Contrasting vulnerability and resilience to drought-induced decline of densely planted vs. natural rear-edge Pinus nigra forests

The southernmost European natural and planted pine forests are among the most vulnerable areas to warming-induced drought decline. Both drought stress and management factors (e.g., stand origin or reduced thinning) may induce decline by reducing the water available to trees but their relative importances have not been properly assessed. The role of stand origin - densely planted vs. naturally regenerated stands - as a decline driver can be assessed by comparing the growth and vigor responses to drought of similar natural vs. planted stands. Here, we compare these responses in natural and planted Black pine (Pinus nigra) stands located in southern Spain. We analyze how environmental factors - climatic (temperature and precipitation anomalies) and site conditions - and biotic factors - stand structure (age, tree size, density) and defoliation by the pine processionary moth - drive radial growth and crown condition at stand and tree levels. We also assess the climatic trends in the study area over the last 60 years. We use dendrochronology, linear mixed-effects models of basal area increment and structural equation models to determine how natural and planted stands respond to drought and current competition intensity. We observed that a temperature rise and a decrease in precipitation during the growing period led to increasing drought stress during the late 20th century. Trees from planted stands experienced stronger growth reductions and displayed more severe crown defoliation after severe droughts than those from natural stands. High stand density negatively drove growth and enhanced crown dieback, particularly in planted stands. Also pine processionary moth defoliation was more severe in the growth of natural than in planted stands but affected tree crown condition similarly in both stand types. In response to drought, sharp growth reduction and widespread defoliation of planted Mediterranean pine stands indicate that they are more vulnerable and less resilient to drought stress than natural stands. To mitigate forest decline of planted stands in xeric areas such as the Mediterranean Basin, less dense and more diverse stands should be created through selective thinning or by selecting species or provenances that are more drought tolerant. (C) 2013 Elsevier B.V. All rights reserved.

Retinal layer measurements after successful macula-off retinal detachment repair using optical coherence tomography

PURPOSE Optical coherence tomography (OCT) was used to analyze the thickness of various retinal layers of patients following successful macula-off retinal detachment (RD) repair. METHODS Optical coherence tomography scans of patients after successful macula-off RD repair were reanalyzed with a subsegmentation algorithm to measure various retinal layers. Regression analysis was performed to correlate time after surgery with changes in layer thickness. In addition, patients were divided in two groups. Group 1 had a follow-up period after surgery of up to 7 weeks (range, 21-49 days). In group 2, the follow-up period was >8 weeks (range, 60-438 days). Findings were compared to a group of age-matched healthy controls. RESULTS Correlation analysis showed a significant positive correlation between inner nuclear-outer plexiform layer (INL-OPL) thickness and time after surgery (P=0.0212; r2=0.1551). Similar results were found for the ellipsoid zone-retinal pigment epithelium complex (EZ-RPE) thickness (P=0.005; r2=0.2215). Ganglion cell-inner plexiform layer thickness (GCL-IPL) was negatively correlated with time after surgery (P=0.0064; r2=0.2101). For group comparison, the retinal nerve fiber layer in both groups was thicker compared to controls. The GCL-IPL showed significant thinning in group 2. The outer nuclear layer was significantly thinner in groups 1 and 2 compared to controls. The EZ-RPE complex was significantly thinner in groups 1 and 2 compared to controls. In addition, values in group 1 were significantly thinner than in group 2. CONCLUSIONS Optical coherence tomography retinal layer thickness measurements after successful macular-off RD repair revealed time-dependent thickness changes. Inner nuclear-outer plexiform layer thickness and EZ-RPE thickness was positively correlated with time after surgery. Ganglion cell-inner plexiform layer thickness was negatively correlated with time after surgery.

Cortical thickness decreases with age in very preterm born school-children but not in term born controls

Background: Cortical gray matter thinning occurs during childhood due to pruning of inefficient synaptic connections and an increase in myelination. Preterms show alterations in brain structure, with prolonged maturation of the frontal lobes, smaller cortical volumes and reduced white matter volume. These findings give rise to the question if there is a differential influence of age on cortical thinning in preterms compared to controls. Aims: To investigate the relationship between age and cortical thickness in preterms when compared to controls. Study design and outcome measures: The automated surface reconstruction software FreeSurfer was applied to obtain measurements of cortical thickness based on T1-weighted MRI images. Subjects: Forty-one preterms (< 32 weeks gestational age and/or < 1500 gram birth weight) and 30 controls were included in the study (7-12 years). Results: Cortical thickness was lower in bilateral frontal and left parietal regions and higher in left temporal gyri in preterms compared to controls. However, these differences depended on age. In preterms, age correlated negatively with cortical thickness in right frontal, parietal and inferior temporal regions. Accordingly, cortical thickness was higher in young compared to old preterms in bilateral frontal, parietal and temporal regions. In controls, age was not associated with cortical thickness. Conclusion: In preterms, cortical thinning still seems to occur between the age of 7 and 12 years, mainly in frontal and parietal areas whereas in controls, a substantial part of cortical thinning appears to be completed before they reach the age of 7 years. These data indicate slower cortical thinning in preterms than in controls.

