Encapsulação de suco de maracujá por co-cristalização com sacarose: cinética de cristalização e propriedades físicas

O processo de co-cristalização consiste na concentração de um xarope de sacarose até a supersaturação, quando então é adicionado o material a ser encapsulado. A partir daí, a mistura é submetida a uma intensa agitação que induz à nucleação e à aglomeração do produto. Neste trabalho, a encapsulação de suco concentrado de maracujá em sacarose por co-cristalização foi avaliada, determinandose o efeito da fração de suco adicionada e do pH do suco sobre a umidade, solubilidade, densidade aparente e ângulo de repouso do produto final e acompanhando-se a cinética de cristalização em um reo-reator, constituído de um cristalizador acoplado a um reômetro rotacional de cilindros concêntricos, cujo cilindro interno foi substituído por um agitador. A cinética de co-cristalização foi representada por um modelo empírico ajustado aos dados obtidos. A co-cristalização foi acelerada em função do aumento do pH e da redução da porcentagem de suco. Os produtos co-cristalizados apresentaram menor umidade e maior solubilidade em baixas concentrações de suco. A densidade aparente e o ângulo de repouso foram similares aos da matriz encapsulante e situaram-se na faixa em que se encontram a maioria dos pós alimentícios.

Modification of commercial poly-lactide for extrusion coated food packaging applications

Poly-L-lactide (PLLA) is a widely used sustainable and biodegradable alternative to replace synthetic non-degradable plastic materials in the packaging industry. Conversely, its processing properties are not always optimal, e.g. insufficient melt strength at higher temperatures (necessary in extrusion coating processes). This thesis reports on research to improve properties of commercial PLLA grade (3051D from NatureWorks), to satisfy and extend end-use applications, such as food packaging by blending with modified PLLA. Adjustment of the processability by chain branching of commercial poly-L-lactide initiated by peroxide was evaluated. Several well-defined branched structures with four arms (sPLLA) were synthesized using pentaerythritol as a tetra-functional initiator. Finally, several block copolymers consisting of polyethylene glycol and PLLA (i.e. PEGLA) were produced to obtain a well extruded material with improved heat sealing properties. Reactive extrusion of poly-L-lactide was carried out in the presence of 0.1, 0.3 and 0.5 wt% of various peroxides [tert-butyl-peroxybenzoate (TBPB), 2,5-dimethyl-2,5-(tert-butylperoxy)-hexane (Lupersol 101; LOL1) and benzoyl peroxide (BPO)] at 190C. The peroxide-treated PLLAs showed increased complex viscosity and storage modulus at lower frequencies, indicating the formation of branched/cross linked architectures. The material property changes were dependent on the peroxide, and the used peroxide concentration. Gel fraction analysis showed that the peroxides, afforded different gel contents, and especially 0.5 wt% peroxide, produced both an extremely high molar mass, and a cross linked structure, not perhaps well suited for e.g. further use in a blending step. The thermal behavior was somewhat unexpected as the materials prepared with 0.5 wt% peroxide showed the highest ability for crystallization and cold crystallization, despite substantial cross linking. The peroxide-modified PLLA, i.e. PLLA melt extruded with 0.3 wt% of TBPB and LOL1 and 0.5 wt% BPO was added to linear PLLA in ratios of 5, 15 and 30 wt%. All blends showed increased zero shear viscosity, elastic nature (storage modulus) and shear sensitivity. All blends remained amorphous, though the ability of annealing was improved slightly. Extrusion coating on paperboard was conducted with PLLA, and peroxide-modified PLLA blends (90:10). All blends were processable, but only PLLA with 0.3 wt% of LOL1 afforded a smooth high quality surface with improved line speed. Adhesion levels between fiber and plastic, as well as heat seal performance were marginally reduced compared with pure 3051D. The water vapor transmission measurements (WVTR) of the blends containing LOL1 showed acceptable levels, only slightly lower than for comparable PLLA 3051D. A series of four-arm star-shaped poly-L-lactide (sPLLA) with different branch length was synthesized by ring opening polymerization (ROP) of L-lactide using pentaerythritol as initiator and stannous octoate as catalyst. The star-shaped polymers were further blended with its linear resin and studied for their melt flow and thermal properties. Blends containing 30 wt% of sPLLA with low molecular weight (30 wt%; Mwtotal: 2500 g mol-1 and 15000 g mol-1) showed lower zero shear viscosity and significantly increased shear thinning, while at the same time slightly increased crystallization of the blend. However, the amount of crystallization increased significantly with the higher molecular weight sPLLA, therefore the star-shaped structure may play a role as nucleating agent. PLLA-polyethylene glycol–PLLA triblock copolymers (PEGLA) with different PLLA block length were synthesized and their applicability as blends with linear PLLA (3051D NatureWorks) was investigated with the intention of improving heat-seal and adhesion properties of extrusion-coated paperboard. PLLA-PEG-PLLA was obtained by ring opening polymerization (ROP) of L-lactide using PEG (molecular weight 6000 g mol-1) as an initiator, and stannous octoate as catalyst. The structures of the PEGLAs were characterized by proton nuclear magnetic resonance spectroscopy (1H-NMR). The melt flow and thermal properties of all PEGLAs and their blends were evaluated using dynamic rheology, and differential scanning calorimeter (DSC). All blends containing 30 wt% of PEGLAs showed slightly higher zero shear viscosity, higher shear thinning and increased melt elasticity (based on tan delta). Nevertheless, no significant changes in thermal properties were distinguished. High molecular weight PEGLAs were used in extrusion coating line with 3051D without problems.

