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Saturn's C ring contains multiple structures that appear to be density waves driven by time-variable anomalies in the planet's gravitational field. Semi-empirical extensions of density wave theory enable the observed wave properties to be translated into information about how the pattern speeds and amplitudes of these gravitational anomalies have changed over time. Combining these theoretical tools with wavelet-based analyses of data obtained by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft reveals a suite of structures in Saturn's gravity field with azimuthal wavenumber 3, rotation rates between 804 degrees/day and 842 degrees/day and local gravitational potential amplitudes between 30 and 150 cm^2/s^2. Some of these anomalies are transient, appearing and disappearing over the course of a few Earth years, while others persist for decades. Most of these persistent patterns appear to have roughly constant pattern speeds, but there is at least one structure in the planet's gravitational field whose rotation rate steadily increased between 1970 and 2010. This gravitational field structure appears to induce two different asymmetries in the planet's gravity field, one with azimuthal wavenumber 3 that rotates at roughly 810 degrees/day and another with azimuthal wavenumber 1 rotating three times faster. The atmospheric processes responsible for generating the latter pattern may involve solar tides., Comment: 60 pages, 29 Figures, accepted for publication in the Planetary Science Journal

BackgroundSleep apnoea has a high disease burden but remains underdiagnosed, in part due to the expensive and resource intensive nature of polysomnography, its definitive investigation. Emerging literature suggests that it may be possible to detect sleep apnoea using single-lead ECG signals, such as those obtained from smartwatches. In this study, we use two forms of recurrent neural networks (RNNs) to detect sleep apnoea events from single-lead ECG signals.MethodsWe use single-lead ECG data from the PhysioNet Apnea-ECG database, which contains data from 70 patients. We train a bidirectional gated recurrent unit (GRU) model and a bidirectional long short-term memory (LSTM) model on labelled ECG signals from 35 patients and test the models on the remaining 35 patients in the dataset.ResultsBoth models achieved 97.1% accuracy, sensitivity and specificity to detect whether the ECG recordings belonged to a patient diagnosed with sleep apnoea. This corresponds to 34/35 patients in the dataset. At detecting individual apnoea events, the GRU and LSTM models achieved 90.4% and 91.7% accuracies respectively.DiscussionThe models achieved high levels of accuracy, specificity and sensitivity. Bidirectional RNNs are strengthened by the ability of the models to be informed by both past and future states when analysing sequential data, such as ECGs. The models also require minimal human intervention as they automatically extract features from the data. If single-lead ECGs prove a suitable tool for sleep apnoea detection, this may enhance the diagnosis of sleep apnoea and potentially allow widespread screening for the condition.ConclusionsWe note that using models such as bidirectional RNNs has the potential to augment model performance. However, more research and validation is required in order to test whether these may be applicable to other datasets and in clinical practice.

Future remote sensing of exoplanets will be enhanced by a thorough investigation of our solar system Ice Giants (Neptune-size planets). What can the configuration of the magnetic field tell us (remotely) about the interior, and what implications does that field have for the structure of the magnetosphere; energy input into the atmosphere, and surface geophysics (for example surface weathering of satellites that might harbour sub-surface oceans). How can monitoring of auroral emission help inform future remote observations of emission from exoplanets? Our Solar System provides the only laboratory in which we can perform in-situ experiments to understand exoplanet formation, dynamos, systems and magnetospheres.

The Princeton IQU Experiment (PIQUE) and the Cosmic Anisotropy Polarization MAPper (CAPMAP) are experiments designed to measure the polarization of the Cosmic Microwave Background (CMB) on sub-degree scales in an area within 1 degree of the North Celestial Pole using heterodyne correlation polarimeters and off-axis telescopes located in central New Jersey. PIQUE produced the tightest limit on the CMB polarization prior to its detection by DASI, while CAPMAP has recently detected polarization at l~1000. The experimental methods and instrumentation for these two projects are described in detail with emphasis on the particular challenges involved in measuring the tiny polarized component of the CMB., Comment: 70 pages, 13 tables, 18 figures. Accepted by ApJS; tentative publication ApJS July 2005, v159 1

We update the limit from the 90 GHz PIQUE ground-based polarimeter on the magnitude of any polarized anisotropy of the cosmic microwave radiation. With a second year of data, we have now limited both Q and U on a ring of 1 degree radius. The window functions are broad: for E-mode polarization, the effective l is = 191 +143 -132. We find that the E-mode signal can be no greater than 8.4 microK (95% CL), assuming no B-mode polarization. Limits on a possible B-mode signal are also presented., Comment: 4 pages, 3 figures, submitted to Astrophysical Journal Letters

The epidermal growth factor receptor and its ligands have been implicated as being involved in normal mammary development and breast cancer genesis. Northern blotting was used to assay the mRNA levels of the epidermal growth factor receptor and three of its ligands: the epidermal growth factor, the transforming growth factor alpha and the Amphiregulin in 16 primary carcinomas, 2 metastases and 5 fibroadenomas. In addition, the mRNA levels of the other members of the epidermal growth factor receptor family, erbB2 and erbB3 were also analysed. We found limited expression in the breast carcinomas while all the fibroadenomas showed expression at high levels. Therefore we suggest that the epidermal growth factor receptor plays an important role in the development of fibroadenomas. The erbB2 and erbB3 were more strongly expressed than the epidermal growth factor receptor in the primary carcinomas. This suggests that they could be of importance in breast carcinogenesis.

Ten gastric carcinomas were studied for loss of heterozygosity by analysis of 21 microsatellite markers from 14 different chromosomes. Four patients had a family history of gastro-intestinal cancer, and six tumours were considered sporadic. We also studied a new mechanism in tumourigenesis recently reported in hereditary non polyposis colon cancer, a defect in mismatch repair that is seen as gain of new bands by the use of dinucleotide repeat markers. Loss of heterozygosity was detected with two markers in one primary tumour and with the majority of markers in one metastasis from a sporadic gastric tumour. Gain of microsatellite bands was seen in one tumour from a gene carrier in a family with hereditary non-polyposis colon cancer and in one sporadic tumour. Two tumours from patients with a family history of gastric cancer showed no rearrangements. Our results suggest that different types of genes are involved in initiation and progression of gastric cancer in sporadic and familial gastric cancer.