Ensemble Random Forests as a tool for modeling rare occurrences

Relative to target species, priority conservation species occur rarely in fishery interactions, resulting in imbalanced, overdispersed data. We present Ensemble Random Forests (ERFs) as an intuitive extension of the Random Forest algorithm to handle rare event bias. Each Random Forest receives individual stratified randomly sampled training/test sets, then down-samples the majority class for each decision tree. Results are averaged across Random Forests to generate an ensemble prediction. Through simulation, we show that ERFs outperform Random Forest with and without down-sampling, as well as with the synthetic minority over-sampling technique, for highly class imbalanced to balanced datasets. Spatial covariance greatly impacts ERFs’ perceived performance, as shown through simulation and case studies. In case studies from the Hawaii deep-set longline fishery, giant manta ray Mobula birostris syn. Manta birostris and scalloped hammerhead Sphyrna lewini presence had high spatial covariance and high model test performance, while false killer whale Pseudorca crassidens had low spatial covariance and low model test performance. Overall, we find ERFs have 4 advantages: (1) reduced successive partitioning effects; (2) prediction uncertainty propagation; (3) better accounting for interacting covariates through balancing; and (4) minimization of false positives, as the majority of Random Forests within the ensemble vote correctly. As ERFs can readily mitigate rare event bias without requiring large presence sample sizes or imparting considerable balancing bias, they are likely to be a valuable tool in bycatch and species distribution modeling, as well as spatial conservation planning, especially for protected species where presence can be rare.

Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion

OBJECTIVES

To compare the proportions of dogs with thoracolumbar disc extrusion that lose pelvic limb pain perception if surgery is performed on the day of admission or delayed overnight. To describe the outcome of those dogs that deteriorate to lose pain perception.

MATERIALS AND METHODS

Retrospective, single centre study on 273 client-owned dogs with thoracolumbar disc extrusion and intact pain perception, but inability to walk unaided on their pelvic limbs. Dogs were subdivided into two groups: early surgery (spinal decompression between their examination at day of admission and the following morning), and delayed surgery (did not undergo surgery between admission and the following morning). The proportion of dogs that lost pelvic limb pain perception overnight was compared between the early and delayed surgery groups.

RESULTS

Seven of 151 dogs in the early surgery group lost pain perception overnight compared to 15 of 122 in the delayed surgery group (Fisher's exact test, P = 0.025). Number-needed-to-treat analysis suggested that 14 dogs (95% confidence interval: 7-106 dogs) need early surgery to prevent one losing pain perception overnight. Five of the seven dogs that lost pain perception in the early surgery group recovered pain perception by 3 weeks post-operatively, compared to eight of 14 in the delayed group.

CLINICAL SIGNIFICANCE

This study suggests that an overnight delay before spinal decompression increases the risk of clinically meaningful deterioration in dogs unable to walk following thoracolumbar disc extrusion.

An investigation of micronutrient supplementation in weaner lambs to improve growth rates in southeast Australia

OBJECTIVE

A producer survey by questionnaire assessed supplements used in sheep and reasons for use. This was followed by field trials on eight sheep properties in SE NSW to determine the effect of commonly used commercially available supplements on growth rates of Merino and crossbred lambs.

DESIGN

On each property, 450 lambs were selected at weaning and randomly allocated to nine groups of 50 sheep (eight treatment and a control group). Supplements were applied as per manufacturer's recommendation every 6-12 weeks. At each application, all sheep were weighed and data on general flock health and management were collected.

RESULTS

All but one of the survey respondents (n = 77) had used supplements in their sheep at some stage. The reasons for use were most commonly for general health and production benefits (n = 21; 26.9%) and to prevent or treat specific diseases/deficiencies (n = 7; 9.0%). The average daily weight gains (ADWG) of the lambs over the trial period varied from 0.074 kg to 0.213 kg/head/day. Statistical analysis showed that overall there was not a significant difference (P = 0.587) between ADWG among lambs that received supplements and lambs that did not.

CONCLUSION

Results of this study show that application of supplements were not linked to improved growth rates in clinically normal crossbred and Merino lambs under the trial farm conditions between weaning and 15 months of age. Effects of supplements on health and production in adult sheep and how supplement response can be best measured in sheep flocks (especially in relation to health and welfare) and linked to productivity requires further investigation.

