apparu comme le plus sensible aux contraintes de températures.En conditions pluviales, la culture de printemps est nettement plus délicate tout particulièrement à cause des retards de levée et des stress hydriques pendant la phase de croissance végétative liés aux faibles précipitations de début de saison. Le soja reste la culture pour laquelle la contrainte de durée de cycle est la plus faible, mais son rendement simulé est fortement réduit par les stress hydriques. Le riz « aérobie » et le maïs sont des options envisageables en conditions strictement pluviales aux altitudes relativement modestes dans tous les climats étudiés. La géographie de l'extension des cultures de printemps au Vietnam est ainsi esquissée. Des perspectives de recherche sont proposées en vue d'accroître cette aire d'extension. Outre ces acquis importants pour l'agriculture locale, cette thèse confirme l'intérêt et l'efficacité d'une approche de modélisation ad hoc pour ce type de question agro-climatique. / The goal of this thesis was to assess the agro-climatic feasibility of introducing a supplementary crop during the spring season in the high valleys of the mountainous northern Vietnam. From hypotheses drawn about the way climate constrained such crops, a simulation model and the experimental device required for calibrating and evaluating it were elaborated. A virtual experiment was carried out in order to submit the candidate crops (rice, “aerobic rice”, maize and soybean) under the contrasted climates of three regions, along the elevation gradient and under several technical management, especially sowing dates. This approach was applied consecutively to the two major cases occurring in these mountains: crop irrigated during the whole spring, and rainfed crop (land irrigable during summer only). This approach led to identify, for each of these two cases and for each of the studied regions and crops, favourable sowing windows, i.e. intervals of sowing dates for which the risks associated to spring crop are low. The size of such windows provides a synthetic indicator of the climatic constraint for a given crop at a given place: the narrower the window, the more difficult it is expected to be for farmers to practice the option.Results clearly confirmed that even if irrigation water is abundant, the climate of the mountains in Vietnam does not allow practicing the spring crop everywhere. The risks that were identified were crop destruction by lethally cold temperature during early vegetative stages, maturity delayed beyond the date at which the irrigated rice of summer must have been sown according to current practice, and obtaining yield neatly decreased due to low global radiation and temperature during the first half of the season. Under irrigated conditions, the simulated crop that best escaped these constraints was soybean, followed by maize and direct seeded rice. Rice sown in nurseries and transplanted showed more sensitive to temperature constraints.Spring crop showed strongly trickier under rainfed conditions, especially due to delays in seedlings emergence and water stresses during vegetative growth, in relation with low rainfall during the early part of the season. Soybean remained the crop with the shortest duration, but its simulated yield was strongly reduced by water stresses. “Aerobic rice” and maize were possible options under fully rainfed regime at relatively low elevations only, under any of the regional climates studied. Thus, the feasibility area of spring crops was thus sketched. Research perspectives were proposed, aiming at increasing this area. Additionally to these results, targeted at serving local agriculture, this work confirmed the value and effectiveness of an ad hoc modelling approach for agro-climatic studies of this kind.

Supply chain management (SCM) practitioners who ship temperature-sensitive diagnostic medical devices (DMDs) to clinicians must use effective cold chain management (CCM) strategies to avoid temperature excursions that contribute to medical device errors. Such errors have caused patient harm and death, which costs the U.S. health care system billions of dollars per year. The purpose of this qualitative multiple case study was to explore strategies for selecting and managing cold chain shipping solutions (CCSSs) requiring SCM executives to trade cost for regulatory compliance and predictability when mitigating temperature variations that occur during shipping. The conceptual framework for the study was the 6-change approaches, and its underpinnings that framed the exploration into the strategies some medical device executives use for shipping temperature-sensitive DMD tests and controls. Data were collected from in-depth interviews, field notes, and existing literature. The target population was 3 SCM executives working in California, New Jersey, and Ireland with at least 5 years of CCM experience in the medical device industry. A purposive sampling procedure guided the selection of participants for in-depth interviews. The data analysis included pattern matching techniques, central analysis, and collapse analysis. The results of this study indicated 3 successful strategies: validation of CCSSs, compliant shipping of DMDs, and CCM best practices. The study was socially significant because the findings may prevent medical device failures that have caused U.S. Food and Drug Administration recalls and patient harm.

