Valuable Measurements Research Articles

Sit-to-walk performance in Parkinson's disease: A comparison between faller and non-faller patients

BackgroundFalls are one of the main concerns in people with Parkinson's disease, leading to poor quality of life and increased mortality. The sit-to-walk movement is the most frequent postural transition task during daily life and is highly demanding in terms of balance maintenance and muscular strength. MethodsWith the aim of identifying biomechanical variables of high risk of falling, we investigated the sit-to-walk task performed by 9 Parkinson's disease patients with at least one fall episode in the six months preceding this study, 15 Parkinson's disease patients without previous falls, and 20 healthy controls. Motor performance was evaluated with an optoelectronic system and two dynamometric force plates after overnight suspension of all dopaminergic drugs and one hour after consumption of a standard dose of levodopa/benserazide. FindingsPoor trunk movements critically influenced the execution of the sit-to-walk movement in patients with a history of falling. The peak velocity of the trunk in the anterior-posterior direction discriminated faller from non-faller patients, with high specificity and sensitivity in both the medication-off and -on state. InterpretationOur results confirm the difficulties in merging consecutive motor tasks in patients with Parkinson's disease. Trunk movements during the sit-to-walk can provide valuable measurements to monitor and possibly predict the risk of falling.

Validation of satellite soil moisture in the absence of <i>in situ</i> soil moisture: the case of the Tropical Yankin Basin

Soil moisture is known to be important in hydrology, agronomy, flood and drought forecasting. Acquisition of in situ soil moisture data is time consuming, costly, and does not cover the scale required for basin analysis. The consideration of remotely-sensed soil moisture is therefore promising. However, considering the limitations of satellite data, there is a need to check their validity prior to their utilization for impact studies. This, in turn, poses a problem in the absence of in situ soil moisture. The present study suggests a methodology for testing the validity of remotely-sensed soil moisture without in situ soil moisture. Hydrological models with a detailed soil moisture routine are calibrated and validated with measured stream flows. The most behavioural solutions of modelled soil moistures are averaged, and used as proxy measurements. This methodology was applied to the Yankin Basin (8,171 km2), a tributary of the Niger River Basin. The soil moistures of three hydrological models (UHP-HRU, SWAT and WaSiM) used as proxy were compared with the daily ESA-CCI soil moisture for a four year period (2005-2008). The coefficient of determination (R2), bias and visual inspection were used as quality criteria. A rather small bias ranging from -0.01cm3/cm3 (SWAT & UHP-HRU) to -0.04cm3/cm3 (WaSiM &UHP-HRU) was determined as well as good R2 varying between 0.71 (SWAT & UHP-HRU) and 0.81 (WaSiM & SWAT & UHP-HRU). The ESA-CCI soil moisture was therefore judged as reliable for the study area. More important, this research shows that averaging soil moistures from different hydrological models provides valuable proxy measurements for testing the reliability of satellite soil moistures.

Assessment of the quality of life of Egyptian and Tunisian autoimmune bullous diseases’ patients using an Arabic version of the autoimmune bullous disease quality of life and the treatment of autoimmune bullous disease quality of life questionnaires

AbstractBackground: The Autoimmune Bullous Disease Quality of Life (ABQOL) and the Treatment of Autoimmune Bullous Disease Quality of Life (TABQOL) questionnaires proved to be reliable tools that measure the disease and treatment burden.Objectives: We aimed to assess the ABQOL and TABQOL in the Arabic population.Methods: The English questionnaires were translated into the Arabic language by a certified translation agency. Eighty autoimmune bullous disease (AIBD) patients were included in this study. Patients were asked to answer 2 questionnaires. After 1 week the same patients were asked to answer the same questionnaires again.Results: The age of the patients ranged from 19 to 81 years (mean=46), 19 males, 61 females. The ABQOL ranged from 0-37 (mean=16.4±9.2). The TABQOL ranged from 2-43 (mean=21.5±9.4). Test-retest reliability was acceptable, Cronbach’s alpha was 0.76 for ABQOL and 0.74 for TABQOL. There was no significant correlation between the age of the patients and ABQOL, r =-0.2, p value was 0.183. There was a significant negative correlation between the age of the patients and the TABQOL, r=−0.2, p value was 0.039. There was a significant negative correlation between the education of the patients and the TABQOL, r=−0.3, p value was 0.007.Study limitations: Small sample size of some AIBDs and patients with severe disease.Conclusion: Objective and valuable measurements such as ABQOL and TABQOL are now available to help physicians understand their patient’s distress and should be used in every patient with AIBD. Younger and less educated patients appear to have more effects on their QOL from the treatments.