Monascus pigment production in bioreactor using a co-product of biodiesel as substrate

The study and use of natural pigments in food industries have increased in recent years due to the toxicity presented by artificial pigments. Monascus ruber is a filamentous fungus that produces red, orange, and yellow pigments under different growing conditions. The growth of health food market has increased in parallel with the growth in biofuels production, such as biodiesel, which generates a concomitant increase in the production of glycerin that can be used in bioprocesses. The objective of this study was to use glycerin and glucose as substrates in the production of natural pigments in a bioreactor. The culture of Monascus ruber was carried out in a Bioflo III reactor with 4 L of working volume and pH, temperature, aeration, and agitation control. The highest pigment production was observed after 60 hours of fungal culture with 8.28 UA510 of red pigment. The pH range remained from 5.45 to 6.23 favoring the release of red pigment in the medium. This study shows the feasibility of the production of natural pigments by Monascus ruber in a bioreactor using a co-product of biodiesel without previous treatment as a substrate.

Production of probiotic fresh white cheese using co-culture with Streptococcus thermophilus

In this research, the probiotic Streptococcus thermophilus was inoculated into milk as co-culture to produce probiotic cheese. The effects of using Streptococcus thermophilus with other probiotic bacteria on cheese composition, and microbiological viability during 28 days of storage were investigated. Sensorial properties were determined only at 1st and 28th days of storage. The results showed that the use of Streptococcus thermophilus as co-culture in probiotic cheese production did not affect negatively the cheese components. Fat and dry matter properties of cheese weren't influenced by added probiotic bacteria. However, different level of pH, salt and lactic acid were detected. All probiotic bacteria were present in high levels throughout storage of cheeses, above 7 Log cfu.g- 1, threshold required for probiotic activity. Sensory panel showed that the highest average sensory evaluation points were recorded in cheeses made with Streptococcus thermophilus plus Lactobacillus casei, whereas other probiotic bacteria combinations had been affected less in regard to taste or appearance.

