956 resultados para Peri
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Dans les cas de lymphopnie, les lymphocytes T rsiduels prolifrent exagrment dans un phnomne appel expansion homostatique priphrique (HPE), qui est efficace pour la rgnration des T CD8+, mais inefficace pour les T CD4+. Linterleukine-7 (IL7) est une cytokine homostatique utilise afin daugmenter les comptes lymphocytaires T des patients lymphopniques. Toutefois, la raison de lexpansion prfrentielle des lymphocytes T CD8+ par lIL7 demeure toujours inconnue. Nous montrons que cette expansion est due au fait que lIL7 induit une prolifration efficace des T CD8+ priphriques (CD8+PERI) ainsi que des migrants thymiques CD8+ (CD8+RTEs). Par contre, leffet prolifratif de lIL7 est restreint presquuniquement aux CD4+RTEs mme si les CD4+PERI survivent mieux que les CD4+RTEs. De plus faibles doses dIL7 sont ncessaires aux CD4+RTEs afin de phosphoryler STAT5 ou de prolifrer comparativement aux CD4+PERI et nous dmontrons que les contacts TCR/CMHII sont ncessaires la prolifration induite par lIL7 des CD4+RTEs en priphrie. De fait, augmenter au Flt3 ligand le nombre de cellules dendritiques priphriques dune souris donneuse, avant de transfrer ses TPERI dans des souris receveuses traites lIL7 induit une prolifration significative des CD4+PERI. Nos rsultats indiquent donc que labondance des contacts TCR/CMHII reus dans le thymus semble contrler la sensibilit lIL7 des CD4+RTEs. Finalement, lobservation que les CD8+PERI et CD8+RTEs prolifrent pareillement pendant la thrapie lIL7, alors que la prolifration des T CD4+ est largement restreinte aux RTEs expliquerait pourquoi, dans les cas de lymphopnie, la rgnration des T CD4+ est aussi dpendante de la thymopose.
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Ce travail financ par l'ACDI a t ralis au Laboratoire TRANSNUT de l'Universit de Montral (Canada)en collaboration avec le Laboratoire National de Sant Publique (Burkina Faso) et HKI-Burkina Faso.
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Depuis les dernires annes, la prvalence de personnes souffrant de dgnrescence des cartilages articulaires, communment appele ostoarthrite (OA), ne cesse daugmenter. Les douleurs articulaires et les raideurs musculaires associes cette pathologie mnent des limitations des capacits fonctionnelles, une perte de mobilit et dautonomie affectant grandement la qualit de vie de ces personnes. Afin de soulager les personnes souffrant de cette pathologie, larthroplastie de la hanche est une procdure chirurgicale frquemment utilise. la suite de cette chirurgie, une amlioration de la qualit de vie et une reprise des capacits fonctionnelles sont souvent observes. Cependant, comparativement des sujets sains, la vitesse de marche est diminue, une faiblesse des muscles abducteurs de la hanche est constate et des mouvements compensatoires au niveau du tronc sont persistants. Lobjectif de cette thse est dvaluer le patron locomoteur chez des patients qui subiront une arthroplastie de la hanche. Plus spcifiquement, les adaptations locomotrices pr et post-opratoires seront quantifies dans le but dapporter des modifications aux programmes de rhabilitation pour ainsi favoriser un patron locomoteur sans dficit. Afin de rpondre cet objectif, trois tudes distinctes ont t effectues. Dans le cadre de la premire tude, limpact de limplantation dune prothse totale de la hanche avec une tte fmorale de large diamtre et une prothse de resurfaage a t valu par rapport aux sujets sains lors de la locomotion. Au cours de cette tude, le contrle du tronc a t analys en utilisant la distance entre le centre de masse corporel et le centre articulaire de la hanche opre. Suite aux rsultats obtenus, aucune diffrence majeure nexiste entre les deux types de prothses en ce qui a trait au contrle du tronc et ce, un an post-opratoire. Lors de la deuxime tude, la symtrie des paramtres biomcaniques des membres infrieurs lors de la locomotion chez des patients ayant bnfici de limplantation dune prothse de la hanche a t caractrise suite un programme dexercices pri-opratoires (pr et post-opratoire). Lors de cette tude, le programme dexercices pri-opratoires tait complmentaire au protocole de radaptation du centre hospitalier. Daprs les rsultats obtenus lors de cette tude exploratoire, ce programme dexercices pri-opratoires semble permettre damliorer la symtrie de la puissance et du travail musculaire au niveau de la hanche, du genou et de la cheville favorisant ainsi un patron de marche avec de minimes compensations. Finalement, dans le cadre de la troisime tude, lapproche prdictive et lapproche fonctionnelle, utilises pour localiser le centre articulaire de la hanche, ont t compares aux mesures radiographiques, chez des patients la suite dun remplacement articulaire de la hanche. la suite de cette tude, les rsultats dmontrent que lutilisation de lapproche fonctionnelle est plus approprie chez des patients ayant bnfici dune arthroplastie de la hanche. En effet, cette approche individualise est plus prcise ce qui, par consquent, permettra dobtenir des rsultats de plus grande qualit lors danalyses biomcaniques de la locomotion.
