Topographic Evidence Research Articles

Reproducibility of keratometric measurements obtained with OCULUS® Pentacam® HR in the evaluation of keratoconus progression

AbstractPurpose To determine the reproducibility of keratometric parameters obtained by OCULUS® Pentacam® HR in the evaluation of keratoconus progression.Methods Thirty nine eyes of 25 patients from the Cornea Department of the Centro Hospitalar de Lisboa Central were included in the study. Fourteen eyes presented with clinical and topographic diagnosis of keratoconus (stage 1‐3) and were defined as the “keratoconus without ring” group; 9 eyes had already an intrastromal ring implanted and were defined as the “keratoconus with ring”; the remaining 16 eyes, without clinical or topographic evidence of disease, were used as controls. Every eye was submitted to identical methodology: 5 consecutive keratometric measurements obtained with OCULUS® Pentacam® HR; central keratometry, SKmax, minimal pachymetry and anterior chamber depth were used to determine the existence of statistically significant reproducibility.Results Overall significant measurement variability was obtained in the “keratoconus without ring” group (Km 0.129 D vs 0.0375 D, SKmax 0.507 D vs 0.0625 D, Minpach 5.429 μm vs 2.5625 μm, ACD 0.024 mm vs 0.0194 mm), with highest variability in the subgroup of patients with more advanced disease. In the “keratoconus with ring” group statistically significant variability was found for all parameters except for anterior chamber depth (Km 0.289 D vs 0.0375 D, SKmax 0.444 D vs 0.0625 D, Minpach 4.333 μm vs 2.5625 μm, ACD 0.024 mm vs 0.0194 mm).Conclusion Keratometric measurements obtained with OCULUS® Pentacam® HR should be assessed cautiously in the evaluation of keratoconus progression, with or without intrastromal ring; the use of single measurements is unadvised.

Accelerated versus conventional corneal collagen cross-linking in the treatment of mild keratoconus: a comparative study.

AimTo evaluate the use of accelerated corneal collagen cross-linking in the management of mild and moderate progressive keratoconus in comparison with conventional cross-linking.Patients and methodsProspective randomized interventional case-control clinical trial. A total 25 eyes of 18 patients were randomly divided into two groups: group A included 14 eyes that received accelerated collagen cross-linking; and group B included eleven eyes that received conventional cross-linking (Dresden protocol). Cases with grade 1 and 2 keratoconus (Krumeich classification) with topographic evidence of progression were included. The uncorrected visual acuity and best spectacle-corrected visual acuity were recorded. Pentacam® corneal analysis imaging was used: The maximum and minimum keratometry and the central corneal thickness were recorded. Ocular Response Analyzer® (ORA) measurements were carried out to document the biomechanical parameters. Corneal hysteresis and corneal resistance factor were recorded. Postoperative evaluation included uncorrected visual acuity, best corrected visual acuity, and Pentacam and ORA measurements at 6 and 12 months. The follow-up period was 12 months.ResultsA progressive decrease in the flat keratometry, steep keratometry, and mean keratometry was noted throughout the follow-up period in both the accelerated and conventional groups. The improvement in keratometry was not statistically significant. The best spectacle-corrected visual acuity showed a statistically significant improvement in both groups by 1 year. The corneal hysteresis and corneal resistance factor showed nonsignificant improvement in both groups. The central corneal thickness showed a significant thinning at 6 months in both groups but approached baseline values by 12 months.ConclusionAccelerated corneal collagen cross-linking appears to show comparable results to conventional cross-linking in arresting the progression of mild keratoconus.

