Effective Lifeguard Scanning: A Review

The purpose of this scientific review was to address the question of what evidence-based visual surveillance/scanning skills exist in the peer-reviewed scholarly literature. It is well known that lifeguards spend a majority of their on-duty time surveying bathers and swimmers in the water. Lifeguards need to quickly distinguish among swimmers in distress and drowning persons from other bathers in order to rapidly come to their aid to prevent drowning. To be able to accomplish this task, Signal Detection Theory reveals that lifeguards need specific and extensive training in identifying the behavioral patterns associated with drowning persons and swimmers in distress. A typical drowning is not what has been popularized in the press and movies that shows a person calling for help and waving his or her arms about. Instead, drowning victims usually demonstrate the instinctive drowning response in which they are in a vertical position in the water, unable to call out because the mouth is underwater and arm and leg movements are ineffective in keeping them near the water’s surface. The literature revealed that expert lifeguard observation, scanning, and surveillance skills need to be acquired through planned systematic practice to identify the presence of the instinctive drowning response among bathers

Assyrian Entropy: City Sieges and Cosmic Dissolution in the Palace Relief Programs

During its heyday in the eight and seventh centuries BCE, the Neo-Assyrian Empire was so militarily powerful that few armies could stand against it in open combat. The annual campaigns of the Assyrian monarchs were thus largely occupied with city sieges, memorialized both in royal inscriptions and in the sculptural relief programs that decorated their royal palaces. Imagery of systematic urban destruction was triumphantly presented over and over again in these reliefs, in portrayals no less graphic than the depictions of death and torture which have long made these sculptural narratives notorious. These images testify to the unprecedented violence and technical expertise which the Assyrians brought to sieges: city walls (an important symbol of political independence in the ancient Near East) are seen dismantled, brick by brick, by complex war engines or digging soldiers, and collapsing masonry and falling enemy combatants echo each other’s demise. The walls of the royal palaces were covered by these vivid portrayals of the violent dissolution of city life, a striking fact when considering that these palaces were often situated within capital cities newly built or renovated by the kings themselves. This dissertation explores how the Assyrian state couched this destructive enterprise within the broader concepts of entropy and dissolution inherent in Mesopotamian cosmology. In Assyrian royal inscriptions the actions of king and army are compared to the violence of natural disaster, or equated with the dissolving power of time itself by turning enemy cities into deserted ruins. Within the reliefs, siege depictions consistently focus upon the entropic touch of soldiers’ weapons and siege engines as they dismantled enemy settlements into constituent parts. And within the architectural environs of at least one royal citadel, Sargon II’s palace at Dur Šarruken, siege images were deployed to structure visitors’ experience of physical space, placed at transitional points between rooms and emphasizing choices in directional movement. Ultimately all of these rhetorical approaches, I argue, attempted to place the Assyrian Empire in violent harmony with the forces of dissolution naturally at play in the cosmos, and to shield its own works from their effects

A Nonce-Based Protocol For Multiple Authentications

The Kerberos authentication service, a part of MIT's Project Athena, is based on the Needham and Schroeder protocol. Timestamps depending on reliable synchronized clocks are used to guarantee the freshness of messages. As an improvement, we present a nonce-based protocol offering the same features as Kerberos. We generate a ticket in an initial message exchange which includes a generalized timestamp. Checking this generalized timestamp is left to the principal who created it. Consequently we do not need synchronized clocks. Our protocol has the property of using a minimal number of messages to establish an authenticated session key. 1 Introduction In computer networks and distributed computing systems a mechanism is needed to provide secure communication. To trust the identity of each other, two principals must run a procedure resulting in mutual authentication. Key distribution protocols establish secret authenticated session keys using conventional cryptography, also called symmetri..