Reducing the incidence of under-skin browning in 'Honey Gold' mango (Mangifera indica L.) fruit

'Honey Gold' mango is a relatively new cultivar in Australia, with an appealing skin colour and a sweet fibre-free flesh. However, fruit can develop 'under-skin browning' (USB), which appears several days after packing as a distinct 'bruise'-like discolouration under the epidermis and can affect large areas of the fruit surface. We investigated the anatomy of USB and the impact of post-harvest fruit handling conditions on the disorder. Starch accumulated around the resin canals and discoloured cells in the affected area, with no visible change to the cuticle or epidermis. Delays of 1 d at ambient temperature (27 degrees - 35 degrees C) before packing, and 2 d at 18 degrees - 20 degrees C (after packing), before placing fruit at 12 degrees - 14 degrees C and road transportation, reduced the incidence of USB by 83% compared to placing fruit at 12 degrees - 14 degrees C within 13 h of picking. The incidence of USB was 88 100% higher in fruit that were cooled to 12 degrees - 14 degrees C within 13 h of picking, then commercially road-freighted for 4 d at 12 degrees - 14 degrees C, than in fruit held under similar temperature conditions, but not road-freighted. Wrapping each fruit in bubble-wrap to minimise direct contact with other fruit, with the plastic insert, or with the cardboard tray, reduced the incidence of USB by 84% after road-freight compared to not using bubble-wrap. These results suggest that USB is a unique disorder of mango skin associated with a rapid post-harvest reduction in temperature, from high ambient temperatures to 12 degrees - 14 degrees C, and with physical damage during road-freight.

A comparison of the electrosensory morphology of a euryhaline and a marine stingray

The electrosensory system is found in all chondrichthyan fishes and is used for several biological functions, most notably prey detection. Variation in the physical parameters of a habitat type, i.e. water conductivity, may influence the morphology of the electrosensory system. Thus, the electrosensory systems of freshwater rays are considerably different from those of fully marine species; however, little research has so far examined the morphology and distribution of these systems in euryhaline elasmobranchs. The present study investigates and compares the morphology and distribution of electrosensory organs in two sympatric stingray species: the (euryhaline) estuary stingray, Dasyatis fluviorum, and the (marine) blue-spotted maskray, Neotrygon kuhlii. Both species possess a significantly higher number of ventral electrosensory pores than previously assessed elasmobranchs. This correlates with a diet consisting of benthic infaunal and epifaunal prey, where the electrosensory pore distribution patterns are likely to be a function of both ecology and phylogeny. The gross morphology of the electrosensory system in D. fluviorum is more similar to that of other marine elasmobranch species, rather than that of freshwater species. Both D. fluviorum and N. kuhlii possess 'macro-ampullae' with branching canals leading to several alveoli. The size of the pores and the length of the canals in D. fluviorum are smaller than in N. kuhlii, which is likely to be an adaptation to habitats with lower conductivity. This study indicates that the morphology of the electrosensmy system in.a euryhaline elasmobranch species seems very similar to that of their fully marine counterparts. However, some morphological differences are present between these two sympatric species, which are thought to be linked to their habitat type. (C) 2013 Elsevier GmbH. All rights reserved.