Volcanic evolution of the South Sandwich volcanic arc, South Atlantic, from multibeam bathymetry

New multibeam bathymetry data are presented for the South Sandwich intra-oceanic arc which occupies the small Sandwich plate in the South Atlantic, and is widely considered to be a simple end-member in the range of intra-oceanic arc types. The images show for the first time the distribution of submarine volcanic, tectonic and erosional–depositional features along the whole length of the 540km long volcanic arc, allowing systematic investigation of along-arc variations. The data confirm that the volcanic arc has a simple structure composed of large volcanoes which form a well-defined volcanic front, but with three parallel cross-cutting seamount chains extending 38–60km from near the volcanic front into the rear-arc. There is no evidence for intra-arc rifting or extinct volcanic lines. Topographic evidence for faulting is generally absent, except near the northern and southern plate boundaries. Most of the volcanic arc appears to be built on ocean crust formed at the associated back-arc spreading centre, as previously proposed from magnetic data, but the southern part of the arc appears to be underlain by older arc or continental crust whose west-facing rifted margin facing the back-arc basin is defined by the new bathymetry. The new survey shows nine main volcanic edifices along the volcanic front and ca. 20 main seamounts. The main volcanoes form largely glaciated islands with summits 3.0–3.5km above base levels which are 2500–3000m deep in the north and shallower at 2000–2500m deep in the south. Some of the component seamounts are interpreted to have been active since the last glacial maximum, and so are approximately contemporaneous with the volcanic front volcanism. Seven calderas, all either submarine or ice-filled, have been identified: Adventure volcano, a newly discovered submarine volcanic front caldera volcano is described for the first time. All but one of the calderas are situated on summits of large volcanoes in the southern part of the arc, and most are associated with current or historic volcanic or hydrothermal activity. Shallow shelves around the islands are generally 1–10km wide. Submerged banks up to 1100m deep are interpreted as subsided erosional surfaces. Seamounts and emergent volcanoes experienced a range of mass wasting processes including by landsliding and smaller mass flows.

Evidence for ring-faults around the Orientale basin on the Moon from gravity

The Orientale basin is the best-preserved multi-ring impact basin on the Moon, spanning ∼900km in diameter at its outermost ring. It consists of three concentric ring structures known as the Inner Rook, Outer Rook, and Cordillera. Based on geologic and topographic evidence, the Cordillera ring has been interpreted as forming through listric normal faulting from the inward collapse of the interior basin. A similar mechanism may have been responsible for the formation of the Outer Rook, though it has also been interpreted as the rim corresponding to the collapsed excavation cavity. This study uses gravity and topography data to examine the subsurface structure of the Orientale rings. A Markov chain Monte Carlo approach was implemented to find the best-fit fault dip and displacement, as well as the depth to an intra-crustal density interface and the density contrast across that interface. We find that the data supports the presence of a low-angle normal fault beneath the Cordillera ring that offsets a shallow interface separating a lower density upper crust from a higher density lower crust. The best-fit solution for the case of faults at both the Cordillera and Outer Rook has a vertical component of fault displacement of 7.8km, a fault dip of 28°, an intra-crustal interface depth of 10.8km, and a density contrast of 350kg/m3 between the upper and lower crust. However, models with faults only at the Cordillera or with faults that do not cross the crust–mantle interface also provide adequate fits to the data. This analysis presents quantitative evidence for the existence of faults beneath the rings of Orientale and for density stratification of the crust beneath the basin based on gravity data.

A branching, positive relief network in the middle member of the Medusae Fossae Formation, equatorial Mars—Evidence for sapping?

The Medusae Fossae Formation (MFF) is a geological formation comprising three geological units (members) spread across five principal lobes. It dominates a quarter of the longitudinal extent of the equatorial region of Mars. Positive relief features referred to as ‘sinuous ridges’ (commonly interpreted as inverted paleoflow channel or valley fills) have been observed in the lowest member of the western MFF, but have not been identified within the central and eastern portions of the formation, in the middle and upper members. This paper presents the identification and analysis of a branching, positive relief system which occurs in the central lobe of the MFF in what appears to be an exposure of the middle member. A simple geomorphological map of the system is presented, from which we have adopted the working hypothesis that this is an inverted fill of a branching fluvial channel or valley system. A suite of morphological and topographic evidence supporting this hypothesis is presented, including analysis of the network using a ∼15m/pixel digital terrain model derived from a Context Imager (CTX) stereo image pair. The evidence supporting this hypothesis includes: (1) the local slope and topography of the upper surface of the network are consistent with a contributory network; (2) the braided, fan-like form at the termination of the branching network is consistent in morphology with it being a depositional fan at the end of a fluvial system; (3) the terminal fan and surrounding deposits show layering and polygonization; and (4) there is strong association between the lower order branches and amphitheater shaped scarps in the depression walls. We evaluate the possible origins of this fluvial system and suggest that seepage sapping is the most probable. Two possible models for the evolution of the network and related features are presented; both require melt of ice within the MFF to form liquid water. We conclude that at least some portions of the Medusae Fossae Formation, if not the entire formation, were once volatile-rich. Finally, we note that our observations do not rule out the case that this network formed before MFF emplacement, and has since been exhumed. However, this conclusion would suggest that much of the surrounding terrain, currently mapped as middle-member MFF, is not in fact MFF material at all.

