7,685 research outputs found
A deseeded Avena test method for small amounts of auxin and auxin precursors
In 1927 Went isolated the growth promoting hormone, auxin, from the tip of the Arena coleoptile, and worked out the now well known Arena test method for its quantitative determination. By the use of this method the chemistry and many phases of the physiological action of auxin have been studied. In physiological work, however, the amounts of hormone involved are frequently so small that quantitative or even qualitative work has often been very difficult or impossible. In this article is presented a supplementary procedure with deseeded Arena seedlings whereby smaller concentrations of the hormone not detectable by the standard method can be quantitatively determined. By the use of this method it has also been possible to demonstrate directly the existence of substances capable of being converted into auxin by the plant. Some data relative to the presence of a precursor of auxin in Arena and synthetic precursors of hereto-auxin are included
BLSS: A Contribution to Future Life Support
The problem of the supply of basic life supporting ingredients was analyzed. Storage volume and launch weight of water, oxygen and food in a conventional nonregenerable life support system are directly proportional to the crew size and the length of the mission. Because of spacecraft payload limitations this requires that the carbon, or food, recycling loop, the third and final part in the life support system, be closed to further reduce logistics cost. Advanced life support systems need to be developed in which metabolic waste products are regenerated and food is produced. Biological life support systems (BLSS) satisfy the space station environmental control functions and close the food cycle. Numerous scientific space experiments were delineated, the results of which are applicable to the support of BLSS concepts. Requirements and concepts are defined and the feasibility of BLSS for space application are analyzed. The BLSS energy mass relation, and the possibilities to influence it to achieve advantages for the BLSS are determined. A program for the development of BLSS is proposed
Progress in European CELSS activities
The European Controlled Ecological Life Support System (CELSS) activities started in the late 1970's with system analysis and feasibility studies of Biological Life Support Systems (BLSS). The initiation for CELSS came from the industry side in Europe, but since then planning and hardware feasibility analyses have been initiated also from customer/agency side. Despite this, it is still too early to state that a CELSS program as a concerted effort has been agreed upon in Europe. However, the general CELSS objectives were accepted as planning and possible development goals for the European effort for manned space activities, and as experimental planning topics in the life sciences community for the next decades. It is expected that ecological life support systems can be tested and implemented on a space station towards the end of this century or early in the next. For the European activities a possible scenario can be projected based on ongoing life support system development activities and the present life sciences goals
Teacher change and development during training in social and emotional learning programs in Sweden
The paper presents the results from a thematic analysis of the process diaries of teachers
involved in teacher training in social and emotional learning (SEL) in Sweden. Twentynine out of the 122 diaries available were analyzed until saturation was reached. The following themes and sub-themes were extracted: development (professional and
personal, and classroom climate), and concomitants of development (need for
collaboration and unease). The themes and sub-themes are related to theoretical aspects of specialised teacher education and to the debate in Sweden on how to proceed with SEL programs, and more generally with life skills programs. The results suggest that training generates both general teacher improvement and better implementation of SEL programs.peer-reviewe
Slow-light enhancement of Beer-Lambert-Bouguer absorption
We theoretically show how slow light in an optofluidic environment
facilitates enhanced light-matter interactions, by orders of magnitude. The
proposed concept provides strong opportunities for improving existing
miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption
measurements widely employed in analytical chemistry.Comment: 4 pages including 4 figures. Accepted for AP
Leveraging ASTM Industry Standard F3269-17 for Providing Safe Operations of a Highly Autonomous Aircraft
This paper expands upon the ASTM industry standard F3269-17 to outline a run-time assurance (RTA) network architecture for use in ensuring safe flight operations of a highly autonomous aircraft. An RTA network architecture is proposed and critical features discussed to implement functions where automation is primarily responsible for the safety of the aircraft instead of a pilot. This shift in responsibility, made possible by the proposed architecture, is key to highly resilient automation and is a core enabler for future pilotless transportation concepts. The findings in this paper stem from the researchers experiences with ASTM in the generation of the standard and some seven years of RTA system development on various flight programs leveraging the RTA concepts outlined in the ASTM standard
Neither worker nor housewife but citizen: BBC’s Woman’s Hour 1946–1955
This article investigates BBC radio’s Woman’s Hour in the post-war period. It explores Woman’s Hour’s focus and insistence on educating women listeners about their role as citizens, and the tensions this caused particularly between broadcasters and different groups of women. The article documents the programme’s development of public and outward looking items, such as the reporting and covering of current affairs, public debates and national politics, women’s party political conferences, and further introducing women MP’s to the microphone. This gave the programme a public and arguably political dimension. The article thus places Woman’s Hour within the broader historiography of the women’s movement in this period, and illuminates the changing role and expectation of women, particularly the middle-class housewife
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