A Property of Recurring Series

If (U): U1, U2, ... , Un,.., denotes a sequence of rational numbers satisfying a linear difference equation of order k with rational coefficients, then if a group of k consecutive terms of (U) ever repeats itself, all the roots of the polynomial associated with the difference equation are roots of unity, and the sequence (U) is periodic. [1] I show here that the like occurs, generally speaking, if one term of the sequence repeats itself at regular intervals a sufficient number of times

A Determination of all Possible Systems of Strict Implication

It is known that the postulates chosen by C. I. Lewis for his "system of strict implication" are not categorical, since three distinct types of such a system have been shown to exist. I shall prove here that the three types already discovered are the only ones possible. The inclusion of an additional modal postulate. will therefore make the system categorical, and allow it to be exhibited as a four-valued truth-value system. The corresponding entscheidung problem may then be solved by the matrix method

Caspar David Friedrich, the Romantic Hero, and Early German Nationalism

Like many artists, Caspar David Friedrich was affected by the events of his time: the defeat of Prussia by the forces of Napoleon (1806), the following occupation of the German lands (1810), the struggles of the Wars of Liberation (1813-1814) and their disappointing aftermath. He was also greatly influenced by the literary trends of the time, especially the concept of the Romantic hero and the cult of the heroic soldier, ideas that he was exposed to among his circle of friends. The paintings that Friedrich created between 1808 and 1821 display the tensions of the era, emphasizing the feelings of upheaval and desolation experienced in northern Germany and making a statement in favor of a united Fatherland based upon common history and exceptional heroes in a more Romantic fashion than his contemporaries. This paper examines Friedrich’s use of the motif of the hero in his works between 1808 and 1821, including the development of his nationalist ideas and his eventual dismissal of them after the end of the war

Modelling the impacts of an invasive species across landscapes: a step-wise approach

We estimate the extent of ecological impacts of the invasive Asian paper wasp across different landscapes in New Zealand. We used: (i) a baseline distribution layer (modelled via MaxEnt); (ii) Asian paper wasp nest density (from >460 field plots, related to their preferences for specific land cover categories); and (iii) and their foraging intensity (rates of foraging success, and the time available to forage on a seasonal basis). Using geographic information systems this information is combined and modelled across different landscapes in New Zealand in a step-wise selection process. The highest densities of Asian paper wasps were in herbaceous saline vegetation, followed closely by built-up areas, and then scrub and shrubland. Nest densities of 34 per ha, and occupancy rates of 0.27 were recorded for herbaceous saline vegetation habitats. However, the extent of impacts of the Asian paper wasp remains relatively restricted because of narrow climate tolerances and spatial restriction of preferred habitats. A step-wise process based on geographic information systems and species distribution models, in combination with factors such as distribution, density, and predation, create a useful tool that allows the extent of impacts of invasive species to be assessed across large spatial scales. These models will be useful for conservation managers as they provide easy visual interpretation of results, and can help prioritise where direct conservation action or control of the invader are required

The effects of lubricant and tendon mass variances on the coefficient of friction in unbonded post-tensioning tendons

Abstract: In unbonded post-tensioning tendons, the coefficient of friction varies from one design standard to another. This variation is caused by the large number of complex factors that must be considered in design. These factors include the thickness of lubricant or grease present in the system, clearance between the strand and the plastic sheath, surface characteristics of the strand and plastic sheath. In order to determine the effect of these factors a series of friction tests were performed on two different diameters of strand, namely; 12.7mm and 15.24mm diameters. Through a regression analysis, it was found that the frictional force decreases with an increase in the thickness of the grease and that friction increases with an increase in the mass of the strand. The degree of friction was found to be dependent on the surface characteristics of the strand and plastic sheath, clearance between the plastic sheath and the strand and the extrusion process of the plastic sheath

CLIENTS AS TEACHERS: THE 7 QUALITIES MOST DESIRED IN A THERAPIST

Little previous research has directly asked clients to identify the qualities they most desire in a therapist. The current study took place over the summer of 2016 utilizing a questionnaire format that asked over 120 individuals receiving out-patient and residential clinical therapeutic services, to identify the top seven qualities they most desired in a therapist. Participants chose from a list of 33 client-generated adjectives derived from an original focus group of partial-hospitalization and intensive outpatient therapy clients. This study’s participants had the opportunity to also identify and add qualities that were not listed among the original 33 options provided. The study found that clients most valued qualities that can be developed through Mindfulness practices, shedding light on an under-emphasized, but potentially rich area of development in the conception of graduate psychology training curricula. The research outcomes identified domains that, from a client-centered perspective, enhance clients’ engagement in therapy, decrease and repair therapeutic ruptures, and advance the field’s understanding of how therapeutic interventions are most effectively delivered

Factors that influence friction in tendons of unbonded post-tensioning systems

The coefficient of friction in an unbonded post tensioning system is influenced by many factors, and these factors include the thickness of lubricant or grease present in the system, clearance between the strand and the plastic sheath, surface characteristics of the strand and plastic sheath. In order to determine the effect of these factors, a series of friction tests were performed on two different diameters of strand, namely; 12.7 mm and 15.24 mm diameters. Through a regression analysis, it was found that the frictional force decreases with increase in the thickness of the grease and that friction increases with increase in the mass of the strand. The amount of friction was found to be dependent on the surface characteristics of the strand and plastic sheath, clearance between the plastic sheath and the strand and the extrusion process of the plastic sheath