Role of cell cycle regulators in development of the inner ear

The inner ear originates from an ectodermal thickening called the otic placode. The otic placode invaginates and closes to an otic vesicle, the otocyst. The otocyst epithelium undergoes morphogenetic changes and cell differentiation, leading to the formation of the labyrinth-like mature inner ear. Epithelial-mesenchymal interactions control inner ear morphogenesis, but the modes and molecules are largely unresolved. The expressions of negative cell cycle regulators in the epithelium of the early-developing inner ear have also not been elucidated. The mature inner ear comprises the hearing (cochlea) and balance (vestibular) organs that contain the nonsensory and sensory cells. In mammals, the inner ear sensory cells, called hair cells, exit the cell cycle during embryogenesis and are mitotically quiescent during late-embryonic differentiation stages and postnatally. The mechanisms that maintain this hair cell quiescense are largely unresolved. In this work I examined 1) the epithelial-mesenchymal interactions involved in inner ear morphogenesis, 2) expression of negative cell cycle regulators in the epithelium of the early developing inner ear and 3) the molecular mechanisms that maintain the postmitotic state of inner ear sensory cells. We observed that during otocyst stages, epithelial fibroblast growth factor 9 (Fgf9) communicates with the surrounding mesenchyme, where its receptors are expressed. Fgf9 inactivation leads to reduced proliferation of the surrounding vestibular mesenchyme and to the absence of semicircular canals. Semicircular canal development is blocked, since fusion plates do not form. These results show that the mesenchyme directs fusion plate formation and give direct evidence for the existence of reciprocal epithelial-mesenchymal interactions in the developing inner ear. Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of proliferation. We show that the members of the Cip/Kip family of CKIs (p21Cip1, p27Kip1 and p57Kip2) are expressed in the early-developing inner ear. Our expression data suggest that CKIs divide the otic epithelium into proliferative and nonproliferative compartments that may underlie shaping of the otocyst. At later stages, CKIs regulate proliferation of the vestibular appendages, and this may regulate their continual growth. In addition to restricting proliferation, CKIs may play a role in regional differentiation of various epithelial cells. Differentiating and adult inner ear hair cells are postmitotic and do not proliferate in response to serum or mitogenic growth factors. In our study, we show that this is the result of the activity of negative cell cycle regulators. Based on expression profiles, we first focused on the retinoblastoma (Rb) gene, which functions downstream of the CKIs. Analysis of the inner ear phenotype of Rb mutant mice show, that the retinoblastoma protein regulates the postmitotic state of hair cells. Rb inactivation leads to hyperplasia of vestibular and cochlear sensory epithelia that is a result of abnormal cell cycle entry of differentiated hair cells and of delayed cell cycle exit of the hair cell precursor cells. In addition, we show that p21Cip1 and p19Ink4d cooperate in maintaining the postmitotic state of postnatal auditory hair cells. Whereas inactivation of p19Ink4d alone leads to low-level S-phase entry (Chen et al., 2003) and p21Cip1 null mutant mice have a normal inner ear phenotype, codeletion of p19Ink4d and p21Cip1 triggers high-level S-phase entry of auditory hair cells during early postnatal life, which leads to supernumerary hair cells. The ectopic hair cells undergo apoptosis in all of the mutant mice studied, DNA damage being the immediate cause of this death. These findings demonstrate that the maintenance of the postmitotic state of hair cells is regulated by Rb and several CKIs, and that these cell cycle regulators are critical for the lifelong survival of hair cells. These data have implications for the future design of therapies to induce hair cell regrowth.

Modern surgical treatment of otosclerosis

The modern unilateral surgical treatment of otosclerosis started in 1956. Simultaneous bilateral surgery has not been reported in stapes surgery and in case of bilateral otosclerosis ears are operated in two different sessions. Simultaneous surgery would give the patient the opportunity to gain advantages of bilateral hearing within one session, with less time spent in hospital and on sick leave. The mechanism for vestibular symptoms and the exact end organ affected after surgery is still unveiled. This thesis presents the results of experimental simultaneous bilateral stapes surgery, and vestibular symptoms and findings before and after unilateral stapes surgery. In addition, we explore reasons for outpatient failures in otosclerosis surgery. -- Study I examines the outcome of simultaneous bilateral surgery. Hearing was evaluated with standard pure tone and speech audiograms and vestibular apparatus with visual feedback posturography (VFP) during the one-year follow-up. Subjective symptoms and quality of life were assessed with questionnaires. In study II, reasons for outpatient failures in stapes surgery were explored. Forty-seven consecutive stapedotomies and stapedectomies performed by the same surgeon were included, and the effect of failures on hearing results were analysed. Vestibular symptoms and the end organ(s) affected after stapes surgery were investigated in studies III and IV. With video-oculography (VOG), nystagmus was measured preoperatively, and at one week, one month and 3 months postoperatively in the first phase (III). In the second phase (IV), recordings were obtained some hours postoperatively. The hearing results of the simultaneous bilateral surgery were comparable with unilateral surgeries reported. Recovery from the surgery was fast. Significant improvement in performance and quality of life was noted already month after operation in subjective evaluations. Based on these results, simultaneous bilateral surgery is a suitable approach in bilateral otosclerosis Significantly more outpatient failures occurred for medical reasons in the stapedectomy group (13%) than in the stapedotomy group (2%). Stapedotomy should be favoured if outpatient surgery is planned. However, unplanned admission did not worsen the prognosis. VOG measurements in study III did not show any specific type of nystagmus in patients having vestibular symptoms postoperatively. However, VOG measurements immediately after surgery (IV) revealed nystagmus consistent with a minor disturbance of the semicircular canals in 33% of the patients. Subjectively, half of the patients reported vestibular symptoms that were probably of diverse origin, and could have originated from both otolith and semicircular canal parts of the vestibular organ. Since vestibular symptoms and signs are mild, patients may be safely discharged some hours after stapes surgery.

