It is known that the calcium-dependent transcription factor NFAT initiates transcription in response to pulsatile loads of calcium signal. However, the relative contributions of calcium oscillation frequency, amplitude, and duty cycle to transcriptional activity remain unclear. Here, we engineer HeLa cells to permit optogenetic control of intracellular calcium concentration using programmable L...

BACKGROUND AND OBJECTIVES In July 2010, the Accreditation Council for Graduate Medical Education (ACGME) published its proposed duty-hour regulations. We conducted a national online survey to assess current family medicine residents' perceptions of the proposed changes. METHODS A 27-question survey was used to assess four ACGME proposal domains: resident supervision, 80-duty-hour week, maximu...

BACKGROUND AIDS, SARS, and the recent epidemics of the avian-flu have all served to remind us the debate over the limits of the moral duty to care. It is important to first consider the question of whether or not the "duty to treat" might be subject to contextual constraints. The purpose of this study was to investigate the opinions and beliefs held by both physicians and dentists regarding the...

John Harris has previously proposed that there is a moral duty to participate in scientific research. This concept has recently been challenged by Iain Brassington, who asserts that the principles cited by Harris in support of the duty to research fail to establish its existence. In this paper we address these criticisms and provide new arguments for the existence of a moral obligation to resea...

Separation of Duty is a principle that has a long history in computer security research. Many computing systems provide rudimentary support for this principle, but often the support is inconsistent with the way the principle is applied in non-computing environments. Furthermore, there appears to be no single accepted meaning of the term. We examine the ways in which Separation of Duty has been ...

BACKGROUND Little is known regarding duty-related risks for sudden cardiac death (SCD) among young firefighters. AIMS To investigate duty-related SCD among US firefighters aged 45 or younger. METHODS We collected data on duty-related SCD from the US Fire Administration (USFA) and the US National Institute for Occupational Safety and Health (NIOSH). Two physicians independently reviewed each...

Low delay and long lifetime are a very important issue for industrial wireless sensor networks (IWSNs) in which it require long-time monitoring of industrial sites and respond quickly to events that is monitored; therefore, high delay communications can cause serious damage to property and personnel at industrial field. Due to delay, lifetime, and other performance involved to multiple layers, ...

This paper investigates the problem of providing network coverage using wireless sensors that operate on low duty cycles (measured by the percentage time a sensor is on or active), i.e., each sensor alternates between active and sleep states to conserve energy with an average sleep period (much) longer than the active period. The dynamic change in topology as a result of such duty-cycling has p...

In this paper, ultra-wideband (UWB) multiple access systems are introduced by using direct-sequence (DS) and hybrid directsequence time-hopping (DS/TH) code division multiple access (CDMA) that use arbitrary chip-duty of the spreading sequences. The bit error probabilities are presented. First of all, the variances of the multiple access interference are developed by investigating the collision...