Optimal distribution of VLBI transmitters in the Galileo space segment for frame ties

Equipping Galileo satellites with a VLBI transmitter (VT) will allow to observe satellites next to quasars with Very Long Baseline Interferometry (VLBI) radio telescopes. This concept will facilitate the direct estimation of the satellite orbits in the celestial reference frame. Moreover, these observations along with usual Galileo observations can be used to transfer the space tie between the VT and the antenna on the Galileo satellite to the Earth surface realizing the frame tie at the geodetic site with VLBI radio telescope and Galileo antenna. In this study, we assess the accuracy of that frame tie by simulating the estimation of station coordinates from VLBI observations to Galileo satellites next to quasars. We find that at least two or three satellites need to be equipped with a VT with the best results if all satellites with a VT are placed in the same plane. Concerning the ratio between satellite and quasar observations within a schedule, the results suggest that the optimal ratio is around 30% to 40% satellite observations out of the total number of observations in order to have enough observations for the estimation of the station coordinates but still enough quasar observations to ensure a sufficient sky-coverage for the estimation of troposphere parameters. The best scenario with two satellites yields repeatabilities for the east and north components between 7.5 and 10 mm, and for the up component between 9.5 and 12 mm. In case there is a third satellite with a VLBI transmitter in the same plane, the repeatabilities are reduced by up to 2 mm for the horizontal components and up to 3 to 4 mm for the up component. Rotating the schedules over the constellation repeat cycle of Galileo of 10 days reveals that there are differences between the individual days, but there are no days with a significantly worse precision of the estimated station coordinates.

Graphical Abstract

Clinical outcomes and quality of life after contemporary isolated coronary bypass grafting: a prospective cohort study

OBJECTIVES

The objective of the European Multicenter Registry to Assess Outcomes in coronary artery bypass grafting (CABG) patients (DuraGraft Registry) was to determine clinical outcomes and quality of life (QoL) after contemporary CABG that included isolated CABG and combined CABG/valve procedures, using an endothelial damage inhibitor (DuraGraft) intraoperatively for conduit preservation. Here, we report outcomes in the patient cohort undergoing isolated CABG.

METHODS

The primary outcome was the composite of all-cause death, myocardial infarction (MI), or repeat revascularization (RR) [major adverse cardiac events (MACE)] at 1 year. Secondary outcomes included the composite of all-cause death, MI, RR, or stroke [major adverse cardiac and cerebrovascular events (MACCE)], and QoL. QoL was assessed with the EuroQol-5 Dimension questionnaire. Independent risk factors for MACE at 1 year were determined using Cox regression analysis.

RESULTS

A total of 2532 patients (mean age, 67.4±9.2 years; 82.5% male) underwent isolated CABG. The median EuroScore II was 1.4 [interquartile range (IQR), 0.9-2.3]. MACE and MACCE rates at 1 year were 6.6% and 7.8%, respectively. The rates of all-cause death, MI, RR, and stroke were 4.4, 2.0, 2.2, and 1.9%, respectively. The 30-day mortality rate was 2.3%. Age, extracardiac arteriopathy, left ventricular ejection fraction less than 50%, critical operative state, and left main disease were independent risk factors for MACE. QoL index values improved from 0.84 [IQR, 0.72-0.92] at baseline to 0.92 [IQR, 0.82-1.00] at 1 year ( P <0.0001).

CONCLUSION

Contemporary European patients undergoing isolated CABG have a low 1-year clinical event rate and an improved QoL.

The Australian mixed-mode observing program

Global geodetic VLBI is upgrading to its next-generation observing system, VGOS. This upgrade has turned out to be a process over multiple years, until VGOS reaches its full capabilities with the envisaged continuous observations. Until then, for the Australian stations, the upgrade means ceasing their legacy S/X observations, leaving a large gap in the global network as well as in the station time series. The Australian mixed-mode observing program is a series of sessions where the VGOS stations in Hobart and Katherine observe legacy S/X VLBI together with other stations in the region. This paper describes the technical details of these observations and their processing strategies and discusses their suitability for geodetic results by comparison with those of standard legacy S/X sessions. The presented mixed-mode sessions allow a continuation of the station time series, a benefit for the stations themselves as well as for future realisations of the terrestrial and celestial reference frames. A novel mode of observing is introduced and tested. The results are promising and it is suggested for acceptance into standard legacy S/X IVS observations, overcoming current gaps in the network due to VGOS upgrades and preventing a worsening of global results otherwise.