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La rgulation transcriptionnelle des gnes est un processus indispensable sans lequel la diversit phnotypique des cellules ainsi que ladaptation leur environnement serait inexistant. Lidentification des lments de rgulation dans le gnome est dune importance capitale afin de comprendre les mcanismes gouvernant lexpression des gnes spcifiques un type cellulaire donn. Ainsi, suite au pic de LH, le follicule ovarien entre dans un programme intensif de diffrentiation cellulaire, orchestr par des modifications majeures du profile transcriptionnel des cellules de granulosa, dclenchant ultimement lovulation et la lutinisation, processus indispensables la fertilit femelle. Lhypothse supporte par cette tude stipule quune rorganisation de la structure chromatinienne survient aux rgions rgulatrices dune panoplie de gnes dans les heures suivant le pic de LH et quen isolant et identifiant ces rgions, il serait possible de retrouver des lments essentiels aux processus dovulation et de lutinisation. Ainsi, en utilisant un protocole standard de superovulation chez la souris, les lments de rgulation se modifiant 4h suivant ladministration de hCG ont t isols et identifis dans les cellules de granulosa en utilisant la mthode FAIRE (Formaldehyde-Assisted Isolation of Regulatory Elements) combine un squenage haut dbit. Cette tude a dmontr que suite au stimulus ovulatoire, les cellules de granulosa subissent une reprogrammation majeure des lments de rgulation, qui est corrle avec une modification drastique de leurs fonctions biologiques. De plus, cette tude a mis en vidence une association majoritaire des lments de rgulation des rgions intergniques distales et des introns, indiquant que ces rgions ont une importance capitale dans la rgulation transcriptionnelle dans les cellules de granulosa. Cette tude a galement permis didentifier une panoplie de rgulateurs transcriptionnels reconnus pour tre essentiels la fonction ovarienne, ainsi que leur sites de liaison dans le gnome, dmontrant que la mthode FAIRE est une mthode assez puissante pour permettre la prdiction dvnements molculaires prcis ayant un sens physiologique rel.
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Le dlai optimal entre une lsion mdullaire traumatique (LMT) et la chirurgie demeure indtermin. Cependant, la relation entre la prvention de complications et le dlai chirurgical na jamais t spcifiquement tudie. Lobjectif principal de ce travail tait de dtecter si les taux de complications chez des LMT taient associs avec le dlai chirurgical. Lobjectif secondaire tait didentifier si le dlai chirurgical est un prdicteur indpendant de la survenue de complications. Un premier article prsente lanalyse dune cohorte rtrospective de 431 LMTs. Une chirurgie ralise dans un dlai infrieur 24h (ou infrieur 72h si un dlai de 24h ne peut tre respect) prdisait une diminution du taux de lensemble des complications, du taux de pneumonies et du taux de plaies de pression. Les autres facteurs prdictifs de complications identifis taient : lge, la svrit de latteinte neurologique de la lsion selon lchelle ASIA, un traumatisme cervical plutt que thoracique, la prsence de comorbidits, la svrit du traumatisme selon lchelle ISS et la complexit de la chirurgie. Les connaissances actuelles suggrent quune opration chirurgicale rapide na que peu deffet sur la rcupration neurologique chez les LMTs compltes (interruption complte des fonctions sensorimotrices). Pour cette raison, notre second article analyse limpact du dlai chirurgical sur la survenue des complications partir dune sous-population de 197 LMTs compltes de notre cohorte. Un dlai chirurgical suprieur 24h prdisait une augmentation des complications, notamment les pneumonies et les infections urinaires. Bien que des tudes prospectives randomises sont ncessaires pour confirmer nos conclusions, nos tudes supportent un dlai chirurgical rapide afin de diminuer le taux de complications non neurologiques chez les LMTs.
