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A semigroup S is said to be right pseudo-finite if the universal right congruence can be generated by a finite set
$U\subseteq S\times S$
, and there is a bound on the length of derivations for an arbitrary pair
$(s,t)\in S\times S$
as a consequence of those in U. This article explores the existence and nature of a minimal ideal in a right pseudo-finite semigroup. Continuing the theme started in an earlier work by Dandan et al., we show that in several natural classes of monoids, right pseudo-finiteness implies the existence of a completely simple minimal ideal. This is the case for orthodox monoids, completely regular monoids, and right reversible monoids, which include all commutative monoids. We also show that certain other conditions imply the existence of a minimal ideal, which need not be completely simple; notably, this is the case for semigroups in which one of the Green’s preorders
${\leq _{\mathcal {L}}}$
or
${\leq _{\mathcal {J}}}$
is left compatible with multiplication. Finally, we establish a number of examples of pseudo-finite monoids without a minimal ideal. We develop an explicit construction that yields such examples with additional desired properties, for instance, regularity or
${\mathcal {J}}$
-triviality.
We call a semigroup $S$weakly right noetherian if every right ideal of $S$ is finitely generated; equivalently, $S$ satisfies the ascending chain condition on right ideals. We provide an equivalent formulation of the property of being weakly right noetherian in terms of principal right ideals, and we also characterize weakly right noetherian monoids in terms of their acts. We investigate the behaviour of the property of being weakly right noetherian under quotients, subsemigroups and various semigroup-theoretic constructions. In particular, we find necessary and sufficient conditions for the direct product of two semigroups to be weakly right noetherian. We characterize weakly right noetherian regular semigroups in terms of their idempotents. We also find necessary and sufficient conditions for a strong semilattice of completely simple semigroups to be weakly right noetherian. Finally, we prove that a commutative semigroup $S$ with finitely many archimedean components is weakly (right) noetherian if and only if $S/\mathcal {H}$ is finitely generated.
McPherson, Smith-Lovin, and Cook’s (2001) Annual Review of Sociology piece “Birds of a Feather” (“Birds”, hereafter) focused on the phenomenon of homophily – the empirical reality that connections are more likely between similar others than dissimilar others.
Taking residual finiteness as a starting point, we consider three related finiteness properties: weak subsemigroup separability, strong subsemigroup separability and complete separability. We investigate whether each of these properties is inherited by Schützenberger groups. The main result of this paper states that for a finitely generated commutative semigroup S, these three separability conditions coincide and are equivalent to every
$\mathcal {H}$
-class of S being finite. We also provide examples to show that these properties in general differ for commutative semigroups and finitely generated semigroups. For a semigroup with finitely many
$\mathcal {H}$
-classes, we investigate whether it has one of these properties if and only if all its Schützenberger groups have the property.
The use of Spratt’s dog cakes is well documented in the diaries and reminiscences of many early Antarctic expedition members. Commercially produced dog food was promoted by the likes of Spratt’s as an advanced form of animal nutrition and would have been of interest to expedition planners who were already concerned with the nutritional requirements of expedition members. An approximately 100-year-old dog cake recovered from Antarctica was compared by chemical analysis and spectroscopic methods with a series of model dog cakes and a commercial dog biscuit to determine the composition and calorific content. The presence of bone fragments within the dog cake was confirmed, whereas starch in the bulk matrix of the sample was consistent with being a mixture of wheat and oat flour, while only minimal fat or oil was present. Calorific content, while insufficient compared to a modern feed for high-performance dogs, would nonetheless have been a valuable addition to the use of dried or frozen whole meat such as seal, fish, or pemmican and contributed additional energy compared to meat alone.
Food pantries provide free food to individuals at nutritional risk given lack of available foods. Frequent use of food pantries is associated with higher dietary quality; however, neither the nutrient contributions of food pantries to participant diets nor their relationship with household food security are known. This cross-sectional analysis used secondary data from rural food pantry participants, including sociodemographic characteristics, household food security and 24-h recalls. Mean intakes of selected food groups and nutrients from food pantries, supermarkets, other stores and restaurants, and other were compared by one-way ANCOVA. Interaction effects of household food security with food sources were evaluated by two-way ANCOVA. About 40 % of participants’ dietary intake came from food pantries. Mean intakes of fibre (P < 0·0001), Na (P < 0·0001), fruit (P < 0·0001), grains (P < 0·0001) and oils (P < 0·0001) were higher from food pantries compared with all other sources, as were Ca (P = 0·004), vitamin D (P < 0·0001) and K (P < 0·0001) from food pantries compared with two other sources. Percentage total energy intake (%TEI) from added sugars (P < 0·0001) and saturated fat (P < 0·0001) was higher from supermarkets than most other sources. Significant interaction effects were observed between food sources and household food security for vegetables (P = 0·01), Na (P = 0·01) and %TEI from saturated fat (P = 0·004), with food-insecure participants having significantly higher intakes from food pantries and/or supermarkets compared with all other sources. Future interventions may incorporate these findings by providing education on purchasing and preparing healthy meals on limited budgets, to complement foods received from pantries, and by reducing Na in pantry environments.