Clinical event rate in patients with and without left main disease undergoing isolated CABG: results from the European DuraGraft registry

OBJECTIVES

Left main coronary artery disease (LMCAD) is considered an independent risk factor for clinical events after coronary artery bypass grafting (CABG). We have conducted a subgroup analysis of the multicentre European DuraGraft registry to investigate clinical event-rates at 1-year in patients with and without LMCAD undergoing isolated CABG in contemporary practice.

METHODS

Patients undergoing isolated CABG were selected. The primary end-point was the incidence of a major adverse cardiac event (MACE) defined as the composite of death, myocardial infarction (MI) or repeat revascularization (RR) at 1-year. The secondary end-point was major adverse cardiac and cerebrovascular events (MACCE) defined as MACE plus stroke. Propensity score matching (PSM) was performed to balance for differences in baseline characteristics.

RESULTS

LMCAD was present in 1,033 (41.2%) and absent in 1,477 (58.8%) patients. At 1-year, the MACE rate was higher for LMCAD patients (8.2% vs 5.1%, p = 0.002) driven by higher rates of death (5.4% vs 3.4%, p = 0.016), MI (3.0% vs 1.3%, p = 0.002) and numerically higher rates of RR (2.8% vs 1.8%, p = 0.13). The incidence of MACCE was 8.8% vs 6.6%, p = 0.043 with a stroke rate of 1.0% and 2.4%, p = 0.011, for LMCAD and non-LMCAD group, respectively. After PSM, the MACE rate was 8.0% vs 5.2%, p = 0.015. The incidence of death was 5.1% vs 3.7%, p = 0.10, MI 3.0% vs 1.4%, p = 0.020, and RR was 2.7% vs 1.6%, p = 0.090, for the LMCAD and non-LMCAD group, respectively. Less strokes occurred in LMCAD patients (1.0% vs 2.4%, p = 0.017). The MACCE rate was not different: 8.5% vs 6.7%, p = 0.12.

CONCLUSIONS

In this large registry, LMCAD was demonstrated to be an independent risk factor for MACE after isolated CABG. Conversely, the risk of stroke was lower in LMCAD patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02922088.

Probing a southern hemisphere VLBI Intensive baseline configuration for UT1 determination

The deviation of Universal Time from atomic time, expressed as UT1-UTC, reflects the irregularities of the Earth rotation speed and is key to precise geodetic applications which depend on the transformation between celestial and terrestrial reference frames. A rapidly varying quantity such as UT1-UTC demands observation scenarios enabling fast delivery of good results. These criteria are currently met only by the Very Long Baseline Interferometry (VLBI) Intensive sessions. Due to stringent requirements of a fast UT1-UTC turnaround, the observations are limited to a few baselines and a duration of one hour. Hence, the estimation of UT1-UTC from Intensives is liable to constraints and prone to errors introduced by inaccurate a priori information. One aspect in this context is that the regularly operated Intensive VLBI sessions organised by the International VLBI Service for Geodesy and Astrometry solely use stations in the northern hemisphere. Any potential systematic errors due to this northern hemisphere dominated geometry are so far unknown. Besides the general need for stimulating global geodetic measurements with southern observatories, this served as a powerful motivation to launch the SI (Southern Intensive) program in 2020. The SI sessions are observed using three VLBI antennas in the southern hemisphere: Ht (South Africa), Hb (Tasmania) and Yg (Western Australia). On the basis of UT1-UTC results from 53 sessions observed throughout 2020 and 2021, we demonstrate the competitiveness of the SI with routinely operated Intensive sessions in terms of operations and UT1-UTC accuracy. The UT1-UTC values of the SI reach an average agreement of 32 µs in terms of weighted standard deviation when compared with the conventional Intensives results of five independent analysis centers and of 27 µs compared with the 14C04 series. The mean scatter of all solutions of the considered northern hemisphere Intensives with respect to C04 is at a comparable level of 29 µs. The quality of the results is only slightly degraded if just the baseline HtHb is evaluated. In combination with the e-transfer capabilities from Ht to Hb, this facilitates continuation of the SI by ensuring rapid service UT1-UTC provision.