Investigation of retinal morphology alterations using spectral domain optical coherence tomography in a mouse model of retinal branch and central retinal vein occlusion.

Retinal vein occlusion is a leading cause of visual impairment. Experimental models of this condition based on laser photocoagulation of retinal veins have been described and extensively exploited in mammals and larger rodents such as the rat. However, few reports exist on the use of this paradigm in the mouse. The objective of this study was to investigate a model of branch and central retinal vein occlusion in the mouse and characterize in vivo longitudinal retinal morphology alterations using spectral domain optical coherence tomography. Retinal veins were experimentally occluded using laser photocoagulation after intravenous application of Rose Bengal, a photo-activator dye enhancing thrombus formation. Depending on the number of veins occluded, variable amounts of capillary dropout were seen on fluorescein angiography. Vascular endothelial growth factor levels were markedly elevated early and peaked at day one. Retinal thickness measurements with spectral domain optical coherence tomography showed significant swelling (p<0.001) compared to baseline, followed by gradual thinning plateauing two weeks after the experimental intervention (p<0.001). Histological findings at day seven correlated with spectral domain optical coherence tomography imaging. The inner layers were predominantly affected by degeneration with the outer nuclear layer and the photoreceptor outer segments largely preserved. The application of this retinal vein occlusion model in the mouse carries several advantages over its use in other larger species, such as access to a vast range of genetically modified animals. Retinal changes after experimental retinal vein occlusion in this mouse model can be non-invasively quantified by spectral domain optical coherence tomography, and may be used to monitor effects of potential therapeutic interventions.

Geometry and kinematics of the Roisan-Cignana Shear Zone, and the orogenic evolution of the Dent Blanche Tectonic System (Western Alps)

The Dent Blanche Tectonic System (DBTS) is a composite thrust sheet derived from the previously thinned passive Adriatic continental margin. A kilometric high-strain zone, the Roisan-Cignana Shear Zone (RCSZ) defines the major tectonic boundary within the DBTS and separates it into two subunits, the Dent Blanche s.s. nappe to the northwest and the Mont Mary nappe to the southeast. Within this shear zone, tectonic slices of Mesozoic and pre-Alpine meta-sediments became amalgamated with continental basement rocks of the Adriatic margin. The occurrence of high pressure assemblages along the contact between these tectonic slices indicates that the amalgamation occurred prior to or during the subduction process, at an early stage of the Alpine orogenic cycle. Detailed mapping, petrographic and structural analysis show that the Roisan-Cignana Shear Zone results from several superimposed Alpine structural and metamorphic stages. Subduction of the continental fragments is recorded by blueschist-facies deformation, whereas the Alpine collision is reflected by a greenschist facies overprint associated with the development of large-scale open folds. The postnappe evolution comprises the development of low-angle brittle faults, followed by large-scale folding (Vanzone phase) and finally brittle extensional faults. The RCSZ shows that fragments of continental crust had been torn off the passive continental margin prior to continental collision, thus recording the entire history of the orogenic cycle. The role of preceding Permo-Triassic lithospheric thinning, Jurassic rifting, and ablative subduction processes in controlling the removal of crustal fragments from the reactivated passive continental margin is discussed. Results of this study constrain the temporal sequence of the tectono-metamorphic processes involved in the assembly of the DBTS, but they also show limits on the interpretation. In particular it remains difficult to judge to what extent precollisional rifting at the Adriatic continental margin preconditioned the efficiency of convergent processes, i.e. accretion, subduction, and orogenic exhumation.

Evaluation of scleral and corneal thickness in keratoconus patients

PURPOSE To determine whether the scleral stroma is affected as much as the corneal stroma in keratoconus. SETTING University Eye Clinic, Bern, Switzerland. DESIGN Comparative case-control study. METHODS Eyes with keratoconus (keratoconus group) and eyes of age-, sex-, and axial length-matched controls (control group) were analyzed. Corneal videokeratometry and pachymetry were performed using a Scheimpflug tomographer (Pentacam). For measurements of the peripheral cornea and the anterior sclera, a spectral-domain anterior segment optical coherence tomography device (Spectralis) was used. RESULTS The study group comprised 51 eyes and the control group, 50 eyes. The mean central corneal thickness in the keratoconus group was statistically significantly lower than in the control group (447.8 μm ± 57.8 [SD] versus 550.5 ± 35.5 μm) (P < .0001). No significant difference in the mean anterior scleral thickness was found between the keratoconus group and the control group (479.1 ± 43.7 μm versus 474.2 ± 43.0 μm) (P =.57). CONCLUSION Although corneal thinning was observed in keratoconus patients, the anterior scleral stroma thickness in these patients seemed to be similar to that in healthy control eyes.