Hybrid triad provides fracture plane stability in a computational model of a Pauwels Type III hip fracture

The study utilized finite element method to determine displacements and stresses in a set of Pauwels Type III femoral neck fractures repaired using 3 techniques (cannulated screws (Triad), sliding hip screw (SHS), and a Hybrid (SHS + cannulated screws). The research found that shear displacement doubled between the 65° and 75° fracture angles regardless of fixation construct. The SHS alone was the least stable construct, with highest construct stresses and shear displacement along the fracture plane. The stability of the Hybrid and Triad constructs were similar, but stress in the Hybrid was lower suggesting it would provide a higher load to failure than the Triad.

Stacked volume holographic gratings for extending the operational wavelength range in LED and solar applications

A novel stacking procedure is presented for volume phase holographic gratings (VPHGs) recorded in photopolymer material using Corning Willow Glass as a flexible substrate in order to achieve broader angular and spectral selectivity in a diffractive device with high efficiency for solar and LED applications. For the first time to our knowledge, we have shown a device designed for use with a white LED that has the same input and output angles and high efficiency when illuminated by different wavelengths. In this paper, two VPHGs were designed, experimentally recorded, and tested when illuminated at normal incidence. The experimental approach is based on stacking two individual gratings in which the spatial frequency and slant have been tailored to the target wavelength and using real-time on-Bragg monitoring of the gratings in order to control the recorded refractive index modulation, thereby optimizing each grating efficiency for its design wavelength. Lamination of the two gratings together was enabled by using a flexible glass substrate (Corning Willow Glass). Recording conditions were studied in order to minimize the change in diffraction efficiency and peak diffraction angle during lamination and bleaching. The final fabricated stacked device was illuminated by a white light source, and its output was spectrally analyzed. Compared to a single grating, the stacked device demonstrated a twofold increase in angular and wavelength range. The angular and wavelength selectivity curves are in good agreement with the theoretical prediction for this design. This approach could be used to fabricate stacked lenses for white light LED or solar applications.

Implementation of an optimization method for parotid gland sparing during inverse planning for head and neck cancer radiotherapy

PURPOSE

To guide parotid gland (PG) sparing at the dose planning step, a specific model based on overlap between PTV and organ at risk (Moore et al.) was developed and evaluated for VMAT in head-and-neck (H&N) cancer radiotherapy.

MATERIALS AND METHODS

One hundred and sixty patients treated for locally advanced H&N cancer were included. A model optimization was first performed (20 patients) before a model evaluation (110 patients). Thirty cases were planned with and without the model to quantify the PG dose sparing. The inter-operator variability was evaluated on one case, planned by 12 operators with and without the model. The endpoints were PG mean dose (D_mean), PTV homogeneity and number of monitor units (MU).

RESULTS

The PG D_mean predicted by the model was reached in 89% of cases. Using the model significantly reduced the PG D_mean: -6.1±4.3Gy. Plans with the model showed lower PTV dose homogeneity and more MUs (+10.5% on average). For the inter-operator variability, PG dose volume histograms without the optimized model were significantly different compared to those with the model; the D_mean standard deviation for the ipsilateral PG decreased from 2.2Gy to 1.2Gy. For the contralateral PG, this value decreased from 2.9Gy to 0.8Gy.

CONCLUSION

During the H&N inverse planning, the optimized model guides to the lowest PG achievable mean dose, allowing a significant PG mean dose reduction of -6.1Gy. Integrating this method at the treatment-planning step significantly reduced the inter-patient and inter-operator variabilities.

Fast Domain Wall Motion Governed by Topology and Œrsted Fields in Cylindrical Magnetic Nanowires

While the usual approach to tailor the behavior of condensed matter and nanosized systems is the choice of material or finite-size or interfacial effects, topology alone may be the key. In the context of the motion of magnetic domain walls (DWs), known to suffer from dynamic instabilities with low mobilities, we report unprecedented velocities >600  m/s for DWs driven by spin-transfer torques in cylindrical nanowires made of a standard ferromagnetic material. The reason is the robust stabilization of a DW type with a specific topology by the Œrsted field associated with the current. This opens the route to the realization of predicted new physics, such as the strong coupling of DWs with spin waves above >600  m/s.