Red- and blue-detuned magneto-optical trapping with liquid crystal variable retarders

We exploit red- and blue-detuned magneto-optical trapping (MOT) of ⁸⁷Rb benefitting from a simplified setup and a novel approach based on liquid crystal variable retarders (LCVR). To maintain the trapping forces when switching from a red- to a blue-detuned MOT, the handedness of the circular polarization of the cooling beams needs to be reversed. LCVRs allow fast polarization control and represent compact, simple, and cost-efficient components, which can easily be implemented in existing laser systems. This way, we achieve a blue-detuned type-II MOT for 8.7 × 10⁸ atoms of ⁸⁷Rb with sub-Doppler temperatures of 44 μK well below the temperatures reached in a conventional ⁸⁷Rb type-I MOT. The phase space density is increased by more than two orders of magnitude compared to the standard red-detuned type-I MOT. The setup can readily be transferred to any other systems working with ⁸⁷Rb.

Baseline-dependent clock offsets in VLBI data analysis

The primary goal of the geodetic Very Long Baseline Interferometry (VLBI) technique is to provide highly accurate terrestrial and celestial reference frames as well as Earth orientation parameters. In compliance with the concept of VLBI, additional parameters reflecting relative offsets and variations of the atomic clocks of the radio telescopes have to be estimated. In addition, reality shows that in many cases significant offsets appear in the observed group delays for individual baselines which have to be compensated for by estimating so-called baseline-dependent clock offsets (BCOs). For the first time, we systematically investigate the impact of BCOs to stress their importance for all kinds of VLBI data analyses. For our investigations, we concentrate on analyzing data from both legacy networks of the CONT17 campaign. Various aspects of BCOs including their impact on the estimates of geodetically important parameters, such as station coordinates and Earth orientation parameters, are investigated. In addition, some of the theory behind the BCO determination, e.g., the impact of changing the reference clock in the observing network on the BCO estimate is introduced together with the relationship between BCOs and triangle delay closures. In conclusion, missing channels, and here in particular at S band, affecting the ionospheric delay calibration, are identified to be the dominant cause for the occurrence of significant BCOs in VLBI data analysis.

Optimal VLBI baseline geometry for UT1-UTC Intensive observations

One of the main tasks of Very Long Baseline Interferometry (VLBI) is the rapid determination of the highly variable Earth's rotation expressed through the difference between Universal Time UT1 and Coordinated Universal Time UTC (dUT1). For this reason, dedicated one hour, single baseline sessions, called "Intensives", are observed on a daily basis. Thus far, the optimal geometry of Intensive sessions was understood to include a long east-west extension of the baseline to ensure a dUT1 estimation with highest accuracy. In this publication, we prove that long east-west baselines are the best choice only for certain lengths and orientations. In this respect, optimal orientations may even require significant inclination of the baseline with respect to the equatorial plane. The basis of these findings is a simulation study with subsequent investigations in the partial derivatives of the observed group delays τ with respect to dUT1 ∂ τ / ∂ d U T 1 . Almost 3000 baselines between artificial stations located on a regular 10 × 10 degree grid are investigated to derive a global and generally valid picture about the best length and orientation of Intensive baselines. Our results reveal that especially equatorial baselines or baselines with a center close to the equatorial plane are not suited for Intensives although they provide a good east-west extension. This is explained by the narrow right ascension band of visible sources and the resulting lack of variety in the partial derivatives. Moreover, it is shown that north-south baselines are also capable of determining dUT1 with reasonable accuracy, given that the baseline orientation is significantly different from the Earth rotation axis. However, great care must be taken to provide accurate polar motion a priori information for these baselines. Finally, we provide a better metric to assess the suitability of Intensive baselines based on the effective spread of ∂ τ / ∂ d U T 1 .

Two most common diagnoses among myriads of cystic lung diseases

BACKGROUND

Diffuse cystic lung diseases are a group of heterogeneous pathophysiological processes and include neoplastic, inflammatory, and infectious etiologies. This manuscript focuses on manifestations of pulmonary Langerhans cell histiocytosis (PLCH) and lymphangioleiomyomatosis (LAM). Description of the cases: Three female patients with LAM and one with PLCH are described. Stress dyspnea was a key symptom. There were similar cyst patterns in more than one lung lobe with a slow, progressive course. Histopathology confirmed the LAM diagnosis resulting from the nodular proliferate and the cyst wall that strongly expressed Human Melanoma Black-45 (HMB-45). A typical constellation for PLCH was demonstrated in high-resolution computed tomography (HRCT). It was found to be disseminated and relatively thick-walled cysts, mainly in the upper and middle parts. An individualized therapy was applied. Three patients with mild symptoms were followed up, including HRCT evaluations. Sirolimus was administered to one patient with a severe manifestation of LAM.

