bluuebunny/crossref_metadata_2025 huggingface dataset:
Hematopoietic Stem Cell Applications: Past, Present and Future
Authors: Varma Subhash , Malhotra Pankaj , Lad Deepesh P
Published: August 2012

Hematopoietic stem cells have been at the forefront of stem cell research and its applications. Several advancements have occurred in the field of hematopoietic stem cell transplantation since this was first accepted as a treatment for otherwise incurable hematological disorders. The progress in this field is to the extent that it is unfathomable to a single person be it a scientific researcher or a practicing clinician. In this internet era, most patients are also well informed of the utility of stem cells. There is a need to bridge the gap in knowledge of this science between the scientists, physicians and the public at large. This review aims to summarize the advances in hematopoietic stem cell applications.

Key messages

Hematopoietic stem cells possess the characteristics of self renewal, differentiation, mobilization and apoptosis.

The transfer of hematopoietic stem cells to rescue a recipient's hematopoiesis, who has received conditioning with high dose chemotherapy and/or total body irradiation, constitutes hematopoietic stem cell transplantation (HSCT).

Hematopoietic stem cells can be obtained from the bone marrow, peripheral blood or umbilical cord blood.

Autologous HSCT involves the infusion of one's own hematopoietic stem cells. An allogeneic HSCT involves the infusion of hematopoietic stem cells from another individual.

Depending on the HLA match, the HSCT is of following types: Syngeneic, matched related, matched unrelated and haploidentical.

Patient selection and the timing of transplant are the most important factors determining transplant outcomes.

Hematopoietic stem cells and umbilical cord stem cells have applications in regenerative medicine as shown in preclinical and early clinical studies.

How to cite this article

Lad DP, Malhotra P, Varma S. Hematopoietic Stem Cell Applications: Past, Present and Future. J Postgrad Med Edu Res 2012;46(2):69-74.
Biomaterials in Regenerative Medicine
Authors: Bhat Sumrita , Kumar Ashok
Published: August 2012

Limitations with the conventional methods have bought biomaterials to the forefront for the repair and restoration of tissue functions. Recent advances in the area of biomaterials have revolutionized the field of tissue engineering and regenerative medicine. According to the nature of polymers they are divided into different classes and each one has found applicability in the area of regenerative medicine. Each class of biomaterials has a set of properties which makes them appropriate for a specific application. The most important property is the behavior of biomaterials when implanted in vivo. It should not elicit any immune rejection reactions neither should its byproducts be toxic to animal tissue. Any type of the biomaterial can be fabricated into a three-dimensional scaffold which can be used as housing for the initial growth and proliferation of the specific cell type. In addition to the conventional methods of scaffold fabrication few contemporary methods include ‘hydrogels’ and ‘cryogels’. These matrices possess interconnected porous network which facilitates the cell migration and proliferation. These gel matrices can be fabricated from both natural and synthetic polymers and have shown applicability in different areas of tissue engineering. Biomaterials have shown applicability as cardiovascular implants, orthopedic implants, dental implants, etc. Furthermore, recent advances in the regenerative medicine have shown that in addition to the use of autologous and allogenic sources, stem cells can prove to be a very good alternative. Stem cells interaction with biomaterials has shown applicability in the regenerative medicine and thus can have an immense potential in future.

How to cite this article

Bhat S, Kumar A. Biomaterials in Regenerative Medicine. J Postgrad Med Edu Res 2012;46(2):81-89.
Late Opacification of Foldable Intraocular Lenses
Authors: Gupta Nishant , Ram Jagat , Chaudhary Manish , Sukhija Jaspreet Singh , Kumar Jaidrath
Published: August 2012

Objective

To report opacification of hydrophilic acrylic and silicone foldable intraocular lenses (IOL).

Designs

Case series.

Participants

Five patients with IOL opacification.

Results

We report five eyes of five patients with late opacification of the intraocular lens (IOL). Three patients had hydrophilic acrylic (SC60B-OUV-MDR, Inc), two had silicone IOL (Allergan SI30NB). Two out of the three patients with opacified hydrophilic acrylic IOLs had diabetes mellitus. Three eyes with opacified acrylic IOL underwent IOL exchange with hydrophobic acrylic IOL. Two silicone IOL patients had no visually significant opacification and were managed conservatively.

Conclusion

IOL optic opacification in hydrophilic acrylic and silicone IOL may be due to defective material, manufacturing process, storage.

How to cite this article

Ram J, Gupta N, Chaudhary M, Sukhija JS, Gupta A, Kumar J. Late Opacification of Foldable Intraocular Lenses. J Postgrad Med Edu Res 2012;46(2):95-97.
The Association between Nasal Septum Deviation and Sagittal Maxillary Growth Discrepancy
Authors: Bansal Ajay , Utreja Ashok Kumar , Panda Naresh Kumar , Jena Ashok Kumar , Singh Satinder Pal
Published: August 2012

Objective

To test the hypothesis that there is no association between the nasal septum deviation and the sagittal growth discrepancy of maxilla.

