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For low-rank Frobenius-norm approximations of matrices with non-negative entries, it is shown that the Lagrange dual is computable by semi-definite programming. Under certain assumptions the duality gap is zero. Even when the duality gap is non-zero, several new insights are provided.
We show that approximating the Becker-Döring equations with a Langevin equation results in multiplicative noise, which in turn leads to a family of possible Fokker-Planck equations according to the Ito-Stratonovich dilemma. Using a simple and general model for the attachment and detachment rates, we find that the Ito choice approximates the nucleation rate best and also coincides with the Fokker-P
The ability to move safely between obstacles is critical for animals that fly rapidly through cluttered environments but surprisingly little is known about how they achieve this. Do they reactively avoid obstacles or do they instead fly towards the gaps between them? If they aim towards gaps, what information do they use to detect and fly through them? Here, we aim to answer these questions by pre
In this paper, an amplifier design using ballistic vertical InAs nanowire (NW) transistors is investigated, focusing on a basic common-source amplifier. The maximum power gain at 90 GHz is evaluated for different NW transistor architectures together with the power dissipation. The linearity of the amplifier is evaluated by estimating the IIP3 and 1-dB compression points. Furthermore, the impact of
This report presents a new, one-pot, facile, selective and green method for methoxycarbonylation of alcohols and synthesis of five- and six-membered cyclic carbonates from corresponding alcohols with dimethyl carbonate (DMC) in the presence of molecular sieves without any additional solvent and catalyst. Syntheses of bifunctional structures comprising a six-membered cyclic carbonate with allyl eth
Coordination of health care exists at many different levels and in many different forms. We describe the similarities and differences in coordination mechanisms among the Nordic countries. In some respects, the Nordic countries approach coordination problems in similar ways although differences exist. The overall pattern shows that Finland and Sweden have less country-wide coordination compared wi
Background: General practice systems in the Nordic countries share certain common features. The sector is based on the Nordic model of a tax-financed supply of services with a political objective of equal access for all. The countries also share the challenges of increased political expectations to deliver primary prevention and increased workload as patients from hospital care are discharged earl
The Nordic countries represent an institutional setting with tax-based health care financing and universal access to health care services. Very few health care services are excluded from what are offered within the publically financed health care system. User fees are often non-existing or low and capped. Nevertheless, the markets for voluntary private health insurance (VPHI) have been rapidly exp
Recurrent ear infection in children during pre-school years is an important public health problem. Common advice given to parents is to minimize exposure of susceptible children to crowding and air pollution. This study aimed at investigating what changes parents undertake to improve the health of an otitis-prone child. Parents of children with 5 events before age thirty months (index children; n
The proliferation of massive open online courses (MOOCs) has been a phenomenon in higher education but only recently the subject of academic literature. MOOCs combine the traditional ideas of cohort and guided learning with open access and a truly global classroom. With over twenty thousand learners attracted to such courses, we argue that they can be a powerful tool in advancing sustainability ed
Savanner är ett landskap med både träd och gräs som skapar en miljö som varken är skog eller gräsmark. Savanner tar upp cirka en sjättedel av världens totala landyta och de har på grund av detta en stor betydelse för den globala kolbalansen. De flesta savanner har två distinkta säsonger, en regnperiod då vegetationen grönskar samt en period med torka utan nederbörd. Detta gör att förändringar i deSavannahs are land areas where grass and trees co-exists to create a landscape that is neither a grassland nor a forest. It is estimated that savannahs cover approximately one sixth of the global land surface. They also play an important role in the global carbon cycle due to their total size. Most savannahs are characterized with two distinct seasons, one dry season and one wet season where a maj
The atrioventricular (AV) node plays an important role during atrial fibrillation (AF). In particular, the refractoriness of its cells influences the conduction of atrial impulses to the ventricles and, thus, the ventricular response. This study introduces a novel statistical model of the AV node, accounting for pathway switching, which can be used for non-invasive assessment of the refractory pro
