1,721,247 research outputs found
Geomorphic change detection in Gadria-Strimm and Moscardo catchments, Italy
Full text linkMethods devoted to the assessment of geomorphic changes can be used to
identify geomorphologically unstable areas, to quantify processes intensity,
and to compute sediment budgets. Digital elevation models (DEMs) built
from repeated topographic surveys can be used to produce DEM of
Difference (DoD) maps whose analysis allows to study morphological
changes in slopes and channels from the quantitative (scour and fill
changes in volume) and the qualitative (spatial patterns of erosion and
deposition) perspectives (Scheidl et al., 2008; Theule et al., 2012; Picco et
al., 2013). The activity carried out by CNR IRPI (PP4) in the frame of the
SedAlp project focused on the analysis of multi temporal high-resolution
Digital Terrain Models (DTMs) derived by Airborne and Terrestrial LiDAR.
The aim is to analyse surface changes due to erosion and deposition in a
bedload and two debris-flow prone basins in the Eastern Italian Alps
(Strimm, Gadria and Moscardo pilot areas). The analysis was carried out at
different temporal and spatial scales basically related to the typology of the
adopted surveying method. In Gadria and Strimm catchments, where two
airborne LiDAR (2005 and 2011) are available, geomorphic changes
induced by debris flows and landslides were investigated at catchment
scale. DoD results have been then compared with field estimations stored
in a historical database. In the Moscardo catchment, Terrestrial Laser
Scanner (TLS) has been used to survey three representative areas of the
catchment in a small time window (August 2011-October 2012). Results of
volumetric budgets of the surveyed sediment source areas derived from
DoD analysis have been compared with debris-flow volumes estimated
from flow stage measurements at the instrumented channel reach
Airborne LiDAR as a new tool for fluvial geomorphology
No full textDetailed topographic data are important for both quantitative and qualitative fluvial studies. Topographic data
available from traditional topographic maps are often not sufficiently accurate to detect, and map all relevant landform
features. Moreover, traditional ground surveys may exert a high demand on operator time and cost. The airborne laser
altimetry technology known as airborne LiDAR (Light Detection And Ranging) provides very accurate topographical
data (vertical accuracy of few centimeters), which can significantly contribute to a better representation of land
surface. A valuable characteristic of this technology is the capability to derive high-resolution Digital Terrain Models
(DTMs) (1-2 m) from ground points generated after removal of vegetation and man-made features.
LiDAR data have been widely applied in all geomorphological fields, especially for studying landslides and soil erosion.
In fluvial geomorphology, the first studies used LiDAR data mainly to improve numerical flood models. Recently,
applications in the same field concern studies estimating mapping gravel-bed river geomorphology (Charlton, 2003),
rapid geomorphological mapping of river valley environments (Jones et al., 2007), evaluating the river long-term
changes created by fluvial and debris flow activity (Magirl et al., 2005), tidal channel geomorphology (Mason et al.,
2006), and objectively mapping of channel network (Tarolli and Dalla Fontana, 2009). Volumetric assessments of
geomorphic change made by differencing sequential LiDAR-derived DTMs can be used to obtain distributed patterns of
erosion and deposition, to compute sediment budget and thereby quantify rates of active fluvial processes, such as
river bank erosion (Thoma et al., 2005).
Nevertheless, significant errors in airborne LiDAR-derived DTMs can be due to the filtering process required to derive
points belonging to the ground surface, and be associated to the presence of deep water. An assessment of the quality
of the LiDAR data is therefore necessary before utilization. It is worth noting that in the last few years significant
advances have been made with the airborne LiDAR bathymetry (ALB) technology, which allows the representation of
river channel bed even under deep water.
In the headwater environment, airborne LiDAR technique has been proven useful in identifying and mapping gullies,
and measuring small ephemeral channels, even under forest cover (James et al., 2007). Where water depth is not
exceeding few tens of centimeters, LiDAR data can be used for characterizing channel bed morphology by
differentiating step pools from riffle pool reaches through measure of bed surface roughness (Cavalli et al., 2008).