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Introduction. In utero, linfection des membranes maternelles et ftales, la chorioamniotite, passe souvent inaperue et, en particulier lorsque associe une acidmie, due locclusion du cordon ombilical (OCO), comme il se produirait au cours du travail, peut entrainer des lsions crbrales et avoir des rpercussions neurologiques pri - et postnatales long terme chez le ftus. Il n'existe actuellement aucun moyen de dtecter prcocement ces conditions pathologiques in utro afin de prvenir ou de limiter ces atteintes. Hypothses. 1)llectroencphalogramme (EEG) ftal obtenu du scalp ftal pourrait servir doutil auxiliaire la surveillance lectronique ftale du rythme cardiaque ftal (RCF) pour la dtection prcoce d'acidmie ftale et d'agression neurologique; 2) la frquence dchantillonnage de lECG ftal (ECGf) a un impact important sur le monitoring continu de la Variabilit du Rythme Cardiaque (VRCf) dans la prdiction de lacidmie ftale ; 3) les patrons de la corrlation de la VRCf aux cytokines pro-inflammatoires reflteront les tats de rponses spontanes versus inflammatoires de la Voie Cholinergique Anti-inflammatoire (VCA); 4) grce au dveloppement dun modle de prdictions mathmatiques, la prdiction du pH et de lexcs de base (EB) la naissance sera possible avec seulement une heure de monitoring dECGf. Mthodes. Dans une srie dtudes fondamentales et cliniques, en utilisant respectivement le mouton et une cohorte de femmes en travail comme modle exprimental et clinique , nous avons modlis 1) une situation dhypoxie crbrale rsultant de squences docclusion du cordon ombilical de svrit croissante jusqu atteindre un pH critique limite de 7.00 comme mthode exprimentale analogue au travail humain pour tester les premire et deuxime hypothses 2) un inflammation ftale modre en administrant le LPS une autre cohorte animale pour vrifier la troisime hypothse et 3) un modle mathmatique de prdictions partir de paramtres et mesures valids cliniquement qui permettraient de dterminer les facteurs de prdiction dune dtresse ftale pour tester la dernire hypothse. Rsultats. Les sries dOCO rptitives se sont solds par une acidose marque (pH artriel 7.350.01 7.000.01), une diminution des amplitudes l'lectroencphalogramme( EEG) synchronis avec les dclrations du RCF induites par les OCO accompagnes d'une baisse pathologique de la pression artrielle (PA) et une augmentation marque de VRCf avec hypoxie-acidmie aggravante 1000 Hz, mais pas 4 Hz, frquence dchantillonnage utilise en clinique. Ladministration du LPS entrane une inflammation systmique chez le ftus avec les IL-6 atteignant un pic 3 h aprs et des modifications de la VRCf retraant prcisment ce profil temporel des cytokines. En clinique, avec nos cohortes originale et de validation, un modle statistique base sur une matrice de 103 mesures de VRCf (R2 = 0,90, P < 0,001) permettent de prdire le pH mais pas lEB, avec une heure denregistrement du RCF avant la pousse. Conclusions. La diminution de l'amplitude l'EEG suggre un mcanisme d'arrt adaptatif neuroprotecteur du cerveau et suggre que l'EEG ftal puisse tre un complment utile la surveillance du RCF pendant le travail haut risque chez la femme. La VRCf tant capable de dtecter une hypoxie-acidmie aggravante tt chez le ftus 1000Hz vs 4 Hz voque quun mode d'acquisition dECG ftal plus sensible pourrait constituer une solution. Des profils distinctifs de mesures de la VRCf, identifis en corrlation avec les niveaux de l'inflammation, ouvre une nouvelle voie pour caractriser le profil inflammatoire de la rponse ftale linfection. En clinique, un monitoring de chevet de prdiction du pH et EB la naissance, partir de mesures de VRCf permettrait des interprtations visuelles plus explicites pour des prises de dcision plus exactes en obsttrique au cours du travail.
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Linfarctus du myocarde est une des consquences possibles de lischmie cardiaque; il se traduit par la mort des cardiomyocytes se situant en aval du blocus coronaire, puis par la formation dune cicatrice forme essentiellement de dpts de matrices extracellulaires scrtes par les myofibroblastes. Nestine est une protine filamenteuse intermdiaire de classe VI couramment associe la prolifration et la migration cellulaire. Chez lhomme et les rongeurs, la suite dun infarctus du myocarde, une sous-population de cardiomyocytes localise la zone infarcie/pri-infarcie exprimait la forme strie de nestine. Le but principal de cette tude tait de dterminer la source cellulaire des cardiomyocytes nestine (+) observe dans le cur infarci ainsi que le mcanisme de signalisation cellulaire sous-jacent impliqu dans lexpression de nestine. Lutilisation de souris transgnique a rvl que laugmentation des cardiomyocytes nestine (+) dans le cur infarci des souris ntait pas attribuable la diffrenciation de cellules souches/prognitrices nestine (+) en cardiomyocytes nestine (+). Le traitement des cardiomyocytes ventriculaires de rats nonataux avec lactivateur des protines kinases C PDBu et linhibition concomitante des voies p38 MAPK a men laugmentation du nombre de ces cellules exprimant nestine. De plus, une population importante de cardiomyocytes ventriculaires de rats nonataux a incorpor la bromodxoxyuridine, signe dune capacit rentrer dans le cycle cellulaire et synthtiser de lADN. Sur la base de ces observations, lapparition de cardiomyocytes nestine (+) dans le cur infarci des rongeurs et des hommes pourrait possiblement reflter une sous-population de cardiomyocytes en prolifration tentant de rgnrer le cur infarci.