Tsumiki: A Meta-Platform for Building Your Own Testbed

Network testbeds are essential research tools that have been responsible for valuable network measurements and major advances in distributed systems research. However, no single testbed can satisfy the requirements of every research project, prompting continual efforts to develop new testbeds. The common practice is to re-implement functionality anew for each testbed. This work introduces a set of ready-to-use software components and interfaces called Tsumiki to help researchers to rapidly prototype custom networked testbeds without substantial effort. We derive Tsumiki's design using a set of component and interface design principles, and demonstrate that Tsumiki can be used to implement new, diverse, and useful testbeds. We detail a few such testbeds: a testbed composed of Android devices, a testbed that uses Docker for sandboxing, and a testbed that shares computation and storage resources among Facebook friends. A user study demonstrated that students with no prior experience with networked testbeds were able to use Tsumiki to create a testbed with new functionality and run an experiment on this testbed in under an hour. Furthermore, Tsumiki has been used in production in multiple testbeds, resulting in installations on tens of thousands of devices and use by thousands of researchers.

Uncertainty analysis: influence of hydraulic fracturing on overlying aquifers in the presence of leaky abandoned wells

Model uncertainty analysis can quantify uncertainty both prior to calibration and postcalibration if the calibration dataset appropriately informs parameter estimates and model predictions. In certain cases calibration data (observations or measurements) may not be immediately apparent, but calibration datasets can be developed from related data for model interrogation and quantification and minimization of uncertainty. This study applies a series of techniques to investigate uncertainty in a simple numerical model of upward flow (leakage) through an abandoned oil and gas well converted into a water well in hydraulically fractured shale. Model calibration was achieved by developing a limited calibration dataset from well-specific measurements at a horizontal well in the Eagle Ford Shale play. Uncertainty in the calibrated model was interrogated using sensitivity, linear, and nonlinear analyses available in the PEST suite. Sensitivity analysis suggests that flowback after hydraulic fracturing could be crucial in reducing leakage. Linear analyses indicate horizontal-well production rates and long-term reservoir pressures are valuable measurements to collect when evaluating potential leakage. Nonlinear analyses identify the range in predictive uncertainty of potential leakage. The results underscore the need to evaluate and include additional types of well data in public records, such as flowback and produced water volumes. Overall, the results of this study illustrate the utility of uncertainty analyses with a limited calibration dataset applied to a simple model.

A New Paradigm in Earth Environmental Monitoring with the CYGNSS Small Satellite Constellation

A constellation of small, low-cost satellites is able to make scientifically valuable measurements of the Earth which can be used for weather forecasting, disaster monitoring, and climate studies. Eight CYGNSS satellites were launched into low Earth orbit on December 15, 2016. Each satellite carries a science radar receiver which measures GPS signals reflected from the Earth surface. The signals contain information about the surface, including wind speed over ocean, and soil moisture and flooding over land. The satellites are distributed around their orbit plane so that measurements can be made more often to capture extreme weather events. Innovative engineering approaches are used to reduce per satellite cost, increase the number in the constellation, and improve temporal sampling. These include the use of differential drag rather than propulsion to adjust the spacing between satellites and the use of existing GPS signals as the science radars’ transmitter. Initial on-orbit results demonstrate the scientific utility of the CYGNSS observations, and suggest that a new paradigm in spaceborne Earth environmental monitoring is possible.

New Cepheid variables in the young open clusters Berkeley 51 and Berkeley 55

As part of a wider investigation of evolved massive stars in Galactic open clusters, we have spectroscopically identified three candidate classical Cepheids in the little-studied clusters Berkeley 51, Berkeley 55 and NGC 6603. Using new multi-epoch photometry, we confirm that Be 51 #162 and Be 55 #107 are bona fide Cepheids, with pulsation periods of 9.83+/-0.01 d and 5.850+/-0.005 d respectively, while NGC 6603 star W2249 does not show significant photometric variability. Using the period-luminosity relationship for Cepheid variables, we determine a distance to Be 51 of 5.3(+1.0,-0.8) kpc and an age of 44(+9,-8) Myr, placing it in a sparsely-attested region of the Perseus arm. For Be 55, we find a distance of 2.2+/-0.3 kpc and age of 63(+12,-11) Myr, locating the cluster in the Local arm. Taken together with our recent discovery of a long-period Cepheid in the starburst cluster VdBH222, these represent an important increase in the number of young, massive Cepheids known in Galactic open clusters. We also consider new Gaia (data release 2) parallaxes and proper motions for members of Be 51 and Be 55; the uncertainties on the parallaxes do not allow us to refine our distance estimates to these clusters, but the well-constrained proper motion measurements furnish further confirmation of cluster membership. However, future final Gaia parallaxes for such objects should provide valuable independent distance measurements, improving the calibration of the period-luminosity relationship, with implications for the distance ladder out to cosmological scales.