These applications highlight the clear potential of airborne LiDAR technology offering new opportunities but also
challenges in fluvial geomorphology research
From Proteins to Nucleic Acid-Based Drugs: The Role of Biotech in Anti-VEGF Therapy
No full textCancer cells, by releasing pro-angiogenic factors, stimulate the growth of the thick capillary net necessary for the nourishment of the tumor mass. The battle to defeat cancer uses today different approaches based on the inhibition of pathological angiogenesis: several compounds, either synthetic or biotech, aimed at this complex process, are under development. Vascular endothelial growth factor (VEGF) is considered the main target for an anti-cancer therapy based on angiogenesis inhibition; the goal is to block the interaction between this cytokine and its receptors in order to stop the intracellular signaling pathways leading to endothelium remodeling. FDA recently approved two drugs specifically aimed at VEGF, bevacizumab, a humanized monoclonal antibody, and pegaptinib, a pegylated aptamer with application in ophthalmic pathologies. These two approvals validate anti-VEGF therapy for clinical use, and show how biotech companies are investing on angiogenesis using different approaches, i.e. exploiting protein drugs and oligonucleotide-based therapeutics. Monoclonal antibodies, as well as other high molecular weight products like cytokine-traps, aptamers and short interfering RNA (siRNA), are designed to target VEGF and its receptors. Their design, production and clinical advancement in cancer and other pathological conditions linked to angiogenesis will be specifically addressed in this review
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The effectiveness of airborne LiDAR data in the recognition of channel bed morphology
No full textHigh-resolution topographic data have the potential to differentiate the main morphological features of a landscape. This paper analyses the capability of airborne LiDAR-derived data in the recognition of channel-bed morphology. For the purpose of this study, 0.5 m and 1 m resolution Digital Terrain Models (DTMs) were derived from the last pulse LiDAR data obtained by filtering the vegetation points. The analysis was carried out both at 1-D scale, i.e. along the longitudinal channel profile, and at 2-D scale, taking into account the whole extent of the channel bed. The 1-D approach analyzed the residuals of elevations orthogonal to the regression line drawn along the channel profile and the standard deviation of local slope. The 2-D analysis was based on two roughness indexes, consisting on the local variability of the elevation and slope of the channel bed. The study was conducted in a headwater catchment located in the Eastern Italian Alps. The results suggested a good capability of LiDAR data in the recognition of river morphology giving the potential to distinguish the riffle-pool and step-pool reaches
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Pubic inguinal pain syndrome: the so-called sports hernia
No full textThe "sportsman's hernia" commonly presents as a painful groin in those sports that involve kicking and twisting movements while running, particularly in rugby, football, soccer, and ice hockey players. Moreover, sportsman's hernia can be encountered even in normally physically active people. The pain experienced is recognized at the common point of origin of the rectus abdominis muscle and the adductor longus tendon on the pubic bone and the insertion of the inguinal ligament on the pubic bone. It is accepted that this chronic pain caused by abdominal wall weakness or injury occurs without a palpable hernia. We proposed the new name "pubic inguinal pain syndrome." In the period between January 2006 and November 2013 all patients afferent in our ambulatory clinic for chronic groin pain without a clinically evident hernia were assessed with medical history, physical examination, dynamic ultrasound, and pelvic and lumbar MRI. All patients were proposed for a conservative treatment and then, if it was not effective, for a surgical treatment. Our etiopathogenetic theory is based on three factors: (1) the compression of the three nerves of the inguinal region, (2) the imbalance in strength of adductor and abdominal wall muscles caused by the hypertrophy and stiffness of the insertion of rectus muscle and adductor longus muscle, and (3) the partial weakness of the posterior wall. Our surgical procedure includes the release of all three nerves of the region, the correction of the imbalance in strength with the partial tenotomy of the rectus and adductor longus muscles, and the repair of the partial weakness of the posterior wall with a lightweight mesh. This treatment reported excellent results with complete relief of symptoms after resumption of physical activity in all cases
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