Abstract The purpose of the study was to examine the cold-induced effects on pineal and thyroid hormones, as well as the associations of these hormones with psychological performance and to determine how psychological performance could be affected by demographic, anthropometric, physiological or biochemical measures during cold acclimatisation. The feasibility of urinary melatonin (MT), rather than 6-sulphatoxymelatonin (aMT6s), as an indicator of MT secretion was also examined. In the laboratory study, seasonal cold acclimatisation, its effects on hormones and their associations with mood and cognition were assessed in 15 young urban subjects exposed to cold in winter or summer in bright or dim light. In the field study, the associations of mood and cognition with demographic, anthropometric, physiological and biochemical measures were determined in healthy, euthyroid subjects (n = 133) in Antarctica in the beginning and at the end of summer and winter seasons. In both seasons, simple task performance was consistently impaired in the cold in experimental and field conditions. In complex tasks, negative, positive and mixed effects were observed. In the experimental study, serum MT and thyroid hormone levels were positively associated with mood. MT was negatively associated with simple task performance. Free triiodothyronine (T3) and thyrotropin (TSH) had mixed effects on simple task performance. TSH was positively associated with complex task performance. In the field study, higher age was associated with impaired cognition, especially in complex task performance. Total T3 was positively associated with mood and total thyroxine (T4) with complex task accuracy. Both urinary MT and aMT6s were good indicators of MT secretion, but the variation was smaller for MT. In conclusion, the associations of serum MT, TSH and thyroid hormone levels with mood and cognition found in experimental and field conditions are consistent with the psychological changes associated with the onset and consequent stages of the previously established polar T3 syndrome. In the field study, cognition and mood were associated with subject’s age and gender, which seemed to affect the physiological changes during acclimatisation to cold and darkness in Antarctica. / Tiivistelmä Tutkimuksen tarkoituksena oli selvittää kylmäaltistuksen aiheuttamia muutoksia käpy- ja kilpirauhasen hormonien tasoissa, hormonien yhteyttä psyykkiseen toimintakykyyn sekä demografisten, antropometristen, fysiologisten ja biokemiallisten tekijöiden yhteyttä psyykkiseen toimintakykyyn kylmäakklimatisaation aikana. Lisäksi verrattiin virtsan melatoniinin (MT) ja 6-sulfatoksimelatoniinin (aMT6s) soveltuvuutta MT-erityksen kuvaajina. Laboratoriotutkimuksessa selvitettiin talveen liittyvää kylmäsopeutumista, sen vaikutusta hormonitasoihin ja näiden yhteyttä mielialaan ja älylliseen toimintakykyyn 15 nuorella miehellä, jotka altistettiin kylmälle talvella ja kesällä sekä kirkkaassa että hämärässä valossa. Kenttäkokeessa Antarktiksella selvitettiin mielialan ja älyllisen toimintakyvyn sekä demografisten, antropometristen, fysiologisten ja biokemiallisten tekijöiden välistä yhteyttä terveillä henkilöillä (n =  133) kesä- ja talvikauden alussa ja lopussa. Suoriutuminen yksinkertaisista tehtävistä huononi kylmässä kesällä ja talvella sekä laboratorio- että kenttäoloissa. Kylmä vaikutti monimutkaisista tehtävistä suoriutumiseen vaihtelevasti. Laboratoriotutkimuksessa seerumin MT- ja kilpirauhashormonitasot korreloivat positiivisesti mielialan kanssa. MT korreloi negatiivisesti yksinkertaisista tehtävistä suoriutumisen kanssa. Vapaa trijodotyroniini (T3) ja tyrotropiini (TSH) korreloivat vaihtelevasti yksinkertaisista tehtävistä suoriutumisen kanssa. TSH korreloi positiivisesti monimutkaisista tehtävistä suoriutumisen kanssa. Kenttätutkimuksessa korkeampi ikä oli yhteydessä huonontuneeseeen älylliseen toimintakykyyn erityisesti monimutkaisissa tehtävissä. T3:n kokonaismäärä korreloi positiivisesti mielialan ja tyroksiinin (T4) kokonaismäärä monimutkaisista tehtävistä suoriutumisen kanssa. Sekä virtsan MT että aMT6s olivat hyviä MT-erityksen mittareita, mutta MT:ssa vaihtelu oli pienempää. Laboratorio- ja kenttäolosuhteissa havaitut MT:n, TSH:n ja kilpirauhashormonien yhteydet mielialaan ja älylliseen toimintakykyyn vahvistavat aiemmin havaittuja tuloksia polaarisen T3 -oireyhtymän synnystä ja oireyhtymän eri vaiheisiin liittyvistä psyykkisistä muutoksista. Kenttätutkimuksessa mieliala ja älyllinen toimintakyky olivat yhteydessä koehenkilön ikään ja sukupuoleen, jotka puolestaan voivat vaikuttaa fysiologisiin muutoksiin kylmään ilmastoon ja pimeyteen sopeutumisen aikana.