Monumentalising the political landscape: a special class of Anglo-Saxon assembly site

This paper outlines the place-name, archaeological and topographical evidence for a special class of Anglo-Saxon open-air assembly site, which we call a ‘hanging promontory’. Discussion of a series of these sites serves to describe the main characteristics of the class as well as their geographical distribution. Consideration is given to the possible functions and dating of the use of hanging promontories. In conclusion, comparisons are drawn with other forms of open-air assembly site to suggest a possible hierarchy of the administrative territories existing in the early medieval period in England.

Keratoconus: A biomechanical perspective on loss of corneal stiffness

Keratoconus (KC) is progressive disease of corneal thinning, steepening and collagen degradation. Biomechanics of the cornea is maintained by the intricate collagen network, which is responsible for its unique shape and function. With the disruption of this collagen network, the cornea loses its shape and function, resulting in progressive visual degradation. While KC is essentially a stromal disease, there is evidence that the epithelium undergoes significant thinning similar to the stroma. Several topographical approaches have been developed to detect KC early. However, it is now hypothesized that biomechanical destabilization of the cornea may precede topographic evidence of KC. Biomechanics of KC has been investigated only to a limited extent due to lack of in vivo measurement techniques and/or devices. In this review, we focus on recent work performed to characterize the biomechanical characteristics of KC.

CONTINUING THE DEBATE ON ROME'S EARLIEST CIRCUIT WALLS

Rome's pre-Imperial circuit walls pose a particular problem of reconstruction: collectively, their 11 km course represents the largest single monument of the early city, but our understanding of this structure is based on an assemblage of several dozen disparate archaeological sites. After tracing the interpretation of these fragments from antiquity to the present, this article examines the literary, topographical and archaeological evidence for the wall's character and date. Ultimately, the non-archaeological data are inconclusive, and the material evidence seems to affirm an early phase (sixth centurybc) focused on individual hilltops, rather than encompassing all hills within a full course. Following this logic, I continue to question the presence of a unified circuit wall at Rome prior to the mid-Republic (fourth centurybc). A concluding section reviews the historical circumstances in support of this view.

Evolution of multilevel caves in the Sierra de Atapuerca (Burgos, Spain) and its relation to human occupation

The evolution of the Torcas cave system (Sierra de Atapuerca) is analysed in order to shed light on the formation of the Atapuerca archaeological sites and human occupation in the area, critical for identifying the paths of the first human dispersal into Europe. The geomorphological analysis of the endokarst system and the regional base levels has revealed a multilevel cave system, with drainage directions from south to north, where old karst springs fed the Pico River. Using morphological and topographic evidence we have correlated the fluvial terraces situated at relative heights of +84–80m and +78–70m above the Arlanzón River (main course), with the first and second cave levels, respectively, both of Early Pleistocene age. The fluvial levels T4 (+60–67m) and T5 (+50–54m) are linked with the third level (Early–Middle Pleistocene), which contains fluvial deposits probably related to terrace T6 (+44–46m). Progressive fluvial incision allowed humans to gain access to the cave system through several entrances from ~1.22Myr until the end of the Middle Pleistocene, when these cave entrances became filled, forming the most interesting hominid-bearing deposits in Europe.