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Study on variable stars is an important topic of modern astrophysics. After the invention of powerful telescopes and high resolving powered CCDs, the variable star data is accumulating in the order of peta-bytes. The huge amount of data need lot of automated methods as well as human experts. This thesis is devoted to the data analysis on variable stars astronomical time series data and hence belong to the inter-disciplinary topic, Astrostatistics. For an observer on earth, stars that have a change in apparent brightness over time are called variable stars. The variation in brightness may be regular (periodic), quasi periodic (semi-periodic) or irregular manner (aperiodic) and are caused by various reasons. In some cases, the variation is due to some internal thermo-nuclear processes, which are generally known as intrinsic vari- ables and in some other cases, it is due to some external processes, like eclipse or rotation, which are known as extrinsic variables. Intrinsic variables can be further grouped into pulsating variables, eruptive variables and flare stars. Extrinsic variables are grouped into eclipsing binary stars and chromospheri- cal stars. Pulsating variables can again classified into Cepheid, RR Lyrae, RV Tauri, Delta Scuti, Mira etc. The eruptive or cataclysmic variables are novae, supernovae, etc., which rarely occurs and are not periodic phenomena. Most of the other variations are periodic in nature. Variable stars can be observed through many ways such as photometry, spectrophotometry and spectroscopy. The sequence of photometric observa- xiv tions on variable stars produces time series data, which contains time, magni- tude and error. The plot between variable stars apparent magnitude and time are known as light curve. If the time series data is folded on a period, the plot between apparent magnitude and phase is known as phased light curve. The unique shape of phased light curve is a characteristic of each type of variable star. One way to identify the type of variable star and to classify them is by visually looking at the phased light curve by an expert. For last several years, automated algorithms are used to classify a group of variable stars, with the help of computers. Research on variable stars can be divided into different stages like observa- tion, data reduction, data analysis, modeling and classification. The modeling on variable stars helps to determine the short-term and long-term behaviour and to construct theoretical models (for eg:- Wilson-Devinney model for eclips- ing binaries) and to derive stellar properties like mass, radius, luminosity, tem- perature, internal and external structure, chemical composition and evolution. The classification requires the determination of the basic parameters like pe- riod, amplitude and phase and also some other derived parameters. Out of these, period is the most important parameter since the wrong periods can lead to sparse light curves and misleading information. Time series analysis is a method of applying mathematical and statistical tests to data, to quantify the variation, understand the nature of time-varying phenomena, to gain physical understanding of the system and to predict future behavior of the system. Astronomical time series usually suffer from unevenly spaced time instants, varying error conditions and possibility of big gaps. This is due to daily varying daylight and the weather conditions for ground based observations and observations from space may suffer from the impact of cosmic ray particles. Many large scale astronomical surveys such as MACHO, OGLE, EROS, xv ROTSE, PLANET, Hipparcos, MISAO, NSVS, ASAS, Pan-STARRS, Ke- pler,ESA, Gaia, LSST, CRTS provide variable stars time series data, even though their primary intention is not variable star observation. Center for Astrostatistics, Pennsylvania State University is established to help the astro- nomical community with the aid of statistical tools for harvesting and analysing archival data. Most of these surveys releases the data to the public for further analysis. There exist many period search algorithms through astronomical time se- ries analysis, which can be classified into parametric (assume some underlying distribution for data) and non-parametric (do not assume any statistical model like Gaussian etc.,) methods. Many of the parametric methods are based on variations of discrete Fourier transforms like Generalised Lomb-Scargle peri- odogram (GLSP) by Zechmeister(2009), Significant Spectrum (SigSpec) by Reegen(2007) etc. Non-parametric methods include Phase Dispersion Minimi- sation (PDM) by Stellingwerf(1978) and Cubic spline method by Akerlof(1994) etc. Even though most of the methods can be brought under automation, any of the method stated above could not fully recover the true periods. The wrong detection of period can be due to several reasons such as power leakage to other frequencies which is due to finite total interval, finite sampling interval and finite amount of data. Another problem is aliasing, which is due to the influence of regular sampling. Also spurious periods appear due to long gaps and power flow to harmonic frequencies is an inherent problem of Fourier methods. Hence obtaining the exact period of variable star from its time series data is still a difficult problem, in case of huge databases, when subjected to automation. As Matthew Templeton, AAVSO, states Variable star data analysis is not always straightforward; large-scale, automated analysis design is non-trivial. Derekas et al. 2007, Deb et.al. 2010 states The processing of xvi huge amount of data in these databases is quite challenging, even when looking at seemingly small issues such as period determination and classification. It will be beneficial for the variable star astronomical community, if basic parameters, such as period, amplitude and phase are obtained more accurately, when huge time series databases are subjected to automation. In the present thesis work, the theories of four popular period search methods are studied, the strength and weakness of these methods are evaluated by applying it on two survey databases and finally a modified form of cubic spline method is intro- duced to confirm the exact period of variable star. For the classification of new variable stars discovered and entering them in the General Catalogue of Vari- able Stars or other databases like Variable Star Index, the characteristics of the variability has to be quantified in term of variable star parameters.