Thyroid hormone (TH) is a critical signalling molecule for all vertebrate organisms, playing an especially crucial role in postembryonic development. Given its importance, many studies have focused on further elucidating the initial TH signal response and its method of transduction. Although the primary mechanism of TH response is genomic signalling, alternative mechanisms of early TH signal transduction have been relatively poorly studied. The North American bullfrog, Rana catesbeiana, is a useful model to study these early responses as tadpole post-embryonic development, or metamorphosis, can be experimentally induced through exposure to TH. The experimental induction of the TH signalling program leads to similar morphological endpoints as seen in natural metamorphosis in the transition of a tadpole to a juvenile froglet, such as regression of the tail. This TH-induced developmental program can also be manipulated through temperature where, as temperatures lower, developmental rate is delayed and at 5°C metamorphosis is completely stalled. Interestingly, when tadpoles exposed to TH at 5°C are introduced to permissive temperatures (24°C), an accelerated developmental program ensues, even when no more endogenous TH signal remains. Previous research has shown that this phenomenon can also be seen on the molecular level where only a select few transcripts have been shown to be responsive to TH at 5°C. However, the characteristic, if not augmented, TH response program is seen on the transcriptomic level when tadpoles are shifted to 24°C. This indicates that there is a molecular memory where the TH signal is induced in cold temperatures but not executed until more permissive temperatures arise. The extent and regulation of the transcriptomic program involved in this TH-induced molecular memory has yet to be understood. Herein we use the broader probing technique of RNA-seq analysis to identify potential components of the molecular memory. Eighty-one gene transcripts were TH-responsive at 5°C in cultured R. catesbeiana tail fin indicating that the molecular memory is more complex than previously thought. A number of these transcripts encoded regulators of transcription. Closer examination of select transcripts including a novel krüppel-like factor family member, klfX, at 5oC indicated that not all of the candidate molecular memory transcripts are regulated through active transcription and active translation is not required. When moved into 24°C an accelerated transcriptomic response occurred even when no additional TH is added, suggesting that a priming event occurs by TH exposure at 5°C allowing an accelerated metamorphosis at permissive temperatures. The molecular memory may be used as a means to isolate the initiating TH signalling response and the regulation of this program to allow further elucidation of early TH signalling in post-embryonic development. / Graduate

Les canaux ASIC3 (« Acid-Sensing Ion Channel 3) sont des canaux ioniques excitateurs qui appartiennent à la famille des ASIC (ASIC1-4). Ils sont activés par une acidose extracellulaire et le proton reste jusqu’à présent leur seul activateur endogène. Les ASIC3 sont notamment exprimés dans les neurones sensoriels périphériques innervant la peau, les muscles, les viscères et les articulations. Ils ont été impliqués dans la détection de différents types de douleur, tels que les douleurs inflammatoires, postopératoires et articulaires. Durant ma thèse, j’ai étudié la régulation des canaux ASIC3 et leur implication dans les perceptions sensorielles et douloureuses. La première partie de mon travail de thèse a permis de mettre en évidence pour la première fois de nouveaux activateurs endogènes des canaux ASIC3, différents des protons. En effet, j’ai pu démontrer que des lipides (i.e., la lysophosphatidylcholine et l’acide