Effects of oil-water mixed frying and pure-oil frying on the quality characteristics of soybean oil and chicken chop

Abstract The effects of oil-water mixed frying (OWF) and pure-oil frying (POF) on changes in quality characteristics of soybean oil and chicken chop during six days of frying were comparatively investigated. The results showed that the changes in specific extinction coefficients, p-anisidine value, carbonyl value, viscosity and color of soybean oil were more pronounced in the case of POF, indicating that oil oxidative and polymeric degradation was retarded by OWF. Concerning fat content of chicken chop, lower (p<0.05) values were observed in the last three days in the case of OWF than POF. Meanwhile, OWF led to lower acrylamide formation in chops during the six days. Sensory evaluation showed that OWF provided chops with five attributes similar to those of chops fried by POF on the first day. As frying days increased, the decreases in scores for color, odor, flavor and overall acceptability were less in the case of OWF. In conclusion, OWF could be a worthwhile alternative for retarding oil deterioration and producing healthier and higher quality fried meat products.

The Co-occurrence of Depressive Symptoms and Alcohol Use for Adolescent Boys and Girls: An Investigation of the Role of Self-Regulation and Approach Behavior

While many studies have been conducted on adolescent depressive symptoms and alcohol use, much of the research has examined these behaviors separately rather than examining their co-occurrence within individuals. In the present study, adolescents (N = 4412; 49% female) were surveyed at four time points (grade 9, 10, 11, and 12) and growth mixture modeling was used to identify groups of individuals reporting various patterns of depressive symptoms and alcohol use across the high school years. Four groups were identified, including co-occurrence (higher depressive symptoms and higher alcohol use relative to peers, comprising 6.1 % of boys and 7.1 % of the girls in the sample), pure depressive symptoms (higher depressive symptoms and lower alcohol use; 12.7% of boys and 12.5% of girls), pure alcohol use (higher alcohol use and lower depressive symptoms; 20.9% of boys and 19.9% of girls), and low co-occurrence (lower depressive symptoms and alcohol use, 60.3% of boys and 60.5% of girls). Groups were compared on self-regulatory (i.e., delay of gratification) and approach behaviors. For both boys and girls, delay of gratification was the strongest predictor of group membership, with the co-occurrence group scoring the lowest and the low co-occurrence group the highest. This finding emphasizes the importance of assessing delay of gratification in the identification of high risk youth.

Bulloch, Lade & Co. Order Form, 31 August 1870

An order form for the exportation of scotch pure malt whiskies, distilled by Bulloch, Lade & Co.

List of goods shipped to Henry Nelles of Grimsby by Gerrard, Gillespie and Moffat Co.

List of goods shipped to Henry Nelles of Grimsby by Gerrard, Gillespie and Moffat Co. of Montreal (6 ½ page list, handwritten) for blankets, food, clothing and other items Sept. 14, 1821.

Une nouvelle stratégie de traitement de la maladie cœliaque basée sur les polymères séquestrants