Measurement of anterior segment parameters in Saudi adults with myopia

PurposeTo measure anterior segment parameters of the eye in myopic Saudi population using Pentacam. MethodThis is retrospective cross-sectional study. Subjects were divided into three groups: low, moderate and high myopia groups. Anterior segment parameters including: central corneal thickness (CCT), thinnest corneal thickness (TCT), apex corneal thickness (Apex CT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and corneal astigmatism (CA) were measured by Pentacam. ResultsA total of 504 eyes of 252 Saudi subjects with myopia were included in this study. The mean age ± standard deviation (SD) of subjects was 28.73 ± 6.18 years. The mean CCT, TCT, Apex CT, CV, ACD, ACV and CA for all myopic subjects were 557.21 ± 29.36, 554.09 ± 29.28, 556.10 ± 37.06, 61.30 ± 3.23 μm, 3.31 ± 0.27 mm, 211.15 ± 34.22 mm3 and 0.89 ± 0.52 D, respectively. No significant differences (P > 0.05) were found between right and left eyes in all anterior segment parameters of all myopic eyes. However, a significant difference (P < 0.05) was found in ACD between low (3.27 ± 0.26 mm) and moderate (3.35 ± 0.30 mm) myopic groups. Within low myopia group, significant differences (P < 0.05) were found in ACD, ACV and CA between different genders. Anterior chamber depth and ACV values were lower in females while CA was lower in males. In addition, significant positive correlation was found between ACV and ACD in all myopic groups. ConclusionThis study provided valuable measurements of the anterior segments parameters of the eye in myopic Saudi population. These parameters could be useful for ophthalmic practitioners in the clinic.

Automated Detection and Classification of Corneal Haze Using Optical Coherence Tomography in Patients With Keratoconus After Cross-Linking.

To evaluate a proposed technology for offering objective grading and mapping of corneal haze as detected by corneal spectral domain optical coherence tomography after corneal cross-linking. This was a retrospective study to evaluate corneal optical coherence tomography images performed on 44 eyes of 44 patients who underwent corneal cross-linking between January 2014 and May 2015, at the American University of Beirut Medical Center. Overall average brightness of the cornea was markedly increased from 43.4% (±6.0) at baseline to 50.2% (±4.4) at 1 month, 47.9% (±4.4) at 3 months, and 46.4% (±5.7) at 6 months with P <0.001, <0.001, and 0.005, respectively. In the anterior stroma, the average brightness significantly increased at 1, 3, and 6 months with values of 54.8% (±3.9), 52.5% (±5.2), and 49.7% (±6.9) with P <0.001, <0.001, and 0.003, respectively. In the mid stroma, the change was clinically significant at 1 and 3 months, whereas in the posterior stroma, it was only significant at 1 month compared with baseline (P = 0.003). Overall, haze was mostly present at 1 month after surgery in all regions, especially in the anterior (32.1%; ±19.2) and mid stromal regions (9.1%; ±18.8), P <0.001 and 0.001, respectively. In contrast, haze in the posterior stromal region peaks at 3 and 6 months after surgery. Anterior stromal haze was the greatest in intensity and area and it was present for a longer time span than mid and posterior stromal haze. At 12 months, the anterior stroma had still more haze intensity than preoperatively. This image-based software can provide objective and valuable quantitative measurements of corneal haze, which may impact clinical decision-making after different corneal surgeries.

Live Confocal Imaging of Brachypodium Spikelet Meristems.

Live confocal imaging of fluorescent reporters and stains in plant meristems provides valuable measurements of gene expression, protein dynamics, cell polarity, cell division, and growth. The spikelet meristem in the grass Brachypodium distachyon (Brachypodium) is well suited to live imaging because of the ease of dissection, small meristem size, simple arrangement of organs, and because each plant provides abundant spikelet meristems. Brachypodium is also far easier to genetically transform than other grass species. Presented here is a protocol for the growth, staging, dissection, mounting, and imaging of Brachypodium spikelet meristems for live confocal imaging.