Short-acting β2-agonists (SABA) bronchodilator sales and outdoor mould in central France

Background

Temporal ecological studies have shown that outdoor moulds are associated with severe asthma exacerbations, as emergency department visits or hospitalisations. The aim of this was to assess the associations between daily sales of short-acting β2-agonists (SABA), a specific and frequent treatment for control of mild asthma exacerbations in children and young adults, and outdoor mould concentrations in the central France area over a 5 year period.

Methods

The relationship between daily changes in mould (25 species) concentrations and daily SABA sales within a population of patients aged 6 to 39 years in a middle-size town of central France (approximately 127,000) was obtained from social security database and analysed with generalized additive models, taking into account confounding factors (air pollution, weather conditions, pollen counts and trend).

Results

Daily SABA sales (mean, SD) rose from 17.3 (9.7) in 2010 to 22.7 (12) in 2015. The relative risk (RR [95% CI]) of SABA sales associated with an interquartile increase in mould concentration was significant in the whole population for Alternaria 1.06 [1.002–1.12]. When the influence of age and sex was accounted for, the relationship was significant only in 6–12 years old males for Alternaria 1.21 [1.04–1.41] and Aspergillus–Penicillium 1.08 [1.04–1.12].

Conclusions

Daily SABA sales are positively associated with Alternaria spores in the general population of children and young adults. The association between daily SABA sales and temporal changes to Alternaria and Aspergillus–Penicillium in male children indicate that outdoor moulds contribute to asthma morbidity.

P11.59 Integrin a5 heterogeneous expression in glioblastoma is related to glioma stem cell subpopulations

BACKGROUND

Glioblastoma (GBM) is the most aggressive primary brain tumor. Treatment failure and recurrence are explained in part by tumoral heterogeneity. Our previous results showed that the integrin α5β1 is implicated in GBM aggressiveness and represents a relevant therapeutic target. Recently, we observed intra- and inter-tumor heterogeneity of integrin α5β1 expression. Heterogeneity may be linked to different glioma stem cell populations.

MATERIAL AND METHODS

Ten glioma stem cell lines were grown as neurospheres in stem cell medium and their differentiation was induced by serum and/or ATRA. Two cell lines (NCH421k and NCH644) were selected and were modified by depletion (CrisprCas9) or transfection of the α5 integrin gene. Polyclonal lines and individual clones were analyzed phenotypically in vitro, before and after differentiation, and in vivo in orthotopic xenografts of 2x104 cells in nude mice. TCGA datasets were used to validate the heterogeneous expression of α5 integrin in GBM.

RESULTS

TCGA data validate that α5 integrin mRNA was only over-expressed in the mesenchymal subclass of GBM. Our results show that α5 integrin protein is not expressed in stem cell culture conditions. However, α5 integrin expression is induced after differentiation in only half of the cell lines supporting the notion of tumoral heterogeneity of glioma stem cells. Interestingly, single cell-derived clone evaluation showed that intra-tumoral stem cell heterogeneity also exists at the level of α5 protein expression. When glioma stem cells are programmed or transduced to express α5 integrin, differentiated cells became more aggressive. Notably, they acquired a fibronectin-dependent motility and a proliferative phenotype. Interestingly, integrin α5 remained expressed in secondary stem cells obtained after dedifferentiation. The in vivo assays suggested that glioma stem cells, programmed to express the integrin, were prone to form larger tumors.

CONCLUSION

Our data support the hypothesis that some glioma stem cells are programmed to express the α5 integrin subunit in their differentiated progeny to form a more aggressive tumor. They add new evidences that both cell populations may be considered for new therapeutic strategies against GBM.

TOTAL THYROIDECTOMY FOR MALIGNANCY - IS CENTRAL NECK DISSECTION A RISK FACTOR FOR RECURRENT NERVE INJURY AND POSTOPERATIVE HYPOCALCEMIA? A TERTIARY CENTER EXPERIENCE IN ROMANIA

Introduction

Surgery for thyroid cancer carries a higher risk of morbidity given the region's complicated anatomy, the setting of malignancy and extent of the surgery.

Aim

To investigate the rate of complications related to the recurrent nerve and parathyroid glands lesions in patients with thyroid carcinoma that undergo thyroid surgery and lymph node dissection.

Patients and Methods

The data of 71 patients who underwent total thyroidectomy and 19 patients who underwent total thyroidectomy and central neck dissection with various associated neck dissection techniques were investigated using appropriate statistical tests.