Materials and methods

Total 80 subjects in the age range of 7 to 51 years were divided into four groups of 20 each. Group I included subjects with normally positioned maxilla, group II included subjects with protruded maxilla, and group III included subjects with retruded maxilla in relation to the anterior cranial base. Subjects who already had a deviated nasal septum were included in group IV. All the subjects were clinically examined for the evaluation of nasal septum deviation. The deviation of nasal septum was categorized into anterior and posterior deviation. The sagittal maxillary growth discrepancy in all subjects was evaluated from lateral cephalograms. The association between the deviation of nasal septum and the discrepancy of maxillary growth in the sagittal plane was tested by Chi-square test.

Results

Deviated nasal septum was more common among subjects with normal and retruded maxilla than subjects with protruded maxilla. Subjects in whom nasal septum was already deviated, various sagittal maxillary growth discrepancies were equally distributed. There was no association between the nasal septum deviation and sagittal growth discrepancy of the maxilla (χ2 = 2.143 and p = 0.342).

Conclusion

There was no association between nasal septum deviation and the sagittal growth discrepancy of the maxilla.

How to cite this article

Bansal A, Utreja AK, Singh SP, Panda NK, Jena AK. The Association between Nasal Septum Deviation and Sagittal Maxillary Growth Discrepancy. J Postgrad Med Edu Res 2012;46(2):98-101.
Understanding and Managing Complete form of Sporadic Koro Syndrome associated with Depression
Authors: Panigrahi Mahima , Padhy Susanta Kumar , Behere Prakash B
Published: August 2012

Koro is a term, probably of Malayasian origin, a culture bound syndrome, which refers to an episode of sudden and intense anxiety that the penis will recede into the body and possibly cause death. The syndrome is reported in South and East Asia including Eastern India, occasionally found in west. It can occur in localized epidemic and sporadic form or in complete and incomplete form. In some, this is reported as a forerunner of mood disorder and is understood in the context of psychosexual conflicts, personality and culture. Moreover, reports of sporadic Koro are rare from Noneastern India and report of a holistic and comprehensive approach to understand and manage such cases are lacking. Hence, In today's era of extinction of psychotherapeutic treatments particularly in India, this rare case is a small example of how such comprehensive holistic treatments can be helpful to our population.

How to cite this article

Panigrahi M, Padhy SK, Behere PB. Understanding and Managing Complete form of Sporadic Koro Syndrome associated with Depression. J Postgrad Med Edu Res 2012;46(2):104-105.
Laboratory measurements and model sensitivity studies of dust deposition ice nucleation
Authors: Kulkarni G. , Fan J. , Comstock J. M. , Liu X. , Ovchinnikov M.
Published: August 2012

Abstract. We investigated the ice nucleating properties of mineral dust particles to understand the sensitivity of simulated cloud properties to two different representations of contact angle in the Classical Nucleation Theory (CNT). These contact angle representations are based on two sets of laboratory deposition ice nucleation measurements: Arizona Test Dust (ATD) particles of 100, 300 and 500 nm sizes were tested at three different temperatures (−25, −30 and −35 °C), and 400 nm ATD and kaolinite dust species were tested at two different temperatures (−30 and −35 °C). These measurements were used to derive the onset relative humidity with respect to ice (RHice) required to activate 1% of dust particles as ice nuclei, from which the onset single contact angles were then calculated based on CNT. For the probability density function (PDF) representation, parameters of the log-normal contact angle distribution were determined by fitting CNT-predicted activated fraction to the measurements at different RHice. Results show that onset single contact angles vary from ~18 to 24 degrees, while the PDF parameters are sensitive to the measurement conditions (i.e. temperature and dust size). Cloud modeling simulations were performed to understand the sensitivity of cloud properties (i.e. ice number concentration, ice water content, and cloud initiation times) to the representation of contact angle and PDF distribution parameters. The model simulations show that cloud properties are sensitive to onset single contact angles and PDF distribution parameters. The comparison of our experimental results with other studies shows that under similar measurement conditions the onset single contact angles are consistent within ±2.0 degrees, while our derived PDF parameters have larger discrepancies.
Stochastic parameterization of dust emission and application to convective atmospheric conditions
Authors: Klose M. , Shao Y.
Published: August 2012