Probing the Diffuse Optical-IR Background with TeV Blazars Detected with the MAGIC Telescopes

Blazars are radio loud quasars whose jet points toward the observer. The observed emission is mostly non-thermal, dominated by the jet emission, and in some cases extends up to the very high energy gamma rays (VHE; E > 100 GeV). To date, more than 60 blazars have been detected at VHE mainly with ground-based imaging atmospheric Cherenkov telescopes (IACTs) such as MAGIC, H.E.S.S., and VERITAS. Energetic photons from a blazar may interact with the diffuse optical and IR background (the extragalactic background light, EBL) leaving an imprint on the blazar energy spectrum. This effect can be used to constrain the EBL, with basic assumptions on the intrinsic energy spectrum. Current generation of IACTs is providing valuable measurements of the EBL density and energy spectrumfromoptical to infrared frequencies. In this contribution, we present the latest results obtained with the data taken with the MAGIC telescopes: using 32 spectra from 12 blazars, the scale factor of the optical density predicted by the EBL model from Dominguez et al. (2011) is constrained to be 0.95 (+0.11, -0.12)_(stat) (+0.16, -0.07)_(sys), where a value of 1 means the perfect match with the model.

Virtual reality software package for implementing motor learning and rehabilitation experiments

Virtual reality games for rehabilitation are attracting increasing growth. In particular, there is a demand for games that allow therapists to identify an individual’s difficulties and customize the control of variables, such as speed, size, distance, as well as visual and auditory feedback. This study presents and describes a virtual reality software package (Bridge Games) to promote rehabilitation of individuals living with disabilities and highlights preliminary researches of its use for implementing motor learning and rehabilitation. First, the study presents seven games in the software package that can be chosen by the rehabilitation team, considering the patient’s needs. All game characteristics are described including name, function presentation, objective and valuable measurements for rehabilitation. Second, preliminary results illustrate some applications of two games, considering 343 people with various disabilities and health status. Based on the results, in the Coincident Timing game, there was a main effect of movement sensor type (in this instance the most functional device was the keyboard when compared with Kinect and touch screen) on average time reached by sample analyzed, F(2, 225) = 4.42, p < 0.05. Similarly, in the Challenge! game, a main effect was found for movement sensor type. However, in this case, touch screen provided better performance than Kinect and Leap Motion, F(2, 709) = 5.90, p < 0.01. Thus, Bridge Games is a possible software game to quantify motor learning. Moreover, the findings suggest that motor skills might be practiced differently depending on the environmental interface in which the game may be used.

Feasibility of GNSS-R Ice Sheet Altimetry in Greenland Using TDS-1

Radar altimetry provides valuable measurements to characterize the state and the evolution of the ice sheet cover of Antartica and Greenland. Global Navigation Satellite System Reflectometry (GNSS-R) has the potential to complement the dedicated radar altimeters, increasing the temporal and spatial resolution of the measurements. Here we perform a study of the Greenland ice sheet using data obtained by the GNSS-R instrument aboard the British TechDemoSat-1 (TDS-1) satellite mission. TDS-1 was primarily designed to provide sea state information such as sea surface roughness or wind, but not altimetric products. The data have been analyzed with altimetric methodologies, already tested in aircraft based experiments, to extract signal delay observables to be used to infer properties of the Greenland ice sheet cover. The penetration depth of the GNSS signals into ice has also been considered. The large scale topographic signal obtained is consistent with the one obtained with ICEsat GLAS sensor, with differences likely to be related to L-band signal penetration into the ice and the along-track variations in structure and morphology of the firn and ice volumes The main conclusion derived from this work is that GNSS-R also provides potentially valuable measurements of the ice sheet cover. Thus, this methodology has the potential to complement our understanding of the ice firn and its evolution.