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The surge in the urban population evident in most developing countries is a worldwide phenomenon, and often the result of drought, conflicts, poverty and the lack of education opportunities. In parallel with the growth of the cities is the growing need for food which leads to the burgeoning expansion of urban and peri-urban agriculture (UPA). In this context, urban agriculture (UA) contributes significantly to supplying local markets with both vegetable and animal produce. As an income generating activity, UA also contributes to the livelihoods of poor urban dwellers. In order to evaluate the nutrient status of urban soils in relation to garden management, this study assessed nutrient fluxes (inputs and outputs) in gardens on urban Gerif soils on the banks of the River Nile in Khartoum, the capital city of Sudan. To achieve this objective, a preliminary baseline survey was carried out to describe the structure of the existing garden systems. In cooperation with the author of another PhD thesis (Ms. Ishtiag Abdalla), alternative uses of cow dung in brick making kilns in urban Khartoum were assessed; and the socio-economic criteria of the brick kiln owners or agents, economical and plant nutritional value of animal dung and the gaseous emission related to brick making activities were assessed. A total of 40 household heads were interviewed using a semi-structured questionnaire to collect information on demographic, socio-economic and migratory characteristics of the household members, the gardening systems used and the problems encountered in urban gardening. Based on the results of this survey, gardens were divided into three groups: mixed vegetable-fodder gardens, mixed vegetable-subsistence livestock gardens and pure vegetable gardens. The results revealed that UA is the exclusive domain of men, 80% of them non-native to Khartoum. The harvested produce in all gardens was market oriented and represented the main source of income for 83% of the gardeners. Fast growing leafy vegetables such as Jews mallow (Corchorous olitorius L.), purslane (Portulaca oleracea L.) and rocket (Eruca sativa Mill.) were the dominant cultivated species. Most of the gardens (95%) were continuously cultivated throughout the year without any fallow period, unless they were flooded. Gardeners were not generally aware of the importance of crop diversity, which may help them overcome the strongly fluctuating market prices for their produce and thereby strengthen the contributions of UA to the overall productivity of the city. To measure nutrient fluxes, four gardens were selected and their nutrients inputs and outputs flows were monitored. In each garden, all plots were monitored for quantification of nutrient inputs and outputs. To determine soil chemical fertility parameters in each of the studied gardens, soil samples were taken from three selected plots at the beginning of the study in October 2007 (gardens L1, L2 and H1) and in April 2008 (garden H2) and at the end of the study period in March 2010. Additional soil sampling occurred in May 2009 to assess changes in the soil nutrient status after the River Nile flood of 2008 had receded. Samples of rain and irrigation water (river and well-water) were analyzed for nitrogen (N), phosphorus (P), potassium (K) and carbon (C) content to determine their nutrient inputs. Catchment traps were installed to quantify the sediment yield from the River Nile flood. To quantify the nutrient inputs of sediments, samples were analyzed for N, P, K and organic carbon (Corg) content, cation exchange capacity (CEC) and the particle size distribution. The total nutrient inputs were calculated by multiplying the sediment nutrient content by total sediment deposits on individual gardens. Nutrient output in the form of harvested yield was quantified at harvest of each crop. Plant samples from each field were dried, and analyzed for their N, P, K and Corg content. Cumulative leaching losses of mineral N and P were estimated in a single plot in garden L1 from December 1st 2008 to July 1st 2009 using 12 ion exchange resins cartridges. Nutrients were extracted and analyzed for nitrate (NO3--N), ammonium (NH4+-N) and phosphate PO4-3-P. Changes in soil nutrient balance were assessed as inputs minus outputs. The results showed that across gardens, soil N and P concentrations increased from 2007 to 2009, while particle size distribution remained unchanged. Sediment loads and their respective contents of N, P and Corg decreased significantly (P < 0.05) from the gardens of the downstream lowlands (L1 and L2) to the gardens of the upstream highlands (H1 and H2). No significant difference was found in K deposits. None of the gardens received organic fertilizers and the only mineral fertilizer applied was urea (46-0-0). This equaled 29, 30, 54, and 67% of total N inputs to gardens L1, L2, H1, and H2, respectively. Sediment deposits of the River Nile floods contributed on average 67, 94, 6 and 42% to the total N, P, K and C inputs in lowland gardens and 33, 86, 4 and 37% of total N, P, K and C inputs in highland gardens. Irrigation water and rainfall contributed substantially to K inputs representing 96, 92, 94 and 96% of total K influxes in garden L1, L2, H1 and H2, respectively. Following the same order, total annual DM yields in the gardens were 26, 18, 16 and 1.8 t ha-1. Annual leaching losses were estimated to be 0.02 kg NH4+-N ha-1 (SE = 0.004), 0.03 kg NO3--N ha-1 (SE = 0.002) and 0.005 kg PO4-3-P ha-1 (SE = 0.0007). Differences between nutrient inputs and outputs indicated negative nutrient balances for P and K and positive