On the causes of the great damage from the tsunami of March 11, 2011 on the northeast coast of Honshu Island

The catastrophic effects of the March 11, 2011 tsunami on the most affected parts of the northeastern Honshu coast are considered. An analysis of topographic maps and evidences of paleotsunamis and the tsunamis occurring in historical time and instrumental period clearly show the high probability of tsunami occurrence and the high vulnerability of the territory to them. We concluded that the principal factors of the tsunami’s catastrophic effects were land use and buildings without taking into account the factors indicated. The main features determining coast vulnerability to tsunamis are considered.

Topography-guided hyperopic and hyperopic astigmatism femtosecond laser-assisted LASIK: long-term experience with the 400 Hz eye-Q excimer platform

The purpose of this study was to evaluate the safety and efficacy of topography-guided ablation using the WaveLight 400 Hz excimer laser in laser-assisted in situ keratomileusis (LASIK) for hyperopia and/or hyperopic astigmatism. We prospectively evaluated 208 consecutive LASIK cases for hyperopia with or without astigmatism using the topography-guided platform of the 400 Hz Eye-Q excimer system. The mean preoperative sphere value was +3.04 ± 1.75 (range 0.75-7.25) diopters (D) and the mean cylinder value was -1.24 ± 1.41 (-4.75-0) D. Flaps were created either with Intralase FS60 (AMO, Irvine, CA) or FS200 (Alcon, Fort Worth, TX) femtosecond lasers. Parameters evaluated included age, preoperative and postoperative refractive error, uncorrected distance visual acuity, corrected distance visual acuity, flap diameter and thickness, topographic changes, higher order aberration changes, and low contrast sensitivity. These measurements were repeated postoperatively at regular intervals for at least 24 months. Two hundred and two eyes were available for follow-up at 24 months. Uncorrected distance visual acuity improved from 5.5/10 to 9.2/10. At 24 (8-37) months, 75.5% of the eyes were in the ±0.50 D range and 94.4% were in the ±1.00 D range of the refractive goal. Postoperatively, the mean sphere value was -0.39 ± 0.3 and the cylinder value was -0.35 ± 0.25. Topographic evidence showed that ablation was made in the visual axis and not in the center of the cornea, thus correlating with the angle kappa. No significant complications were encountered in this small group of patients. Hyperopic LASIK utilizing the topography-guided platform of the 400 Hz Eye-Q Allegretto excimer and a femtosecond laser flap appears to be safe and effective for correction of hyperopia and/or hyperopic astigmatism. The results are impressive for refractive error correction and stability and for improvement of both uncorrected and corrected distance visual acuity.