La maladie cœliaque ou sprue cœliaque est une intolérance au gluten. Il s’agit d’une maladie inflammatoire de l’intestin liée à l’ingestion de gluten chez des personnes génétiquement susceptibles. Ce désordre présente une forte prévalence puisqu’il touche 1 % de la population mondiale. En l’état actuel des choses, il n’existe aucun outil pharmacologique pour traiter ou pallier à cette maladie. Cependant, grâce aux avancées dans la compréhension de sa pathogenèse, de nouvelles cibles thérapeutiques ont été identifiées. À l’heure actuelle, le seul traitement efficace consiste à suspendre la consommation de l’agent pathogène, à savoir le gluten. Le gluten est un ensemble de protéines de stockage des céréales contenu dans le blé, l’orge et le seigle. Le gluten du blé se subdivise en gluténines et gliadines. Ce sont ces dernières qui semblent les plus impliquées dans la maladie cœliaque. Les gliadines et ses protéines apparentées (i.e. sécalines et hordéines, respectivement dans le seigle et l’orge) sont riches en prolines et en glutamines, les rendant résistantes à la dégradation par les enzymes digestives et celles de la bordure en brosse. Les peptides résultant de cette digestion incomplète peuvent induire des réponses immunitaires acquises et innées. L’objectif principal de cette thèse était de tester un nouveau traitement d’appoint de la maladie cœliaque utile lors de voyages ou d’évènements ponctuels. Dans les années 80, une observation italienne montra l’inhibition de certains effets induits par des gliadines digérées sur des cultures cellulaires grâce à la co-incubation en présence de mannane: un polyoside naturel composé de mannoses. Malheureusement, ce traitement n’était pas applicable in vivo à cause de la dégradation par les enzymes du tractus gastro-intestinales du polymère, de par sa nature osidique. Les polymères de synthèse, grâce à la diversité et au contrôle de leurs propriétés physico-chimiques, se révèlent être une alternative attrayante à ce polymère naturel. L’objectif de cette recherche était d’obtenir un polymère liant la gliadine, capable d’interférer dans la genèse de la maladie au niveau du tube digestif, afin d’abolir les effets délétères induits par la protéine. Tout d’abord, des copolymères de type poly (hydroxyéthylméthacrylate)-co-(styrène sulfonate) (P(HEMA-co-SS)) ont été synthétisés par polymérisation radicalaire contrôlée par transfert d’atome (ATRP). Une petite bibliothèque de polymères a été préparée en faisant varier la masse molaire, ainsi que les proportions de chacun des monomères. Ces polymères ont ensuite été testés quant à leur capacité de complexer la gliadine aux pH stomacal et intestinal et les meilleurs candidats ont été retenus pour des essais cellulaires. Les travaux ont permis de montrer que le copolymère P(HEMA-co-SS) (45:55 mol%, 40 kDa) permettait une séquestration sélective de la gliadine et qu’il abolissait les effets induits par la gliadine sur différents types cellulaires. De plus, ce composé interférait avec la digestion de la gliadine, suggérant une diminution de peptides immunogènes impliqués dans la maladie. Ce candidat a été testé in vivo, sur un modèle murin sensible au gluten, quant à son efficacité vis-à-vis de la gliadine pure et d’un mélange contenant du gluten avec d’autres composants alimentaires. Le P(HEMA-co-SS) a permis de diminuer les effets sur les paramètres de perméabilité et d’inflammation, ainsi que de moduler la réponse immunitaire engendrée par l’administration de gliadine et celle du gluten. Des études de toxicité et de biodistribution en administration aigüe et chronique ont été réalisées afin de démontrer que ce dernier était bien toléré et peu absorbé suite à son administration par la voie orale. Enfin des études sur des échantillons de tissus de patients souffrants de maladie cœliaque ont montré un bénéfice therapeutique du polymère. L’ensemble des travaux présentés dans cette thèse a permis de mettre en évidence le potentiel thérapeutique du P(HEMA-co-SS) pour prévenir les désordres reliés à l’ingestion de gluten, indiquant que ce type de polymère pourrait être exploité dans un avenir proche.

Tailoring Magnetic Properties of Co-Fe Thin Films by Topographical Modifications Using Thermal Annealing and Swift Heavy Ion Irradiation and Fabrication of Magnetoelectric Multilayers for Device Applications