Abstract. We develop a parameterization scheme of convective dust emission for regional and global atmospheric models. Convective dust emission occurs in the absence of saltation as large eddies intermittently produce strong shear stresses on the surface and entrain dust particles into the air. This dust emission mechanism has not been included in the traditional dust models. The scheme presented in this study is a new approach which takes account of the stochastic nature of convective dust emission. It consists of the statistical representations of soil particle size, inter-particle cohesion, and instantaneous surface shear stress. A method of determining the probability density function of the latter quantity is proposed. Dust emission is then estimated from the overlap of the probability density functions of the aerodynamic lifting and inter-particle cohesive forces. The new scheme is implemented into the WRF/Chem model and applied to dust modeling in the Taklimakan Desert. A comparison with lidar data shows that the model can reproduce the main features of the dust patterns and their diurnal variations. For the case studied, convective dust emission is typically several μg m−2 s−1 and at times up to 50 μg m−2 s−1.
Importance of tropospheric volcanic aerosol for indirect radiative forcing of climate
Authors: Schmidt A. , Carslaw K. S. , Mann G. W. , Rap A. , Pringle K. J. , Spracklen D. V. , Wilson M. , Forster P. M.
Published: August 2012

Abstract. Observations and models have shown that continuously degassing volcanoes have a potentially large effect on the natural background aerosol loading and the radiative state of the atmosphere. We use a global aerosol microphysics model to quantify the impact of these volcanic emissions on the cloud albedo radiative forcing under pre-industrial (PI) and present-day (PD) conditions. We find that volcanic degassing increases global annual mean cloud droplet number concentrations by 40% under PI conditions, but by only 10% under PD conditions. Consequently, volcanic degassing causes a global annual mean cloud albedo effect of −1.06 W m−2 in the PI era but only −0.56 W m−2 in the PD era. This non-equal effect is explained partly by the lower background aerosol concentrations in the PI era, but also because more aerosol particles are produced per unit of volcanic sulphur emission in the PI atmosphere. The higher sensitivity of the PI atmosphere to volcanic emissions has an important consequence for the anthropogenic cloud radiative forcing because the large uncertainty in volcanic emissions translates into an uncertainty in the PI baseline cloud radiative state. Assuming a −50/+100% uncertainty range in the volcanic sulphur flux, we estimate the annual mean anthropogenic cloud albedo forcing to lie between −1.16 W m−2 and −0.86 W m−2. Therefore, the volcanically induced uncertainty in the PI baseline cloud radiative state substantially adds to the already large uncertainty in the magnitude of the indirect radiative forcing of climate.
Mixing of dust and NH3 observed globally over anthropogenic dust sources
Authors: Ginoux P. , Clarisse L. , Clerbaux C. , Coheur P.-F. , Dubovik O. , Hsu N. C. , Van Damme M.
Published: August 2012

Abstract. The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH3, with only 1% difference between land-use databases. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m2 g−1 as NH3 burden increases from 0 to 40 mg m−2. The fine mode extinction efficiency, ranging from 4 to 16 m2 g−1, does not appear to depend on NH3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties.
Sources of atmospheric mercury in the tropics: continuous observations at a coastal site in Suriname
Authors: Müller D. , Wip D. , Warneke T. , Holmes C. D. , Dastoor A. , Notholt J.
Published: August 2012

Abstract. Mercury measurements at a coastal site in Nieuw Nickerie (5°56' N, 56°59' W), Suriname, provide the only continuous records of atmospheric mercury in the tropics. Here we evaluate observations of total gaseous mercury (TGM) during 2007. Nieuw Nickerie typically samples marine air from the Atlantic Ocean, with occasional influence from continental South America. Over the year, average concentrations are 1.40 ng m−3. As the intertropical convergence zone passes over Suriname twice each year, the site samples both northern and southern hemispheric air masses. We use back trajectories to classify each measurement by hemisphere, as well as continental or ocean. For air passing over ocean before sampling, TGM concentrations are 10% higher in air coming from the Northern Hemisphere (1.45 ng m−3) than from the Southern Hemisphere (1.32 ng m−3). Air from the South American continent also carries higher TGM (1.43 ng m−3) than air from the South Atlantic Ocean, with most of these trajectories occurring in August and September. Biomass burning in Brazil peaks in the same months and likely contributes significantly to elevated concentrations seen in Nickerie. We also compare the observed seasonal cycle to two atmospheric mercury chemistry and transport models (GRAHM and GEOS-Chem). Both models simulate transition between northern and southern hemispheric air, thus capturing the seasonal cycle; however the models overestimate the TGM concentrations during months when Nickerie samples Northern Hemisphere air. It is difficult to determine whether the models' sources or sinks in the Northern Hemisphere tropics are responsible.
Chlorine activation on stratospheric aerosols: uncertainties in parameterizations and surface area
Authors: Wegner T. , Grooß J.-U. , von Hobe M. , Stroh F. , Sumińska-Ebersoldt O. , Volk C. M. , Hösen E. , Mitev V. , Shur G. , Müller R.
Published: August 2012