arachidonique) présents dans les liquides synoviaux issus de patients souffrants de différentes pathologies articulaires douloureuses, étaient capables d’activer les canaux ASIC3 sans acidification extracellulaire. Ces lipides sont capables de générer un comportement douloureux chez les rongeurs, qui implique au moins en partie les canaux ASIC3. Lors de la seconde partie de ma thèse je me suis intéressé à la régulation des canaux ASIC3 par la température. J’ai pu montrer que ces canaux sont activés par une température froide (i.e., 15°C) à pH physiologique. Ces résultats sont renforcés par des expériences de comportement, in vivo, qui montrent une implication d’ASIC3 dans la perception du froid nocif et non nocif. / Acid-Sensing Ion channel 3 (ASIC3) is a member of the ASIC family (ASIC1-4), which are excitatory ion channels activated by extracellular acidosis. Proton remains so far the unique endogenous activator of ASIC. ASIC3 channels are expressed in peripheral sensory neurons which innervate skin, muscles, viscera and joints. In rodents, they have been reported to be involved in the detection of different types of pain, including inflammatory pain, postoperative pain and arthritis. During my thesis, I studied the regulation of ASIC3 channels and their involvement in sensory and painful perceptions. The first part of my thesis project allowed the discovery for the first time of new endogenous activators of ASIC3 channels, which differ from protons. I demonstrated that lipids (i.e., lysophosphatidylcholine and arachidonic acid) present in human painful synovial fluids from patient with different joint pathologies, are able to activate ASIC3 channels without any extracellular acidification. These lipids are able to generate an acute painful behavior in rodents mediated, in a large part, by ASIC3. During the second part of my thesis I was interested by the regulation of ASIC3 channels by temperature. I demonstrated that these channels are activated by cold temperature (i.e., 15°C) at physiological pH. These results are reinforced by behavior experiments, showing an implication of ASIC3 in the perception of noxious and innocuous cold.

Early planting is one technique to avoid or reduce heat and drought problems that negatively affecting grain crop production. If producers adopt early planting, cold temperatures may negatively affect corn yield. It is important to select hybrids that are suited for planting earlier in the southern United States. Experiments were conducted by imposing low temperatures during seed germination. Twenty commercially available corn hybrids were evaluated for seed germination and root elongation. The first objective was: 1) To determine if some hybrids germinate better at cooler temperatures than others; and 2) Determine variation in root elongation at cold temperatures among commercially available hybrids. Corn hybrids varied significantly for seed germination and root traits under cold temperatures. Some hybrids have significantly surpassed others in seed germination traits, and they germinated earlier as well having longer radicle length. Also, there were significant differences across temperatures for all traits measured. A second objective was: 1) To quantify the effects of cold temperature on seed germination rate; 2) To evaluate the effects of different cold temperatures on seed germination behavior of corn hybrids under laboratory conditions to determine how fast they germinated; and 3) To classify hybrids for response to cold temperature using cumulative seed germination. The results showed that standard germination performance occurred at 10ºC for all hybrids, but these hybrids performed well under other cold treatments (7.2°C and 8.6° C). There were no big differences between early hybrids 93 to 105 RM (Relative Maturity) and full season 115 to 120 RM in germination % and rate in both experiments, so that means that it pretty much depends on the hybrid. Therefore, the temperature had a major influence on seed germination parameters. These findings are useful for hybrid selection with respect to cool soil temperature conditions during early planting.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010.

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