Ten year follow up of laser in situ keratomileusis for all levels of myopia

Editor, In 2004, we performed a retrospective study assessing the refractive and visual outcome of patients 5 years post laser in situ keratomileusis (LASIK) surgery for all levels of myopia (O’Doherty et al. 2006). All 49 patients (94 eyes) in the original study were invited to attend for a 10-year review. Thirty patients (54 eyes) attended for examination. The original range of myopia treated was from −1.5 to −13 dioptres. The eyes were grouped into mild (<−3 D), moderate (−3 to −6 D) and high (>−6D) myopia. All surgery was performed by one experienced surgeon (MO’K) using the Bausch and Lomb Technolas 217 laser platform (Bausch & Lomb, Surrey, UK). The treatment algorithm used was the plano programme. Flaps were cut to a depth of 140 μm using the Hansatome microkeratome (Bausch and Lomb) and hinged superiorly with a flap diameter of 8.5–9.5 mm. The ablation zone ranged from 6 to 7 mm. At 10-year follow-up, uncorrected (UCVA), best corrected visual acuity (BCVA), manifest refractive spherical equivalent (MRSE), corneal topography and aberrometry were measured. Patients completed a questionnaire regarding satisfaction with LASIK. Questions asked included those relating to symptoms of dry eye and night vision problems such as glare and haloes. Regression was measured in this study as eyes that had regressed more than 0.5 dioptres. Of the 94 eyes originally included (49 patients), 54 eyes of 30 patients were examined. Nineteen women and 11 men of mean age of 42.8 years (range 30–65) were assessed 10 years post-LASIK. There were seven eyes in the mild, 29 in the moderate and 18 in the highly myopic groups. The original cohort of patients (94 eyes) had 23 mild, 49 moderate and 22 highly myopic eyes. Therefore, 30% of mild myopes, 59% of moderate myopes and 82% of high myopes returned for the follow-up study. At 10-year postoperative review, 52% were within ±0.50 D and 87 within ±1.0 D of emmetropia. Fifty-six per cent of eyes had UCVA better than or equal to 6/6 and 82% better than or equal to 6/9. Fifteen eyes (27.8%) had regressed. The overall mean regression (MRSE) was −1.6D. Mean regression in the mild, moderate and high myopic groups were −1.15, −0.93 and −1.94 D, respectively. Eleven eyes (20.4%) underwent retreatment during the 10-year follow-up period with a mean time to retreatment from the original surgery of 6.1 years. Of these, 4 (36%) were retreated prior to 5-year review and 7 (64%) between 5 and 10 years. The mean overall retreatment refractive error (MRSE) was −1.77 D. The mean retreatments performed in the low, moderate and high myopic groups were −1.15, −0.88 and −1.89 dioptres, respectively. The retreatment rate was greatest in the highly myopic group. No eye was retreated more than once (see Table 1). Four eyes of three patients regressed but no retreatment was performed. Two patients with unilateral regression had useful monovision. The third patient with bilateral regression returned to wearing glasses and declined further treatment. In the 43 eyes that were not retreated, 56% had a vision of 6/6 or better and 89% had a vision of 6/9 or better. During the 10-year follow-up period, three eyes were treated for retinal tears and one underwent retinal detachment repair. Ten patients reported glare. Seven patients reported the symptoms of dry eye. There was no topographical evidence of corneal ectasia. On questioning, all patients stated to be very happy with their original decision to undergo LASIK surgery. In our study, we found that better results were achieved in mild and moderate myopia and poorer outcomes were achieved in high myopia. These findings are similar to those of Zalentein (Zalentein et al. 2009). The trend towards regression may be explained by both corneal and non-corneal changes. Clearly changes in the corneal mechanics such as ectasia and corneal epithelial thickness could be one explanation. Non-corneal causes such as increase in axial length secondary to vitreous chamber elongation have been shown to increase myopia in adulthood (Kinge & Miledfart 1999; Jorge et al. 2007) In the twelve-year follow-up after PRK, we reported a continuous small regression (O’Connor et al. 2006). There is a reasonable inference from these studies that it is very likely that non-corneal changes over time will induce an increase in myopia. Those undergoing LASIK for high myopia and younger patients who are highly myopic should be advised of this potential and that they may indeed need retreatment in the future. This study shows LASIK to be a safe procedure associated with high patient satisfaction. Long-term stability was found in low to moderate myopia; however, a much greater tendency towards regression was seen in highly myopic patients with the need for retreatment.

The Location of Ziklag: A Review of the Candidate Sites, Based on Biblical, Topographical and Archaeological Evidence

In a previous article, consideration was given to the location of the large mound which Felix Fabri, on his journey from Hebron to Gaza in 1483, believed to be Ziklag (PEQ 143.1, 19–30). Here, six principal sites are examined as candidates for Ziklag by documenting their archaeological history, especially in the formative period of W. F. Albright and his contemporary German archaeologists.

Incidence and Characteristics of Unilateral Keratoconus Classified on Corneal Topography

To evaluate the characteristics of unilateral keratoconus defined on the basis of corneal topography and analyze videokeratography parameters between fellow eyes and normal controls. A total of 111 patients with clinical keratoconus were prospectively enrolled. Both eyes were evaluated with Tomey (Tomey Corp) and Orbscan II (Bausch & Lomb) corneal topography systems. The patient was classified as having unilateral keratoconus if one eye had clinical keratoconus and the other eye did not have any topographic signs of keratoconus such as asymmetric videokeratographic pattern, positive result in Tomey keratoconus screening, maximum posterior elevation >40 μm, or corneal thinnest pachymetry <500 μm. Clinical characteristics and 13 Orbscan II quantitative indices between keratoconic and fellow eyes and normal control eyes were evaluated. Five (4.5%) of 111 patients with keratoconus had no topographic evidence of keratoconus in the fellow eye. All clinically normal fellow eyes had symmetric bowtie patterns. Statistically significant differences were noted in maximum posterior elevation, corneal irregularity, and corneal thinnest values between keratoconic eyes and fellow eyes, and between keratoconic eyes and control eyes. Only 3-mm irregularity was significantly higher in the fellow eyes compared with control eyes (P<.05). An increased trend for corneal 5-mm irregularity was found in fellow eyes compared to control eyes. The incidence of unilateral keratoconus was 4.5%. A trend of higher irregularity was found in fellow eyes compared with control eyes. This finding indicates that fellow eyes may show a certain low-expressivity morphologic feature of keratoconus.

