Mangrove growth along the Harney River

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Benthic and substrate cover data derived from photo-transect surveys in Lizard Island Reef conducted on December 10-15, 2011

Underwater georeferenced photo-transect surveys were conducted on December 10-15, 2011 at various sections of the reef at Lizard Island, Great Barrier Reef. For this survey a snorkeler or diver swam over the bottom while taking photos of the benthos at a set height using a standard digital camera and towing a GPS in a surface float which logged the track every five seconds. A standard digital compact camera was placed in an underwater housing and fitted with a 16 mm lens which provided a 1.0 m x 1.0 m footprint, at 0.5 m height above the benthos. Horizontal distance between photos was estimated by three fin kicks of the survey diver/snorkeler, which corresponded to a surface distance of approximately 2.0 - 4.0 m. The GPS was placed in a dry-bag and logged the position as it floated at the surface while being towed by the photographer. A total of 5,735 benthic photos were taken. A floating GPS setup connected to the swimmer/diver by a line enabled recording of coordinates of each benthic photo (Roelfsema 2009). Approximation of coordinates of each benthic photo was conducted based on the photo timestamp and GPS coordinate time stamp, using GPS Photo Link Software (www.geospatialexperts.com). Coordinates of each photo were interpolated by finding the GPS coordinates that were logged at a set time before and after the photo was captured. Benthic or substrate cover data was derived from each photo by randomly placing 24 points over each image using the Coral Point Count for Microsoft Excel program (Kohler and Gill, 2006). Each point was then assigned to 1 of 78 cover types, which represented the benthic feature beneath it. Benthic cover composition summary of each photo scores was generated automatically using CPCE program. The resulting benthic cover data of each photo was linked to GPS coordinates, saved as an ArcMap point shapefile, and projected to Universal Transverse Mercator WGS84 Zone 55 South.

Benthic and substrate cover data derived from photo-transect surveys in Lizard Island, Great Barrier Reef conducted on October 3-7, 2012

Underwater georeferenced photo-transect surveys were conducted on October 3-7, 2012 at various sections of the reef and lagoon at Lizard Island, Great Barrier Reef. For this survey a snorkeler swam while taking photos of the benthos at a set distance from the benthos using a standard digital camera and towing a GPS in a surface float which logged the track every five seconds. A Canon G12 digital camera was placed in a Canon underwater housing and photos were taken at 1 m height above the benthos. Horizontal distance between photos was estimated by three fin kicks of the survey snorkeler, which corresponded to a surface distance of approximately 2.0 - 4.0 m. The GPS was placed in a dry bag and logged the position at the surface while being towed by the photographer (Roelfsema, 2009). A total of 1,265 benthic photos were taken. Approximation of coordinates of each benthic photo was conducted based on the photo timestamp and GPS coordinate time stamp, using GPS Photo Link Software (www.geospatialexperts.com). Coordinates of each photo were interpolated by finding the GPS coordinates that were logged at a set time before and after the photo was captured. Benthic or substrate cover data was derived from each photo by randomly placing 24 points over each image using the Coral Point Count for Microsoft Excel program (Kohler and Gill, 2006). Each point was then assigned to 1 of 79 cover types, which represented the benthic feature beneath it. Benthic cover composition summary of each photo scores was generated automatically using CPCE program. The resulting benthic cover data of each photo was linked to GPS coordinates, saved as an ArcMap point shapefile, and projected to Universal Transverse Mercator WGS84 Zone 55 South.

Principal Component Analysis of Results Obtained from Finite-Difference Time-Domain Algorithms

Finite-Differences Time-Domain (FDTD) algorithms are well established tools of computational electromagnetism. Because of their practical implementation as computer codes, they are affected by many numerical artefact and noise. In order to obtain better results we propose using Principal Component Analysis (PCA) based on multivariate statistical techniques. The PCA has been successfully used for the analysis of noise and spatial temporal structure in a sequence of images. It allows a straightforward discrimination between the numerical noise and the actual electromagnetic variables, and the quantitative estimation of their respective contributions. Besides, The GDTD results can be filtered to clean the effect of the noise. In this contribution we will show how the method can be applied to several FDTD simulations: the propagation of a pulse in vacuum, the analysis of two-dimensional photonic crystals. In this last case, PCA has revealed hidden electromagnetic structures related to actual modes of the photonic crystal.

Metastatic meningioma: positron emission tomography CT imaging findings

The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy.