Prosopis, an Alien among the Sacred Trees of South India

The problematic of invasive species in an alien environment has aroused the attention of scientists all over the world for quite some time. One of the exotic tree species that has provoked special attention in the tropical drylands is Prosopis juliflora. Originating in South America, prosopis (hereafter referred to as prosopis) has been introduced in the hot and semi-arid zones of the world particularly to provide fuelwood, to stabilize sand dunes and to combat desertification. The tree has become an essential source for fuelwood and a provider of several other products and services in areas where it has become established. However, despite the numerous benefits the tree provides to rural people, in several regions prosopis has become a noxious weed with a negative impact on the environment and to the economy of farmers and landowners. In India, prosopis was introduced in Andhra Pradesh in 1877. The tree was then proclaimed as the precious child of the plant world by scientists and local people alike. The purpose of this study was to investigate the overall impact of prosopis on local rural livelihoods in the drylands of South India. Of particular interest was the examination of the different usages of the tree, especially as fuelwood, and people s perceptions of it. Furthermore, the study examined the negative impacts of the uncontrolled invasion of prosopis on croplands, and its occupation of the banks of irrigation canals and other water sources. As another central theme, this study analysed the Hindu classification system for nature and for trees in particular. In India, several tree species are regarded as sacred. This study examined the position of the exotic prosopis among sacred trees, such as the bodhi, banyan and neem trees. The principle method for collecting the field data was by using individual and thematic group interviews. These interviews were semi-structured with open ended questions. Moreover, unstructured interviews as well as general observations provided complementary information. The data were gathered during two fieldwork periods in the states of Andhra Pradesh and Tamil Nadu, in South India. The results confirmed that prosopis both provides benefits and causes hazards to different stakeholders. Farmers and agriculturalists suffer economic losses in areas where prosopis has invaded crop fields and competes with other plants for water and nutrients. On the other hand, for a significant number of poor rural people, prosopis has become an important source of livelihood benefits. This tree, which grows on government wastelands, is commonly a free resource for all and has thus become a major local source of fuelwood. It also provides several other goods and services and cash income that contributes to improve livelihoods in rural communities. Prosopis ranked lowest in the tree classificatioin system of the Hindus of South India. Although it is appreciated for many benefits it provides for poor people, it has remained an outsider compared with the indigenous tree species. On the other hand, the most sacred trees, such as the bodhi or the banyan, are completely excluded from extraction and it is seen as a sacrilege to even cut branches from any of these trees. An unexpected finding was that, in a few cases, prosopis had also been elevated to the status of a sacred tree. Goods and services from prosopis are not utilized in the most beneficial way. Silvicultural management practices are suggested that would provide additional income and employment opportunities. Interventions are recommended to control further invasion of the tree that might cause serious negative effects in the future. For Hindus, the sacred always ranks highest, even above economic gain. The conservation of sacred groves and sacred trees is a tradition that has its roots in ancient history. These socio-religious practices need to be respected and continued. Successful management of tree and forest resources depends on the willingness of the local people to manage their natural resources, and this willingness exists and has always existed in South India. Keywords: South India, drylands, livelihood, fuelwood, invasive, resource, silviculture.