Angiogenesis-related ultrastructural changes to capillaries in human skeletal muscle in response to endurance exercise

The ultrastructure of capillaries in skeletal muscle was morphometrically assessed in vastus lateralis muscle (VL) biopsies taken before and after exercise from 22 participants of two training studies. In study 1 (8 wk of ergometer training), light microscopy revealed capillary-fiber (C/F) ratio (+27%) and capillary density (+16%) to be higher (P ≤ 0.05) in postexercise biopsies than in preexercise biopsies from all 10 participants. In study 2 (6 mo of moderate running), C/F ratio and capillary density were increased (+23% and +20%; respectively, P ≤ 0.05) in VL biopsies from 6 angiogenesis responders (AR) after training, whereas 6 nonangiogenesis responders (NR) showed nonsignificant changes in these structural indicators (-4%/-4%, respectively). Forty capillary profiles per participant were evaluated by point and intersection counting on cross sections after transmission electron microscopy. In study 1, volume density (Vv) and mean arithmetic thickness (T) of endothelial cells (ECs; +19%/+17%, respectively) and pericytes (PCs; +20%/+21%, respectively) were higher (P ≤ 0.05), whereas Vv and T of the pericapillary basement membrane (BM) were -23%/-22% lower (P ≤ 0.05), respectively, in posttraining biopsies. In study 2, exercise-related differences between AR and NR-groups were found for Vv and T of PCs (AR, +26%/+22%, respectively, both P ≤ 0.05; NR, +1%/-3%, respectively, both P > 0.05) and BM (AR, -14%/-13%, respectively, both P ≤ 0.05; NR, -9%/-11%, respectively, P = 0.07/0.10). Vv and T of ECs were higher (AR, +16%/+18%, respectively; NR, +6%/+6%, respectively; all P ≤ 0.05) in both groups. The PC coverage was higher (+13%, P ≤ 0.05) in VL biopsies of individuals in the AR group but nonsignificantly altered (+3%, P > 0.05) in those of the NR group after training. Our study suggests that intensified PC mobilization and BM thinning are related to exercise-induced angiogenesis in human skeletal muscle, whereas training per se induces EC-thickening.

Development and characterization of chemical cochleostomy in the Guinea pig

OBJECTIVES Creation of an atraumatic, hearing-preservation cochleostomy is integral to the future of minimally invasive inner ear surgery. The goal of this study was to develop and characterize a novel chemical approach to cochleostomy. STUDY DESIGN Prospective animal study. SETTING Laboratory. METHODS Experimental animal study in which phosphoric acid gel (PAG) was used to decalcify the otic capsule in 25 Hartley guinea pigs. Five animals in each of 5 surgical groups were studied: (1) mechanically opening the auditory bulla alone, (2) PAG thinning of the basal turn otic capsule, leaving endosteum covered by a layer of bone, (3) micro-pick manual cochleostomy, (4) PAG chemical cochleostomy, exposing the endosteum, and (5) combined PAG/micro-pick cochleostomy, with initial chemical thinning and subsequent manual removal of the last osseous layer. Preoperative and postoperative auditory brainstem responses and otoacoustic emissions were obtained at 2, 6, 10, and 16 kHz. Hematoxylin and eosin-stained paraffin sections were compared. RESULTS Surgical and histologic findings confirmed that application of PAG provided reproducible local bone removal, and cochlear access was enabled. Statistically significant auditory threshold shifts were observed at 10 kHz (P = .048) and 16 kHz (P = .0013) following cochleostomy using PAG alone (group 4) and at 16 kHz using manual cochleostomy (group 3) (P = .028). No statistically significant, postoperative auditory threshold shifts were observed in the other groups, including PAG thinning with manual completion cochleostomy (group 5). CONCLUSION Hearing preservation cochleostomy can be performed in an animal model using a novel technique of thinning cochlear bone with PAG and manually completing cochleostomy.

