Patch selection behaviour in the presence of environmental constraints

Habitat selection behaviour is the primary way in which organisms are able to regulate encounters with their biotic and abiotic environment. An individual chooses an area that best meets their current needs, particularly regarding safety and the presence of high-quality food. Several physical aspects of the environment can make it difficult for individuals to assess the relative habitat quality of the areas available, thus leading to suboptimal habitat selection. In this thesis, I investigated the way in which two aquatic habitat constraints - obstacles to movement between patches and turbidity - affected the ability of fish to make optimal patch choices, using threespine stickleback Gasterosteus aculeatus as a model species. Laboratory experiments showed that when movement between patches was hindered by increasingly challenging obstacles, groups of stickleback did not move as freely between the patches, and thus had greater deviations from the predictions of the Ideal Free Distribution (IFD). I also demonstrated that, unlike other species, stickleback do not use turbid environments to avoid predator detection. A trend was seen towards avoidance of a turbid food patch regardless of risk level, although this was not statistically significant. As expected, the stickleback avoided feeding in the presence of a predator regardless of water clarity. Overall, I found that both turbidity and movement constraints can have significant impacts on patch use and distribution in the threespine stickleback. Both turbidity and ease of transit will impact the distribution of ecologically important species like the threespine stickleback, and therefore should be taken into account when studying habitat selection in the wild.

Hierarchical spatial segregation of two Mediterranean vole species : the role of patch-network structure and matrix composition

Acknowledgments This study was financed by FEDER funds through the Programa Operacional Factores de Competitividade— COMPETE, and National funds through the Portuguese Foundation for Science and Technology—FCT, within the scope of the projects PERSIST (PTDC/BIA-BEC/105110/2008), NETPERSIST (PTDC/ AAG-MAA/3227/2012), and MateFrag (PTDC/BIA-BIC/6582/2014). RP was supported by the FCT grant SFRH/BPD/73478/2010 and SFRH/BPD/109235/2015. PB was supported by EDP Biodiversity Chair. We thank Rita Brito and Marta Duarte for help during field work. We thank Chris Sutherland, Douglas Morris, William Morgan, and Richard Hassall for critical reviews of early versions of the paper. We also thank two anonymous reviewers for helpful comments to improve the paper.

Development of a dissolvable microneedle influenza vaccine patch

Delivery of large molecular weight biological molecules to the epidermis and dermis is constrained by the tough outer layer of the epidermis, the stratum corneum (sc). Microneedle technologies attempt to overcome this physical barrier using sharp micron-size projections to penetrate the sc. Dissolvable microneedles (DMN), are a particular microneedle design whereby the needle structure is composed of a soluble matrix that upon application to the skin, dissolves releasing the vaccine load into skin. This thesis examines (1) the formulation and processing considerations around DMN fabrication, (2) the immunogenicity of DMN containing trivalent influenza vaccine (TIV) in pre-clinical mouse and pig models and (3) the thermostability of these DMN formulations during storage. The results demonstrate the importance of formulation for microneedle formation and mechanical strength. Trehalose and polyvinylalcohol based formulations produced optimal microneedle structures and were amenable to piezoelectric dispensing; allowing for precise multi-layered DMN to be fabricated. The effect of drying conditions was assessed and found to be critical for DMN mechanical strength and skin penetration. The antibody responses to TIV generated by DMN-mediated vaccination were comparable or greater to those induced by immunization with a commercial TIV via the IM route in mice. DMN mediated immunisation resulted in a significantly broader humoral response to heterotypic influenza viruses compared to IM delivery. Stored at 40°C, a licensed seasonal influenza vaccine incorporated into DMN array was thermostable for at least 6 month as determined by Single Radial Immunodiffusion and immunogenicity in mice. The thesis advances the field of DMN influenza vaccination by elucidating important processing and formulation considerations in the fabrication of highly reproducible DMN. It also demonstrated that DMN can induce broader, larger humoral responses than conventional IM administration while demonstrating enhanced accelerated stability. Crucially, this works advances an automated fabrication system that will allow for clinical translation of DMN.

