Correlating the Ancient Maya and Modern European Calendars with High-Precision AMS 14C Dating

The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS C-14 dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martinez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization.

Subclinical thyroid dysfunction and the risk of stroke: a systematic review and meta-analysis

Subclinical thyroid dysfunction has been associated with coronary heart disease, but the risk of stroke is unclear. Our aim is to combine the evidence on the association between subclinical thyroid dysfunction and the risk of stroke in prospective cohort studies. We searched Medline (OvidSP), Embase, Web-of-Science, Pubmed Publisher, Cochrane and Google Scholar from inception to November 2013 using a cohort filter, but without language restriction or other limitations. Reference lists of articles were searched. Two independent reviewers screened articles according to pre-specified criteria and selected prospective cohort studies with baseline thyroid function measurements and assessment of stroke outcomes. Data were derived using a standardized data extraction form. Quality was assessed according to previously defined quality indicators by two independent reviewers. We pooled the outcomes using a random-effects model. Of 2,274 articles screened, six cohort studies, including 11,309 participants with 665 stroke events, met the criteria. Four of six studies provided information on subclinical hyperthyroidism including a total of 6,029 participants and five on subclinical hypothyroidism (n = 10,118). The pooled hazard ratio (HR) was 1.08 (95 % CI 0.87-1.34) for subclinical hypothyroidism (I (2) of 0 %) and 1.17 (95 % CI 0.54-2.56) for subclinical hyperthyroidism (I (2) of 67 %) compared to euthyroidism. Subgroup analyses yielded similar results. Our systematic review provides no evidence supporting an increased risk for stroke associated with subclinical thyroid dysfunction. However, the available literature is insufficient and larger datasets are needed to perform extended analyses. Also, there were insufficient events to exclude clinically significant risk from subclinical hyperthyroidism, and more data are required for subgroup analyses.

A systematized workflow for assessing land resources using readily available spatial datasets

Land degradation as well as land conservation maps at a (sub-) national scale are critical for pro-ject planning for sustainable land management. It has long been recognized that online accessible and low-cost raster data sets (e.g. Landsat imagery, SRTM-DEM’s) provide a readily available basis for land resource assessments for developing countries. However, choice of spatial, tempo-ral and spectral resolution of such data is often limited. Furthermore, while local expert knowl-edge on land degradation processes is abundant, difficulties are often encountered when linking existing knowledge with modern approaches including GIS and RS. The aim of this study was to develop an easily applicable, standardized workflow for preliminary spatial assessments of land degradation and conservation, which also allows the integration of existing expert knowledge. The core of the developed method consists of a workflow for rule-based land resource assess-ment. In a systematic way, this workflow leads from predefined land degradation and conserva-tion classes to field indicators, to suitable spatial proxy data, and finally to a set of rules for clas-sification of spatial datasets. Pre-conditions are used to narrow the area of interest. Decision tree models are used for integrating the different rules. It can be concluded that the workflow presented assists experts from different disciplines in col-laboration GIS/RS specialists in establishing a preliminary model for assessing land degradation and conservation in a spatially explicit manner. The workflow provides support when linking field indicators and spatial datasets, and when determining field indicators for groundtruthing.

Depositional modes and lake-level variability at Lake Towuti, Indonesia, during the past ~29 kyr BP