Abstract. Chlorine activation in the Arctic is evaluated by examining the different parameterizations for uptake coefficients on stratospheric aerosols, high-resolution in-situ measurements and vortex-wide satellite observations. The parameterizations for heterogeneous chemistry on liquid aerosols are most sensitive to temperature with the reaction rates doubling for each Kelvin increase in temperature. However, differences between the parameterizations are negligible. For Nitric Acid Trihydrate particles (NAT) the major factors of uncertainty are the number density of nucleated particles and different parameterization choices. These two factors induce an uncertainty that covers several orders of magnitude on the reaction rate. But as predicted reaction rates on liquid aerosols always exceed those on NAT the overall uncertainty is small. In-situ observations of ClOx from Arctic winters in 2005 and 2010 are used to validate the heterogeneous chemistry parameterizations. The ambient conditions for these measurements proved to be very different between those two winters with HCl being the limiting reacting partner for the 2005 measurements and ClONO2 for the 2010 measurements. Modeled levels of chlorine activation are in very good agreement with the in-situ observations and the surface area provided by Polar Stratospheric Clouds (PSCs) has only a limited impact on modeled chlorine activation. This indicates that the parameterizations give a good representation of the processes in the atmosphere. Back-trajectories started on the location of the observations in 2005 indicate temperatures on the threshold for PSC formation, hence the surface area is mainly provided by the background aerosol. Still, the model shows additional chlorine activation during this time-frame, providing cautionary evidence for chlorine activation even in the absence of PSCs. Vortex-averaged satellite observations also show no definite connection between chlorine activation and PSC formation. The inter- and intra-annual variability of vortex-average HCl and HNO3 based on MLS observations is examined for the Arctic winters 2004/2005 to 2010/2011. These observations show that removal of HCl and HNO3 from the gas-phase are not correlated. HNO3 loss exhibits great inter-annual variability depending on prevailing temperatures while HCl loss is continuous through December without considerable inter- or intra-annual variability. Only the recovery of HCl in late in winter depends on the level of denitrification. Hence, the occurrence of HNO3 containing PSC particles does not seem to have a significant effect on the speed of initial chlorine activation on a vortex-wide scale.
Consistent assimilation of MERIS FAPAR and atmospheric CO2 into a terrestrial vegetation model and interactive mission benefit analysis
Authors: Kaminski T. , Knorr W. , Scholze M. , Gobron N. , Pinty B. , Giering R. , Mathieu P.-P.
Published: August 2012

Abstract. The terrestrial biosphere is currently a strong sink for anthropogenic CO2 emissions. Through the radiative properties of CO2, the strength of this sink has a direct influence on the radiative budget of the global climate system. The accurate assessment of this sink and its evolution under a changing climate is, hence, paramount for any efficient management strategies of the terrestrial carbon sink to avoid dangerous climate change. Unfortunately, simulations of carbon and water fluxes with terrestrial biosphere models exhibit large uncertainties. A considerable fraction of this uncertainty reflects uncertainty in the parameter values of the process formulations within the models. This paper describes the systematic calibration of the process parameters of a terrestrial biosphere model against two observational data streams: remotely sensed FAPAR (fraction of absorbed photosynthetically active radiation) provided by the MERIS (ESA's Medium Resolution Imaging Spectrometer) sensor and in situ measurements of atmospheric CO2 provided by the GLOBALVIEW flask sampling network. We use the Carbon Cycle Data Assimilation System (CCDAS) to systematically calibrate some 70 parameters of the terrestrial BETHY (Biosphere Energy Transfer Hydrology) model. The simultaneous assimilation of all observations provides parameter estimates and uncertainty ranges that are consistent with the observational information. In a subsequent step these parameter uncertainties are propagated through the model to uncertainty ranges for predicted carbon fluxes. We demonstrate the consistent assimilation at global scale, where the global MERIS FAPAR product and atmospheric CO2 are used simultaneously. The assimilation improves the match to independent observations. We quantify how MERIS data improve the accuracy of the current and future (net and gross) carbon flux estimates (within and beyond the assimilation period). We further demonstrate the use of an interactive mission benefit analysis tool built around CCDAS to support the design of future space missions. We find that, for long-term averages, the benefit of FAPAR data is most pronounced for hydrological quantities, and moderate for quantities related to carbon fluxes from ecosystems. The benefit for hydrological quantities is highest for semi-arid tropical or sub-tropical regions. Length of mission or sensor resolution is of minor importance.
The relative roles of CO2 and palaeogeography in determining late Miocene climate: results from a terrestrial model–data comparison
Authors: Bradshaw C. D. , Lunt D. J. , Flecker R. , Salzmann U. , Pound M. J. , Haywood A. M. , Eronen J. T.
Published: August 2012

