Polyhedra with few 3-cuts are hamiltonian

In 1956, Tutte showed that every planar 4-connected graph is hamiltonian. In this article, we will generalize this result and prove that polyhedra with at most three 3-cuts are hamiltonian. In 2002 Jackson and Yu have shown this result for the subclass of triangulations. We also prove that polyhedra with at most four 3-cuts have a hamiltonian path. It is well known that for each $k \ge 6$ non-hamiltonian polyhedra with $k$ 3-cuts exist. We give computational results on lower bounds on the order of a possible non-hamiltonian polyhedron for the remaining open cases of polyhedra with four or five 3-cuts.Comment: 21 pages; changed titl

On almost hypohamiltonian graphs

A graph $G$ is almost hypohamiltonian (a.h.) if $G$ is non-hamiltonian, there exists a vertex $w$ in $G$ such that $G - w$ is non-hamiltonian, and $G - v$ is hamiltonian for every vertex $v \ne w$ in $G$. The second author asked in [J. Graph Theory 79 (2015) 63--81] for all orders for which a.h. graphs exist. Here we solve this problem. To this end, we present a specialised algorithm which generates complete sets of a.h. graphs for various orders. Furthermore, we show that the smallest cubic a.h. graphs have order 26. We provide a lower bound for the order of the smallest planar a.h. graph and improve the upper bound for the order of the smallest planar a.h. graph containing a cubic vertex. We also determine the smallest planar a.h. graphs of girth 5, both in the general and cubic case. Finally, we extend a result of Steffen on snarks and improve two bounds on longest paths and longest cycles in polyhedral graphs due to Jooyandeh, McKay, {\"O}sterg{\aa}rd, Pettersson, and the second author.Comment: 18 pages. arXiv admin note: text overlap with arXiv:1602.0717

Assessing the potential for food-based strategies to reduce Vitamin A and iron deficiencies

This paper reviews current knowledge and experience with food-based approaches to reduce vitamin A and iron deficiencies. It presents a review of recently published literature, highlights some of the lessons learned, and identifies knowledge gaps and research priorities. Plant breeding strategies are also discussed because of their potential to increase the content of vitamin A and iron in the diet as well as their bioavailability. populations. The same question as that posed in previous reviews decades ago remains at the end of the present review: what really can be achieved with food-based interventions to control vitamin A and iron deficiency? Food based approaches could be an essential part of the long-termglobal strategy to alleviate micronutrient deficiencies but their real potential is still to be explored.Minerals in human nutrition. ,Nutrition. ,Plant breeding. ,

How Cool is C.O.O.L.?

This paper develops a partial equilibrium model of a small open-economy producing and trading an unsafe product that is supplied by perfectly competitive producers. The presence of product safety considerations, in this case risks to health, introduces a wedge between the market prices producers receive and the higher risk-adjusted prices consumers respond to. The size of the wedge depends positively on the per-unit cost of illness and the proportion of unsafe units embodied in the parent risky product. The model is used to analyze the welfare effects of trade with and without a country-of-origin labeling (COOL) program. Assuming imports are less safe than domestic production, the welfare gains from trade in the absence of COOL are ambiguous and may justify the imposition of a trade ban. Even if a full ban does not improve welfare, some restriction of trade is always welfare-enhancing. These outcomes derive from an informational distortion that prevents consumers from distinguishing the different country-specific risks embodied in the foreign and domestic products resulting in a pooling equilibrium. The presence of a COOL program removes the informational distortion and generates a welfare maximizing separating equilibrium in which the safer (domestic) product commands a higher market price. In the presence of a COOL program, more trade caused by a reduction in protection is better than less trade.country-of-origin labeling, protection, product safety, welfare, Food Consumption/Nutrition/Food Safety, International Relations/Trade, F10, F13, L15,

On-line analysis capabilities developed to support the AFW wind-tunnel tests

A variety of on-line analysis tools were developed to support two active flexible wing (AFW) wind-tunnel tests. These tools were developed to verify control law execution, to satisfy analysis requirements of the control law designers, to provide measures of system stability in a real-time environment, and to provide project managers with a quantitative measure of controller performance. Descriptions and purposes of the developed capabilities are presented along with examples. Procedures for saving and transferring data for near real-time analysis, and descriptions of the corresponding data interface programs are also presented. The on-line analysis tools worked well before, during, and after the wind tunnel test and proved to be a vital and important part of the entire test effort

Multiple-function multi-input/multi-output digital control and on-line analysis

The design and capabilities of two digital controller systems for aeroelastic wind-tunnel models are described. The first allowed control of flutter while performing roll maneuvers with wing load control as well as coordinating the acquisition, storage, and transfer of data for on-line analysis. This system, which employs several digital signal multi-processor (DSP) boards programmed in high-level software languages, is housed in a SUN Workstation environment. A second DCS provides a measure of wind-tunnel safety by functioning as a trip system during testing in the case of high model dynamic response or in case the first DCS fails. The second DCS uses National Instruments LabVIEW Software and Hardware within a Macintosh environment

Survey of two-dimensional acute triangulations

AbstractWe give a brief introduction to the topic of two-dimensional acute triangulations, mention results on related areas, survey existing achievements–with emphasis on recent activity–and list related open problems, both concrete and conceptual

Survey of Social Work Educators: Qualifications and Compliance Criteria

In its Criteria for Accreditation (1987), the College Commission of the Southern Association of Colleges and Schools (SACS) implemented faculty qualifications standards that were strictly defined. Compliance with these standards in undergraduate and graduate schools of social work was the focus of this study. Data were gathered on 137 social work programs and include faculty qualifications information on 874 social work educators teaching in private and public institutions of higher education in the southern region. The findings indicate that baccalaureate programs in social work were more likely to be in compliance with SACS criteria than graduate schools. Strict compliance rates across all programs was low