balances of N and C for all gardens. The negative balances in P and K call for adoptions of new agricultural techniques such as regular manure additions or mulching which may enhance the soil organic matter status. A quantification of fluxes not measured in our study such as N2-fixation, dry deposition and gaseous emissions of C and N would be necessary to comprehensively assess the sustainability of these intensive gardening systems. The second part of the survey dealt with the brick making kilns. A total of 50 brick kiln owners/or agents were interviewed from July to August 2009, using a semi-structured questionnaire. The data collected included general information such as age, family size, education, land ownership, number of kilns managed and/or owned, number of months that kilns were in operation, quantity of inputs (cow dung and fuel wood) used, prices of inputs and products across the production season. Information related to the share value of the land on which the kilns were built and annual income for urban farmers and annual returns from dung for the animal raisers was also collected. Using descriptive statistics, budget calculation and Gini coefficient, the results indicated that renting the land to brick making kilns yields a 5-fold higher return than the rent for agriculture. Gini coefficient showed that the kiln owners had a more equal income distribution compared to farmers. To estimate emission of greenhouse gases (GHGs) and losses of N, P, K, Corg and DM from cow dung when used in brick making, samples of cow dung (loose and compacted) were collected from different kilns and analyzed for their N, P, K and Corg content. The procedure modified by the Intergovernmental Panel on Climate Change (IPCC, 1994) was used to estimate the gaseous emissions of cow dung and fuel wood. The amount of deforested wood was estimated according to the default values for wood density given by Dixon et al. (1991) and the expansion ratio for branches and small trees given by Brown et al. (1989). The data showed the monetary value of added N and P from cow dung was lower than for mineral fertilizers. Annual consumption of compacted dung (381 t DM) as biomass fuel by far exceeded the consumption of fuel wood (36 t DM). Gaseous emissions from cow dung and fuel wood were dominated by CO2, CO and CH4. Considering that Gerif land in urban Khartoum supports a multifunctional land use system, efficient use of natural resources (forest, dung, land and water) will enhance the sustainability of the UA and brick making activities. Adoption of new kilns with higher energy efficiency will reduce the amount of biomass fuels (cow dung and wood) used the amount of GHGs emitted and the threat to the few remaining forests.
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The regional population growth in West Africa, and especially its urban centers, will bring about new and critical challenges for urban development policy, especially in terms of ensuring food security and providing employment for the growing population. (Peri-) urban livestock and vegetable production systems, which can contribute significantly to these endeavours, are limited by various constraints, amongst them limited access to expensive production factors and their (in)efficient use. To achieve sustainable production systems with low consumer health risks, that can meet the urban increased demand, this doctoral thesis determined nutrient use efficiencies in representative (peri-) urban livestock production systems in three West African cities, and investigated potential health risks for consumers ensuing from there. The field study, which was conducted during July 2007 to December 2009, undertook a comparative analysis of (peri-) urban livestock production strategies across 210 livestock keeping households (HH) in the three West African cities of Kano/Nigeria (84 HH), Bobo Dioulasso/Burkina Faso (63 HH) and Sikasso/Mali (63 HH). These livestock enterprises were belonging to the following three farm types: commercial gardening plus field crops and livestock (cGCL; 88 HH), commercial livestock plus subsistence field cropping (cLsC; 109 HH) and commercial gardening plus semi-commercial livestock (cGscL; 13 HH) which had been classified in a preceding study; they represented the diversity of (peri-) urban livestock production systems in West Africa. In the study on the efficiency of ruminant livestock production, lactating cowsand sheep herd units were differentiated based on whether feed supplements were offered to the animals at the homestead (Go: grazing only; Gsf: mainly grazing plus some supplement feeding). Inflows and outflows of nutrients were quantified in these herds during 18 months, and the effects of seasonal variations in nutrient availability on animals productivity and reproductive performance was determined in Sikasso. To assess the safety of animal products and vegetables, contamination sources of irrigated lettuce and milk with microbiological contaminants, and of tomato and cabbage with pesticide residues in (peri-) urban agriculture systems of Bobo Dioulasso and Sikasso were characterized at three occasions in 2009. Samples of irrigation water, organic fertilizer and ix lettuce were collected in 6 gardens, and samples of cabbage and tomato in 12 gardens; raw and curdled milk were sampled in 6 dairy herds. Information on health risks for consumers of such foodstuffs was obtained from 11 health centers in Sikasso. In (peri-) urban livestock production systems, sheep and goats dominated (P<0.001) in Kano compared to Bobo Dioulasso and Sikasso, while cattle and poultry were more frequent (P<0.001) in Bobo Dioulasso