Abstract. The late Miocene palaeorecord provides evidence for a warmer and wetter climate than that of today, and there is uncertainty in the palaeo-CO2 record of at least 200 ppm. We present results from fully coupled atmosphere-ocean-vegetation simulations for the late Miocene that examine the relative roles of palaeogeography (topography and ice sheet geometry) and CO2 concentration in the determination of late Miocene climate through comprehensive terrestrial model-data comparisons. Assuming that these data accurately reflect the late Miocene climate, and that the late Miocene palaeogeographic reconstruction used in the model is robust, then results indicate that: 1. Both palaeogeography and atmospheric CO2 contribute to the proxy-derived precipitation differences between the late Miocene and modern reference climates. However these contributions exibit synergy and so do not add linearly. 2. The vast majority of the proxy-derived temperature differences between the late Miocene and modern reference climates can only be accounted for if we assume a palaeo-CO2 concentration towards the higher end of the range of estimates.
Minor effect of meltwater on the ocean circulation during deglaciation
Authors: Lohmann G. , Grosfeld K. , Butzin M. , Huybrechts P. , Zweck C.
Published: August 2012

Abstract. Decaying Northern Hemisphere ice sheets during deglaciation affect the high latitude hydrological balance in the North Atlantic and therefore the ocean circulation after the Last Glacial Maximum. Surprisingly, geological data suggest that meltwater fluxes of about 14–20 m sea-level equivalent flushed into the North Atlantic without significantly influencing the Atlantic meridional overturning circulation. Using a three-dimensional ocean circulation model coupled to an energy balance model of the atmosphere, we investigate the response of the ocean circulation to spatio-temporal variable deglacial freshwater discharges. Freshwater inputs are simulated by a three-dimensional thermo-mechanical ice sheet model of the Northern Hemisphere. In our experiments, we find a strong sensitivity of the ocean circulation when the deglacial meltwater is injected into the surface layers yielding a quasi shut-down. On the other hand, the parameterization of huge sub-glacial outbursts as so-called hyperpycnal flows are mimicked through bottom injections in ocean models leading to a reduced sensitivity of the overturning circulation against freshwater perturbations and providing a consistent representation of the deglacial climate evolution.
Multi-scale auroral observations in Apatity: winter 2010–2011
Authors: Kozelov B. V. , Pilgaev S. V. , Borovkov L. P. , Yurov V. E.
Published: August 2012

Abstract. Routine observations of the aurora are conducted in Apatity by a set of five cameras: (i) all-sky TV camera Watec WAT-902K (1/2"CCD) with Fujinon lens YV2.2 × 1.4A-SA2; (ii) two monochromatic cameras Guppy F-044B NIR (1/2"CCD) with Fujinon HF25HA-1B (1:1.4/25 mm) lens for 18° field of view and glass filter 558 nm; (iii) two color cameras Guppy F-044C NIR (1/2"CCD) with Fujinon DF6HA-1B (1:1.2/6 mm) lens for 67° field of view. The observational complex is aimed at investigating spatial structure of the aurora, its scaling properties, and vertical distribution in the rayed forms. The cameras were installed on the main building of the Apatity division of the Polar Geophysical Institute and at the Apatity stratospheric range. The distance between these sites is nearly 4 km, so the identical monochromatic cameras can be used as a stereoscopic system. All cameras are accessible and operated remotely via Internet. For 2010–2011 winter season the equipment was upgraded by special blocks of GPS-time triggering, temperature control and motorized pan-tilt rotation mounts. This paper presents the equipment, samples of observed events and the web-site with access to available data previews.
Design and operation of a field telescope for cosmic ray geophysical tomography
Authors: Lesparre N. , Marteau J. , Déclais Y. , Gibert D. , Carlus B. , Nicollin F. , Kergosien B.
Published: August 2012

Abstract. The cosmic ray muon tomography gives an access to the density structure of geological targets. In the present article we describe a muon telescope adapted to harsh environmental conditions. In particular the design optimizes the total weight and power consumption to ease the deployment and increase the autonomy of the detector. The muon telescopes consist of at least two scintillator detection matrices readout by photosensors via optical fibres. Two photosensor options have been studied. The baseline option foresees one multianode photomultiplier (MAPM) per matrix. A second option using one multipixel photon counter (MPPC) per bar is under development. The readout electronics and data acquisition system developed for both options are detailed. We present a first data set acquired in open-sky conditions compared with the muon flux detected across geological objects.
Results from the intercalibration of optical low light calibration sources 2011
Authors: Brändström B. U. E. , Enell C.-F. , Widell O. , Hansson T. , Whiter D. , Mäkinen S. , Mikhaylova D. , Axelsson K. , Sigernes F. , Gulbrandsen N. , Schlatter N. M. , Gjendem A. G. , Cai L. , Reistad J. P. , Daae M. , Demissie T. D. , Andalsvik Y. L. , Roberts O. , Poluyanov S. , Chernouss S.
Published: August 2012

Abstract. Following the 38th Annual European Meeting on Atmospheric Studies by Optical Methods in Siuntio in Finland, an intercalibration workshop for optical low light calibration sources was held in Sodankylä, Finland. The main purpose of this workshop was to provide a comparable scale for absolute measurements of aurora and airglow. All sources brought to the intercalibration workshop were compared to the Fritz Peak reference source using the Lindau Calibration Photometer built by Wilhelm Barke and Hans Lauche in 1984. The results were compared to several earlier intercalibration workshops. It was found that most sources were fairly stable over time, with errors in the range of 5–25%. To further validate the results, two sources were also intercalibrated at UNIS, Longyearbyen, Svalbard. Preliminary analysis indicates agreement with the intercalibration in Sodankylä within about 15–25%.
Martian dust devils detector over FPGA
Authors: de Lucas E. , Miguel M. J. , Mozos D. , Vázquez L.
Published: August 2012