Anglo-Saxon Fortifications in Western Mercia

The present state of our knowledge and understanding of the public defences erected in the western half of the kingdom of Mercia between the eighth century and the mid eleventh is surveyed — both those which have already been sampled by excavation, and also those about which we know largely or wholly from written sources and topographical evidence alone. The historical contextualisation of the several main phases of these defences is then reviewed, in particular those which were built or rebuilt in the late ninth and early tenth centuries by Æthelred and Æthelflæd. Finally, the issue is addressed of what needs to be done if we are to achieve a significant improvement in our as yet only hazy perceptions of the historical importance of these defences, and why we need to set about doing so.

The Potential of Transvaginal Three-dimensional Color/Power Doppler Ultrasound in Detection of Colorectal Cancer

ABSTRACT Colorectal cancer (CRC) is the fourth most common cancer in men and the third most common cancer in women worldwide. The recent decline of CRC in the USA has been attributed to successful development of screening programs. In the last 20 years, endorectal ultrasound (ERUS) has become the primary method for locoregional staging of rectal cancer. Transvaginal sonography (TVS), with a high-frequency probe, obtains excellent image resolution of deep pelvic organs. TVS not only enables diagnosis and treatment in gynecology, infertility, and early pregnancy but also has the potential to detect other structural abnormalities within its reach, such as neoplasm of the rectosigmoid. Three-dimensional power Doppler ultrasound (3D PD) can depict the morphology of the vessel tree of tumors, and thus help to discriminate between benign and malignant neoplasm. In this case of a 42-year-old patient, an adnexal mass was diagnosed by TVS. Three-dimensional ultrasound gave topographic evidence of sigmoid colon tumor. Spectral Doppler and 3D PD diagnostic criteria of tumor vasculature, demonstrated in this neoplasm, were highly suspicious of malignancy. TVS diagnosis initiated endoscopic histological verification of adenocarcinoma of the sigma and timely surgical intervention.

Evaluation of bilateral minimum thickness of normal corneas based on Fourier-domain optical coherence tomography

To determine the normative ranges and various aspects of the relationship between the minimum corneal thicknesses (MCT) in fellow eyes and the location of the MCT in relation to the central cornea using Fourier-domain optical coherence tomography (OCT). Tertiary care ophthalmic hospital, Chennai, India. In this cross-sectional observational trial, both eyes of consecutive healthy young subjects with a low refractive error and no clinical or topographic evidence of corneal disorders had bilateral pachymetric assessment with a Fourier-domain OCT platform (RTVue). The MCT, central corneal thickness (CCT), and x-y coordinates of the MCT location were noted. The CCT and MCT followed a normal distribution with a good correlation. The difference between CCT and MCT was approximately 5 microm in right eyes and left eyes (P<.05 for both). The difference in CCT was the best predictor of the difference in MCT. The mean distance from the center (0.63 mm +/- 0.13 [SD], right eyes; 0.66 +/- 0.17 mm, left eyes) was well correlated. The MCT points in fellow eyes tended to be symmetrical along the vertical midline. The mean angular distance between mirror-superimposed MCT points was 20.54 +/- 17.6 degrees and the mean linear distance, 0.25 +/- 0.17 mm. The findings establish normative MCT pachymetry data and location using Fourier-domain OCT. The MCT and CCT points, although symmetrical, differed significantly in location and magnitude and should be evaluated separately in normal eyes and eyes with disease. No author has a financial or proprietary interest in any material or method mentioned. Additional financial disclosures are found in the footnotes.

