Abundant hydrocarbons in the disk around a very-low-mass star.

Very-low-mass stars (those less than 0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars. The compositions of those planets are largely unknown but are expected to relate to the protoplanetary disk in which they form. We used James Webb Space Telescope mid-infrared spectroscopy to investigate the chemical composition of the planet-forming disk around ISO-ChaI 147, a 0.11-solar-mass star. The inner disk has a carbon-rich chemistry; we identified emission from 13 carbon-bearing molecules, including ethane and benzene. The high column densities of hydrocarbons indicate that the observations probe deep into the disk. The high carbon-to-oxygen ratio indicates radial transport of material within the disk, which we predict would affect the bulk composition of any planets forming in the disk.

Water in the terrestrial planet-forming zone of the PDS 70 disk.

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

The diverse chemistry of protoplanetary disks as revealed by JWST.

Early results from the James Webb Space Telescope-Mid-InfraRed Instrument (JWST-MIRI) guaranteed time programs on protostars (JOYS) and disks (MINDS) are presented. Thanks to the increased sensitivity, spectral and spatial resolution of the MIRI spectrometer, the chemical inventory of the planet-forming zones in disks can be investigated with unprecedented detail across stellar mass range and age. Here, data are presented for five disks, four around low-mass stars and one around a very young high-mass star. The mid-infrared spectra show some similarities but also significant diversity: some sources are rich in CO2, others in H2O or C2H2. In one disk around a very low-mass star, booming C2H2 emission provides evidence for a "soot" line at which carbon grains are eroded and sublimated, leading to a rich hydrocarbon chemistry in which even di-acetylene (C4H2) and benzene (C6H6) are detected. Together the data point to an active inner disk gas-phase chemistry that is closely linked to the physical structure (temperature, snowlines, presence of cavities and dust traps) of the entire disk and which may result in varying CO2/H2O abundances and high C/O ratios >1 in some cases. Ultimately, this diversity in disk chemistry will also be reflected in the diversity of the chemical composition of exoplanets.

Risk factors for RhD immunisation in a high coverage prevention programme of antenatal and postnatal RhIg: a nationwide cohort study.

OBJECTIVE: To evaluate which risk factors for RhD immunisation remain, despite adequate routine antenatal and postnatal RhIg prophylaxis (1000 IU RhIg) and additional administration of RhIg. The second objective was assessment of the current prevalence of RhD immunisations. DESIGN: Prospective cohort study. SETTING: The Netherlands. POPULATION: Two-year nationwide cohort of alloimmunised RhD-negative women. METHODS: RhD-negative women in their first RhD immunised pregnancy were included for risk factor analysis. We compared risk factors for RhD immunisation, occurring either in the previous non-immunised pregnancy or in the index pregnancy, with national population data derived from the Dutch perinatal registration (Perined). RESULTS: In the 2-year cohort, data from 193 women were eligible for analysis. Significant risk factors in women previously experiencing a pregnancy of an RhD-positive child (n = 113) were: caesarean section (CS) (OR 1.7, 95% CI 1.1-2.6), perinatal death (OR 3.5, 95% CI 1.1-10.9), gestational age >42 weeks (OR 6.1, 95% CI 2.2-16.6), postnatal bleeding (>1000 ml) (OR 2.0, 95% CI 1.1-3.6), manual removal of the placenta (MRP) (OR 4.3, 95% CI 2.0-9.3); these factors often occurred in combination. The miscarriage rate was significantly higher than in the Dutch population (35% versus 12.-5%, P < 0.001). CONCLUSION: Complicated deliveries, including cases of major bleeding and surgical interventions (CS, MRP), must be recognised as a risk factor, requiring estimation of fetomaternal haemorrhage volume and adjustment of RhIg dosing. The higher miscarriage rate suggests that existing RhIg protocols need adjustment or better compliance. TWEETABLE ABSTRACT: Complicated delivery (caesarean section, manual removal placenta, major bleeding) is the most valid risk factor for RhD immunization despite antenatal and postnatal RhIg.

Associations between road traffic noise exposure at home and school and ADHD in school-aged children: the TRAILS study.