Magnetism and magnetic materials have been playing a lead role in improving the quality of life. They are increasingly being used in a wide variety of applications ranging from compasses to modern technological devices. Metallic glasses occupy an important position among magnetic materials. They assume importance both from a scientific and an application point of view since they represent an amorphous form of condensed matter with significant deviation from thermodynamic equilibrium. Metallic glasses having good soft magnetic properties are widely used in tape recorder heads, cores of high-power transformers and metallic shields. Superconducting metallic glasses are being used to produce high magnetic fields and magnetic levitation effect. Upon heat treatment, they undergo structural relaxation leading to subtle rearrangements of constituent atoms. This leads to densification of amorphous phase and subsequent nanocrystallisation. The short-range structural relaxation phenomenon gives rise to significant variations in physical, mechanical and magnetic properties. Magnetic amorphous alloys of Co-Fe exhibit excellent soft magnetic properties which make them promising candidates for applications as transformer cores, sensors, and actuators. With the advent of microminiaturization and nanotechnology, thin film forms of these alloys are sought after for soft under layers for perpendicular recording media. The thin film forms of these alloys can also be used for fabrication of magnetic micro electro mechanical systems (magnetic MEMS). In bulk, they are drawn in the form of ribbons, often by melt spinning. The main constituents of these alloys are Co, Fe, Ni, Si, Mo and B. Mo acts as the grain growth inhibitor and Si and B facilitate the amorphous nature in the alloy structure. The ferromagnetic phases such as Co-Fe and Fe-Ni in the alloy composition determine the soft magnetic properties. The grain correlation length, a measure of the grain size, often determines the soft magnetic properties of these alloys. Amorphous alloys could be restructured in to their nanocrystalline counterparts by different techniques. The structure of nanocrystalline material consists of nanosized ferromagnetic crystallites embedded in an amorphous matrix. When the amorphous phase is ferromagnetic, they facilitate exchange coupling between nanocrystallites. This exchange coupling results in the vanishing of magnetocrystalline anisotropy which improves the soft magnetic properties. From a fundamental perspective, exchange correlation length and grain size are the deciding factors that determine the magnetic properties of these nanocrystalline materials. In thin films, surfaces and interfaces predominantly decides the bulk property and hence tailoring the surface roughness and morphology of the film could result in modified magnetic properties. Surface modifications can be achieved by thermal annealing at various temperatures. Ion irradiation is an alternative tool to modify the surface/structural properties. The surface evolution of a thin film under swift heavy ion (SHI) irradiation is an outcome of different competing mechanism. It could be sputtering induced by SHI followed by surface roughening process and the material transport induced smoothening process. The impingement of ions with different fluence on the alloy is bound to produce systematic microstructural changes and this could effectively be used for tailoring magnetic parameters namely coercivity, saturation magnetization, magnetic permeability and remanence of these materials. Swift heavy ion irradiation is a novel and an ingenious tool for surface modification which eventually will lead to changes in the bulk as well as surface magnetic property. SHI has been widely used as a method for the creation of latent tracks in thin films. The bombardment of SHI modifies the surfaces or interfaces or creates defects, which induces strain in the film. These changes will have profound influence on the magnetic anisotropy and the magnetisation of the specimen. Thus inducing structural and morphological changes by thermal annealing and swift heavy ion irradiation, which in turn induce changes in the magnetic properties of these alloys, is one of the motivation of this study. Multiferroic and magneto-electrics is a class of functional materials with wide application potential and are of great interest to material scientists and engineers. Magnetoelectric materials combine both magnetic as well as ferroelectric properties in a single specimen. The dielectric properties of such materials can be controlled by the application of an external magnetic field and the magnetic properties by an electric field. Composites with magnetic and piezo/ferroelectric individual phases are found to have strong magnetoelectric (ME) response at room temperature and hence are preferred to single phasic multiferroic materials. Currently research in this class of materials is towards optimization of the ME coupling by tailoring the piezoelectric and magnetostrictive properties of the two individual components of ME composites. The magnetoelectric coupling constant (MECC) (_ ME) is the parameter that decides the extent of interdependence of magnetic and electric response of the composite structure. Extensive investigates have been carried out in bulk composites possessing on giant ME coupling. These materials are fabricated by either gluing the individual components to each other or mixing the magnetic material to a piezoelectric matrix. The most extensively investigated material combinations are Lead Zirconate Titanate (PZT) or Lead Magnesium Niobate-Lead Titanate (PMNPT) as the piezoelectric, and Terfenol-D as the magnetostrictive phase and the coupling is measured in different configurations like transverse, longitudinal and inplane longitudinal. Fabrication of a lead free multiferroic composite with a strong ME response is the need of the hour from a device application point of view. The multilayer structure is expected to be far superior to bulk composites in terms of ME coupling since the piezoelectric (PE) layer can easily be poled electrically to enhance the piezoelectricity and hence the ME effect. The giant magnetostriction reported in the Co-Fe thin films makes it an ideal candidate for the ferromagnetic component and BaTiO3 which is a well known ferroelectric material with improved piezoelectric properties as the ferroelectric component. The multilayer structure of BaTiO3- CoFe- BaTiO3 is an ideal system to understand the underlying fundamental physics behind the ME coupling mechanism. Giant magnetoelectric coupling coefficient is anticipated for these multilayer structures of BaTiO3-CoFe-BaTiO3. This makes it an ideal candidate for cantilever applications in magnetic MEMS/NEMS devices. SrTiO3 is an incipient ferroelectric material which is paraelectric up to 0K in its pure unstressed form. Recently few studies showed that ferroelectricity can be induced by application of stress or by chemical / isotopic substitution. The search for room temperature magnetoelectric coupling in SrTiO3-CoFe-SrTiO3 multilayer structures is of fundamental interest. Yet another motivation of the present work is to fabricate multilayer structures consisting of CoFe/ BaTiO3 and CoFe/ SrTiO3 for possible giant ME coupling coefficient (MECC) values. These are lead free and hence promising candidates for MEMS applications. The elucidation of mechanism for the giant MECC also will be the part of the objective of this investigation.