The Origins of the 'Four Branches of the Mabinogi' by Andrew Breeze

830 Reviews Looking Westward is thus perhaps not for junior students,who may be confused bymodish postcolonial remarks in it,picked up fromwriters less able and honest thanHill. Yet itdoes merit attention fromprofessional scholars. Reinterpretation of itsclues and arguments will let them see theworld of theGawain-Poet more closely: his familiaritywith luxury; his expertise inhunting; his curiosity aboutWales; and his first-hand knowledge of France, especially the Toulouse region. By working on this and other evidence, theymay determine whether or not the Gawain-Poet was (as this reviewer proposes) Sir John Stanley (d. 1414), north-western magnate, courtier, huntsman, campaigner in the French wars, Garter Knight, and valued servant ofRichard II and Henry IV. University of Navarre, Pamplona Andrew Breeze The Origins of the 'FourBranches of the MabinogV. By Andrew Breeze. Leomin ster:Gracewing. 2009. viii+155 pp. ?9-99- ISBN 978-0-85244-533-2. After publishing his hypothesis on the authorship of the Four Branches of the Mabinogi in the third chapter of his book Medieval Welsh Literature (Dublin: Four Courts, 1997), Andrew Breeze has devoted an entire book to the controversial viewpoint that awoman, namely princess Gwenllian ofDyfed, wrote one of Wales's most significant contributions tomedieval literature. First, the author cites textual evidence from the Four Branches for a female writer by evoking several striking features of the narratives. Breeze points out the dialogues where the female characters are often presented as being stronger than theirmale counterparts. Another argument in favour of a woman author consists in the lengthypassages dedicated to female interests such asmotherhood, wet-nursing, fostering, or childlessness, in contrast to the shortmentions of battles and war. In addition the author of the Four Branches shows compassion for the defeated army and is aware of the human tragedy.Having presented all arguments that hint at a female author in general, Breeze goes on to narrow down possible female candidates for a prose narrative in early twelfth-century Wales. First of all, the style of the narrative hints at an author familiarwith etiquette, who isprobably amember of a royal court. In the following section Breeze listsnineteen arguments forGwenllian's authorship and the probable time of composition. He makes use of internal textual evidence as well as references to other manuscripts of the time in bothWelsh and Irish literature, and makes a semantic comparison between poems ofHywel ab Owain Gwynedd, Gwenllian's nephew, and theFour Branches. Reaching beyond literary argumentation, Breeze backs up his theory by exploit ing archaeological and topographical evidence, e.g. the frequency of toponyms in the text.He claims that the detailed knowledge of the local geography ofGwynedd, a somewhat limited acquaintance with Dyfed, and even lesswith Ireland coincide very strongly with Gwenllian's biography as a Gwynedd princess married to a Dyfed ruler with whom she spent some time in exile in Ireland. Several of the points he makes are taken up later in the book for a detailed line of arguments. MLR, 105.3, 2010 831 The chapter entitled 'Politics and the Four Branches' argues that the evident knowledge of the system of government?including diplomacy and warfare, the function of native law, the political constellation at the time in southWales, in particular interest in the fate of Dyfed and the threat of the rise of the kingdom of England?strongly points to amember of the court ofDyfed, corroborating the previous arguments. The chapters entitled 'The Four Branches inOur Time' and 'Some Recent Views of theFour Branches' deserve special mention. In the firstBreeze reviews themajor works on the origin of these tales over the last century, among others the public ations of Sir JohnLloyd,W. J. Gruffydd, and Rachel Bromwich. The other chapter contains very detailed replies to dissenting opinions on the authorship of theFour Branches in recent papers by Fiona Winward, William Parker, and others. The book in its entirety reads like an academic detective story,approaching the case to be solved from different angles. This is apparently the author's intention when, in the introduction, he challenges his readers to sharpen theirwits, develop their opinion on the hypothesis, and, ifpossible, find evidence against it.Breeze also compares his methodology tomodern criminology and theuse of circumstan tial evidence such...