Lake Towuti (2.5°S, 121.5°E) is a long-lived, tectonic lake located on the Island of Sulawesi, Indonesia, and in the center of the Indo-Pacific warm pool (IPWP). Lake Towuti is connected with upstream lakes Matano and Mahalona through the Mahalona River, which constitutes the largest inlet to the lake. The Mahalona River Delta is prograding into Lake Towuti’s deep northern basin thus exerting significant control on depositional processes in the basin. We combine high-resolution seismic reflection and sedimentological datasets from a 19.8-m-long sediment piston core from the distal edge of this delta to characterize fluctuations in deltaic sedimentation during the past ~29 kyr BP and their relation to climatic change. Our datasets reveal that, in the present, sedimentation is strongly influenced by deposition of laterally transported sediments sourced from the Mahalona River Delta. Variations in the amount of laterally transported sediments, as expressed by coarse fraction amounts in pelagic muds and turbidite recurrence rates and cumulative thicknesses, are primarily a function of lake-level induced delta slope instability and delta progradation into the basin. We infer lowest lake-levels between ~29 and 16, a gradual lake level rise between ~16 and 11, and high lake-levels between ~11 and 0 kyr BP. Periods of highest turbidite deposition, ~26 to 24 and ~18 to 16 kyr BP coincide with Heinrich events 2 and 1, respectively. Our lake-level reconstruction therefore supports previous observations based on geochemical hydroclimate proxies of a very dry last glacial and a wet Holocene in the region, and provides new evidence of millennial-scale variations in moisture balance in the IPWP.

[The role of PET imaging in patients with lymphoma]

Positron-Emission-Tomography (PET) has emerged as a diagnostic gold standard for most tumor entities during the last 20 years, especially for patients suffering from malignant lymphoma. The development and distribution of machines allowing for hybrid imaging, i.e. the simultaneous acquisition of PET and CT datasets, and the possibility to assess even small pathologic findings with fused PET/CT image visualization, once more significantly improved the diagnostic accuracy of PET. Based on an excellent sensitivity the metabolic imaging with PET or PET/CT allows for a reliable overall assessment of patients with malignant lymphoma before therapy, for the early identification of non-responders during therapy, and for the diagnosis of relapse after therapy.

Altered blood coagulation in patients with posttraumatic stress disorder

OBJECTIVE: Posttraumatic stress disorder (PTSD) has been associated with an increased cardiovascular risk, though the pathophysiologic mechanisms involved are elusive. A hypercoagulable state before occurrence of coronary thrombosis contributes to atherosclerosis development. We investigated whether PTSD would be associated with increased coagulation activity. METHODS: We measured resting plasma levels of clotting factor VII activity (FVII:C), FVIII:C, FXII:C, fibrinogen, and D-dimer in 14 otherwise healthy patients with PTSD and in 14 age- and gender-matched, trauma-exposed non-PTSD controls. Categorical and dimensional diagnoses of PTSD were made using the Clinician-Administered PTSD Scale (CAPS) interview. We also investigated to what extent the relationship between PTSD and coagulation measures would be confounded by demographics, cardiovascular risk factors, lifestyle variables, time since trauma, and mood. RESULTS: Coagulation factor levels did not significantly differ between patients with a categorical diagnosis of PTSD and controls while controlling for covariates. In all subjects, FVIII:C was predicted by hyperarousal severity (beta = 0.46, p = .014) independent of covariates and by overall PTSD symptom severity (beta = 0.38, p = .045); the latter association was of borderline significance when separately controlling for gender, smoking, exercise, and anxiety (p values <.07). In patients, fibrinogen was predicted by hyperarousal severity (beta = 0.70, p = .005) and by overall PTSD symptom severity (beta = 0.61, p = .020), with mood partially affecting these associations. FVII:C, fibrinogen, and D-dimer showed no independent association with PTSD symptoms. CONCLUSIONS: PTSD may elicit hypercoagulability, even at subthreshold levels, offering one psychobiological pathway by which posttraumatic stress might contribute to atherosclerosis progression and clinical cardiovascular disease.

Precise estimation of postoperative cup alignment from single standard X-ray radiograph with gonadal shielding

This paper addresses the problem of estimating postoperative cup alignment from single standard X-ray radiograph with gonadal shielding. The widely used procedure of evaluation of cup orientation following total hip arthroplasty using single standard anteroposterior radiograph is known inaccurate, largely due to the wide variability in individual pelvic position relative to X-ray plate. 2D-3D image registration methods have been introduced to estimate the rigid transformation between a preoperative CT volume and postoperative radiograph(s) for an accurate estimation of the postoperative cup alignment relative to an anatomical reference extracted from the CT data. However, these methods require either multiple radiographs or a radiograph-specific calibration, both of which are not avaiable for most retrospective studies. Furthermore, these methods were only evaluated on X-ray radiograph(s) without gonadal shielding. In this paper, we propose to use a hybrid 2D-3D registration scheme combining an iterative landmark-to-ray registration with a 2D-3D intensity-based registration to estimate the rigid transfromation for a precise estimation of cup alignment. Quantitative and qualitative results evaluated on clinical and cadaveric datasets are given which indicate the validity of our approach.

