Reducing lead time risk through multiple sourcing: the case of stochastic demand and variable lead time

This paper studies a buyer sourcing a product from multiple suppliers under stochastic demand. The buyer uses a (Q, s) continuous review, reorder point, order quantity inventory control system to determine the size and timing of orders. Lead time is assumed to be deterministic and to vary linearly with the lot size, wherefore lead time and the associated stockout risk may be influenced by varying the lot size and the number of contracted suppliers. This paper presents mathematical models for a multiple supplier single buyer integrated inventory problem with stochastic demand and variable lead time and studies the impact of the delivery structure on the risk of incurring a stockout during lead time

Rare truncating variants in the sarcomeric protein titin associate with familial and early-onset atrial fibrillation

Common genetic variants in structural proteins contribute to risk of atrial fibrillation (AF). Here, using whole-exome sequencing, the authors identify rare truncating variants in TTN that associate with familial and early-onset AF and show defects in cardiac sarcomere assembly in ttn.2-mutant zebrafish

A polymorphism associated with increased levels of YKL-40 and the risk of early onset of lone atrial fibrillation

<p>Abstract</p> <p>Background</p> <p>Plasma levels of YKL-40 are elevated in patients with atrial fibrillation (AF). We hypothesized that a single nucleotide polymorphism (SNP) that affects YKL-40 plasma levels is associated to the risk of lone AF.</p> <p>Findings</p> <p>We included 178 young patients with lone AF and the first episode before the age of 40 years, and a control group of 875 healthy individuals. We analyzed a promoter SNP (−131CG) (rs4950928) in the Chitinase 3–like 1 (<it>CHI3L1</it>) gene encoding YKL-40, which had previously been associated with elevated levels of YKL-40.</p> <p>Conclusions</p> <p>The (−131CG) genotype was not associated with increased risk of AF. Genetically increased YKL-40 levels were not associated to AF.</p