A landscape approach to conservation of birds

Landscape ecology as a discipline in science is rather young. However its principles appear promising in outlining conservation strategies including a wide range of organisms, particularly birds. Birds due to their mobility use a variety of environmental resources, especially habitats. However, currently these habitats are only available in patches over most of the tropical world. Further whatever is left is under constant human pressure. This paper, therefore, addresses this problem and suggests means of dealing with it using the landscape approach as outlined by landscape ecology. The landscape approach starts with the realization that patches of habitats are open and interact with one another. Corridors of trees along roads, hedgerows and canals in a landscape can aid in the movement of species. Hence the landscape approach considers patches of habitats as interacting elements in the large matrix of the landscape. The landscape approach also integrates concepts. It puts together often debated issues such as whether to preserve maximum species diversity, to maximize representativeness, or to preserve only the valuable species. Based on a case study of the Uttara Kannada district in Karnataka, these oft-opposing views and complications can be dealt with practically and synthesized into a conservation strategy far the diverse avifauna of the Western Chats.

Optimal management of beaver population using a reduced-order distributed parameter model and single network adaptive critics

Beavers are often found to be in conflict with human interests by creating nuisances like building dams on flowing water (leading to flooding), blocking irrigation canals, cutting down timbers, etc. At the same time they contribute to raising water tables, increased vegetation, etc. Consequently, maintaining an optimal beaver population is beneficial. Because of their diffusion externality (due to migratory nature), strategies based on lumped parameter models are often ineffective. Using a distributed parameter model for beaver population that accounts for their spatial and temporal behavior, an optimal control (trapping) strategy is presented in this paper that leads to a desired distribution of the animal density in a region in the long run. The optimal control solution presented, imbeds the solution for a large number of initial conditions (i.e., it has a feedback form), which is otherwise nontrivial to obtain. The solution obtained can be used in real-time by a nonexpert in control theory since it involves only using the neural networks trained offline. Proper orthogonal decomposition-based basis function design followed by their use in a Galerkin projection has been incorporated in the solution process as a model reduction technique. Optimal solutions are obtained through a "single network adaptive critic" (SNAC) neural-network architecture.

Sapientia, 1998, Vol. LIII, nº 204 (número completo)

Contenido: El tiempo como medida de la primera esfera en la Física de Aristóteles / Marcelo L. Imperiale – Verdad, tiempo y justicia. Un tema de la filosofía de Anselmo de Canterbury / Ubaldo Pérez Paoli – La aportación de Tomás de Aquino a la filosofía de la justicia / Carlos Ignacio Massini Correas – Libertad y naturaleza: la voluntad como naturaleza y como razón según Tomás de Aquino / Guillermo Eduardo Spiegel Sosa – La representación como desvelamiento en Tomás de Aquino / Patrica Moya C. – Las condiciones de una nueva teoría del ente natural tras la condena de 1277. La Physica de Walter Burley y sus peculiaridades / Olga L. Larre – Gewibheit und Wahrheit. Descartes’ Grundlegung der Ersten Philosophie / Wilhelm Metz – La noción aristotélico-tomista de verdad y su interpretación en “El ser y el tiempo” de Martin Heidegger / Silvana Filippi – Subjetivistas radicales y hermenéutica en la escuela austríaca de economía / Ricardo F. Crespo – Examen de los principios de la bioética contemporánea predominantes / Camilo Tale – Sguardi sulla fine dei tempi e sulle cose ultime. A proposito Della struttura escatologica del cristianísimo / Vittorio Possenti – Naturaleza teleológica: articulación entre ser, deber ser y virtud / Jorge Peña Vial -- ¿Qué es un doctor de la Iglesia? / Francisco Canals Vidal – Anotaciones sobre la recepción y la crítica de la metafísica tomista en el pensamiento contemporáneo / Mario Enrique Sacchi – Notas y comentarios -- Bibliografía