and Sikasso than in Kano. Across cities, ruminant feeding relied on grazing and homestead supplementation with fresh grasses, crop residues, cereal brans and cotton seed cake; cereal grains and brans were the major ingredients of poultry feeds. There was little association of gardens and livestock; likewise field cropping and livestock were rarely integrated. No relation existed between the education of the HH head and the adoption of improved management practices (P>0.05), but the proportion of HH heads with a long-term experience in (peri-) urban agriculture was higher in Kano and in Bobo Dioulasso than in Sikasso (P<0.001). Cattle and sheep fetched highest market prices in Kano; unit prices for goats and chicken were highest in Sikasso. Animal inflow, outflow and dairy herd growth rates were significantly higher (P<0.05) in the Gsf than in the Go cattle herds. Maize bran and cottonseed expeller were the main feeds offered to Gsf cows as dry-season supplement, while Gsf sheep received maize bran, fresh grasses and cowpea pods. The short periodic transhumance of Go dairy cows help them maintaining their live weight, whereas Gsf cows lost weight during the dry season despite supplement feeding at a rate of 1506 g dry matter per cow and day, resulting in low productivity and reproductive performance. The daily live weight gains of calves and lambs, respectively, were low and not significantly different between the Go and the Gsf system. However, the average live weight gains of lambs were significantly higher in the dry season (P<0.05) than in the rainy season because of the high pressure of gastrointestinal parasites and of Trypanosoma sp. In consequence, 47% of the sheep leaving the Go and Gsf herds died due to diseases during the study period. Thermo-tolerant coliforms and Escherichia coli contamination levels of irrigation water significantly exceeded WHO recommendations for the unrestricted irrigation of vegetables consumed raw. Microbial contamination levels of lettuce at the farm gate and the market place in Bobo Dioulasso and at the farm gate in Sikasso were higher than at the market place in Sikasso (P<0.05). Pesticide residues were detected in only one cabbage and one tomato sample and were below the maximum residue limit for consumption. Counts of thermo-tolerant coliforms and Escherichia coli were higher in curdled than in raw milk (P<0.05). From 2006 to x 2009, cases of diarrhea/vomiting and typhoid fever had increased by 11% and 48%, respectively, in Sikasso. For ensuring economically successful and ecologically viable (peri-) urban livestock husbandry and food safety of (peri-) urban foodstuffs of animal and plant origin, the dissemination and adoption of improved feeding practices, livestock healthcare and dung management are key. In addition, measures fostering the safety of animal products and vegetables including the appropriate use of wastewater in (peri-) urban agriculture, restriction to approve vegetable pesticides and the respect of their latency periods, and passing and enforcement of safety laws is required. Finally, the incorporation of environmentally sound (peri-) urban agriculture in urban planning by policy makers, public and private extension agencies and the urban farmers themselves is of utmost importance. To enable an efficient (peri-) urban livestock production in the future, research should concentrate on cost-effective feeding systems that allow meeting the animals requirement for production and reproduction. Thereby focus should be laid on the use of crop-residues and leguminous forages. The improvement of the milk production potential through crossbreeding of local cattle breeds with exotic breeds known for their high milk yield might be an accompanying option, but it needs careful supervision to prevent the loss of the local trypanotolerant purebreds.
Resumo:
The paper deals with some relevant and contradictory aspects of urban and peri-urban agriculture in Italy: the traditional exclusion of agricultural areas from the goals of territorial planning; the separation between top-down policies and bottom-up practices; the lack of agricultural policies at local scale. In the first part the paper summarises the weak relation between urban planning and agriculture, showing how in Italy this gap has been only partially overcome by new laws and plans. Moreover the paper focuses on how, due to the lack of suitable solutions coming from regional and local planning, a large number of vibrant initiatives were started by local stakeholders. In order to show the limitations and the potentialities of these various approaches, three peculiar experiences based on Milan, Turin and Pisa are presented. They give a cross-section of the variegated Italian situation, demonstrating that a major challenge in Italian context affects the fields of governance and inclusiveness.
Resumo:
Se presenta experiencia educativa que propone dar a conocer el peri??dico escolar como medio de acercamiento de la escuela a la comunidad. Se realiza en el CPR Monte Hacho en Cuesta de la Palma, Granada. Los objetivos son: potenciar e implicar a todos los miembros de la comunidad educativa; intentar que el peri??dico sea un cauce de informaci??n y conocimiento entre los diversos miembros de la comunidad educativa; desarrollar objetivos curriculares de educaci??n en valores; dar a conocer determinadas actividades que se han desarrollado tanto fuera como dentro del centro y que se consideren de inter??s; crear un canal de comunicaci??n entre el alumnado de las diferentes localidades, ya que aunque pertenecen al mismo centro s??lo coinciden en salidas y convivencias espor??dicas.