A Micro-Opto-Electro-Mechanical System (MOEMS) for Microstructure Manipulation

Microstructure manipulation is a fundamental process to the study of biology and medicine, as well as to advance micro- and nano-system applications. Manipulation of microstructures has been achieved through various microgripper devices developed recently, which lead to advances in micromachine assembly, and single cell manipulation, among others. Only two kinds of integrated feedback have been demonstrated so far, force sensing and optical binary feedback. As a result, the physical, mechanical, optical, and chemical information about the microstructure under study must be extracted from macroscopic instrumentation, such as confocal fluorescence microscopy and Raman spectroscopy. In this research work, novel Micro-Opto-Electro-Mechanical-System (MOEMS) microgrippers are presented. These devices utilize flexible optical waveguides as gripping arms, which provide the physical means for grasping a microobject, while simultaneously enabling light to be delivered and collected. This unique capability allows extensive optical characterization of the structure being held such as transmission, reflection, or fluorescence. The microgrippers require external actuation which was accomplished by two methods: initially with a micrometer screw, and later with a piezoelectric actuator. Thanks to a novel actuation mechanism, the “fishbone”, the gripping facets remain parallel within 1 degree. The design, simulation, fabrication, and characterization are systematically presented. The devices mechanical operation was verified by means of 3D finite element analysis simulations. Also, the optical performance and losses were simulated by the 3D-to-2D effective index (finite difference time domain FDTD) method as well as 3D Beam Propagation Method (3D-BPM). The microgrippers were designed to manipulate structures from submicron dimensions up to approximately 100 µm. The devices were implemented in SU-8 due to its suitable optical and mechanical properties. This work demonstrates two practical applications: the manipulation of single SKOV-3 human ovarian carcinoma cells, and the detection and identification of microparts tagged with a fluorescent “barcode” implemented with quantum dots. The novel devices presented open up new possibilities in the field of micromanipulation at the microscale, scalable to the nano-domain.

Acción política y participación de las y los jóvenes de escuelas secundarias de la ciudad de La Plata

Esta investigación sobre la relación que establecen los jóvenes con la política busca interpretar analíticamente las formas a través de las cuales las y los estudiantes secundarios de la ciudad de La Plata participan políticamente. Desde la segunda mitad del siglo XX diversos estudios provenientes de campos como la sociología, la antropología y la teoría política, colocaron en el centro del debate teórico dimensiones clásicas del análisis de lo social (el Estado, las esferas pública y privada, lo político). Allí aparece una nueva problemática en torno del lazo social y la pluralidad de formas que asume la acción política. En ese contexto, emergen preguntas sobre las acciones políticas de jóvenes escolarizados y su relación con el contexto de surgimiento. E0ste análisis brindará elementos interesantes a partir de los cuales realizar una lectura epocal que recupere las formas y sentidos bajo los cuales las y los jóvenes desarrollan en la actualidad la acción política. El propósito de esta investigación es conocer e interpretar las formas que asume hoy la acción política juvenil estudiantil en la ciudad de La Plata, en torno a qué contenidos e intereses participan, bajo que formatos, cuáles son los territorios y estrategias que despliegan. Se utilizan tres categorías para describir las prácticas más características que se encuentran en nuestro campo: trayectorias de participación, enfoque de derechos humanos y performance. Por último, la investigación busca comprender las posibles variaciones de prácticas de acción política en función de las propuestas de escolarización de la que participan como alumnas y alumnos de escuelas secundarias

Acción política y participación de las y los jóvenes de escuelas secundarias de la ciudad de La Plata

Esta investigación sobre la relación que establecen los jóvenes con la política busca interpretar analíticamente las formas a través de las cuales las y los estudiantes secundarios de la ciudad de La Plata participan políticamente. Desde la segunda mitad del siglo XX diversos estudios provenientes de campos como la sociología, la antropología y la teoría política, colocaron en el centro del debate teórico dimensiones clásicas del análisis de lo social (el Estado, las esferas pública y privada, lo político). Allí aparece una nueva problemática en torno del lazo social y la pluralidad de formas que asume la acción política. En ese contexto, emergen preguntas sobre las acciones políticas de jóvenes escolarizados y su relación con el contexto de surgimiento. E0ste análisis brindará elementos interesantes a partir de los cuales realizar una lectura epocal que recupere las formas y sentidos bajo los cuales las y los jóvenes desarrollan en la actualidad la acción política. El propósito de esta investigación es conocer e interpretar las formas que asume hoy la acción política juvenil estudiantil en la ciudad de La Plata, en torno a qué contenidos e intereses participan, bajo que formatos, cuáles son los territorios y estrategias que despliegan. Se utilizan tres categorías para describir las prácticas más características que se encuentran en nuestro campo: trayectorias de participación, enfoque de derechos humanos y performance. Por último, la investigación busca comprender las posibles variaciones de prácticas de acción política en función de las propuestas de escolarización de la que participan como alumnas y alumnos de escuelas secundarias

Acción política y participación de las y los jóvenes de escuelas secundarias de la ciudad de La Plata

Esta investigación sobre la relación que establecen los jóvenes con la política busca interpretar analíticamente las formas a través de las cuales las y los estudiantes secundarios de la ciudad de La Plata participan políticamente. Desde la segunda mitad del siglo XX diversos estudios provenientes de campos como la sociología, la antropología y la teoría política, colocaron en el centro del debate teórico dimensiones clásicas del análisis de lo social (el Estado, las esferas pública y privada, lo político). Allí aparece una nueva problemática en torno del lazo social y la pluralidad de formas que asume la acción política. En ese contexto, emergen preguntas sobre las acciones políticas de jóvenes escolarizados y su relación con el contexto de surgimiento. E0ste análisis brindará elementos interesantes a partir de los cuales realizar una lectura epocal que recupere las formas y sentidos bajo los cuales las y los jóvenes desarrollan en la actualidad la acción política. El propósito de esta investigación es conocer e interpretar las formas que asume hoy la acción política juvenil estudiantil en la ciudad de La Plata, en torno a qué contenidos e intereses participan, bajo que formatos, cuáles son los territorios y estrategias que despliegan. Se utilizan tres categorías para describir las prácticas más características que se encuentran en nuestro campo: trayectorias de participación, enfoque de derechos humanos y performance. Por último, la investigación busca comprender las posibles variaciones de prácticas de acción política en función de las propuestas de escolarización de la que participan como alumnas y alumnos de escuelas secundarias