The role of 3D fusion imaging in sentinel lymphadenectomy for vulvar cancer

OBJECTIVES: To evaluate the feasibility of fusion imaging compound tomography (FICT) of CT/MRI and single photon emission tomography (SPECT) versus planar scintigraphy only (plSc) in pre-surgical staging for vulvar cancer. MATERIALS AND METHODS: Analysis of consecutive patients with vulvar cancer who preoperatively underwent sentinel scintigraphy (planar and 3D-SPECT imaging) and CT or MRI. Body markers were used for exact anatomical co-registration and fusion datasets were reconstructed using SPECT and CT/MRI. The number and localisation of all intraoperatively identified and resected sentinel lymph nodes (SLN) were compared between planar and 3D fusion imaging. RESULTS: Twenty six SLN were localized on planar scintigraphy. Twelve additional SLN were identified after SPECT and CT/MRI reconstruction, all of them were confirmed intraoperatively. In seven cases where single foci were identified at plSc, fusion imaging revealed grouped individual nodes and five additional localisations were discovered at fusion imaging. In seven patients both methods identified SLN contra lateral to the primary tumor site, but only fusion imaging allowed to localise iliac SLN in four patients. All SLN predicted on fusion imaging could be localised and resected during surgery. CONCLUSIONS: Fusion imaging using SPECT and CT/MRI can detect SLN in vulvar cancer more precisely than planar imaging regarding number and anatomical localisation. FICT revealed additional information in seven out of ten cases (70%).

A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum

A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets and recent decades have seen an upsurge in such data gathering around the continent and Sub-Antarctic islands. Here, we report a new synthesis of those datasets, based on an accompanying series of reviews of the geological data, organised by sector. We present a series of timeslice maps for 20 ka, 15 ka, 10 ka and 5 ka, including grounding line position and ice sheet thickness changes, along with a clear assessment of levels of confidence. The reconstruction shows that the Antarctic Ice sheet did not everywhere reach the continental shelf edge at its maximum, that initial retreat was asynchronous, and that the spatial pattern of deglaciation was highly variable, particularly on the inner shelf. The deglacial reconstruction is consistent with a moderate overall excess ice volume and with a relatively small Antarctic contribution to meltwater pulse 1a. We discuss key areas of uncertainty both around the continent and by time interval, and we highlight potential priorities for future work. The synthesis is intended to be a resource for the modelling and glacial geological community.

Afdeyu Research Substation: Hydrometeorological Data Analysis 1984-2007

This report presents a basic analyis of the data collected on agroclimatology, erosion, and soil and water conservation at Afdeyu Station in the central highlands of Eritrea between 1984 and 2007. Datasets and graphs include rainfall, air and soil surface temperatures, soil loss, surface runoff, river discharge, and land use including cropping patterns of the measured catchment.

Capacity building in the use of geospatial tools for natural resource management in Tajikistan: Final Report

The Swiss Swiss Consultant Trust Fund (CTF) support covered the period from July to December 2007 and comprised four main tasks: (1) Analysis of historic land degradation trends in the four watersheds of Zerafshan, Surkhob, Toirsu, and Vanj; (2) Translation of standard CDE GIS training materials into Russian and Tajik to enable local government staff and other specialists to use geospatial data and tools; (3) Demonstration of geospatial tools that show land degradation trends associated with land use and vegetative cover data in the project areas, (4) Preliminary training of government staff in using appropriate data, including existing information, global datasets, inexpensive satellite imagery and other datasets and webbased visualization tools like spatial data viewers, etc. The project allowed building of local awareness of, and skills in, up-to-date, inexpensive, easy-to-use GIS technologies, data sources, and applications relevant to natural resource management and especially to sustainable land management. In addition to supporting the implementation of the World Bank technical assistance activity to build capacity in the use of geospatial tools for natural resource management, the Swiss CTF support also aimed at complementing the Bank supervision work on the ongoing Community Agriculture and Watershed Management Project (CAWMP).