CONCLUSION

LAM and PLCH are rare. High-resolution computed tomography is an essential diagnostic tool. Lung emphysema as misdiagnosis should be avoided. The characteristics of pulmonary cysts, the cyst's wall regularity, and identification of associated pulmonary lesions, should be evaluated. A promising new therapy concept are mTOR inhibitors are, especially in LAM. The most important recommendation in PLCH is the cessation of cigarette smoking. HIPPOKRATIA 2021, 25 (2):83-86.

The impact of emotional development in people with autism spectrum disorder and intellectual developmental disability

BACKGROUND

Intellectual developmental disabilities (IDDs) and autism spectrum disorders (ASDs) are developmental conditions, which may also be associated with impairments in emotional development (ED). ED can be assessed using the Scale of Emotional Development - Short (SED-S), a five-stage model consisting of eight domains, which allows to study the relationship between ASD and ED in people with IDD.

METHODS

In this retrospective study, the level of ED was compared in 327 adults with IDD with [n = 83; mean age 38.3 years; level of IDD: mild (6), moderate (21), severe (45) and profound (11)] and without [n = 244, mean age 36.9 years; level of IDD: mild (67), moderate (73), severe (68) and profound (36)] ASD. The discriminative ability of the SED-S was determined by a regression in a training and a validation sample.

RESULTS

The level of ED correlated with the severity of IDD (r_s  = -.654) and the presence of ASD (r_s  = -.316). People with additional ASD showed lower levels of ED compared with those with IDD only (mean reference ages 7-18 vs 19-36 months). The developmental profiles were equally balanced in ASD and IDD-only. A regression analysis revealed three domains ('Relating-to-Peers', 'Differentiating-Emotions', and 'Regulating-Affect') to be useful for ASD assignment (AUC > 0.70, sensitivity 0.76-0.80, specificity 0.62-0.63).

CONCLUSIONS

In people with IDD, additional ASD was associated with delays in ED, which may be considered in diagnostics, treatment and care.

Optimal antenna locations of the VLBI Global Observing System for the estimation of Earth orientation parameters

To support monitoring subtle effects in the Earth system such as a mean sea level rise of 3 mm/year, a next-generation VLBI system, the VLBI Global Observing System (VGOS), has been developed and a new VGOS station network is being built. However, the geometry of the current VGOS network and its planned extension suffer from a lack of stations in the southern hemisphere. In this investigation, we identify optimal locations for additional VGOS radio telescopes with a new method based on bulk observing schedule generation and subsequent large-scale Monte-Carlo simulations. The location of the additional station is varied over 477 possible locations, homogeneously distributed over land areas on the globe. For each antenna location, several schedules have been generated and simulated to minimize the effects of scheduling and the randomness of simulations. Thereby, it is possible to judge, in which regions an additional VGOS station would have the biggest impact on the precision of the estimated geodetic parameters, in our case assessed by the repeatabilities of the estimated Earth orientation parameters (EOPs). To generate highly optimized schedules and to remove effects due to non-optimized scheduling, a total of 93 thousand schedules were iteratively generated, investigating over 300 billion scans and 2.4 trillion observations. Each schedule was further simulated 1000 times, leading to over 5 trillion simulated and analyzed observations. Although the optimum location of a future VLBI station depends on the EOP of interest and the geometry of the existing network, it is shown that the more the VGOS network grows, the more the lack of southern stations becomes prominent. The best location for an additional VGOS station for most EOP components and especially in the case of future VGOS networks would be the southern part of South America. It is further shown that the location of the additional antenna highly determines the expectable precision of the EOP estimates. For a 6-station network, the location of an additional seventh antenna can improve the precision of the EOP by a factor of 2.4 to 3.8. For an 18-station network, the location of an additional 19th station still improves the repeatability by a factor of 1.6. It is also found that adding a station at some locations will not improve the precision at all.

