Filip Cools

Hardikar syndrome: A new syndrome with cleft lip/palate, pigmentary retinopathy and cholestasis

We present a child with a remarkable constellation of abnormalities comprising cleft lip and palate, pigmentary retinopathy, hydronephrosis, malrotation of the gut and obstructive liver disease. This patient, together with two other reported cases, seems to represent a new syndrome with some similarities to the Kabuki syndrome.

A MINIMAL SET OF GENERATORS FOR THE CANONICAL IDEAL OF A NONDEGENERATE CURVE

We give an explicit way of writing down a minimal set of generators for the canonical ideal of a non-degenerate curve, or of a more general smooth projective curve in a toric surface, in terms of its defining Laurent polynomial.

On Grassmann secant extremal varieties

— In this paper we give a sharp lower bound on the dimension of Grassmann secant varieties of a given variety and we classify varieties for which the bound is attained. MSC.— 14M07, 14M15, 14N15

A new method of surfactant administration in preterm infants.

Surfactant treatment substantially improves outcomes for preterm infants with respiratory distress syndrome. However, the optimal timing and method of administration of this treatment are less clear. In The Lancet, Wolfgang Göpel and colleagues, on behalf of the German Neonatal Network, report the results of a multicentre randomised controlled trial investigating a new minimally invasive method of early surfactant administration in spontaneously breathing preterm infants who are supported with continuous positive airway pressure. Compared with the intubate, surfactant, and extubate technique, in which surfactant is administered during a short period of positive pressure ventilation, this new intervention could off er an advantage because positive pressure ventilation can be avoided completely. In Göpel and colleagues’ trial 220 preterm infants of a gestational age between 26 and 28 weeks and a birthweight less than 1500 g were randomly assigned to receive either early surfactant administration during spontaneous breathing or a standard approach of intubation when judged appropriate, then surfactant administration during mechanical ventilation. In the intervention group, the need for mechanical ventilation on day 2 or 3 after birth, or the risk of being not ventilated but having a partial pressure of carbon dioxide more than 65 mm Hg (8·6 kPa) or a fraction of inspired oxygen of more than 0·60, or both, for more than 2 h between 25 h and 72 h of age, was signifi cantly lower than in the control group, with an absolute risk reduction of 0·18 (95% CI 0·30–0·05) and a number needed to treat of 6 (3–20). The evaluation of new treatments in rigorous randomised controlled trials investigating both safety and effi cacy is essential, before they are introduced into clinical practice. To interpret the results of this study correctly, however, a few remarks should be made. In studies for which the intervention cannot be masked, as is the case for this study, it is important that the primary outcome is robust and, if possible, the outcome assessment masked. Co-interventions should be controlled as much as possible by detailed descriptions in the study protocol, to avoid diff erences between the experimental and control groups. In this study, for which the primary outcome was any mechanical ventilation, or no ventilation but having a partial pressure of carbon dioxide more than 65 mm Hg (8·6 kPa) or a fraction of inspired oxygen (FiO2) more than 0·60, or both, for more than 2 h between 25 h and 72 h of age, criteria for intubation and extubation were not prespecifi ed in the protocol. Therefore, physicians might have been biased by the patient’s group assignment when deciding whether to intubate or extubate. Similarly, the use of some important co-interventions, such as analgesics and sedatives, were left to the discretion of the attending neonatologist. Morphine use has been associated with an increased duration of mechanical ventilation. Physicians might have been more reluctant to use analgesics or sedatives in infants in the early surfactant group, which could have contributed to the relatively high success rate of extubation in this group. These two methodological issues might have introduced some bias, most likely in favour of the intervention. The patient–intervention–comparison–outcome cri teria for this study were whether in preterm neonates with respiratory distress syndrome receiving nasal continuous positive airway pressure in the fi rst hours after birth, but with an increasing oxygen requirement (patient), the early administration of surfactant by a non-invasive technique, then continuation of nasal continuous positive airway pressure (intervention), is safe (outcome), and results in improved pulmonary outcomes (outcome). Diff erent standard treatments could be considered as comparators (comparison), such as the intubate, surfactant, and extubate technique and then continuous positive airway pressure, early therapeutic surfactant Published Online September 30, 2011 DOI:10.1016/S01406736(11)61339-1

The lattice size of a lattice polygon

We give upper bounds on the minimal degree of a model in P 2 and the minimal bidegree of a model in P 1 × P 1 of the curve defined by a given Laurent polynomial, in terms of the combinatorics of the Newton polygon of the latter. We prove in various cases that this bound is sharp as soon as the polynomial is sufficiently generic with respect to its Newton polygon.

On metric graphs with prescribed gonality

We prove that in the moduli space of genus-g metric graphs the locus of graphs with gonality at most d has the classical dimension min{3g-3,2g+2d-5}. This follows from a careful parameter count to establish the upper bound and a construction of sufficiently many graphs with gonality at most d to establish the lower bound. Here, gonality is the minimal degree of a non-degenerate harmonic map to a tree that satisfies the Riemann-Hurwitz condition everywhere. Along the way, we establish a convenient combinatorial datum capturing such harmonic maps to trees.

Classification of (1,2)-Grassmann secant defective threefolds

Abstract In this paper, we classify all smooth threefolds , for which the Grassmann secant variety G 1,2(X) ⊂ 𝔾(1, N) (i.e. the closure of the set of lines contained in the span of 3 independent points of X) has not the expected dimension.

On High G k−1,k -Defective Varieties

We give a rough characterization for n-dimensional varieties with Gk−1,k-defect equal to a > 0 if k ≥ n. Then we apply this in the case that a ≥ n − 2 to become a fine classification.

Intrinsicness of the Newton polygon for smooth curves on \({\mathbb {P}}^1\times {\mathbb {P}}^1\)

Let C be a smooth projective curve in