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This paper presents a new data compression concept, "on-board processing," for infrared astronomy, where space observatories have limited processing resources. The proposed approach has been developed and tested for the PACS camera from the European Space Agency (ESA) mission, Herschel. Using lossy and lossless compression, the presented method offers high compression ratio with a minimal loss of potentially useful scientific data. It also provides higher signal-to-noise ratio than that for standard compression techniques. Furthermore, the proposed approach presents low algorithmic complexity such that it is implementable on the resource-limited hardware. The various modules of the data compression concept are discussed in detail.

The potential influence of lunar phases on human life has been widely discussed by the lay press. The purpose of this study was to find out whether the timing of surgery during particular lunar phases influences the survival of breast cancer patients. It has been postulated that breast cancer surgery performed during the waxing moon, or particularly at full moon, is associated with a poorer outcome. We tested this hypothesis by evaluating the overall survival for 3,757 consecutive patients with invasive breast cancer. All patients underwent either modified radical mastectomy or breast conserving surgery plus radiotherapy, followed by adjuvant cytotoxic or hormonal therapy. The date of definitive surgery was allocated to the lunar phases. 1,904 (50.7%) patients were operated on during the waxing moon and 1,853 (47.3%) during the waning moon. The median follow-up was 74 months (range 1–372 months). The mean age at primary surgery did not differ significantly in the two groups 58.39 (SD 13.14) versus 58.34 (12.75) (p> 0.05, t-test). Breast cancer stages at initial diagnosis were evenly distributed according to the lunar phases (p= 0.325; chi-square). Survival curves were plotted according to the method of Kaplan–Meier. No significant differences were observed when timing of surgery was allocated to the lunar phases (p= 0.4841, log-rank). Subgroup analysis of premenopausal patients revealed similar results (p= 0.2950, log-rank; n= 1072). Using multivariate Cox modelling, we found a significant association between the patient's age, stage of disease and survival, whereas no association with survival was observed for the timing of surgery (RR= 1.062; 95% CI, 0.970–1.163; p= 0.1937). No significant differences in overall survival of breast cancer patients were observed when timing of breast cancer surgery during the lunar cycle was considered. Although this was not a prospective randomized trial, the statistical magnitude of the results do not support any recommendations for scheduling patients for surgery at any particular day of the lunar phase.

Abstract: Exploratory synthetic spectra were computed for carbon-rich long-period variables. We used dynamic model atmospheres of Hfner & Dorfi (1997) and calculated partial pressures, absorption- and scattering coefficients as input for the spectral synthesis code of Jrgensen et al. (1992). First ISO SWS-observations of the carbon-Mira T Dra are compared with our synthetic spectra.

Abstract: ISO-SWS spectra of two Mira variables (R Cas and T Dra), taken at two different pulsational phases, are presented. We describe the reduction of the data and the encountered problems. The dust features observed by ISO at different phases and with the Low Resolution Spectrometer of IRAS are compared. We briefly discuss the results in terms of current models for the circumstellar dust shells of AGB variables.

Samples of optical semiregular variables (SRV's) of types SRa and SRb are correlated with the IRAS point source catalog. We extract bolometrically limited subsamples containing 352 objects in total. New near infrared photometry and data from the literature leads to complete energy distributions for 260 stars. On the basis of optical and IRAS low-resolution spectra we separate the samples into groups of defined chemistry, in particular C- and O-rich stars. The pulsational properties, visual and infrared colours, derived effective temperatures, mass loss rates, luminosities, scale heights and volume densities in the galactic plane of our subsamples are compared with corresponding characteristics of optical Miras. Moreover, it is possible to fit two blackbodies to most of the objects using visual and new near infrared photometry as well as mid and far infrared IRAS data. The resulting temperatures and other fit parameters support the findings gathered from the previous investigation. The results concerning variability and chemistry can be summarised as follows: (i) The SRa's are not a distinct class of variables but a mixture of 'intrinsic' Miras and SRb's. (ii)~The O-rich SRb's form a homogeneous group in terms of periods, amplitudes and temperatures. They consist of a 'blue' group with no indication of circumstellar matter, P < 150dand Teff> 3200 K and a 'red' group with temperatures and mass loss rates comparable to those of Miras but with periods a factor of 2 smaller. Scale heights and number densities are similar for 'red' SRV's and Miras. 'Blue' SRV's are about twice as numerous as the 'red' ones, half as luminous and without C-rich stars. (iii) The C-rich SRV's generally have smaller periods and are more abundant than C-rich Miras but their scale heights closely agree. (iv) Among all groups there are stars with much longer periods than expected from their temperatures and mass loss rates. This may be due to observational effects, irregular light curves or multiple periods. (v) A new classification scheme for O-rich SRV's and Miras in the groups 'blue' SRV's, 'red' SRV's and true Miras is proposed using period, amplitude and colours. The evolutionary status of the SRV's is discussed. On the basis of temperatures, luminosities, mass loss and number densities, the 'blue' SRV's appear to be on the non thermally pulsing AGB. One of the interpretations for O-rich 'red' SRV's is in terms of a phase preceding the Mira phase, with similar life times. The C-rich SRV's may show more variety in their pulsational characteristics.