Environmental noise may play a role in the manifestation and severity of attention deficit/hyperactivity disorder (ADHD) symptoms, but evidence is limited. We investigated the cross-sectional associations between residential and school road traffic noise exposure and ADHD symptoms and diagnosis. The sample included n = 1710, 10-12-year-old children from the TRAILS study in The Netherlands. ADHD symptoms were measured using a DSM-IV based subscale from the Child Behavior Checklist. Children with diagnosed ADHD originated from the clinic-referred cohort. Road traffic noise (Lden) was estimated at the residence and school level, by model calculation. Risk ratios for ADHD symptoms and ADHD diagnoses, and regression coefficients for symptom severity were estimated separately and simultaneously for residential and school road traffic noise. Adjusted multinomial models with residential road traffic noise showed that residential noise was not associated with ADHD symptoms, but was associated with lower risks for ADHD diagnosis (RR = 0.93; 95% CI 0.89, 0.97). Similar associations were observed for models including school road traffic noise and models including both exposures. No clear exposure response relationship was observed for associations between residential or school noise and ADHD symptom severity. We found no evidence for a harmful association between road traffic noise and ADHD. Associations between noise and lower risks for ADHD were observed only in referred cases with a confirmed ADHD diagnosis and may be due to residual confounding or selection bias. Future studies should focus on residential and school noise exposure, and study associations with ADHD symptoms and diagnosis over time.

Diagnostic value of far-IR water ice features in T Tauri disks.

AIMS: This paper investigates how the far-IR water ice features can be used to infer properties of disks around T Tauri stars and the water ice thermal history. We explore the power of future observations with SOFIA/HIRMES and SPICA's proposed far-IR instrument SAFARI. METHODS: A series of detailed radiative transfer disk models around a representative T Tauri star are used to investigate how the far-IR water ice features at 45 and 63 µm change with key disk properties: disk size, grain sizes, disk dust mass, dust settling, and ice thickness. In addition, a series of models is devised to calculate the water ice emission features from warmup, direct deposit and cooldown scenarios of the water ice in disks. RESULTS: Photodesorption from icy grains in disk surfaces weakens the mid-IR water ice features by factors 4-5. The far-IR water ice emission features originate from small grains at the surface snow line in disks at distance of 10-100 au. Unless this reservoir is missing in disks (e.g. transitional disks with large cavities), the feature strength is not changing. Grains larger than 10 µm do not contribute to the features. Grain settling (using turbulent description) is affecting the strength of the ice features by at most 15%. The strength of the ice feature scales with the disk dust mass and water ice fraction on the grains, but saturates for dust masses larger than 10-4 M⊙ and for ice mantles that increase the dust mass by more than 50%. The various thermal histories of water ice leave an imprint on the shape of the features (crystalline/amorphous) as well as on the peak strength and position of the 45 µm feature. SOFIA/HIRMES can only detect crystalline ice features much stronger than simulated in our standard T Tauri disk model in deep exposures (1 hr). SPICA/SAFARI can detect the typical ice features in our standard T Tauri disk model in short exposures (10 min). CONCLUSIONS: The sensitivity of SPICA/SAFARI will allow the detailed study of the 45 and 63 µm water ice feature in unbiased surveys of T Tauri stars in nearby star forming regions and an estimate of the mass of their ice reservoir. The water ice emission features carry an imprint of the thermal history of the ice and thus can distinguish between various formation and transport scenarios. Amorphous ice at 45 µm that has a much broader and flatter peak could be detected in deep surveys if the underlying continuum can be well characterized and the baseline stability of SAFARI is better than a few percent.

Individual variation in temporal relationships between exposure to radiofrequency electromagnetic fields and non-specific physical symptoms: A new approach in studying 'electrosensitivity'.

BACKGROUND: Everyday exposure to radiofrequency electromagnetic fields (RF-EMF) emitted from wireless devices such as mobile phones and base stations, radio and television transmitters is ubiquitous. Some people attribute non-specific physical symptoms (NSPS) such as headache and fatigue to exposure to RF-EMF. Most previous laboratory studies or studies that analyzed populations at a group level did not find evidence of an association between RF-EMF exposure and NSPS. OBJECTIVES: We explored the association between exposure to RF-EMF in daily life and the occurrence of NSPS in individual self-declared electrohypersensitive persons using body worn exposimeters and electronic diaries. METHODS: We selected seven individuals who attributed their NSPS to RF-EMF exposure. The level of and variability in personal RF-EMF exposure and NSPS were determined during a three-week period. Data were analyzed using time series analysis in which exposure as measured and recorded in the diary was correlated with NSPS. RESULTS: We found statistically significant correlations between perceived and actual exposure to wireless internet (WiFi - rate of change and number of peaks above threshold) and base stations for mobile telecommunications (GSM + UMTS downlink, rate of change) and NSPS scores in four of the seven participants. In two persons a higher EMF exposure was associated with higher symptom scores, and in two other persons it was associated with lower scores. Remarkably, we found no significant correlations between NSPS and time-weighted average power density, the most commonly used exposure metric. CONCLUSIONS: RF-EMF exposure was associated either positively or negatively with NSPS in some but not all of the selected self-declared electrohypersensitive persons.

Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks.

CONTEXT: Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism which is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not been well constrained by observations so far. AIMS: We aim at studying the processes involved in disk photoevaporation when it is driven by far-UV photons (i.e. 6 < E < 13.6 eV). METHODS: We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). For the analysis of these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code and we computed the far infrared line emission. RESULTS: With this model, we successfully reproduce most of the observations and derive key physical parameters, i.e. densities at the disk surface of about 106 cm-3 and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs i.e. grain photo-electric effect and cooling by [OI] and [CII] FIR lines. This specific energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to keep the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From the physical parameters derived from our best-fit models, we estimate mass-loss rates - of the order of 10-7 M⊙/yr - that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume photoevaporation in the supercritical regime where the evaporation flow is launched from the disk surface at sound speed. CONCLUSIONS: We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks.

Complications of intrauterine intravascular blood transfusion: lessons learned after 1678 procedures.

OBJECTIVE: Maternal alloimmunization to fetal red-blood-cell antigens is a major cause of fetal anemia, which can lead to hydrops and perinatal death if untreated. The cornerstone of management during pregnancy is intrauterine intravascular blood transfusion (IUT). Although this procedure is considered relatively safe, complications continue to occur. The aim of this study was to evaluate rates of procedure-related complications and perinatal loss following IUT, and their change over time, in order to identify factors leading to improved outcome. METHODS: This was a retrospective analysis of all IUTs for red-cell alloimmunization performed at the national referral center for fetal therapy in The Netherlands, from 1988 to 2015. Differences in complication rates and their associations with alterations in transfusion technique after 2001 were assessed. RESULTS: Between 1988 and 2015, 1678 IUTs were performed in 589 fetuses. For IUTs performed in 2001 and onwards, there was significant improvement in survival (88.6% vs 97.0%, P < 0.001) and a decline in procedure-related complications per fetus (9.8% vs 3.3%, P = 0.001) and per procedure (3.4% vs 1.2%, P = 0.003) compared with those performed before 2001. Procedure-related perinatal loss declined from 4.7% to 1.8% per fetus (P = 0.053). Beneficial changes in transfusion technique were routine use of fetal paralysis, increased use of intrahepatic transfusion and avoidance of arterial puncture. CONCLUSIONS: IUT has become an increasingly safe procedure in recent years when performed by experienced hands. The chosen technique should be fine-tuned according to the patient's individual situation. The declining complication rates are most likely related to center volume: this rare procedure is best performed in experienced fetal therapy centers. © 2016 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Third trimester screening for alloimmunisation in Rhc-negative pregnant women: evaluation of the Dutch national screening programme.

OBJECTIVE: To evaluate the effect of red blood cell (RBC) antibody screening in the 27th week of pregnancy in Rhc-negative women, on detection of alloimmunisation, undetected at first trimester screening ('late' alloimmunisation), and subsequent haemolytic disease of the fetus and newborn (HDFN), to assess risk factors for late alloimmunisation. DESIGN: Prospective cohort and nested case-control study. SETTING: The Netherlands. POPULATION: Two-year nationwide cohort. METHODS: Prospective inclusion of Rhc-negative women with negative first trimester screening and of screen-negative controls. Assessment of incidence and numbers needed to screen (NNS) of late alloimmunisation and HDFN; logistic regression analysis to establish risk factors for late alloimmunisation. MAIN OUTCOME MEASURES: Late alloimmunisation, HDFN. RESULTS: Late alloimmunisation occurred in 99 of 62 096 (0.159%) Rhc-negative women; 90% had c/E antibodies and 10% non-Rhesus antibodies. Severe HDFN (fetal/neonatal transfusion) occurred in two of 62 096 (0.003%) of Rhc-negative women and 2% of late alloimmunisations; moderate HDFN (phototherapy) occurred in 20 children [22.5%; 95% confidence interval (CI), 13.8-31.1%]. Perinatal survival was 100%. The NNS to detect one HDFN case was 2823 (31 048 for severe, 3105 for moderate HDFN). Significant risk factors were former blood transfusion [odds ratio (OR), 10.4; 95% CI, 1.14-94.9], parity (P-1: OR, 11.8; 95% CI, 3.00-46.5; P > 1: OR, 7.77; 95% CI, 1.70-35.4) and amniocentesis/chorionic villus sampling during current pregnancy (OR, 9.20; 95% CI, 1.16-72.9). CONCLUSIONS: Additional screening of Rhc-negative women improved the detection of late alloimmunisation and HDFN, facilitating timely treatment, with a NNS of 2823. Independent risk factors for late alloimmunisation were blood transfusion, parity and chorionic villus sampling/amniocentesis in the current pregnancy. The occurrence of most factors before the current pregnancy suggests a secondary immune response explaining most late alloimmunisations. TWEETABLE ABSTRACT: Third trimester screening for alloimmunisation in Rhc-neg women improves detection and treatment of severe HDFN.