VMF3o: the Vienna Mapping Functions for optical frequencies

The troposphere is considered as one of the major error sources in space geodetic techniques. Thus, accurate troposphere delay models are essential to provide high-quality products, such as reference frames, satellite orbits, or Earth rotation parameters. In this paper, a new troposphere delay model for satellite laser ranging, the Vienna Mapping Functions 3 for optical frequencies (VMF3o), is introduced. The model parameters are derived from ray-traced delays generated by an in-house ray-tracing software. VMF3o comprises not only zenith delays and mapping functions, but also linear horizontal gradients, which are not part of the standard SLR analysis yet. The model parameters are dedicated to a signal wavelength of 532 nm. Since some SLR stations operate also with other wavelengths, VMF3o provides a correction formula to transform the model parameters to any requested wavelength between 350 and 1064 nm. A test demonstrates that the correction formula approximates slant delays calculated at different wavelengths very accurately. The remaining error for slant delays at a wavelength of 1064 nm adds up to only a few millimetres at 10 ∘ elevation angle. A comparison study of the modelled delays that are derived from VMF3o and ray-traced delays was carried out to examine the quality of the model approach. The remaining differences of modelled and ray-traced delays are expressed as mean absolute error. At 5 ∘ elevation angle, the mean absolute error is only a few millimetres. At 10 ∘ elevation angle, it is at the 1 mm level. The results of the comparison also reveal that introducing linear horizontal gradients reduces the mean absolute error by more than 80% for low elevation angles.

Optimizing schedules for the VLBI global observing system

Very long baseline interferometry (VLBI) scheduling is a challenging optimization problem. With the development of the new VLBI global observing system (VGOS) consisting of smaller but very fast slewing antennas, new opportunities arise. In this work, we give a deep insight into optimized VGOS scheduling using a newly developed VLBI scheduling software called VieSched++, and we show how different scheduling parameters and approaches affect the precision of geodetic results. Therefore, the results of over one thousand generated schedules and over one million simulated sessions are analyzed. The simulations reveal that the most important parameters to optimize VGOS schedules with VieSched++ are the so-called weight factors. A proper selection of individually optimized weight factors can improve the quality of a schedule significantly. It is shown that the values of the weight factors used to generate the schedule are highly correlated with the expected precision of the geodetic parameters. We highlight the benefit of selecting schedules based on large-scale Monte Carlo simulations and show why scheduling statistics like the number of observations or the sky-coverage are not necessarily the best metric to evaluate schedules.

Observing APOD with the AuScope VLBI Array

The possibility to observe satellites with the geodetic Very Long Baseline Interferometry (VLBI) technique is vividly discussed in the geodetic community, particularly with regard to future co-location satellite missions. The Chinese APOD-A nano satellite can be considered as a first prototype-suitable for practical observation tests-combining the techniques Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS) and VLBI on a single platform in a Low Earth Orbit (LEO). Unfortunately, it has hardly been observed by VLBI, so major studies towards actual frame ties could not be performed. The main reason for the lack of observations was that VLBI observations of satellites are non-standard, and suitable observing strategies were not in place for this mission. This work now presents the first serious attempt to observe the satellite with a VLBI network over multiple passes. We introduce a series of experiments with the AuScope geodetic VLBI array which were carried out in November 2016, and describe all steps integrated in the established process chain: the experiment design and observation planning, the antenna tracking and control scheme, correlation and derivation of baseline-delays, and the data analysis yielding delay residuals on the level of 10 ns. The developed procedure chain can now serve as reference for future experiments, hopefully enabling the global VLBI network to be prepared for the next co-location satellite mission.

Refined discrete and empirical horizontal gradients in VLBI analysis

Missing or incorrect consideration of azimuthal asymmetry of troposphere delays is a considerable error source in space geodetic techniques such as Global Navigation Satellite Systems (GNSS) or Very Long Baseline Interferometry (VLBI). So-called horizontal troposphere gradients are generally utilized for modeling such azimuthal variations and are particularly required for observations at low elevation angles. Apart from estimating the gradients within the data analysis, which has become common practice in space geodetic techniques, there is also the possibility to determine the gradients beforehand from different data sources than the actual observations. Using ray-tracing through Numerical Weather Models (NWMs), we determined discrete gradient values referred to as GRAD for VLBI observations, based on the standard gradient model by Chen and Herring (J Geophys Res 102(B9):20489-20502, 1997. 10.1029/97JB01739) and also for new, higher-order gradient models. These gradients are produced on the same data basis as the Vienna Mapping Functions 3 (VMF3) (Landskron and Böhm in J Geod, 2017. 10.1007/s00190-017-1066-2), so they can also be regarded as the VMF3 gradients as they are fully consistent with each other. From VLBI analyses of the Vienna VLBI and Satellite Software (VieVS), it becomes evident that baseline length repeatabilities (BLRs) are improved on average by 5% when using a priori gradients GRAD instead of estimating the gradients. The reason for this improvement is that the gradient estimation yields poor results for VLBI sessions with a small number of observations, while the GRAD a priori gradients are unaffected from this. We also developed a new empirical gradient model applicable for any time and location on Earth, which is included in the Global Pressure and Temperature 3 (GPT3) model. Although being able to describe only the systematic component of azimuthal asymmetry and no short-term variations at all, even these empirical a priori gradients slightly reduce (improve) the BLRs with respect to the estimation of gradients. In general, this paper addresses that a priori horizontal gradients are actually more important for VLBI analysis than previously assumed, as particularly the discrete model GRAD as well as the empirical model GPT3 are indeed able to refine and improve the results.