Interim report on salt-water encroachment in Dade County, Florida

Recently there has been much activity in reclaiming the low-lying coastal areas of Dade County for residential use, by the addition of fill. The fill is obtained by digging canals both normal to and parallel to Biscayne Bay. The canals serve the additional purpose of providing an access to the Bay for boats. A problem needing to be considered is the effect that these canals will have on the ground-water resources. It is expected that the canals will have little effect on ground water in parts of the county distant from the coast, but their effect in coastal areas is a matter of concern. In order to predict what, may happen in the vicinity of these new canals if they are not equipped with adequate control structures, it is instructive to review what has happened in the vicinity of similar canals in the past. The U. S. Geological Survey, in cooperation with Dade County, the cities of Miami and Miami Beach, the Central and Southern Florida Flood Control District, and the Florida Geological Survey has collected water-level and salinity data on wells and canals in Dade County since 1939. Some of the agencies named, and others, collected similar data before 1939. Analysis of all the data shows that sea water in the Atlantic Ocean and Biscayne Bayis the sole source of salt-water contamination in the Biscayne aquifer of the Dade County area. (PDF has 19 pages.)

Interim report on the hydrologic features of the Green Swamp area in Central Florida

The Green Swamp area in central Florida is another area where man is developing agricultural land from marginal land. Though the area is by no means as extensive as that of the Everglades, the present efforts for its development are similar to the early efforts for developing the Everglades in that many miles of canals and ditches have been constructed to improve the drainage. Lest the early mistakes of the Everglades be repeated, the Florida Department of Water Resources considered that an appraisal of the physical and hydrologic features of the area was needed to determine the broad effects of draining and developing the swamp. This reconnaissance provides information required by the State of Florida for determining its responsibility and policy in regard to the Green Swamp area and for formulating future plans for water management of the area. Some of the features that have been determined are: the amount of rainfall on the area; the pattern of surfacewater drainage; the amount and direction of surface-water runoff; the direction of ground-water movement; the interrelationship of rainfall, surface water, and ground water; the effects of improved drainage facilities'; and the effects of the hydrologic environment on the chemical quality of water of the area.(PDF contains 106 pages.)

Influence of Dilute Acetic Acid Treatments on American Pondweed Winter Buds in the Nevada Irrigation District, California

American pondweed ( Potamogeton nodosus Poir.) is commonly found in northern California irrigation canals. The purpose of this study was to test the hypothesis that exposure of American pondweed winter buds to dilute acetic acid under field conditions would result in reduced subsequent biomass.

Clearigate ® Treatments for Control of Giant Salvinia

Results of recent field trials using the chelated copper formulation Clearigate® 4 showed that applying a 20% solution by volume was effective for controlling populations of giant salvinia in irrigation canals. 5 Lower rates may be efficacious, thereby reducing chemical use and cost; however, little is known about the dose-response effects of Clearigate® against giant salvinia. The objective of this study was to determine the effective rate range of chelated copper applied as Clearigate® for control of giant salvinia.

Influence of Sediment Nutrients on Growth of Emergent Hygrophila

Hygrophila ( Hygrophila polysperma (Roxb.) T. Anderson) is a plants which forms serious aquatic weed problems. Both submerged and emergent growth forms occur. Nutritional studies with a controlled release fertilizer and sediments collected from hygrophila-infested areas were conducted with the emergent growth habit to provide insights into growth of this introduced plant. Plant dry weights for experimental 16- week culture periods with low average temperatures were associated with low amounts of hygrophila biomass as compared to culture periods with high average temperatures. Hygrophila cultured in sand rooting media with the controlled release fertilizer produced as much as 20 times more dry weight than plants cultured in sediments only. First-degree linear regression statistics showed hygrophila dry weights were highly related to ammonia nitrogen, magnesium, sodium, and pH values in the sediments. These findings show the close relationship of the emergent growth habit of hygrophila to sediment nutrients. Analyses for certain sediment characteristics may provide an indication of the potential growth that may be expected for weed infestations of this plant. Hygrophila grows year round in south Florida; however, visual observations of canals and other bodies of water indicate that lower amounts of hygrophila plants occur during the cooler months of year than during the summer season. These findings show the seasonal growth of emergent hygrophila occurs with biomass dependent on both sediment nutrients and temperature.