Comfortable mobile offices: A literature review of the ergonomic aspects of mobile device use in transportation settings.

BACKGROUND: The use of mobile devices as an addition to or replacement of desktop computers for traditional office work results in more flexibility of workplaces. Consequently transportation time is used for office work and this asks for comfortable mobile offices. OBJECTIVE: The aim of this review is providing a framework of the relevant elements for comfortable mobile offices and defining needs for future research. METHODS: This literature review draws on 68 papers, theses, reviews and critiques. RESULTS: The framework is based on existing literature on traditional office ergonomics and comfort literature for different transportation modes like trains, buses, airplanes and cars. CONCLUSIONS: The main differences with traditional offices are the type of devices, dynamic versus static situation, the sole use of mobile devices and therefore the need for a good arm support to avoid an uncomfortable neck flexion, limited space, and the presence of strangers which influence the privacy perception. Important topics for future research are: the effect on the employee and the environment of the ability and demand of working anywhere, and the requirements for the physical aspects of mobile offices.

The influence of active seating on car passengers' perceived comfort and activity levels.

New technologies have led to an increasingly sedentary lifestyle. Sedentary behaviour is characterised by physical inactivity and is associated with several health risks. This excessive sitting does not only take place in the office or at home, but also during daily commute. Therefore, BMW AG developed an active seating system for the back seat of a car, consisting of sensors in the back rest that register upper body movements of the passenger, with which the passenger controls a game. This study evaluated three different aspects of active seating compared to other tasks (reading, working on laptop, and gaming on tablet). First, discomfort and comfort perception were measured in a 30-minute driving test. Discomfort was very low for all activities and participants felt significantly more challenged, more fit and more refreshed during active seating. Second, heart rate was measured, indicating a light intensity, but nevertheless non-sedentary, activity. Third, average and variability in activity of six postural muscles was measured by electromyography (EMG), showing a higher muscle activity and higher muscle variability for active seating compared to other activities. Active seating might stimulate movements, thereby increasing comfort and well-being.

Improving car passengers' comfort and experience by supporting the use of handheld devices.

BACKGROUND: There is a demand for interiors to support other activities in a car than controlling the vehicle. Currently, this is the case for the car passengers and--in the future--autonomous driving cars will also facilitate drivers to perform other activities. One of these activities is working with handheld devices. OBJECTIVE: Previous research shows that people experience problems when using handheld devices in a moving vehicle and the use of handheld devices generally causes unwanted neck flexion [Young et al. 2012; Sin and Zu 2011; Gold et al.2011]. In this study, armrests are designed to support the arms when using handheld devices in a driving car in order to decrease neck flexion. METHODS: Neck flexion was measured by attaching markers on the C7 and tragus. Discomfort was indicated on a body map on a scale 1-10. User experience was evaluated in a semi-structured interview. RESULTS: Neck flexion is significantly decreased by the support of the armrests and approaches a neutral position. Furthermore, overall comfort and comfort in the neck region specifically are significantly increased. Subjects appreciate the body posture facilitated by the armrests and 9 out of 10 prefer using handheld devices with the armrests compared to using handheld devices without the armrests. CONLUSION: More efforts are needed to develop the mock-up into an established product, but the angles and dimensions presented in this study could serve as guidelines.