Results

As expected, the rate of recurrent nerve injury observed in the neck dissection group was higher than in the total thyroidectomy group (15.7% vs. 2.8%, p=0.05). As for postoperative hypocalcemia, the rate observed in the neck dissection group, both for postoperative day 1 (p<0.0001) and day 30 (p=0.0003) was higher than in the total thyroidectomy group (68.4% vs. 19.7% postoperative day 1, 31.5% vs. 4.2% postoperative day 30).

Conclusions

The risk of morbidity concerning the recurrent nerve injury and postoperative hypoparathyroidism increases with the extent of surgery. Extensive surgery may achieve proper oncologic outcomes but increases the risk of postoperative morbidity and decreases quality of life. In deciding for extensive surgery, both patient and medical team need to understand these risks.

The description and definition of Emergency Department Pharmacist Practitioners in the United Kingdom (the ENDPAPER study)

Background Due to a shortage of emergency department doctors and nurses, hospitals have started to employ pharmacists who have additional clinical skills, known as Emergency Department Pharmacist Practitioners, to help deliver services. Objective To describe, compare and define the Emergency Department Pharmacist Practitioner role. Setting UK emergency departments. Method Using a purpose developed questionnaire hosted on a tablet computer, Emergency Department Pharmacist Practitioners were asked to report their contribution to patient care and the wider emergency department over 10 work days. Main outcome measure Emergency Department Pharmacist Practitioners’ work. Results Twenty Emergency Department Pharmacist Practitioners from 15 UK hospitals were recruited. Of 682 patients cared for, 4.8% (n=33) were of blue triage category (least urgent) and 4.1% (n=28) red (immediate need). Specific activities to inform patient diagnosis included clinical examinations (264/682 patients, 38.7%) and the review of investigation/test/procedure results (270, 39.6%). For treatment, EDPPs prescribed a total of 603 medicines (for administration in the ED) to 266 patients (39.0%) and performed procedures for 63 (9.2%). Eleven of the practitioners also took on the role of designated care provider (i.e. the healthcare professional with overall clinical responsibility) for at least some of their patients. From application of the care typology, all 20 practitioners carried out both ‘traditional’ and ‘practitioner’ activity and 9/20 of them sometimes provided more ‘practitioner’ than ‘traditional’ care to individual patients. Seven key role attributes were identified including how these pharmacists support patients with medical complaints and injuries of any severity and at any stage of their visit. Conclusion Emergency Department Pharmacist Practitioners combine traditional clinical pharmacy activities with more hands-on medical practise including being designated care provider. The role is versatile in that care and support provided to patients and the wider emergency department professional team is varied and therefore somewhat adaptable to situations which present.

Neuroimaging of acute and chronic unilateral and bilateral thalamic lesions

The thalami are bilateral ovoid grey matter cerebral structures bordering the third ventricle on both sides, which participate in functions such as relaying of sensory and motor signals, regulation of consciousness, and alertness. Pathologies affecting the thalami can be of neoplastic, infectious, vascular, toxic, metabolic, or congenital origin.The purpose of this review is to provide a comprehensive approach to the thalamus focusing on its anatomy, the main pathologies affecting this structure and their radiological semiology on CT and MRI. We will also illustrate the importance of multimodal MR imaging (morphologic sequences, diffusion-weighted imaging, perfusion, spectroscopy) for the diagnosis and treatment of these conditions.

Photo-dissociation of naphthalene dimer cations stored in a compact electrostatic ion storage ring

Naphthalene dimer cations [C₁₀H₈]₂ ⁺ have been produced by using an electron cyclotron resonance plasma ion source and stored in a compact electrostatic ion storage ring. We show that the radiative cooling of these cations is much slower than the isolated monomer naphthalene cations. We also report on photo-dissociation studies in the gas phase of naphthalene dimer cations at high internal energy. The dissociation energy is estimated to 0.5 eV in close agreement with previous measurements but a factor of 2 smaller than recent (density functional theory (DFT) and ab initio) theoretical studies. As uncertainties on theory as well as on the experiment cannot be as large as this difference, we conclude that this discrepancy may be due to temperature effects with possible isomerization. As an interpretation of the photo-dissociation spectrum of naphthalene dimer cations, we propose a tentative simple analytical model based on effective Morse potentials. These effective potentials are expected to "average" temperature effects that would apparently result in a smaller energy difference between the fundamental and dissociation states due to the twisting vibration modes of the naphthalene dimer cations.