Modified patch repair of femoral hernia after inguinal herniorrhaphy

Background and aim. It has been reported that femoral hernias are rather common after a previous repair of inguinal hernia. We herein present a modified patch repair technique for large femoral hernias that develop after a Lichtenstein operation for ipsilateral inguinal hernia. Patients and methods. The modified technique for femoral hernia was applied to three patients who had a Lichtenstein repair for inguinal hernia. All patients were male. Hernia sac is dissected completely and sent back into to the preperitoneal space. Special attention should be given to the prevascular component of the sac. It is dissected as deep as possible into the preperitoneal space over the femoral vein. The defect is quite wide in this particular type of femoral hernia following Lichtenstein repair. A prosthetic patch that matches the defect is prepared. The medial edge of the mesh is configured to correspond to the pubic corner and lacunar ligament. The lateral margin of the patch is cut to create several petals for inverting the mesh above and medial to the femoral vein to prevent prevascular herniation. The mesh is secured to inguinal ligament, ilioinguinal tract, lacunar ligament, and Cooper ligament. Few sutures are put on the pubic corner and lacunar ligament. Results. One patient was discharged after two hours, other two stayed overnight. Readmission because of seroma development was recorded in two cases where standard polypropylene meshes were used. No complication was observed in the other patient who received lightweight meshes. No early recurrences were recorded after 4, 9, and 30 months. Conclusion. Femoral recurrence after previous inguinal hernia repair seems to be a specific entity. It has a prevascular component and the hernia defect can be much larger than that of a primary femoral hernia. A patch repair with infra-inguinal approach can be a valuable alternative with low complication rate.

The bovine pericardial patch in breast reconstruction: a case report

In the last years there has been a growing demand of plastic surgery for soft tissue reconstruction. In response to this, many biological and synthetic devices have been produced, aiming to allow wide and complex body reshapings. Acellular dermal matrices are one of these devices, and are made of human or animal tissues made acellular after their sampling. They are used for cervical, breast and abdominal wall reconstruction. Tutopatch®, generally used for face reconstruction or neurosurgery, is made of acellular bovine pericardium, and its high amount of collagen allows a fast tissue healing and a scaffold for the surrounding tissue rigeneration. In our case report Tutopatch® has been used in immediate breast reconstruction after mastectomy. This device has been used to close laterally the subpectoral pocket, allowing a bigger volume prosthesis to be placed We have not experienced particular postoperatory complications, and after 12 months of follow up we have found a valid functional and aesthetic result. We consider Tutopatch® as a valid alternative to other acellular dermal matrices specifically designed for breast reconstruction.

Nouveaux indices de suppression de la lipolyse par l'insuline déterminés lors de l'hyperglycémie provoquée par voie orale : comparaisons avec le clamp euglycémique-hyperinsulinémique et les paramètres métaboliques chez les femmes