Increased perinatal loss after intrauterine transfusion for alloimmune anaemia before 20 weeks of gestation.

OBJECTIVES: To evaluate and compare perinatal outcome after intrauterine transfusions (IUT) performed before and after 20 weeks of gestation. To analyse contributing factors. DESIGN: Retrospective analysis. SETTING: The Dutch referral centre for fetal therapy. POPULATION: IUTs for fetal alloimmune anaemia. METHODS: Fetuses were divided into two groups: fetuses requiring the first IUT before 20 weeks of gestation (Group 1) and those in which the IUTs started after 20 weeks (Group 2). The cause of perinatal loss was classified as procedure-related (PR) or not procedure-related (NPR). The cohort was divided into two periods to describe the change of perinatal loss over time. MAIN OUTCOME MEASURES: Perinatal loss of fetuses requiring the first IUT before 20 weeks of gestation, compared with perinatal loss later in gestation. RESULTS: A total of 1422 IUTs were performed in 491 fetuses. Perinatal loss rate in Group 1 was higher (7/29 24% versus 35/462 8%, P = 0.002). Especially NPR was higher for IUTs performed before 20 weeks (4/37 11% versus 19/1385 1%, P < 0.001). Kell alloimmunisation was overrepresented in Group 1 (7/29 24% versus 52/462 11%, P = 0.04). In a multivariate regression analysis, only hydrops was independently associated with perinatal loss (P = 0.001). In recent years, a decline in total perinatal loss was found (36/224 16% versus 6/267 2%, P < 0.001), but perinatal loss in Group 1 did not decline (4/224 1.8% versus 3/267 1.1%, P = 0.5). CONCLUSIONS: Perinatal loss after IUT performed before 20 weeks of gestation is increased compared with loss after IUT performed later in gestation. In addition, we confirmed earlier observations that hydrops is a major contributor to adverse outcome. Early and timely detection and treatment may prevent hydrops and improve outcome.

Three experiments to support the design of lightweight comfortable vehicle seats.

Seats need to be more lightweight for airplanes, cars, busses and even trains to contribute to a better environment and to reduce energy consumption. However, a reduction in comfort due to weight reduction is not preferable, which opens a new area of research: improving comfort with a minimum of material or with lightweight materials and systems. In this paper three experiments are performed to test the effects of light weight seats and parts of a seat on comfort. The first experiment shows that a new developed light weight massage system improves comfort and reduces muscle activity. The second experiment shows that the automatic seat adjustment without motors improves the comfort as well. The third experiment showed that a light weight seat following closely the human body contour is experienced on many aspects in the same way as current more heavy seats. More research and models will be needed in this ergonomic field which needs more attention.

Thrombocytopenia at birth in neonates with red cell alloimmune haemolytic disease.

OBJECTIVE: To evaluate the incidence and severity of and risk factors for thrombocytopenia at birth in neonates with red cell alloimmunization. STUDY DESIGN: All neonates with haemolytic disease of the foetus/newborn (HDFN) due to red cell alloimmunization admitted to our centre between January 2000 and September 2010 were included in this retrospective study. We measured platelet counts at birth and determined the incidence of thrombocytopenia (platelet count<150×10(9)/l) and severe thrombocytopenia (platelet count<50×10(9)/l). Risk factors for thrombocytopenia at birth were evaluated. RESULTS: Thrombocytopenia was present in 26% (94/362) of included neonates with HDFN at birth. Severe thrombocytopenia was found in 6% (20/362) of neonates. Three risk factors were found to be independently associated with thrombocytopenia at birth: treatment with intrauterine red cell transfusion (IUT) (OR 3·32, 95% CI 1·67-6·60, P=0·001), small for gestational age (SGA) below the 10th percentile (OR 3·32, 95% CI 1·25-8·80, P=0·016) and lower gestational age at birth (OR 1·22/week, 95% CI 1·02-1·44, P=0·025). CONCLUSIONS: Thrombocytopenia at birth occurs in 26% of neonates with HDFN due to red cell alloimmunization and is independently associated with IUT treatment, SGA and lower gestational age at birth.

Possibilities to improve the aircraft interior comfort experience.