Talos Dome Ice Core Deuterium Data

During the 1996 Programma Nazionale di Ricerche in Antartide-International Trans-Antarctic Scientific Expedition traverse, two firn cores were retrieved from the Talos Dome area (East Antarctica) at elevations of 2316 m (TD, 89 m long) and 2246 m (ST556, 19 m long). Cores were dated by using seasonal variations in non-sea-salt (nss) SO42- concentrations coupled with the recognition of tritium marker level (1965-1966) and nss SO42- spikes due to the most important volcanic events in the past (Pinatubo 1991, Agung 1963, Krakatoa 1883, Tambora 1815, Kuwae 1452, Unknown 1259). The number of annual layers recognized in the TD and ST556 cores was 779 and 97, respectively. The dD record obtained from the TD core has been compared with other East Antarctic isotope ice core records (Dome C EPICA, South Pole, Taylor Dome). These records suggest cooler climate conditions between the middle of 16th and the beginning of 19th centuries, which might be related to the Little Ice Age (LIA) cold period. Because of the high degree of geographical variability, the strongest LIA cooling was not temporally synchronous over East Antarctica, and the analyzed records do not provide a coherent picture for East Antarctica. The accumulation rate record presented for the TD core shows a decrease during part of the LIA followed by an increment of about 11% in accumulation during the 20th century. At the ST556 site, the accumulation rate observed during the 20th century was quite stable.

Modelling responses to spatially fractionated radiation fields using preclinical image-guided radiotherapy

OBJECTIVES: Radiotherapy is planned to achieve the optimal physical dose distribution to the target tumour volume whilst minimising dose to the surrounding normal tissue. Recent in vitro experimental evidence has demonstrated an important role for intercellular communication in radiobiological responses following non-uniform exposures. This study aimed to model the impact of these effects in the context of techniques involving highly modulated radiation fields or spatially fractionated treatments such as GRID therapy.

METHODS: Using the small animal radiotherapy research platform (SARRP) as a key enabling technology to deliver precision imaged-guided radiotherapy, it is possible to achieve spatially modulated dose distributions that model typical clinical scenarios. In this work, we planned uniform and spatially fractionated dose distributions using multiple isocentres with beam sizes of 0.5 - 5 mm to obtain 50% volume coverage in a subcutaneous murine tumour model, and applied a model of cellular response that incorporates intercellular communication to assess the potential impact of signalling effects with different ranges.

RESULTS: Models of GRID treatment plans which incorporate intercellular signalling showed increased cell killing within the low dose region. This results in an increase in the Equivalent Uniform Dose (EUD) for GRID exposures compared to standard models, with some GRID exposures being predicted to be more effective than uniform delivery of the same physical dose.

CONCLUSIONS: This study demonstrates the potential impact of radiation induced signalling on tumour cell response for spatially fractionated therapies and identifies key experiments to validate this model and quantify these effects in vivo.

ADVANCES IN KNOWLEDGE: This study highlights the unique opportunities now possible using advanced preclinical techniques to develop a foundation for biophysical optimisation in radiotherapy treatment planning.

Fiducial Marker Guided Prostate Radiotherapy: A Review

Image guided radiotherapy (IGRT) is an essential tool in the accurate delivery of modern radiotherapy techniques. Prostate radiotherapy positioned using skin marks or bony anatomy may be adequate for delivering a relatively homogenous whole pelvic radiotherapy dose but these are not reliable when using reduced margins, dose escalation or hypo-fractionated stereotactic radiotherapy. Fiducial markers (FMs) for prostate IGRT have been in use since the 1990's. They require surgical implantation and provide a surrogate for the position of the prostate gland. A variety of FMs are available and they can be used in a number of ways. This review aims to establish the evidence for using prostate FMs in terms of feasibility, implantation procedures, types of FMs used, FM migration, imaging modalities used and the clinical impact of FMs. A search strategy was defined and a literature search was carried out in Medline. Inclusion and exclusion criteria were applied which resulted in 50 papers being included in this review. The evidence demonstrates that FMs provide a more accurate surrogate for the position of the prostate than either external skin marks or bony anatomy. A combination of FM alignment and soft tissue analysis is currently the most effective and widely available approach to ensuring accuracy in prostate IGRT. FM implantation is safe and well tolerated. FM migration is possible but minimal. Standardisation of all techniques and procedures in relation to the use of prostate FMs is required. Finally a clinical trial investigating a non-surgical alternative to prostate FMS is introduced.