Resumo:
Se presenta experiencia educativa que propone la elaboraci??n de un peri??dico escolar para informar a la familia del alumnado de nuestras actividades y del proyecto educativo llevado a cabo en el aula. Se realiza en el CEIP La Almohada en Belicena, Granada. Los objetivos son: crear un instrumento de comunicaci??n para acercarnos m??s a nuestra comunidad educativa y poder compartir experiencias, ideas, inquietudes, sobre nuestra labor docente, as?? como todo lo que acontece en el aula y concretamente con los verdaderos protagonistas, el alumnado de educaci??n infantil; fomentar la paz, la cooperaci??n y la solidaridad en nuestra comunidad educativa; respeto de los derechos y libertades fundamentales y el ejercicio de la tolerancia.
Resumo:
Con este proyecto se ha tratado de dar una respuesta a la situaci??n de un grupo de alumnas y alumnos con graves dificultades de comportamiento que les imped??an la normal integraci??n en las actividades docentes, y que se ve??a claramente que les llevar??a a un rotundo fracaso escolar y en muchos casos al absentismo. Adem??s de contar con los medios de los que se dispone en un centro p??blico, se ha optado por una atenci??n m??s individualizada: entrevistas personales, di??logos peri??dicos; por unas actividades basadas fundamentalmente en talleres que favorecieran el trabajo colaborativo: horticultura, jardiner??a, embellecimiento de espacios escolares; salidas que ayudaran a la integraci??n del grupo, la convivencia... Todo ello con el objetivo de poder lograr peque??os cambios significativos en su comportamiento diario. A trav??s del curso se fue viendo que en la mayor??a de estos alumnos y alumnas se fueron dando estos peque??os cambios, no tanto a nivel de notas como de comportamiento y de asistencia escolar. Este proyecto persigue la integraci??n social del alumnado, teniendo en cuenta su nivel participativo en los cauces que la sociedad pone a su alcance y siempre bajo el prisma de los valores sociales y humanos que capacitan a las personas a una vida plena y de felicidad.
Resumo:
Analizar la compleja evoluci??n de la Primera Ense??anza en Asturias y los elementos innovadores que aparecen en la ??poca estudiada. Proceso de consolidaci??n profesional del Magisterio, movimiento societario y reivindicativo del Magisterio Primario, actitudes ideol??gicas de la sociedad respecto de la Primera Ense??anza y la lucha entre tendencias ideol??gicas. Se inicia la investigaci??n con un esbozo del panorama socioecon??mico de la regi??n, un estudio sobre la evoluci??n pol??tica de la sociedad y un breve an??lisis sobre la prensa asturiana respecto a la educaci??n. Se analizan las actitudes de la sociedad y sus ??rganos de expresi??n ante la Primera Ense??anza en el campo de las ideolog??as entonces en pugna: confesionalismo y laicismo. Se realiza un estudio del Magisterio nacional, sus condiciones de vida, asociaciones profesionales, aspiraciones y relaciones entre las entidades societarias. Se analiza, por ??ltimo, el movimiento escolar de renovaci??n y perfeccionamiento profesional. Bibliograf??a. Archivos municipales. Manuscritos. Peri??dicos, revistas y publicaciones oficiales. An??lisis de cada uno de los factores de manera particularizada. Se analizan por un lado los elementos coadyuvantes al cambio y de otro, el proceso mismo de perfeccionamiento y renovaci??n profesional. La sociedad asturiana pese a sus deficiencias de escolarizaci??n, di?? muestras de inter??s para poner fin a aquella situaci??n mediante muy distintas f??rmulas. El tipo de escuela imperante era la llegada por la tradici??n secular. El objetivo b??sico era la mera alfabetizaci??n, obstaculizada por la masificaci??n escolar y el absentismo escolar. La acci??n innovadora se centr?? en una visi??n de la escuela y de la labor del maestro que se concret?? en la introducci??n de nuevas materias escolares (Trabajos Manuales, Dibujo, M??sica y Gimnasia), y en la adopci??n de nuevas metodolog??as did??cticas, proceso en el que tuvo destacado protagonismo la inspecci??n y el medio de difusi??n que, con este objetivo, hab??a previsto el Ministerio: el Bolet??n de cada provincia. Tambi??n se pusieron en pr??ctica otras actividades, como excursiones, prensa escolar, bibliotecas, etc. Con todo, se puede concluir que las t??cnicas de la escuela activa se hab??an difundido lo suficiente como para remover la escuela tradicional a la que se opon??a. Hay que se??alar tambi??n la fuerte influencia de las concepciones de la escuela nueva en lo que se refiere a las metodolog??as did??cticas impartidas y a las opiniones sobre Organizaci??n Escolar. Permite comprobar hasta qu?? punto la innovaci??n educativa fue una de las caracter??sticas de la II Rep??blica en Asturias. Quedar??an por analizar la consideraci??n social de la profesi??n en cuanto a la pr??ctica profesional y la formaci??n del Magisterio asturiano (Escuela Normal).