Résumé : Une dysrégulation de la lipolyse des tissus adipeux peut conduire à une surexposition des tissus non-adipeux aux acides gras non-estérifiés (AGNE), qui peut mener à un certain degré de lipotoxicité dans ces tissus. La lipotoxicité constitue, par ailleurs, l’une des causes majeures du développement de la résistance à l’insuline et du diabète de type 2. En plus de ses fonctions glucorégulatrices, l’insuline a pour fonction d’inhiber la lipolyse et donc de diminuer les niveaux d’AGNE en circulation, prévenant ainsi la lipotoxicité. Il n’y a pas d’étalon d’or pour mesurer la sensibilité de la lipolyse à l’insuline. Le clamp euglycémique hyperinsulinémique constitue la méthode étalon d’or pour évaluer la sensibilité du glucose à l’insuline mais il est aussi utilisé pour mesurer la suppression de la lipolyse par l’insuline. Par contre, cette méthode est couteuse et laborieuse, et ne peut pas s’appliquer à de grandes populations. Il existe aussi des indices pour estimer la fonction antilipolytique de l’insuline dérivés de l’hyperglycémie provoquée par voie orale (HGPO), un test moins dispendieux et plus simple à effectuer à grande échelle. Cette étude vise donc à : 1) Étudier la relation entre les indices de suppressibilité des AGNE par l’insuline dérivés du clamp et ceux dérivés de l’HGPO; et 2) Déterminer laquelle de ces mesures corrèle le mieux avec les facteurs connus comme étant reliés à la dysfonction adipeuse : paramètres anthropométriques et indices de dysfonction métabolique. Les résultats montrent que dans le groupe de sujets étudiés (n=29 femmes, 15 témoins saines et 14 femmes avec résistance à l’insuline car atteintes du syndrome des ovaires polykystiques), certains indices de sensibilité à l’insuline pour la lipolyse dérivés de l’HGPO corrèlent bien avec ceux dérivés du clamp euglycémique hyperinsulinémique. Parmi ces indices, celui qui corrèle le mieux avec les indices du clamp et les paramètres anthropométriques et de dysfonction adipeuse est le T50[indice inférieur AGNE] (temps nécessaire pour diminuer de 50% le taux de base – à jeun – des AGNE). Nos résultats suggèrent donc que l’HGPO, facile à réaliser, peut être utilisée pour évaluer la sensibilité de la lipolyse à l’insuline. Nous pensons que la lipo-résistance à l’insuline peut être facilement quantifiée en clinique humaine.

Diurnal temporal patterns of the diversity and the abundance of reef fishes in a branching coral patch in New Caledonia

Small-scale spatial and temporal variability in animal abundance is an intrinsic characteristic of marine ecosystems but remains largely unknown for most animals, including coral reef fishes. In this study, we used a remote autonomous unbaited video system and recorded reef fish assemblages during daylight hours, 10 times a day for 34 consecutive days in a branching coral patch of the lagoon of New Caledonia. In total, 50 031 fish observations belonging to 114 taxa, 66 genera and 31 families were recorded in 256 recorded videos. Carnivores and herbivore-detritus feeders dominated the trophic structure. We found significant variations in the composition of fish assemblages between times of day. Taxa richness and fish abundance were greater in the early morning and in the late afternoon than during the day. Fourteen taxa displayed well-defined temporal patterns in abundance with one taxon influenced by time of day, six influenced by tidal state and seven influenced by both time of day and tidal state. None of these 14 taxa were piscivores, 10 were herbivore-detritus feeders, three were carnivores and one was plankton feeder. Our results suggest a diel migration from feeding grounds to shelter areas and highlight the importance of taking into account small-scale temporal variability in animal diversity and abundance when studying connectivity between habitats and monitoring communities.

Hierarchical spatial segregation of two Mediterranean vole species: the role of patch‑network structure and matrix composition

According to ecological theory, the coexistence of competitors in patchy environments may be facilitated by hierarchical spatial segregation along axes of environmental variation, but empirical evidence is limited. Cabrera and water voles show a metapopulation-like structure in Mediterranean farmland, where they are known to segregate along space, habitat, and time axes within habitat patches. Here, we assess whether segregation also occurs among and within landscapes, and how this is influenced by patch-network and matrix composition. We surveyed 75 landscapes, each covering 78 ha, where we mapped all habitat patches potentially suitable for Cabrera and water voles, and the area effectively occupied by each species (extent of occupancy). The relatively large water vole tended to be the sole occupant of landscapes with high habitat amount but relatively low patch density (i.e., with a few large patches), and with a predominantly agricultural matrix, whereas landscapes with high patch density (i.e.,many small patches) and low agricultural cover, tended to be occupied exclusively by the small Cabrera vole. The two species tended to co-occur in landscapes with intermediate patch-network and matrix characteristics, though their extents of occurrence were negatively correlated after controlling for environmental effects. In combination with our previous studies on the Cabrera-water vole system, these findings illustrated empirically the occurrence of hierarchical spatial segregation, ranging from withinpatches to among-landscapes. Overall, our study suggests that recognizing the hierarchical nature of spatial segregation patterns and their major environmental drivers should enhance our understanding of species coexistence in patchy environments.