Effect of surface restoring on subsurface variability in a climate model during 1949–2005

Initializing the ocean for decadal predictability studies is a challenge, as it requires reconstructing the little observed subsurface trajectory of ocean variability. In this study we explore to what extent surface nudging using well-observed sea surface temperature (SST) can reconstruct the deeper ocean variations for the 1949–2005 period. An ensemble made with a nudged version of the IPSLCM5A model and compared to ocean reanalyses and reconstructed datasets. The SST is restored to observations using a physically-based relaxation coefficient, in contrast to earlier studies, which use a much larger value. The assessment is restricted to the regions where the ocean reanalyses agree, i.e. in the upper 500 m of the ocean, although this can be latitude and basin dependent. Significant reconstruction of the subsurface is achieved in specific regions, namely region of subduction in the subtropical Atlantic, below the thermocline in the equatorial Pacific and, in some cases, in the North Atlantic deep convection regions. Beyond the mean correlations, ocean integrals are used to explore the time evolution of the correlation over 20-year windows. Classical fixed depth heat content diagnostics do not exhibit any significant reconstruction between the different existing bservation-based references and can therefore not be used to assess global average time-varying correlations in the nudged simulations. Using the physically based average temperature above an isotherm (14°C) alleviates this issue in the tropics and subtropics and shows significant reconstruction of these quantities in the nudged simulations for several decades. This skill is attributed to the wind stress reconstruction in the tropics, as already demonstrated in a perfect model study using the same model. Thus, we also show here the robustness of this result in an historical and observational context.

Cup Implant Planning Based on 2-D/3-D Radiographic Pelvis Reconstruction-First Clinical Results.

GOAL: In the following, we will present a newly developed X-ray calibration phantom and its integration for 2-D/3-D pelvis reconstruction and subsequent automatic cup planning. Two different planning strategies were applied and evaluated with clinical data. METHODS: Two different cup planning methods were investigated: The first planning strategy is based on a combined pelvis and cup statistical atlas. Thereby, the pelvis part of the combined atlas is matched to the reconstructed pelvis model, resulting in an optimized cup planning. The second planning strategy analyzes the morphology of the reconstructed pelvis model to determine the best fitting cup implant. RESULTS: The first planning strategy was compared to 3-D CT-based planning. Digitally reconstructed radiographs of THA patients with differently severe pathologies were used to evaluate the accuracy of predicting the cup size and position. Within a discrepancy of one cup size, the size was correctly identified in 100% of the cases for Crowe type I datasets and in 77.8% of the cases for Crowe type II, III, and IV datasets. The second planning strategy was analyzed with respect to the eventually implanted cup size. In seven patients, the estimated cup diameter was correct within one cup size, while the estimation for the remaining five patients differed by two cup sizes. CONCLUSION: While both planning strategies showed the same prediction rate with a discrepancy of one cup size (87.5%), the prediction of the exact cup size was increased for the statistical atlas-based strategy (56%) in contrast to the anatomically driven approach (37.5%). SIGNIFICANCE: The proposed approach demonstrated the clinical validity of using 2-D/3-D reconstruction technique for cup planning.

RNetCDF – A Package for Reading and Writing NetCDF Datasets

This paper describes the RNetCDF package (version 1.6), an interface for reading and writing files in Unidata NetCDF format, and gives an introduction to the NetCDF file format. NetCDF is a machine independent binary file format which allows storage of different types of array based data, along with short metadata descriptions. The package presented here allows access to the most important functions of the NetCDF C-interface for reading, writing, and modifying NetCDF datasets. In this paper, we present a short overview on the NetCDF file format and show usage examples of the package.