Effects of low to moderate levels of deoxynivalenol on feed and water intake, weight gain, and slaughtering traits of broiler chickens

The aim of the study was to evaluate the effects of low to moderate oral exposure to the Fusarium toxin deoxynivalenol (DON; derived from culture material) on performance, water intake, and carcass parameters of broilers during early and late developmental phases. A total of 160 Ross 308 broilers were randomly allocated to four different feeding groups (n = 40/group) including 0 (control), 2.5, 5, and 10 mg DON/kg wheat-soybean meal-based feed. Three consecutive replicates of the experiment were performed. Half of the broilers were slaughtered in week 3 of the trial whereas the other half were slaughtered in week 5. Dry matter intake (DMI) and water intake (WI) were recorded on a daily basis and the body weight (BW) and BW gain (BWG) were determined weekly. The following carcass traits were recorded and calculated in absolute and relative data: dressed carcass weight, breast muscle weight, leg weight, and liver weight. Data showed that BW (P < 0.001), BWG (P = 0.005), and DMI (P < 0.001) were reduced by DON-feeding during the entire feeding period. The ratio of DMI to body weight gain (DMI/BWG) was not affected by the treatment. However, the ratio of water to DMI (WI/DMI) increased in DON-treated birds (P = 0.021). Contrast analysis showed that DON tendentially reduced slaughter weight (P = 0.082) and decreased leg yield (P = 0.037) in DON-fed chickens in week 5 of the experiment. Liver organ weight decreased in the 3-week-old DON-fed broilers compared to that in the control-fed birds (P = 0.037). In conclusion, the study suggests that DMI and BW were negatively affected under the experimental conditions at DON levels lower than the current guidance value in the European Union of 5 mg/kg feed. The study also indicates that broilers fed on low to moderate level DON-contaminated diets showed increased WI/DMI ratio which might have negative influence on wet litter syndrome.

VMF3/GPT3: refined discrete and empirical troposphere mapping functions

Incorrect modeling of troposphere delays is one of the major error sources for space geodetic techniques such as Global Navigation Satellite Systems (GNSS) or Very Long Baseline Interferometry (VLBI). Over the years, many approaches have been devised which aim at mapping the delay of radio waves from zenith direction down to the observed elevation angle, so-called mapping functions. This paper contains a new approach intended to refine the currently most important discrete mapping function, the Vienna Mapping Functions 1 (VMF1), which is successively referred to as Vienna Mapping Functions 3 (VMF3). It is designed in such a way as to eliminate shortcomings in the empirical coefficients b and c and in the tuning for the specific elevation angle of 3 ∘ . Ray-traced delays of the ray-tracer RADIATE serve as the basis for the calculation of new mapping function coefficients. Comparisons of modeled slant delays demonstrate the ability of VMF3 to approximate the underlying ray-traced delays more accurately than VMF1 does, in particular at low elevation angles. In other words, when requiring highest precision, VMF3 is to be preferable to VMF1. Aside from revising the discrete form of mapping functions, we also present a new empirical model named Global Pressure and Temperature 3 (GPT3) on a5 ∘ × 5 ∘ as well as a1 ∘ × 1 ∘ global grid, which is generally based on the same data. Its main components are hydrostatic and wet empirical mapping function coefficients derived from special averaging techniques of the respective (discrete) VMF3 data. In addition, GPT3 also contains a set of meteorological quantities which are adopted as they stand from their predecessor, Global Pressure and Temperature 2 wet. Thus, GPT3 represents a very comprehensive troposphere model which can be used for a series of geodetic as well as meteorological and climatological purposes and is fully consistent with VMF3.

Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the National Aeronautics and Space Administration Goddard Space Flight Center (NASA GSFC) (Eriksson and MacMillan in http://lacerta.gsfc.nasa.gov/tropodelays, 2016) with respect to the analysis performances in terms of BLR results. If tropospheric gradient estimation is included in the analysis, 51.3% of the baselines benefit from the RADIATE ray-traced delays at sub-mm difference level. If no tropospheric gradients are estimated within the analysis, the RADIATE ray-traced delays deliver a better BLR at 63% of the baselines compared to the NASA GSFC ray-traced delays.

