Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series

The TerraSAR-X (TSX) synthetic aperture radar (SAR) marks the recent emergence of a new generation of spaceborne radar sensors that can for the first time lay claim to localization accuracies in the sub-meter range. The TSX platform's extremely high orbital stability and the sensor's hardware timing accuracy combine to enable direct measurements of atmospheric refraction and solid Earth movements. By modeling these effects for individual TSX acquisitions, absolute pixel geolocation accuracy on the order of several centimeters can be achieved without need for even a single tiepoint. A 16-month time series of images was obtained over a fixed test site, making it possible to validate both an atmospheric refraction and a solid Earth tide model, while at the same time establishing the instrument's long-term stability. These related goals were achieved by placing trihedral corner reflectors (CRs) at the test site and estimating their phase centers with centimeter-level accuracy using differential GPS (DGPS). Oriented in pairs toward a given satellite track, the CRs could be seen as bright "points” in the images, providing a geometric reference set. SAR images from the high-resolution spotlight (HS) mode were obtained in alternating ascending and descending orbit configurations. The highest-resolution products were selected for their small sample dimensions, as positions can be more precisely determined. Based on the delivered product annotations, the CR image positions were predicted, and these predictions were compared with their measured image positions both before and after compensation for atmospheric refraction and systematic solid Earth deviations. It was possible to show that when the atmospheric distortion and Earth tides are taken into account, the TSX HS products have geolocation accuracies far exceeding the specified requirements. Furthermore, this accuracy was maintained for the duration of the 16-month test period. It could be demonstrated that with a correctly calibrated sensor, and after accounting for atmospheric and tidal effects, tiepoint-free geolocation is possible with TSX with an absolute product accuracy of about 5c

The impact of pain-related fear on neural pathways of pain modulation in chronic low back pain

Introduction Pain-related fear plays a substantial role in chronic low back pain (LBP) by amplifying the experienced disability. Related dysfunctional emotions and cognitions may also affect sensory aspects of pain through a modulatory pathway in which the periaqueductal gray (PAG) and the amygdala play key roles. Objectives We therefore hypothesized a differential amygdala-PAG functional connectivity (FC) in patients with chronic LBP that is modulated by the degree of pain-related fear. Methods We used data of a previously reported fMRI study where 20 chronic LBP patients (7 females, mean age = 39.35) and 20 healthy controls (12 females, mean age = 32.10) were asked to observe video clips showing potentially harmful and neutral activities for the back. Pain-related fear was assessed using the Tampa Scale of kinesiophobia (TSK) and Fear Avoidance Beliefs questionnaires (FABQ). Generalized psychophysiological interactions were used to reveal task-based FC. Results Compared to controls, patients exhibited a significant decrease in amygdala-PAG-FC (P = 0.022) during observation of harmful activities, but not of neutral activities. Furthermore, amygdala-PAG-FC correlated negatively with Tampa Scale of kinesiophobia scores in patients (R2 = 0.28, P = 0.01) but not with Fear Avoidance Beliefs questionnaires scores. Discussion Our findings might indicate a maladaptive psychobiological interaction in chronic LBP patients characterized by a disrupted amygdala-PAG-FC that is modulated by the degree of pain-related fear. These results shed new light on brain mechanisms underlying psychological factors that may have pronociceptive effects in chronic LBP

Processing of COBRA FMCW SAR Data

We present results from air-borne SAR campaigns using the FMCW SAR system COBRA operating at 35 GHz. Thanks to its large bandwidth the theoretical image resolution is below 10 cm in both the range and azimuth dimensions. Highly precise navigation data as well as very accurate synchronization of navigation and SAR data enables equally accurate absolute positioning. The SAR data were focused using a Frequency Scaling Algorithm (FSA) that accounts for the movement of the platform during the long ramp duration. The focusing chain integrates a two-step motion compensation scheme. The geometric and radiometric characteristics of the resulting single look complex (SLC) images were analyzed based on corner reflectors deployed within the test site. The scene was illuminated several times from two opposite directions in a standard strip-map mode. For each track, highly overlapping data segments were focused and geocoded individually. These products were subsequently mosaicked to generate a single geocoded image. Examples of change detection and moving target indication are also given

Spaceborne SAR product geolocation accuracy: A Sentinel-1 update

Sentinel-1A (S1A), launched by the European Space Agency (ESA) on April 3, 2014, is a state-of-the-art spaceborne Synthetic Aperture Radar (SAR) Earth observation platform. S1A products are expected to provide high and consistent geolocation accuracy. As of the end of May, 2014, the satellite has not yet reached its reference orbit. However, estimation of product geolocation accuracy is ongoing, and improvements are continually being made. The results reported here represent the early situation, with continued progress expected

A Novel RNA Editing Sensor Tool and a Specific Agonist Determine Neuronal Protein Expression of RNA-Edited Glycine Receptors and Identify a Genomic APOBEC1 Dimorphism as a New Genetic Risk Factor of Epilepsy

