We study Lorentzian spacetimes for which all scalar invariants constructed from the Riemann tensor and its covariant derivatives are constant (CSI spacetimes). We obtain a number of general results in arbitrary dimensions. We study and construct warped product CSI spacetimes and higher-dimensional Kundt CSI spacetimes. We show how these spacetimes can be constructed from locally homogeneous spa...

Customer relationship is increasingly influencing the performance of inventory management in a supply chain, and customer retention or migration directly affect the number of customer orders and demands as well as the inventory level. Therefore, the aim of this paper is to propose a customer satisfaction inventory (CSI) model that incorporates customer relationship management into an inventory ...

OBJECTIVES The Caregiver Strain Index (CSI) is a 13-item index originally developed in the early 1980s to screen for caregiver strain after hospital discharge of an elderly family member. This study examined the reliability of a modified CSI for applications with contemporary long-term family caregivers. METHODS As part of a larger family caregiver study using focus groups, telephone intervie...

Most works on amplify and forward (AF) relaying assume that the relay obtains perfect channel state information (CSI) of the source-relay channel. This renders variable-gain relaying (VGR) an attractive technique, as the relay can ideally invert the channel at its input and thus ensure constant output power. What happens to the output power, however, if the CSI at the input is outdated? As an a...

In this work, we consider the joint precoding across K transmitters (TXs), sharing the knowledge of the user’s data symbols to be transmitted towards K single-antenna receivers (RXs). We consider a distributed channel state information (DCSI) configuration where each TX has its own local estimate of the overall multiuser MIMO channel. The focus of this work is on the optimization of the allocat...

PURPOSE To compare the corticosteroid injection (CSI) with or without thumb spica cast (TSC) for de Quervain tendinitis. METHODS In this prospective trial, 67 eligible patients with de Quervain tenosynovitis were randomly assigned into CSI + TSC (33 cases) and CSI (34 cases) groups. All patients received 40 mg of methylprednisolone acetate with 1 cc lidocaine 2% in the first dorsal compartmen...

For wireless transmission, the assumption that the transmitter always obtains the channel state information (CSI) is unreasonable because of feedback delays, estimation error and quantization error. When the transmitter can’t receive the CSI perfectly, some prescribed quality of service (QoS) requirements may not be satisfied. The performance of the wireless systems will degrade. In order to av...

The metabolites, transporters, and enzymes involved in choline metabolism are regarded as biomarkers for disease progression in a variety of cancers, but their in vivo detection is not ideal. Both magnetic resonance spectroscopy [MRS using chemical shift imaging (CSI) total choline (tCho)] and C-choline positron emission tomography (PET) can probe this pathway, but they have not been compared s...

Recently, broadband analog network coding (ANC) has intensively been studied due to its potential to increase the network capacity by exploiting the broadcasting nature of the wireless channel. However, channel state information (CSI) knowledge is required for self-information removal and signal detection. A low-complexity pilot-assisted channel estimation (PACE) scheme has been presented for b...

Human land use and climate change are regarded as the main driving forces of present-day and future species extinction. They may potentially lead to a profound reorganisation of the composition and structure of natural communities throughout the world. However, studies that explicitly investigate both forms of impact--land use and climate change--are uncommon. Here, we quantify community change...