Molecular Epidemiology of Escherichia coli isolates from Environmental, Food and Clinical Sources

In the present study diversity of E. coli in the water samples of Cochin estuary were studied for a period of 3 years ranging from January 2010- December 2012. The stations were selected based on the closeness to satellite townships and waste input. Two of the stations (Chitoor and Thevara) were fixed upstream, two in the central part of the estuary namely Bolgatty and Off Marine Science Jetty, and one at the Barmouth. Diversity was assessed in terms of serotypes, phylogenetic groups and genotypes. Two groups of seafood samples such as fish and shellfish collected from the Cochin estuary were used for isolation of E. coli. One hundred clinical E. coli isolates were collected from one public health centre, one hospital and five medical labs in and around Cochin City, Kerala. From our results it was clear that pathogen cycling is occurring through food, water and clinical sources. Pathogen cycling through food is very common and fish and shellfish that harbour these strains might pose potential health risk to consumer. Estuarine environment is a melting pot for various kinds of wastes, both organic and inorganic. Mixing up of waste water from various sources such as domestic, industries, hospitals and sewage released into these water bodies resulting in the co-existence of E. coli from various sources thus offering a conducive environment for horizontal gene transfer. Opportunistic pathogens might acquire genes for drug resistance and virulence turning them to potential pathogens. Prevalence of ExPEC in the Cochin estuary, pose threat to people who use this water for fishing and recreation. Food chain also plays an important role in the transit of virulence genes from the environments to the human. Antibiotic resistant E. coli are widespread in estuarine water, seafood and clinical samples, for reasons well known such as indiscriminate use of antibiotics in animal production systems, aquaculture and human medicine. Since the waste water from these sources entering the estuary provides selection pressure to drug resistant mutants in the environment. It is high time that the authorities concerned should put systems in place for monitoring and enforcement to curb such activities. Microbial contamination can limit people’s enjoyment of coastal waters for contact recreation or shellfish-gathering. E. coli can make people sick if they are present in high levels in water used for contact recreation or shellfish gathering. When feeding, shellfish can filter large volumes of seawater, so any microorganisms present in the water become accumulated and concentrated in the shellfish flesh. If E. coli contaminated shellfish are consumed the impact to human health includes gastroenteritis, urinary tract infections (UTIs), and bacteraemia. In conclusion, the high prevalence of various pathogenic serotypes and phylogenetic groups, multidrug-resistance, and virulence factor genes detected among E. coli isolates from stations close to Cochin city is a matter of concern, since there is a large reservoir of antibiotic resistance genes and virulence traits within the community, and that the resistance genes and plasmid-encoded genes for virulence were easily transferable to other strains. Given the severity of the clinical manifestations of the disease in humans and the inability and/or the potential risks of antibiotic administration for treatment, it appears that the most direct and effective measure towards prevention of STEC and ExPEC infections in humans and ensuring public health may be considered as a priority.