Abstract. Digital applications that must be on-board of space missions must accomplish a very restrictive set of requirements. These include energy efficiency, small volume and weight, robustness and high performance. Moreover these circuits can not be repaired in case of error, so they must be reliable or provide some way to recover from errors. These features make reconfigurable hardware (FPGAs, Field Programmable Gate Arrays) a very suitable technology to be used in space missions. This paper presents a Martian dust devil detector implemented on a FPGA. The results show that a hardware implementation of the algorithm present very good numbers in terms of performance compared with the software version. Moreover, as the amount of time needed to perform all the computations on the reconfigurable hardware is small, this hardware can be used more of the time to realize other applications.
Influence of high-latitude geomagnetic pulsations on recordings of broad-band force-balanced seismic sensors
Authors: Kozlovskaya E. , Kozlovsky A.
Published: August 2012

Abstract. Seismic broad-band sensors with electromagnetic feedback are sensitive to variations of surrounding magnetic field, including variations of geomagnetic field. Usually, the influence of the geomagnetic field on recordings of such seismometers is ignored. It might be justified for seismic observations at middle and low latitudes. The problem is of high importance, however, for observations in Polar Regions (above 60° geomagnetic latitude), where magnitudes of natural magnetic disturbances may be two or even three orders larger. In our study we investigate the effect of ultra-low frequency (ULF) magnetic disturbances, known as geomagnetic pulsations, on the STS-2 seismic broadband sensors. The pulsations have their sources and, respectively, maximal amplitudes in the region of the auroral ovals, which surround the magnetic poles in both hemispheres at geomagnetic latitude (MLAT) between 60° and 80°. To investigate sensitivity of the STS-2 seismometer to geomagnetic pulsations, we compared the recordings of permanent seismic stations in northern Finland to the data of the magnetometers of the IMAGE network located in the same area. Our results show that temporary variations of magnetic field with periods of 40–150 s corresponding to regular Pc4 and irregular Pi2 pulsations are seen very well in recordings of the STS-2 seismometers. Therefore, these pulsations may create a serious problem for interpretation of seismic observations in the vicinity of the auroral oval. Moreover, the shape of Pi2 magnetic disturbances and their periods resemble the waveforms of glacial seismic events reported originally by Ekström (2003). The problem may be treated, however, if combined analysis of recordings of collocated seismic and magnetic instruments is used.
Fractal analysis of INSAR and correlation with graph-cut based image registration for coastline deformation analysis: post seismic hazard assessment of the 2011 Tohoku earthquake region
Authors: Dutta P. K. , Mishra O. P.
Published: August 2012

Abstract. Satellite imagery for 2011 earthquake off the Pacific coast of Tohoku has provided an opportunity to conduct image transformation analyses by employing multi-temporal images retrieval techniques. In this study, we used a new image segmentation algorithm to image coastline deformation by adopting graph cut energy minimization framework. Comprehensive analysis of available INSAR images using coastline deformation analysis helped extract disaster information of the affected region of the 2011 Tohoku tsunamigenic earthquake source zone. We attempted to correlate fractal analysis of seismic clustering behavior with image processing analogies and our observations suggest that increase in fractal dimension distribution is associated with clustering of events that may determine the level of devastation of the region. The implementation of graph cut based image registration technique helps us to detect the devastation across the coastline of Tohoku through change of intensity of pixels that carries out regional segmentation for the change in coastal boundary after the tsunami. The study applies transformation parameters on remotely sensed images by manually segmenting the image to recovering translation parameter from two images that differ by rotation. Based on the satellite image analysis through image segmentation, it is found that the area of 0.997 sq km for the Honshu region was a maximum damage zone localized in the coastal belt of NE Japan forearc region. The analysis helps infer using matlab that the proposed graph cut algorithm is robust and more accurate than other image registration methods. The analysis shows that the method can give a realistic estimate for recovered deformation fields in pixels corresponding to coastline change which may help formulate the strategy for assessment during post disaster need assessment scenario for the coastal belts associated with damages due to strong shaking and tsunamis in the world under disaster risk mitigation programs.
A mobile X-POL weather radar for hydrometeorological applications in the metropolitan area of São Paulo, Brazil
Authors: Pereira Filho A. J.
Published: August 2012