The Positive Effect of Micro-Dams for Groundwater Enhancement: a Case Study around Tsinkanet and Rubafeleg Area, Tigray, Northern Ethiopia

The government of Tigray Regional State, Northern Ethiopia has been conducting a massive construction of micro-dams (small reservoirs) in order to decrease the rainfall dependency and alleviate food insecurity in drought prone areas of the region. Tsenkanet and Rubafeleg reservoirs are examples of this endeavor. The purpose of this investigation is to evaluate the role of these micro-dams in enhancing the surrounding groundwater by artificial recharge. In this study the physical characteristics of the reservoir are discussed including the groundwater surface water relationship with respect to water level elevation and also hydro-chemical composition. Six water samples have been analyzed. Samples are taken after rinsing the plastic bottles with distilled water and the sample to be taken. One surface water sample from each reservoir and one groundwater samples from each well next to each reservoir has been collected. Moreover, one sample from spring and one from river has been analyzed. The chemical composition of the reservoir water and the surrounding groundwater seem to suggest a similar origin and to be resulting from similar hydro-chemical processes. The chemical composition of all samples is found to be of the CaHCO3 type, which could be explained as resulting from precipitation water in which the mineral calcite has been dissolved. Both the topographic evidence and the water level monitoring data has confirmed the feeding of the reservoir to the near by shallow groundwater system. Quantifying the amount of groundwater accretion by the use of modeling and water balance method is recommended. Keywords: Groundwater, Surface water, Topography, Water Level, Type, Hardness, Class.

Possible causes of arc development in the Apennines, central Italy

Research Article| September 01, 2009 Possible causes of arc development in the Apennines, central Italy Andrea Billi; Andrea Billi † 1Dipartimento di Scienze Geologiche, Università “Roma Tre,” Largo S.L. Murialdo, 00146 Rome, Italy †E-mail: billi@uniroma3.it Search for other works by this author on: GSW Google Scholar Mara Monica Tiberti Mara Monica Tiberti 2Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy Search for other works by this author on: GSW Google Scholar GSA Bulletin (2009) 121 (9-10): 1409–1420. https://doi.org/10.1130/B26335.1 Article history received: 28 Sep 2007 rev-recd: 21 Nov 2008 accepted: 24 Dec 2008 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Andrea Billi, Mara Monica Tiberti; Possible causes of arc development in the Apennines, central Italy. GSA Bulletin 2009;; 121 (9-10): 1409–1420. doi: https://doi.org/10.1130/B26335.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract In central Italy, the geometry, kinematics, and tectonic evolution of the late Neogene Umbrian Arc, which is one of the main thrusts of the northern Apennines, have long been studied. Documented evidence for orogenic curvature includes vertical-axis rotations along both limbs of the arc and a positive orocline test along the entire arc. The cause of the curvature is, however, still unexplained. In this work, we focus our attention on the southern portion of the Umbrian Arc, the so-called Olevano-Antrodoco thrust. We analyze, in particular, gravity and seismic-reflection data and consider available paleomagnetic, stratigraphic, structural, and topographic evidence from the central Apennines to infer spatial extent, attitude, and surface effects of a midcrustal anticlinorium imaged in the CROP-11 deep seismic profile. The anticlinorium has horizontal dimensions of ~50 by 30 km, and it is located right beneath the Olevano-Antrodoco thrust. Stratigraphic, structural, and topographic evidence suggests that the anticlinorium produced a surface uplift during its growth in early Pliocene times. We propose an evolutionary model in which, during late Neogene time, the Olevano-Antrodoco thrust developed in an out-of-sequence fashion and underwent ~16° of clockwise rotation when the thrust ran into and was then raised and folded by the growing anti clinorium (late Messinian–early Pliocene time). This new model suggests a causal link between midcrustal folding and surficial orogenic curvature that is consistent with several available data sets from the northern and central Apennines; more evidence is, however, needed to fully test our hypothesis. Additionally, due to the occurrence of mid-crustal basement-involved thrusts in other orogens, this model may be a viable mechanism for arc formation elsewhere. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.