VLBI observations of GNSS-satellites: from scheduling to analysis

The possibility of observing satellites with the very long baseline interferometry (VLBI) technique has been discussed for several years in the geodetic community, with observations of either existing satellites of the global navigation satellite systems or of satellites dedicated to realise a space tie. Such observations were carried out using the Australian telescopes in Hobart and Ceduna which, for the first time, integrated all the necessary steps: planning the observations (automated scheduling), correlation of the data and the generation of a series of time delay observables suitable for a subsequent geodetic analysis. We report on the development of new and the adaptation of existing routines for observing and data processing, focusing on technology development. The aim was to use methods that are routinely used in geodetic VLBI. A series of test experiments of up to six hours duration was performed, allowing to improve the observations from session to session and revealing new problems still to be solved. The newly developed procedures and programs now enable more observations. Further development assumed, this bears the prospect of being directly applied to the observation of dedicated space-tie satellites.

Laparoscopic Wide Mesocolic Excision and Central Vascular Ligation for Carcinoma of the Colon

Background and Aims:

The principle of complete mesocolic excision for colon cancer has been introduced to improve oncologic outcome. However, this approach is scantily discussed for laparoscopic surgery and there is a lack of randomized trials. This study examined oncologic and clinical outcome after laparoscopic wide mesocolic excision and central vascular ligation for colon cancer.

Material and Methods:

This is a review of prospectively gathered data from a single-institution colorectal cancer database. This study was conducted in the Central Hospital of Central Finland. From January 2003 to December 2011, 222 patients underwent laparoscopic colonic resections with wide mesocolic excision and central vascular ligation in the multimodal setting. The main measures of outcome were cancer recurrence and survival, with early recovery, 30d-mortality and morbidity, reoperation, readmission, and late complications as secondary outcomes.

Results:

The median follow-up was 5.5 (interquartile range (IQR) = 3.7–8.0) years. The 5-year overall survival for all 222 patients was 80.2% and disease-specific survival was 87.5%, and for those 210 R0-patients with stage I–III disease, 83.9% and 91.3%, respectively. The 5-year disease-free survival was 85.8%: stage I was 94.7%, stage II was 90.8%, and stage III was 75.6% ( p = 0.004). Increasing lymph node ratio significantly decreased the 5-year disease-free survival. Conversion rate to open surgery was 12.2%. Thirty-day mortality was 1.3% and morbidity, 19.7%. Median postoperative hospital stay was 5 (IQR = 3–7) days.

Conclusion:

Laparoscopic wide mesocolic excision and central vascular ligation for colon cancer resulted in good long-term oncologic outcome. Randomized trials are needed to show that laparoscopic complete mesocolic excision technique would become the standard of care for the carcinoma of the colon.

The AUSTRAL VLBI observing program

The AUSTRAL observing program was started in 2011, performing geodetic and astrometric very long baseline interferometry (VLBI) sessions using the new Australian AuScope VLBI antennas at Hobart, Katherine, and Yarragadee, with contribution from the Warkworth (New Zealand) 12 m and Hartebeesthoek (South Africa) 15 m antennas to make a southern hemisphere array of telescopes with similar design and capability. Designed in the style of the next-generation VLBI system, these small and fast antennas allow for a new way of observing, comprising higher data rates and more observations than the standard observing sessions coordinated by the International VLBI Service for Geodesy and Astrometry (IVS). In this contribution, the continuous development of the AUSTRAL sessions is described, leading to an improvement of the results in terms of baseline length repeatabilities by a factor of two since the start of this program. The focus is on the scheduling strategy and increased number of observations, aspects of automated operation, and data logistics, as well as results of the 151 AUSTRAL sessions performed so far. The high number of the AUSTRAL sessions makes them an important contributor to VLBI end-products, such as the terrestrial and celestial reference frames and Earth orientation parameters. We compare AUSTRAL results with other IVS sessions and discuss their suitability for the determination of baselines, station coordinates, source coordinates, and Earth orientation parameters.

Venus Flytrap HKT1-Type Channel Provides for Prey Sodium Uptake into Carnivorous Plant Without Conflicting with Electrical Excitability

The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na(+)- and K(+)-permeable mutants function as ion channels rather than K(+) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na(+)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.