Appendectomy for Therapy-Refractory Ulcerative Colitis Results in Pathological Improvement of Colonic Inflammation: Short-Term Results of the PASSION Study

BACKGROUND AND AIMS

The objective of this study was to examine the modulating effect of an appendectomy on the disease course of therapy-refractory ulcerative colitis [UC] patients, and to analyse appendiceal pathological characteristics predictive of pathological response.

METHODS

Patients with therapy-refractory UC, and referred for proctocolectomy, were invited to undergo laparoscopic appendectomy first. The primary end points were clinical response after 3 and 12 months. Secondary end points were endoscopic remission, failure, and pathologic response. Appendiceal specimens, and pre- and post-operative biopsies were histologically graded according to the validated Geboes score.

RESULTS

Thirty patients [53% male] with a median age of 40 (interquartile range [IQR], 33-47) underwent appendectomy, with a median preoperative total Mayo score of 9 [IQR, 8-11]. After 12 months, 9 patients [30%] had lasting clinical response, of whom 5 [17%] were in endoscopic remission. Pathological evaluation was possible in 28 patients. After a median of 13.0 weeks [range 7-51], pathological response was seen in 13 patients [46%], with a median decrease of 2 points [range 1-3]. Appendiceal inflammation was highly predictive of pathological response when compared with no inflammation or extensive ulcerations [85% vs 20%, p = 0.001].

CONCLUSIONS

Appendectomy was effective in one-third of therapy-refractory UC patients, with a substantial proportion of patients demonstrating complete endoscopic remission after 1 year. Pathological response was seen in almost 50% of patients and was related to active inflammation in the appendix, limited disease, and shorter disease duration. These early results suggest that there is a UC patient group that may benefit from appendectomy.

Fetal supraventricular tachycardia and cystic fibrosis: Coincidence or association? Two case reports

Prenatal diagnosis of cystic fibrosis (CF) is difficult and is mainly considered upon identification of digestive sonographic signs. Although such an association has never been described until now to our knowledge, we report two cases of fetal arrhythmia associated with cystic fibrosis. This association may be explained by the physiopathology of heart in the context of CF, but nevertheless needs to be confirmed by other reports. The prenatal diagnosis of CF is important in order to implement early appropriate care, with better prognosis. The finding of possibly new associated prenatal signs may then improve the global management of the disease.

Short-term effect of outdoor mould spore exposure on prescribed allergy medication sales in Central France

BACKGROUND

Outdoor moulds are classically associated with exacerbations of asthma.

OBJECTIVE

The aim of this paper was to examine nasal allergy morbidity by studying the short-term relationship between mould spore exposure and daily sales of reimbursable anti-allergic treatment in central France.

METHODS

The relationship between daily changes in mould concentrations and daily sales obtained from the national healthcare database was analysed with generalized additive models, taking into account confounding factors such as air pollution, weather conditions, pollen counts, and days of the week.

RESULTS

During the study, the average total yearly number of treated people was around 10 000 over approximately 230 000 surveyed. The relative risk (95% CI confidence interval) of sales of oral antihistamines with topical treatment associated with an interquartile increase in mould concentration was significant for Cladosporium 1.079 [1.019-1.142] and Aspergillus-Penicillium (Asp-Pen) 1.051 [1.021-1.082] in the whole population. When the influence of age and sex was considered, the relationship was significant only in male children aged 0-12 years and those aged between 13 and 49 years for Cladosporium: 1.256 [1.081-1.460] and 1.151 [1.063-1.245], respectively. The relationship was also significant for Asp-Pen: 1.038 [1.003-1.075] for those aged between 13 and 49 years and 1.056 [1.007-1.108] for adults over 50 years of age.

CONCLUSION

The association between prescribed daily sales of oral antihistamines with topical treatment sales is associated with temporal changes to Cladosporium and Aspergillus-Penicillium in the whole population. When the influence of age and sex was considered, these two moulds contributed to prescribed medication sales only in the male general population.