C-to-U RNA editing of glycine receptors (GlyR) can play an important role in disease progression of temporal lobe epilepsy (TLE) as it may contribute in a neuron type-specific way to neuropsychiatric symptoms of the disease. It is therefore necessary to develop tools that allow identification of neuron types that express RNA-edited GlyR protein. In this study, we identify NH4 as agonist of C-to-U RNA edited GlyRs. Furthermore, we generated a new molecular C-to-U RNA editing sensor tool that detects Apobec-1- dependent RNA editing in HEPG2 cells and rat primary hippocampal neurons. Using this sensor combined with NH4 application, we were able to identify C-to-U RNA editing-competent neurons and expression of C-to-U RNA-edited GlyR protein in neurons. Bioinformatic analysis of 1,000 Genome Project Phase 3 allele frequencies coding for human Apobec-1 80M and 80I variants showed differences between populations, and the results revealed a preference of the 80I variant to generate RNA-edited GlyR protein. Finally, we established a new PCR-based restriction fragment length polymorphism (RFLP) approach to profile mRNA expression with regard to the genetic APOBEC1 dimorphism of patients with intractable temporal lobe epilepsy (iTLE) and found that the patients fall into two groups. Patients with expression of the Apobec-1 80I variant mostly suffered from simple or complex partial seizures, whereas patients with 80M expression exhibited secondarily generalized seizure activity. Thus, our method allows the characterization of Apobec-1 80M and 80l variants in the brain and provides a new way to epidemiologically and semiologically classify iTLE according to the two different APOBEC1 alleles. Together, these results demonstrate Apobec-1-dependent expression of RNA-edited GlyR protein in neurons and identify the APOBEC1 80I/M-coding alleles as new genetic risk factors for iTLE patients

Sociodemographic variables, clinical features, and the role of preassessment cross-sex hormones in older trans people

Introduction: As referrals to gender identity clinics have increased dramatically over the last few years, no studies focusing on older trans people seeking treatment are available. Aims: The aim of this study was to investigate the sociodemographic and clinical characteristics of older trans people attending a national service and to investigate the influence of cross-sex hormones (CHT) on psychopathology. Methods: Individuals over the age of 50 years old referred to a national gender identity clinic during a 30-month period were invited to complete a battery of questionnaires to measure psychopathology and clinical characteristics. Individuals on cross-sex hormones prior to the assessment were compared with those not on treatment for different variables measuring psychopathology. Main Outcome Measures: Sociodemographic and clinical variables and measures of depression and anxiety (Hospital Anxiety and Depression Scale), self-esteem (Rosenberg Self-Esteem Scale), victimization (Experiences of Transphobia Scale), social support (Multidimensional Scale of Perceived Social Support), interpersonal functioning (Inventory of Interpersonal Problems), and nonsuicidal self-injury (Self-Injury Questionnaire). Results: The sex ratio of trans females aged 50 years and older compared to trans males was 23.7:1. Trans males were removed for the analysis due to their small number (n ¼ 3). Participants included 71 trans females over the age of 50, of whom the vast majority were white, employed or retired, and divorced and had children. Trans females on CHT who came out as trans and transitioned at an earlier age were significantly less anxious, reported higher levels of self-esteem, and presented with fewer socialization problems. When controlling for socialization problems, differences in levels of anxiety but not self-esteem remained. Conclusion: The use of cross-sex hormones prior to seeking treatment is widespread among older trans females and appears to be associated with psychological benefits. Existing barriers to access CHT for older trans people may need to be re-examined

Nogo-A Expression in the Brain of Mice with Cerebral Malaria

Cerebral malaria (CM) is associated with a high rate of transient or persistent neurological sequelae. Nogo-A, a protein that is highly expressed in the endoplasmic reticulum (ER) of the mammalian central nervous system (CNS), is involved in neuronal regeneration and synaptic plasticity in the injured CNS. The current study investigates the role of Nogo-A in the course of experimental CM. C57BL/6J mice were infected with Plasmodium berghei ANKA blood stages. Brain homogenates of mice with different clinical severity levels of CM, infected animals without CM and control animals were analyzed for Nogo-A up-regulation by Western blotting and immunohistochemistry. Brain regions with Nogo-A upregulation were evaluated by transmission electron microscopy. Densitometric analysis of Western blots yielded a statistically significant upregulation of Nogo-A in mice showing moderate to severe CM. The number of neurons and oligodendrocytes positive for Nogo-A did not differ significantly between the studied groups. However, mice with severe CM showed a significantly higher number of cells with intense Nogo-A staining in the brain stem. In this region ultrastructural alterations of the ER were regularly observed. Nogo-A is upregulated during the early course of experimental CM. In the brain stem of severely affected animals increased Nogo-A expression and ultrastructural changes of the ER were observed. These data indicate a role of Nogo-A in neuronal stress response during experimental CM