Abstract. This paper presents the first mobile X-band dual-polarization Doppler weather radar termed MXPOL operated by the Laboratory of Hydrometeorology (LABHIDRO) of the University of São Paulo, São Paulo, Brazil. It is used in graduate and under graduate courses, real time monitoring and nowcasting of severe weather in the Metropolitan Area of São Paulo (MASP). It is one of the first of its kind to be used operationally to provide real time high spatial resolution polarimetric data. MXPOL is an important component of a Hydrometeorological Forecast System (Pereira Filho et al., 2005) for MASP. This manuscript presents some instances of MXPOL polarimetric measurements of weather systems and their respective microphysical, dynamical and boundary layer features that can improve nowcasting.
Solving the orientation problem for an automatic magnetic observatory
Authors: Khokhlov A. , Le Mouël J. L. , Mandea M.
Published: August 2012

Abstract. The problem of the absolute calibration of a vectorial (tri-axial) magnetometer is addressed with the objective that the apparatus, once calibrated, gives afterwards, for a few years, the absolute values of the three components of the geomagnetic field (say the Northern geographical component, Eastern component and vertical component) with an accuracy of the order of 1 nT. The calibration procedure comes down to measure the orientation in space of the three physical axes of the sensor or, in other words, the entries of the transfer matrix from the local geographical axes to these physical axes. Absolute calibration follows indeed an internal calibration which provides accurate values of the three scale factors corresponding to the three axes – and in addition their relative angles. The absolute calibration can be achieved through classical absolute measurements made with an independent equipment. It is shown – after an error analysis which is not trivial – that, while it is not possible to get the axes absolute orientations with a high accuracy, the assigned objective (absolute values of the Northern geographical component, Eastern component and vertical component, with an accuracy of the order of 1 nT) is nevertheless reachable; this is because in the time interval of interest the field to measure are not far from the field prevailing during the calibration process.
The GPlates Geological Information Model and Markup Language
Authors: Qin X. , Müller R. D. , Cannon J. , Landgrebe T. C. W. , Heine C. , Watson R. J. , Turner M.
Published: August 2012

Abstract. Understanding tectonic and geodynamic processes leading to the present-day configuration of the Earth involves studying data and models across a variety of disciplines, from geochemistry, geochronology and geophysics, to plate kinematics and mantle dynamics. All these data represent a 3-dimensional spatial and 1-dimensional temporal framework, a formalism which is not exploited by traditional spatial analysis tools. This is arguably a fundamental limit in both the rigour and sophistication in which datasets can be combined for geological "deep time" analysis, and often confines the extent of data analyses to the present-day configurations of geological objects. The GPlates Geological Information Model (GPGIM) represents a formal specification of geological and geophysical data in a time-varying plate tectonics context, used by the GPlates virtual-globe software. It provides a framework in which relevant types of geological data are attached to a common plate tectonic reference frame, allowing the data to be reconstructed in a time-dependent spatio-temporal plate reference frame. The GPlates Markup Language (GPML), being an extension of the open standard Geography Markup Language (GML), is both the modelling language for the GPGIM and an XML-based data format for the interoperable storage and exchange of data modelled by it. The GPlates software implements the GPGIM allowing researchers to query, visualise, reconstruct and analyse a rich set of geological data including numerical raster data. The GPGIM has recently been extended to support time-dependent geo-referenced numerical raster data by wrapping GML primitives into the time-dependent framework of the GPGIM. Coupled with GPlates' ability to reconstruct numerical raster data and import/export from/to a variety of raster file formats, as well as its handling of time-dependent plate boundary topologies, interoperability with geodynamic softwares is established, leading to a new generation of deep-time spatio-temporal data analysis and modelling, including a variety of new functionalities such as 4-D data-mining.
Electric solar wind sail mass budget model
Authors: Janhunen P. , Quarta A. A. , Mengali G.
Published: August 2012

Abstract. The electric solar wind sail (E-sail) is a new type of propellantless propulsion system for Solar System transportation, which uses the natural solar wind for producing spacecraft propulsion. This paper discusses a mass breakdown and a performance model for an E-sail spacecraft that hosts a scientific payload of prescribed mass. In particular, the model is able to estimate the total spacecraft mass and its propulsive acceleration as a function of various design parameters such as the tethers number and their length. A number of subsystem masses are calculated assuming existing or near-term E-sail technology. In light of the obtained performance estimates, an E-sail represents a promising propulsion system for a variety of transportation needs in the Solar System.
Potential soil moisture products from the Aquarius radiometer and scatterometer using an observing system simulation experiment
Authors: Luo Y. , Feng X. , Houser P. , Anantharaj V. , Fan X. , De Lannoy G. , Zhan X. , Dabbiru L.
Published: August 2012