EUROCAT: an update on its functions and activities

This paper provides an outline of the development and growth of EUROCAT, the European network of congenital anomaly registers. In recent years the network has been through a period of transition and change. The Central Register of data has transferred from the Ulster University to the EU Joint-Research-Centre, Ispra, Italy.The benefits of combining data from across Europe, from different populations and countries are described by the uses to which these data can be put. These uses include:. surveillance of anomalies at a local, regional or pan-European level. pharmacovigilance. registration of rare diseasesNew studies and projects are underway, including EUROlinkCAT (a Horizon 2020 funded data-linkage project), promising a fruitful future in further research of congenital anomalies.

Salvage high-dose chemotherapy in female patients with relapsed/refractory germ-cell tumors: a retrospective analysis of the European Group for Blood and Marrow Transplantation (EBMT)

Background

High-dose chemotherapy (HDC) with hematopoietic progenitor cell transplantation is a standard option for relapsed/refractory testicular germ-cell tumor (GCT), but only few data have been reported in female patients with GCT. We conducted a retrospective analysis of female patients with GCT treated with HDC and registered with the European Society for Blood and Marrow Transplantation.

Patients and methods

Between 1985 and 2013, 60 registered female patients with GCT, median age 27 years (range 15-48), were treated with salvage HDC. Forty patients (67%) had primary ovarian GCT, 8 (13%) mediastinal, 7 (12%) retroperitoneal and 5 (8%) other primary sites/unknown. Twenty-two patients (37%) received HDC as second-line therapy, 29 (48%) as third-line, and 9 (15%) as fourth- to sixth-line. Nine of 60 patients (15%) received HDC as late-intensification with no evidence of metastasis before HDC. The conditioning HDC regimens comprised carboplatin in 51 of 60 cases (85%), and consisted of a single HDC cycle in 31 cases (52%), a multi-cycle HDC regimen in 29 (48%).

Results

Nine cases who underwent late intensification HDC were not evaluable for response. Of the other 51 assessable patients, 17 (33%) achieved a complete response (CR), 8 (16%) a marker-negative partial remission (PRm-), 5 (10%) a marker-positive partial remission, 5 (10%) stable disease, and 13 (25%) progressive disease. There were 3 toxic deaths (6%). With an overall median follow-up of 14 months (range 1-219), 7 of 9 (78%) patients with late intensification and 18 of the 25 patients (72%) achieving a CR/PRm- following HDC were free of relapse/progression. In total, 25 of 60 patients (42%) were progression-free following HDC at a median follow-up of 87 months (range 3-219 months).

Conclusions

Salvage HDC based on carboplatin represents a therapeutic option for female patients with relapsed/refractory GCT.

Time-resolved photoion imaging spectroscopy: Determining energy distribution in multiphoton absorption experiments

We propose an approach to determine the excitation energy distribution due to multiphoton absorption in the case of excited systems following decays to produce different ion species. This approach is based on the measurement of the time-resolved photoion position spectrum by using velocity map imaging spectrometry and an unfocused laser beam with a low fluence and homogeneous profile. Such a measurement allows us to identify the species and the origin of each ion detected and to depict the energy distribution using a pure Poisson's equation involving only one variable which is proportional to the absolute photon absorption cross section. A cascade decay model is used to build direct connections between the energy distribution and the probability to detect each ionic species. Comparison between experiments and simulations permits the energy distribution and accordingly the absolute photon absorption cross section to be determined. This approach is illustrated using C₆₀ as an example. It may therefore be extended to a wide variety of molecules and clusters having decay mechanisms similar to those of fullerene molecules.

The TGFβ pathway is a key player for the endothelial-to-hematopoietic transition in the embryonic aorta

The embryonic aorta produces hematopoietic stem and progenitor cells from a hemogenic endothelium localized in the aortic floor through an endothelial to hematopoietic transition. It has been long proposed that the Bone Morphogenetic Protein (BMP)/Transforming Growth Factor ß (TGFß) signaling pathway was implicated in aortic hematopoiesis but the very nature of the signal was unknown. Here, using thorough expression analysis of the BMP/TGFß signaling pathway members in the endothelial and hematopoietic compartments of the aorta at pre-hematopoietic and hematopoietic stages, we show that the TGFß pathway is preferentially balanced with a prominent role of Alk1/TgfßR2/Smad1 and 5 on both chicken and mouse species. Functional analysis using embryonic stem cells mutated for Acvrl1 revealed an enhanced propensity to produce hematopoietic cells. Collectively, we reveal that TGFß through the Alk1/TgfßR2 receptor axis is acting on endothelial cells to produce hematopoiesis.