Isogeometric analysis of large-deformation thin shells using RHT-splines for multiple-patch coupling

We present an isogeometric thin shell formulation for multi-patches based on rational splines over hierarchical T-meshes (RHT-splines). Nitsche’s method is employed to efficiently couple the patches. The RHT-splines have the advantages of allowing a computationally feasible local refine- ment, are free from linear independence, possess high order continuity and satisfy the partition of unity and non-negativity, properties. In addition, C 1 continuity of the RHT-splines obviates to use of rotational degrees of freedom. The good performance of the present method is demonstrated by a number of numerical examples.

Epicardial And Pericardial Fat In Type 2 Diabetes: Favourable Effects Of Biliopancreatic Diversion.

Ectopic fat is often identified in obese subjects who are susceptible to the development of type 2 diabetes mellitus (T2DM). The ectopic fat favours the decrease in insulin sensitivity (IS) and adiponectin levels. We aimed to evaluate the effect of biliopancreatic diversion (BPD) on the accumulation of ectopic fat, adiponectin levels and IS in obese with T2DM. A nonrandomised controlled study was performed on sixty-eight women: 19 lean-control (23.0 ± 2.2 kg/m(2)) and 18 obese-control (35.0 ± 4.8 kg/m(2)) with normal glucose tolerance and 31 obese with T2DM (36.3 ± 3.7 kg/m(2)). Of the 31 diabetic women, 20 underwent BPD and were reassessed 1 month and 12 months after surgery. The subcutaneous adipose tissue, visceral adipose tissue, epicardial adipose tissue and pericardial adipose tissue were evaluated by ultrasonography. The IS was assessed by a hyperglycaemic clamp, applying the minimal model of glucose. One month after surgery, there was a reduction in visceral and subcutaneous adipose tissues, whereas epicardial and pericardial adipose tissues exhibited significant reduction at the 12-month assessment (p < 0.01). Adiponectin levels and IS were normalised 1 month after surgery, resembling lean-control values and elevated above the obese-control values (p < 0.01). After 12 months, the improvement in IS and adiponectin was maintained, and 17 of the 20 operated patients exhibited fasting glucose and glycated haemoglobin within the normal range. After BPD, positive physiological adaptations occurred in grade I and II obese patients with T2DM. These adaptations relate to the restoration of IS and decreased adiposopathy and explain the acute (1 month) and chronic (12 months) improvements in the glycaemic control.

Biópsia hepática por laparotomia paracostal em bovinos e búfalos

A técnica de biópsia hepática em ruminantes tem importante valor no diagnóstico clínico de doenças tóxicas e metabólicas, em especial nos desequilíbrios minerais. As técnicas mais comumente utilizadas restringem análises devido ao limitado volume de tecido obtido. No presente trabalho, avaliou-se o uso de uma técnica de biópsia hepática por laparotomia paracostal em bovinos e búfalos. Foram utilizados 10 bovinos e 10 búfalos hígidos. Os animais foram mantidos em estação, sedados com xilazina e infiltrados localmente com lidocaína e epinefrina. O acesso à cavidade abdominal foi realizado por meio de uma incisão dorso-ventral de 15cm no flanco direito, iniciada ventralmente (cerca de 4-5cm) ao processo transverso da 2a ou 3a vértebra lombar e situada caudalmente (cerca de 4cm) e paralelamente à 13a costela, obtendo-se visualização do fígado. Foi então realizado pinçamento do bordo caudal do órgão com pinça Doyen para remoção de fragmento hepático (2 a 4g). Procedeu-se o fechamento da cavidade abdominal como de rotina. Foram analisados os parâmetros bioquímicos e hematológicos antes do procedimento (tempo zero) e após 24 horas, 48 horas, 5 dias e 10 dias após a biópsia. Todas as variáveis bioquímicas estudadas retornaram aos valores basais 5 e 10 dias após o procedimento nos bovinos e búfalos, respectivamente. O tempo médio de cirurgia por animal foi de 25 minutos. A biópsia hepática por laparotomia paracostal demonstrou ser uma técnica eficaz e de baixo risco à saúde dos animais, permitindo a coleta de suficiente quantidade de tecido hepática para realização de múltiplas análises.

