Incentivizing the Dynamic Workforce: Learning Contracts in the Gig-Economy

In principal-agent models, a principal offers a contract to an agent to perform a certain task. The agent exerts a level of effort that maximizes her utility. The principal is oblivious to the agent's chosen level of effort, and conditions her wage only on possible outcomes. In this work, we consider a model in which the principal is unaware of the agent's utility and action space. She sequentially offers contracts to identical agents, and observes the resulting outcomes. We present an algorithm for learning the optimal contract under mild assumptions. We bound the number of samples needed for the principal obtain a contract that is within $\epsilon$ of her optimal net profit for every $\epsilon>0$

Vertebral tongue-like deformity in mucopolysaccharidosis VI

Teaching point: Defective development of the anterior portion of the vertebral body at the thoracolumbar junction may be an important imaging clue in the diagnosis of mucopolysaccharidosis

Methylmalonic acidaemia in pregnancy

A 27-year-old woman with vitamin B(12) responsive form of methylmalonic acidaemia (MMA) was pregnant with her first child. Treatment was unaltered during pregnancy: a low-protein diet and supplements. Her pregnancy was uncomplicated. She had a spontaneous delivery of a healthy girl with no MMA. The postpartum period was uneventful. MMA is a rare autosomal recessive metabolic disorder caused by a deficiency of methylmalonyl coenzyme A mutase or its vitamin B(12)-dependent cofactor, leading to a toxic accumulation of methylmalonyl acid in plasma and urine. Clinical presentation involves otherwise unexplained deterioration and neurological dysfunction, recurrent vomiting, dehydration, lethargy, respiratory distress and muscular hypotonia. Long-term sequelae are neurological problems, renal failure, pancreatitis and cardiomyopathy. This is the 11th reported case of pregnancy in a woman with MMA

Left ventricular hypertrophy : do not forget Fabry disease. Diagnostic work-up and differential diagnosis

Abstract: BackgroundLeft ventricular (LV) hypertrophy is a common clinical finding. Differential diagnosis includes Fabry disease, a rare and progressive, but treatable storage disease caused by deficiency of alpha-galactosidase A. However, diagnosis of Fabry is often hampered by its clinical heterogeneity, LV hypertrophy phenocopies and unawareness of the clinician.MethodsThis review summarises clinical data, family history, electrocardiogram (ECG) and imaging (echocardiogram and cardiovascular magnetic resonance (CMR)) characteristics to differentiate aetiologies of LV hypertrophy including clues for the diagnosis of Fabry.ResultsLV hypertrophy is a consequence of pressure overload mostly, but differential diagnosis includes hypertrophic cardiomyopathy and infiltrative diseases. Clinical data, ECG, type and degree of LV hypertrophy, functional and tissue characteristics differ among aetiologies. LV hypertrophy in Fabry is progressive and mostly concentric but may copy any hypertrophic cardiomyopathy. Dependent on residual alfa-galactosidase A enzyme activity, degree of LV hypertrophy in Fabry may vary. Initially, low myocardial CMR T1-map values are calculated. At a later stage, midwall late gadolinium enhancement of the inferolateral LV wall may occur. Global longitudinal strain may be depressed in the inferolateral wall. Voltage criteria for LV hypertrophy and short PQ interval are common. Right ventricular (RV) hypertrophy is frequent. In addition, multisystemic symptoms including neuropathic pain, hypohidrosis, proteinuria, renal insufficiency and familial young stroke are pointing to Fabry.ConclusionsLV hypertrophy should raise suspicion of Fabry disease, especially if LV hypertrophy is unexplained and/or associated with RV hypertrophy. In Fabry, LV hypertrophy may be heterogeneous and mimic any hypertrophic cardiomyopathy. ECG, multisystemic symptoms and imaging may provide clues for Fabry

Can psychiatric childhood disorders be due to inborn errors of metabolism?

Many patients who visit a centre for hereditary metabolic diseases remarkably also suffer from a child psychiatric disorder. Those child psychiatric disorders may be the first sign or manifestation of an underlying metabolic disorder. Lack of knowledge of metabolic disorders in child psychiatry may lead to diagnoses being missed. Patients therefore are also at risk for not accessing efficacious treatment and proper counselling. To search the literature for the co-occurrence of child psychiatric disorders, such as ADHD, autism, psychosis, learning disorders and eating disorders and metabolic disorders. A search of the literature was conducted by performing a broad search on PubMed, using the terms “ADHD and metabolic disorders”, “autism and metabolic disorders”, “psychosis and metabolic disorders”, “learning disorders and metabolic disorders”, and “eating disorders and metabolic disorders”. Based on inclusion criteria (concerning a clear psychiatric disorder and concerning a metabolic disorder) 4441 titles and 249 abstracts were screened and resulted in 71 relevant articles. This thorough literature search provides child and adolescent psychiatrists with an overview of metabolic disorders associated with child psychiatric symptoms, their main characteristics and recommendations for further investigations