Abstract. Using an Observing System Simulation Experiment (OSSE), we investigate the potential soil moisture retrieval capability of the National Aeronautics and Space Administration (NASA) Aquarius radiometer (L-band 1.413 GHz) and scatterometer (L-band, 1.260 GHz). We estimate potential errors in soil moisture retrievals and identify the sources that could cause those errors. The OSSE system includes: (i) a land surface model in the NASA Land Information System, (ii) a radiative transfer and backscatter model, (iii) a realistic orbital sampling model and (iv) an inverse soil moisture retrieval model. We execute the OSSE over a 1000 × 2200 km2 region in the central US, including the Red and Arkansas river basins. Spatial distributions of soil moisture retrieved from the radiometer and scatterometer are close to the synthetic truth. High root mean square errors (RMSEs) of radiometer retrievals are found over the heavily vegetated regions, while large RMSE of scatterometer retrievals are scattered over the entire domain. The temporal variations of soil moisture are realistically captured over a sparely vegetated region with correlations 0.98 and 0.63, and RMSEs 1.28% and 8.23% vol vol−1 for radiometer and scatterometer, respectively. Over the densely vegetated region, soil moisture exhibits larger temporal variation than the truth, leading to correlation 0.70 and 0.67 respectively, and RMSEs 9.49% and 6.09% vol vol−1 respectively. The domain averaged correlations and RMSEs suggest that radiometer is more accurate than scatterometer in retrieving soil moisture. The analysis also demonstrates that the accuracy of the retrieved soil moisture is affected by vegetation coverage and spatial aggregation.
Optimization of CPMG sequences for NMR borehole measurements
Authors: Ronczka M. , Müller-Petke M.
Published: August 2012

Abstract. Nuklear Magnetic Resonance (NMR) can provide key information such as porosity and permeability for hydrological characterization of geological material. Especially the NMR transverse relaxation time T2 is used to estimate permeability since it reflects a pore-size dependent relaxation process. The measurement sequence (CPMG) usually used consists of several thousands of electromagnetic pulses to densely record the relaxation process. These pulses are equidistantly spaced by a time constant τ. In NMR borehole applications the use of CPMG sequences for measuring the transverse relaxation time T2 is limited due to requirements on energy consumption. It is state of the art to conduct at least two sequences with different echo spacings (τ) for recording fast and slow relaxing processes that correspond to different pore-sizes. For the purpose to reduce the amount of energy used for conducting CPMG sequences and to obtain both, slow and fast, decaying components within one sequence we tested the usage of CPMG sequences with an increasing τ and a decreasing number of pulses. A synthetic study as well as laboratory measurements on samples of glass beads and granulate of different grain size spectra were conducted to evaluate the effects of of an increasing τ spacing, e.g. an enhanced relaxation due to diffusion processes. The results are showing broadened T2 distributions if the number of pulses is decreasing and the mean grain size is increasing, which is mostly an effect of a significantly shortened acquisition time. The shift of T2 distributions to small decay times in dependence of the τ spacing and the mean grain size distribution is observable. We found that it is possible to conduct CPMG sequences with an increased τ spacing. According to the acquisition time and enhanced diffusion the sequence parameters (number of pulses and τmax) has to be chosen carefully. Otherwise the underestimated relaxation time (T2) will lead to misinterpretations.
Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China
Authors: Zeng Z. , Liu J. , Koeneman P. H. , Zarate E. , Hoekstra A. Y.
Published: August 2012

Abstract. Increasing water scarcity places considerable importance on the quantification of water footprint (WF) at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB), a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr−1 in the HRB over 2004–2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production). The remaining 4% was for the industrial and domestic sectors. The "blue" (surface- and groundwater) component of WF was 811 million m3 yr−1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than "green" (soil water) WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.
Predictability, stationarity, and classification of hydraulic responses to recharge in two karst aquifers
Authors: Long A. J. , Mahler B. J.
Published: August 2012

Abstract. Karst aquifers, many of which are rapidly filled and depleted, are likely to be highly susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. We compare hydraulic responses (spring flow, groundwater level, and stream base flow) at several sites in two karst aquifers: the Edwards aquifer (Texas, USA) and the Madison aquifer (South Dakota, USA). A one-dimensional, lumped-parameter model simulates nonstationary soil moisture changes for estimation of recharge, and a nonstationary convolution model simulates the aquifer response to this recharge. Model fit to data was 4% better for calibration periods than for validation periods. We use metrics that describe the shapes of the impulse-response functions (IRFs) obtained from convolution modeling to make comparisons in the distribution of response times among sites and among aquifers. Combined principal component analysis and cluster analysis of metrics describing the shapes of the IRFs separated those sites with IRFs having a large ratio of the mean response time to the system memory from those with large skewness and kurtosis. Classification of the IRF metrics indicate that there is a range of IRF characteristics for different site types (i.e., spring flow, groundwater level, base flow) within a karst system. Further, similar site types did not necessarily display similar IRFs. Results indicate that the differences existing within either aquifer are larger than the differences between the two aquifers and that the two aquifers are similar according to this classification. The use of multiple metrics to describe the IRFs provides a novel way to characterize and compare the way in which multiple sites respond to recharge. As convolution models are developed for additional aquifers, they could contribute to an IRF database and a general classification system for karst aquifers.