Direct monitoring of active geohazards: emerging geophysical tools for deep‐water assessments

ABSTRACTSeafloor networks of cables, pipelines, and other infrastructure underpin our daily lives, providing communication links, information, and energy supplies. Despite their global importance, these networks are vulnerable to damage by a number of natural seafloor hazards, including landslides, turbidity currents, fluid flow, and scour. Conventional geophysical techniques, such as high‐resolution reflection seismic and side‐scan sonar, are commonly employed in geohazard assessments. These conventional tools provide essential information for route planning and design; however, such surveys provide only indirect evidence of past processes and do not observe or measure the geohazard itself. As such, many numerical‐based impact models lack field‐scale calibration, and much uncertainty exists about the triggers, nature, and frequency of deep‐water geohazards. Recent advances in technology now enable a step change in their understanding through direct monitoring. We outline some emerging monitoring tools and how they can quantify key parameters for deep‐water geohazard assessment. Repeat seafloor surveys in dynamic areas show that solely relying on evidence from past deposits can lead to an under‐representation of the geohazard events. Acoustic Doppler current profiling provides new insights into the structure of turbidity currents, whereas instrumented mobile sensors record the nature of movement at the base of those flows for the first time. Existing and bespoke cabled networks enable high bandwidth, low power, and distributed measurements of parameters such as strain across large areas of seafloor. These techniques provide valuable new measurements that will improve geohazard assessments and should be deployed in a complementary manner alongside conventional geophysical tools.

Blood Flow Measurements in Clinical Practice of Hip Surgery

This review provides a summary of blood flow measurements relevant to hip surgery. An overview of the blood supply to the femoral head and the effect of surgical approaches on bone blood flow will be supported by available measurements. Laser Doppler flowmetry is currently the most commonly used quantitative assessment of bone blood flow intraoperatively, at present mostly for research questions. The technique is user-dependant but safe and inexpensive. It may offer the opportunity to be developed into a clinical tool providing valuable real-time measurements.

Physical controls on half‐hourly, daily, and monthly turbulent flux and energy budget over a high‐altitude small lake on the Tibetan Plateau

AbstractPrecise measurements of evaporation and understanding of the physical controls on turbulent heat flux over lakes have fundamental significance for catchment‐scale water balance analysis and local‐scale climate modeling. The observation and simulation of lake‐air turbulent flux processes have been widely carried out, but studies that examine high‐altitude lakes on the Tibetan Plateau are still rare, especially for small lakes. An eddy covariance (EC) system, together with a four‐component radiation sensor and instruments for measuring water temperature profiles, was set up in a small lake within the Nam Co basin in April 2012 for long‐term evaporation and energy budget observations. With the valuable measurements collected during the ice‐free periods in 2012 and 2013, the main conclusions are summarized as follows: First, a bulk aerodynamic transfer model (B model), with parameters optimized for the specific wave pattern in the small lake, could provide reliable and consistent results with EC measurements, and B model simulations are suitable for data interpolation due to inadequate footprint or malfunction of the EC instrument. Second, the total evaporation in this small lake (812 mm) is approximately 200 mm larger than that from adjacent Nam Co (approximately 627 mm) during their ice‐free seasons. Third, wind speed shows significance at temporal scales of half hourly, whereas water vapor and temperature gradients have higher correlations over temporal scales of daily and monthly in lake‐air turbulent heat exchange. Finally, energy stored during April to June is mainly released during September to November, suggesting an energy balance closure value of 0.97.

Spatially-Resolved Fluorescence Lifetime Measurement for Optical Interrogation of Electrically Dynamic Biological Systems

The excited-state lifetimes of fluorophores in biological samples are valuable measurements, reporting a concentration-independent measurement of the physical environment of the fluorophore. We describe the development of an instrument based on a total internal reflection microscope capable of measuring fluorescence lifetimes within user-defined regions while simultaneously acquiring full field-of-view fluorescent images. Collecting photons only from regions defined via spatial light modulation is critical for measuring localized fluorescence signals, such as fluorescence from a small region on a cell membrane. Our platform, which utilizes time-correlated single photon counting from a selected space, would be especially suitable for complex biological contexts where fluorescence is used as an indicator for expeditious, transient physical changes. Recent development of a Genetically Encoded Voltage Indicator (GEVI), ASAP1, has provided a new method for optically measuring neuronal membrane potential. To demonstrate the utility of the instrument, we hope to follow the changes in membrane potential in two ASAP1-expressing cultured cell models, PC-12 neurites and H9c2 myotubes, by measuring the voltage-dependent lifetime of the ASAP1 fluorescence signal. Using a standard tabletop microscope and spatial light modulation, alongside easy-to-access software and hardware solutions to implement the necessary components, broadly-acting electrically dynamic biological environments can be easily and effectively interrogated without the use of expensive specialized equipment. Additionally, the implementation of TIRF imaging and spatially-restricted analysis allows for improved levels of detail within individual firing events. Furthermore, the relative ease of accessibility of the software and hardware comprising this system would allow for the integration of our platform into an existing experimental setup.