The Global S[Formula: see text] Tide in Earth's Nutation

Diurnal S[Formula: see text] tidal oscillations in the coupled atmosphere-ocean system induce small perturbations of Earth's prograde annual nutation, but matching geophysical model estimates of this Sun-synchronous rotation signal with the observed effect in geodetic Very Long Baseline Interferometry (VLBI) data has thus far been elusive. The present study assesses the problem from a geophysical model perspective, using four modern-day atmospheric assimilation systems and a consistently forced barotropic ocean model that dissipates its energy excess in the global abyssal ocean through a parameterized tidal conversion scheme. The use of contemporary meteorological data does, however, not guarantee accurate nutation estimates per se; two of the probed datasets produce atmosphere-ocean-driven S[Formula: see text] terms that deviate by more than 30 [Formula: see text]as (microarcseconds) from the VLBI-observed harmonic of [Formula: see text] [Formula: see text]as. Partial deficiencies of these models in the diurnal band are also borne out by a validation of the air pressure tide against barometric in situ estimates as well as comparisons of simulated sea surface elevations with a global network of S[Formula: see text] tide gauge determinations. Credence is lent to the global S[Formula: see text] tide derived from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and the operational model of the European Centre for Medium-Range Weather Forecasts (ECMWF). When averaged over a temporal range of 2004 to 2013, their nutation contributions are estimated to be [Formula: see text] [Formula: see text]as (MERRA) and [Formula: see text] [Formula: see text]as (ECMWF operational), thus being virtually equivalent with the VLBI estimate. This remarkably close agreement will likely aid forthcoming nutation theories in their unambiguous a priori account of Earth's prograde annual celestial motion.

[Death of two mares with retained fetal membranes]

Retained fetal membranes in mares is a relative frequent disease which can lead to severe complications. Two case studies are described in which mares died acutely despite intensive care. Pathological examination confirmed severe hemorrhage as the cause of death in both animals.

Non-linear VLBI station motions and their impact on the celestial reference frame and Earth orientation parameters

The increasing accuracy and growing time span of Very Long Baseline Interferometry (VLBI) observations allow the determination of seasonal signals in station positions which still remain unmodelled in conventional analysis approaches. In this study we focus on the impact of the neglected seasonal signals in the station displacement on the celestial reference frame and Earth orientation parameters. We estimate empirical harmonic models for selected stations within a global solution of all suitable VLBI sessions and create mean annual models by stacking yearly time series of station positions which are then entered a priori in the analysis of VLBI observations. Our results reveal that there is no systematic propagation of the seasonal signal into the orientation of celestial reference frame but position changes occur for radio sources observed non-evenly over the year. On the other hand, the omitted seasonal harmonic signal in horizontal station coordinates propagates directly into the Earth rotation parameters causing differences of several tens of microarcseconds.

Deoxynivalenol in chicken feed alters the vaccinal immune response and clinical biochemical serum parameters but not the intestinal and carcass characteristics

This study was conducted to investigate the impacts of deoxynivalenol (DON) feeding either alone or in combination with a microbial feed additive (MFA) on the immune response to a viral vaccine and serum clinical chemical parameters. Forty 1-day-old boiler chicks were weighed and randomly divided into four groups, 10 birds in each group: (i) control group fed with basal diet; (ii) DON group fed with basal diet artificially contaminated with 10 mg DON/kg feed; (iii) DON + MFA group fed with basal diet contaminated with 10 mg DON/kg feed and supplemented with 2.5 kg of MFA/ton feed; and (iv) MFA group fed with basal diet supplemented with 2.5 kg of MFA/ton feed. At 35 days of age, birds were slaughtered and blood was collected for investigating the antibody titre against infectious bronchitis virus (IBV) and clinical chemical parameters. The results showed that DON reduced (p = 0.032) the titre against IBV, decreased (p = 0.005) the level of alanine transaminase (ALT) (4.2 ± 0.5 U/l) compared with control birds (6.4 ± 0.5 U/l), increased (p = 0.002) the serum cholesterol concentration (144 ± 6 mg/dl) compared with their control counterparts (123 ± 5 mg/dl) and increased (p = 0.074) the amount of circulating triglycerides (62.25 ± 7.50 mg/dl) compared with controls (39.55 ± 4.74). These results indicate that dietary DON altered the humoral immune response to viral vaccine and affected the serum clinical biochemistry. However, DON in combination with MFA did not affect serum IBV titre. Taken together, DON in the feed of broilers produced an impairment of the success of IBV vaccine and affected the health of birds.