Agricultural practices and horizontal nutrient balances in urban gardens and the alternative use of urban agricultural land in Khartoum, Sudan

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 Jew’s 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.

Effects of In-Kind transfers on female labor supply: evidence from the food supply program comedores comunitarios

En la literatura se argumenta que las transferencias en especie podrían tener efectos positivos sobre la oferta laboral. En este trabajo utilizamos el programa de nutrición de la ciudad de Bogotá, Comedores Comunitarios, para esclarecer dicho punto. El programa otorga un almuerzo diario a las personas pobres que son vecinas de los comedores. Utilizando la técnica de emparejamiento con la Encuesta de Calidad de Vida 2007, una encuesta de corte transversal, se encuentra tanto efectos significativos positivos como negativos en la oferta laboral femenina para diferentes grupos de mujeres (con diferencias en edad, composición del hogar y acceso a redes sociales). Estos resultados son relevantes para entender los incentivos al trabajo heterogéneos generados cuando se aplica esta clase de programas.

Eficacia del plasma rico en plaquetas en procedimientos médicos estéticos faciales . Evaluación en contorno de ojos.

Introducción: En la actualidad se están implementando nuevas técnicas, para el tratamiento de líneas de expresión facial. El Plasma Rico en Plaquetas (PRP) utiliza factores de crecimiento humano autólogos con fines médicos estéticos. El objetivo de este trabajo fue evaluar el tratamiento con plasma rico en plaquetas en el manejo del rejuvenecimiento periocular. Materiales y métodos: Estudio descriptivo retrospectivo en una cohorte de 27 pacientes entre 30 a 70 años de ambos sexos,tratados con PRP sin tratamientos médicos estéticos previos . Se compararon fotografías del sistema VISIA®, previo y posterior el PRP, para determinar los cambios del área periocular. Con análisis comparativo de medias utilizando pruebas t de student. Resultados: De 27 historias clínicas revisadas 96,3% eran mujeres, la edad promedio fue de 52.67 años. Se observaron cambios clínicos satisfactorios en el manejo del foto envejecimiento periocular con mejoría estadísticamente significativa entre el promedio inicial y el post tratamiento en arrugas, textura y porfirinas (p: 0.000). No se observaron diferencias estadísticamente significativas entre los grupos de edad (p = 0,62). Los pacientes analizados posterior al tratamiento se encuentran en mejor estado que el 63,78% de la población de su mismo sexo, edad y fototipo de piel. Los eventos adversos fueron disminuyendo en su frecuencia en cada una de las sesiones siguientes. Discusión: El PRP proporciona una mejoría global en los parámetros de envejecimiento periocular lo cual se correlaciono con los estudios previos in vitro. Conclusiones: El PRP es seguro y eficaz en contorno de ojos.

Continuous improvement programs as processes for organizational learning: a case study of a company in the food products industry

This article intends to show the relationships between quality practices and the process of organizational learning. When we look at the literature about programs of continuous improvement we see that theoreticians consider that the process of organizational learning is a superior stage in the quality culture adopted by companies. To investigate this possibility, we put together a series of indicators taken from classic authors who have written about organizational learning. Adopting a multiple methodology, we applied these indicators to two plants belonging to the Nestlé food product company which have introduced continuous improvement programs over the last two years.