Intrahepatic Glissonian Approach for Pure Laparoscopic Left Hemihepatectomy

Background: Recent advances in laparoscopic devices and experience with advanced techniques have increased the indications for laparoscopic liver. Aim: The aim of this work was to present a video with technical aspects of a pure laparoscopic left hemi-hepatectomy (segments 2, 3, and 4) by using the intrahepatic Glissonian approach and control of venous outflow without hilar dissection or the Pringle maneuver. Patient and Method: A 63-year-old woman with a 5-cm solitary liver metastasis was referred for treatment. Four trocars were used. The left lobe was pulled upward and the lesser omentum was divided, exposing Arantius' ligament. This ligament is a useful landmark for the identification of the main left Glissonian pedicle. A small anterior incision was made in front of the hilum, and a large clamp was introduced behind the Arantius' ligament toward the anterior incision, allowing control of the left main sheath. Ischemic discoloration of the left liver was achieved and marked with cautery. The vascular clamp was replaced by a stapler. If ischemic delineation was coincident with a previously marked area, the stapler was fired. The left hepatic vein was dissected and encircled. Parenchymal transection and vascular control of the hepatic veins were accomplished with a Harmonic scalpel and an endoscopic stapling device, as appropriate. All these steps were performed without the Pringle maneuver and without hand assistance. Results: Operative time was 220 minutes with minimum blood loss. Hospital stay was 4 days. Pathology showed free surgical margins. The patient is alive with no signs of recurrence 18 months after the operation. Conclusion: Totally laparoscopic left hemihepatectomy is safe and feasible in selected patients and should be considered for patients with benign or malignant liver neoplasms. The described technique, with the use of the intrahepatic Glissonian approach and control of venous outflow, may facilitate laparoscopic left hemihepatectomy by reducing the technical difficulties in pedicle control and may decrease bleeding during liver transection.

Beyond the Fragmentation Threshold Hypothesis: Regime Shifts in Biodiversity Across Fragmented Landscapes

Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andren proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions - that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework, providing a powerful tool for analysing the potential effectiveness of management interventions.

A classification methodology for the risk of weed infestation using fuzzy logic

Despite modern weed control practices, weeds continue to be a threat to agricultural production. Considering the variability of weeds, a classification methodology for the risk of infestation in agricultural zones using fuzzy logic is proposed. The inputs for the classification are attributes extracted from estimated maps for weed seed production and weed coverage using kriging and map analysis and from the percentage of surface infested by grass weeds, in order to account for the presence of weed species with a high rate of development and proliferation. The output for the classification predicts the risk of infestation of regions of the field for the next crop. The risk classification methodology described in this paper integrates analysis techniques which may help to reduce costs and improve weed control practices. Results for the risk classification of the infestation in a maize crop field are presented. To illustrate the effectiveness of the proposed system, the risk of infestation over the entire field is checked against the yield loss map estimated by kriging and also with the average yield loss estimated from a hyperbolic model.

Influence of EVA and acrylate polymers on some mechanical properties of cementitious repair mortars

In repair works of reinforced concrete, patch repairs tend to crack in the interfacial zone between the mortar and the old concrete. This occurs basically due to the high degree of restriction that acts on a patch repair. For this reason, the technology of patch repair needs to be the subject of a discussion involving professionals who work with projects, construction maintenance and mix proportioning of repair mortars. In the present work, a study is presented on the benefits that the ethylene vinyl acetate copolymer (EVA) and acrylate polymers can provide in the mix proportioning of a repair mortar with respect to compressive, tensile and direct-shear bond strength. The results indicated that the increase in bond strength and the reduction in the influence of the deficiency in Curing conditioning are the main contributions offered by the polymers studied here. (C) 2009 Elsevier, Ltd. All rights reserved.