Gingival labial recessions and the post-treatment proclination of mandibular incisors

INTRODUCTION A prerequisite for development of gingival recession is the presence of alveolar bone dehiscence. Proclination of mandibular incisors can result in thinning of the alveolus and dehiscence formation. OBJECTIVE To assess an association between proclination of mandibular incisor and development of gingival recession. METHODS One hundred and seventeen subjects who met the following inclusion criteria were selected: 1. age 11-14 years at start of orthodontic treatment (TS), 2. bonded retainer placed immediately after treatment (T0), 3. dental casts and lateral cephalograms available pre-treatment (TS), post-treatment (T0), and 5 years post-treatment (T5), and 4. post-treatment (T0) lower incisor inclination (Inc_Incl) <95° or >100.5°. Two groups were formed: non-proclined (N = 57; mean Inc_Incl = 90.8°) and proclined (N = 60; mean Inc_Incl = 105.2°). Clinical crown heights of mandibular incisors and the presence of gingival recession sites in this region were assessed on plaster models. Fisher's exact tests, t-tests, and regression models were computed for analysis of inter-group differences. RESULTS The mean increase of clinical crown heights (from T0 to T5) of mandibular incisors ranged from 0.75 to 0.83mm in the non-proclined and proclined groups, respectively (P = 0.273). At T5, gingival recession sites were present in 12.3% and 11.7% patients from the non-proclined and proclined groups, respectively. The difference was also not significant (P = 0.851). CONCLUSIONS The proclination of mandibular incisors did not increase a risk of development of gingival recession during five-year observation in comparison non-proclined teeth.

Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

The Ivrea–Verbano Zone (IVZ), northern Italy, exposes an attenuated section through the Permian lower crust that records high-temperature metamorphism under lower crustal conditions and a protracted history of extension and exhumation associated partly with the Jurassic opening of the Alpine Tethys ocean. This study presents SHRIMP U–Pb geochronology of rutile from seven granulite facies metapelites from the base of the IVZ, collected from locations spanning ~35 km along the strike of Paleozoic fabrics. Rutile crystallised during Permian high-temperature metamorphism and anatexis, yet all samples give Jurassic rutile U–Pb ages that record cooling through 650–550 °C. Rutile age distributions are dominated by a peak at ~160 Ma, with a subordinate peak at ~175 Ma. Both ~160 and ~175 Ma age populations show excellent agreement between samples, indicating that the two distinctive cooling stages they record were synchronous on a regional scale. The ~175 Ma population is interpreted to record cooling in the footwall of rift-related faults and shear zones, for which widespread activity in the Lower Jurassic has been documented along the western margin of the Adriatic plate. The ~160 Ma age population postdates the activity of all known rift-related structures within the Adriatic margin, but coincides with extensive gabbroic magmatism and exhumation of sub-continental mantle to the floor of the Alpine Tethys, west of the Ivrea Zone. We propose that this ~160 Ma early post-rift age population records regional cooling following episodic heating of the distal Adriatic margin, likely related to extreme lithospheric thinning and associated advection of the asthenosphere to shallow levels. The partial preservation of the ~175 Ma age cluster suggests that the post-rift (~160 Ma) heating pulse was of short duration. The regional consistency of the data presented here, which is in contrast to many other thermochronometers in the IVZ, demonstrates the value of the rutile U–Pb technique for probing the thermal evolution of high-grade metamorphic terrains. In the IVZ, a significant decoupling between Zr-in-rutile temperatures and U–Pb ages of rutile is observed, with the two systems recording events ~120 Ma apart.

"Citizenship Lite" revisited

In a small book and article published in 2010, I argued that citizenship in the West was undergoing a process of "lightening": it has become easier to obtain, connotes fewer rights exclusively attached to it, and is capped by thin and thinning identities. In my presentation, I review the `citizenship lite` hypothesis in light of recent trends and scholarship.

Quantification of retinal layer thickness changes in acute macular neuroretinopathy.

PURPOSE To quantitatively evaluate retinal layer thickness changes in acute macular neuroretinopathy (AMN). METHODS AMN areas were identified using near-infrared reflectance (NIR) images. Intraretinal layer segmentation using Heidelberg software was performed. The inbuilt ETDRS -grid was moved onto the AMN lesion and the mean retinal layer thicknesses of the central grid were recorded and compared with the corresponding area of the fellow eye at initial presentation and during follow-up. RESULTS Eleven patients were included (mean age 26±6 years). AMN lesions at baseline had a significantly thinner outer nuclear layer (ONL) (51±21 µm vs 73±17 µm, p=0.002). The other layers, including inner nuclear layer (37±8 µm vs 38±6 µm, p=0.9) and outer plexiform layer (OPL) (45±19 µm vs 33±16 µm, p=0.1) did not show significant differences between the study eyes and fellow eyes. Adjacent to NIR image lesions, areas of OPL thickening were identified (study eye: 50±14 µm vs fellow eye: 39±16 µm, p=0.005) with corresponding thinning of ONL (study eye: 52±16 µm vs fellow eye: 69±16 µm, p=0.002). CONCLUSIONS AMN presents with characteristic quantitative retinal changes and the extent of the lesion may be more extensive than initially presumed from NIR image lesions.