Innovations in Outcomes and Designs of Clinical Trials for Respiratory Drug Development

Clinical trials for the development of respiratory drugs have for years been reliant upon measurements of physiologic tests, combined with the use of questionnaires. New drugs were mostly administered by inhalation and increasingly in fixed combinations. However, these lung function tests have a lack of sensitivity for patient-relevant clinical outcomes. Moreover, new insights in phenotypes and endotypes of these diseases in the basic mechanisms and the discovery of new targets for therapy, have led to the need for a more personalized patient-centered approach and precision medicine. In recent years, a great number of techniques have been proposed but some need further validation. These include fractional exhaled nitric oxide, health-related quality of life and the use of biomarkers like blood and sputum eosinophils and neutrophils, IgE, sIgE, periostin, copeptin and specific cytokines. Additionally, exhaled breath condensate and lung deposition studies by functional residual imaging and by local bronchial pharmacokinetics can be used. In rare diseases like cystic fibrosis, Lung Clearance Index and CT and PET scan fusion images seem to be valuable outcome measurements. Lastly leverage of lung function tests can be done by using body plethysmography, measuring respiratory impedance, variability and the use of modeling and simulation. The need for a patient-centric approach through all stages of clinical development is becoming mandatory. So, an evolution from classical randomized clinical trials (RCTs) to more efficient and patient-relevant designs will be seen more in the future. RCTs will remain necessary for regulatory submission but more efficient and adaptive designs with lower heterogeneity and the use of pragmatic trials are needed. This evolution from undefined targets to a more targeted approach will lead us closer to precision medicine. In this overview, the unmet medical need for better outcomes and study designs in the development of treatments for respiratory diseases, are discussed.

Identify the Atrophy of Alzheimer's Disease, Mild Cognitive Impairment and Normal Aging Using Morphometric MRI Analysis.

Quantitatively assessing the medial temporal lobe (MTL) structures atrophy is vital for early diagnosis of Alzheimer’s disease (AD) and accurately tracking of the disease progression. Morphometry characteristics such as gray matter volume (GMV) and cortical thickness have been proved to be valuable measurements of brain atrophy. In this study, we proposed a morphometric MRI analysis based method to explore the cross-sectional differences and longitudinal changes of GMV and cortical thickness in patients with AD, MCI (mild cognitive impairment) and the normal elderly. High resolution 3D MRI data was obtained from ADNI database. SPM8 plus DARTEL was carried out for data preprocessing. Two kinds of z-score map were calculated to, respectively, reflect the GMV and cortical thickness decline compared with age-matched normal control database. A volume of interest (VOI) covering MTL structures was defined by group comparison. Within this VOI, GMV, and cortical thickness decline indicators were, respectively, defined as the mean of the negative z-scores and the sum of the normalized negative z-scores of the corresponding z-score map. Kruskal–Wallis test was applied to statistically identify group wise differences of the indicators. Support vector machines (SVM) based prediction was performed with a leave-one-out cross-validation design to evaluate the predictive accuracies of the indicators. Linear least squares estimation was utilized to assess the changing rate of the indicators for the three groups. Cross-sectional comparison of the baseline decline indicators revealed that the GMV and cortical thickness decline were more serious from NC, MCI to AD, with statistic significance. Using a multi-region based SVM model with the two indicators, the discrimination accuracy between AD and NC, MCI and NC, AD and MCI was 92.7, 91.7, and 78.4%, respectively. For three-way prediction, the accuracy was 74.6%. Furthermore, the proposed two indicators could also identify the atrophy rate differences among the three groups in longitudinal analysis. The proposed method could serve as an automatic and time-sparing approach for early diagnosis and tracking the progression of AD.

Measurement of the mass composition of ultra-high energy cosmic rays with the Pierre Auger Observatory

The understanding of the nature of ultra-high energy cosmic rays is one of the most intriguing open questions for current and future observatories. With its hybrid design and huge exposure, the Pierre Auger Observatory provides valuable statistical measurements of the chemical composition of cosmic rays with energies above 1017 eV, including the search for neutral primaries such as neutrinos and photons. We report on the most recent results which are based on the accurate measurement of the depth of the shower maximum, Xmax, by the fluorescence telescopes and on the shape of the signals recorded by the water-Cherenkov detectors. The interpretation of these results in terms of mass composition is also discussed related to the hadronic interaction models used to describe the development of air showers.