Comfort plays an increasingly important role in the interior design of airplanes. Although ample research has been conducted on airplane design technology, only a small amount of public scientific information is available addressing the passenger's opinion. In this study, more than 10,000 internet trip reports and 153 passenger interviews were used to gather opinions about aspects which need to be improved in order to design a more comfortable aircraft interior. The results show clear relationships between comfort and legroom, hygiene, crew attention and seat/personal space. Passengers rate the newer planes significantly better than older ones, indicating that attention to design for comfort has proven effective. The study also shows that rude flight attendants and bad hygiene reduce the comfort experience drastically and that a high comfort rating is related to higher "fly again" values.

Exchange transfusions and top-up transfusions in neonates with Kell haemolytic disease compared to Rh D haemolytic disease.

OBJECTIVE: To evaluate neonatal outcome in Kell haemolytic disease compared to Rh D haemolytic disease. STUDY DESIGN: Retrospective study of all (near)-term neonates with Kell (n=34) and Rh D haemolytic disease (n=157) admitted to our centre between January 2000 and December 2008. We recorded the need for exchange transfusion and top-up transfusions up to 3 months of age. RESULTS: Neonates in the Kell group required less days of phototherapy than neonates in the Rh D group [2.4 vs. 4.1 days, respectively (P<0.01)]. The percentage of neonates requiring an exchange transfusion was lower in the Kell group than in the Rh D group [6% (2/34) and 62% (98/157), respectively (P<0.01)]. The percentage of neonates in the Kell group and Rh D group requiring a top-up transfusion was 62% (21/34) and 72% (113/157), respectively (P=0.20). The median number of top-up transfusions per neonate in the Kell group and Rh D group was 1 [interquartile range (IQR) 0-2] and 2(IQR 0-2), respectively (P=0.07). CONCLUSION: Neonates with Kell haemolytic disease require less phototherapy and less exchange transfusions compared to neonates with Rh D haemolytic disease, but an equal number of top-up transfusions.

Quantitative health impact assessment of transport policies: two simulations related to speed limit reduction and traffic re-allocation in the Netherlands.

BACKGROUND: Few quantitative health impact assessments (HIAs) of transport policies have been published so far and there is a lack of a common methodology for such assessments. OBJECTIVE: To evaluate the usability of existing HIA methodology to quantify health effects of transport policies at the local level. METHODS: Health impact of two simulated but realistic transport interventions - speed limit reduction and traffic re-allocation - was quantified by selecting traffic-related exposures and health endpoints, modelling of population exposure, selecting exposure-effect relations and estimating the number of local traffic-related cases and disease burden, expressed in disability-adjusted life-years (DALYs), before and after the intervention. RESULTS: Exposure information was difficult to retrieve because of the local scale of the interventions, and exposure-effect relations for subgroups and combined effects were missing. Given uncertainty in the outcomes originating from this kind of missing information, simulated changes in population health by two local traffic interventions were estimated to be small (<5%), except for the estimated reduction in DALYs by less traffic accidents (60%) due to speed limit reduction. CONCLUSIONS: Quantitative HIA of transport policies at a local scale is possible, provided that data on exposures, the exposed population and their baseline health status are available. The interpretation of the HIA information should be carried out in the context of the quality of input data and assumptions and uncertainties of the analysis.

Obstetric history and antibody titer in estimating severity of Kell alloimmunization in pregnancy.

OBJECTIVE: To evaluate the usefulness of the obstetric history and the maternal serum Kell antibody titer in the management of pregnancies with Kell alloimmunization. METHODS: In a retrospective cohort study of 41 pregnancies complicated by Kell alloimmunization, the obstetric history, divided into presence or absence of a previous Kell-positive child, and Kell antibody titers in the index pregnancy were correlated with the gestational age at the onset of fetal anemia. RESULTS: Women with a previous Kell-positive child had a lower gestational age at the first intrauterine transfusion compared with those without a previous Kell-positive child (P=.01). However, in two of 29 pregnancies in the latter group, severe fetal anemia requiring transfusion was detected before 20 weeks of gestation. In neither group were maternal Kell antibody titers significantly correlated with gestational age at first intrauterine transfusion (P=.62 and P=.72, respectively). In all but two pregnancies (1:2 and 1:4, respectively), antibody titers were at least 1:32 before the first intrauterine transfusion. CONCLUSION: For timely detection of all cases of severe fetal anemia, Kell-alloimmunized pregnancies with a Kell-positive fetus and titers greater than or equal to 1:2 should be closely monitored from 16 to 17 weeks of gestation onward.