Extent and toxicity of contaminated marine sediments in Southeastern Florida

Thirty sites were sampled in southern Biscayne Bay and Manatee Bay in December 1999 to determine the extent of toxicity in sediments. Analyses and assays included: pesticides and phenols in seawater; chemical contaminants in sediment; amphipod mortality, HRGS P450, sea urchin sperm fertilization and embryology, MicrotoxTM, MutatoxTM, grass shrimp AChE and juvenile clam mortality assays; sea urchin sperm, amphipod and oyster DNA damage; and benthic community assessment. Sediment sites near the mouth of canals showed evidence of contamination. Contaminant plumes and associated toxicity do not appear to extend seaward of the mouth of the canals in an appreciable manner. Concentrations of contaminants in the sediments in open areas of Biscayne and Manatee Bays are generally low. (PDF contains 140 pages)

Magnitude and extent of chemical contamination and toxicity in sediments of Biscayne Bay and vicinity

The toxicity of sediments in Biscayne Bay and many adjoining tributaries was determined as part of a bioeffects assessments program managed by NOAA’s National Status and Trends Program. The objectives of the survey were to determine: (1) the incidence and degree of toxicity of sediments throughout the study area; (2) the spatial patterns (or gradients) in chemical contamination and toxicity, if any, throughout the study area; (3) the spatial extent of chemical contamination and toxicity; and (4) the statistical relationships between measures of toxicity and concentrations of chemicals in the sediments. The survey was designed to characterize sediment quality throughout the greater Biscayne Bay area. Surficial sediment samples were collected during 1995 and 1996 from 226 randomly-chosen locations throughout nine major regions. Laboratory toxicity tests were performed as indicators of potential ecotoxicological effects in sediments. A battery of tests was performed to generate information from different phases (components) of the sediments. Tests were selected to represent a range in toxicological endpoints from acute to chronic sublethal responses. Toxicological tests were conducted to measure: reduced survival of adult amphipods exposed to solid-phase sediments; impaired fertilization success and abnormal morphological development in gametes and embryos, respectively, of sea urchins exposed to pore waters; reduced metabolic activity of a marine bioluminescent bacteria exposed to organic solvent extracts; induction of a cytochrome P-450 reporter gene system in exposures to solvent extracts; and reduced reproductive success in marine copepods exposed to solid-phase sediments. Contamination and toxicity were most severe in several peripheral canals and tributaries, including the lower Miami River, adjoining the main axis of the bay. In the open basins of the bay, chemical concentrations and toxicity generally were higher in areas north of the Rickenbacker Causeway than south of it. Sediments from the main basins of the bay generally were less toxic than those from the adjoining tributaries and canals. The different toxicity tests, however, indicated differences in severity, incidence, spatial patterns, and spatial extent in toxicity. The most sensitive test among those performed on all samples, a bioassay of normal morphological development of sea urchin embryos, indicated toxicity was pervasive throughout the entire study area. The least sensitive test, an acute bioassay performed with a benthic amphipod, indicated toxicity was restricted to a very small percentage of the area. Both the degree and spatial extent of chemical contamination and toxicity in this study area were similar to or less severe than those observed in many other areas in the U.S. The spatial extent of toxicity in all four tests performed throughout the bay were comparable to the “national averages” calculated by NOAA from previous surveys conducted in a similar manner. Several trace metals occurred in concentrations in excess of those expected in reference sediments. Mixtures of substances, including pesticides, petroleum constituents, trace metals, and ammonia, were associated statistically with the measures of toxicity. Substances most elevated in concentration relative to numerical guidelines and associated with toxicity included polychlorinated biphenyls, DDT pesticides, polynuclear aromatic hydrocarbons, hexachloro cyclohexanes, lead, and mercury. These (and other) substances occurred in concentrations greater than effects-based guidelines in the samples that were most toxic in one or more of the tests. (PDF contains 180 pages)