This paper presents the results of the work of the new field initiative launched by the British Museum at the Darband-i Rania pass in the Kurdistan Region of Iraq. The pass is located at the northeastern corner of Lake Dokan, where, though now subsumed into the lake, the Lower Zab flows from the Peshdar into the Rania Plain. It is a strategic location on a major route from Mesopotamia into Iran, and control of both the road and the river must always have been important. The aim of the work, which commenced in autumn of 2016, is to explore a cluster of sites that commanded the pass, with a particular focus on the first millennium b.c. Excavation is being carried out principally at two sites: Qalatga Darband, a large fortified site at the western end of the pass, and Usu Aska, a fort inside the pass itself. The occupations of these two sites are predominantly Parthian and Assyrian respectively. Smaller operations have also been carried out at Murad Rasu, a multi-period site situated on a headland across the waters on the southern shore of Lake Dokan. The results have included the discovery at Qalatga Darband of a monumental complex built of stone and roofed with terracotta roof tiles containing the smashed remains of Hellenistic statuary. Other features indicative of Hellenistic material culture are Mediterranean-type oil-presses and Corinthian column bases and capitals. At Usu Aska remains are being uncovered of an Assyrian fortification of massive proportions.
We review aspects of the recently released National Academies of Sciences, Engineering, and Medicine report A National Trauma Care System: Integrating Military and Civilian Trauma Systems to Achieve Zero Preventable Deaths After Injury most relevant to disaster health, particularly the concepts of focused empiricism and building a learning health system. The article references battlefield success utilizing these concepts and the emerging Disaster Research Response Program. We call upon disaster health researchers to apply the report’s recommendations to their work. (Disaster Med Public Health Preparedness. 2017;11:510–511)
An experiment compared 2 yr of mowing, mulching, spot treatment with glyphosate, or no maintenance for reed canarygrass control and measured their effect on the establishment of red alder and arroyo willow. At one site, pretransplant control of reed canarygrass was poor, and mulching or no maintenance gave 9 and 14% control, respectively, at 5 mo after planting (MAP), but glyphosate spot treatment and mowing resulted in 89% and 72% control, respectively. The highest leafiness percentage by 24 MAP for arroyo willow and red alder at that site occurred in spot-treated plots (59 and 6%, respectively). Tree protection resulted in 30% more arroyo willow saplings with leaves at 24 MAP, at an average height of 68 cm at 17 MAP. Over the 2-yr trial at that site, mowing required far more time (30.6 min/plot) than either mulching or spot spraying (18.6 and 13.5 min/plot, respectively). At a second site, pretransplant weed control was excellent and maintenance programs controlled reed canarygrass from 88 to 98% by 5 MAP. Tree leafiness of red alder was improved 20% at 24 MAP by tree protection, with protected trees being 107 cm tall compared with 64 cm when left bare. Over the 2-yr trial at that site, mulching required 14.8 min/plot, compared with 12.9 and 7.6 min/plot for mowing and spot treatment. Annual spot treatment of reed canarygrass regrowth with glyphosate may be the most cost-effective means of achieving successful reestablishment of native broadleaf trees in northwestern riparian systems.
Field experiments were conducted in 2003 and 2004 to evaluate the effects of reduced rates of glufosinate on development and yield of three nonglufosinate-resistant cotton varieties. The varieties evaluated were selected on their relative maturity with PayMaster (PM) 1218, early maturity; FiberMax (FM) 960, medium maturity; and Delta and Pine Land (DP) 555, late maturity. Rates of 47, 23, and 4.7 g ai/ha were applied, representing 10, 5, and 1% of the typical use rate per application of 467 g ai/ha, respectively. As might be expected, when averaged over varieties, the 10% rate showed more injury than the 5%, and the 5% rate caused more visual injury than the 1% rate. Pooled over timing and rate, PM1218 showed more injury (18%) than FM960 (7%), which showed more injury than DP555 (1%) 7 days after application (DAA) at the 10% rate. However, although PM1218 showed the most visual injury, this did not translate into delay in maturity or loss of lint yield. DP555 showed 70 kg ai/ha and 50 kg ai/ha lint yield loss when glufosinate was applied at the 10% rate on the fifth and eighth node stage, respectively. DP555 was delayed in maturity when glufosinate was applied at the 10% rate on the eighth node stage. FM960 showed 30 kg/ha lint yield loss when glufosinate was applied at the 10 and 5% rates at the fifth node stage. Maturity of FM960 was delayed with the 10 and 5% rates applied at the fifth node stage.
Field experiments were conducted at five locations in Kansas, Nebraska, and Wyoming to determine the effects of imazamox rate and application timing on winter annual grass control and crop response in imidazolinone-tolerant winter wheat. Imazamox at 35, 44, or 53 g ai/ha applied early-fall postemergence (EFP), late-fall postemergence, early-spring postemergence (ESP), or late-spring postemergence (LSP) controlled jointed goatgrass at least 95% in all experiments. Feral rye control with imazamox was 95 to 99%, regardless of rate or application timing at Hays, KS, in 2001. Feral rye control at Sidney, NE, and Torrington, WY, was highest (78 to 85%) with imazamox at 44 or 53 g/ha. At Sidney and Torrington, feral rye control was greatest when imazamox was applied EFP. Imazamox stunted wheat <10% in two experiments at Torrington, but EFP or LSP herbicide treatments in the Sidney experiment and ESP or LSP treatments in two Hays experiments caused moderate (12 to 34%) wheat injury. Wheat injury increased as imazamox rate increased. Wheat receiving imazamox LSP yielded less grain than wheat treated at other application timings in each Hays experiment and at Sidney in 2001. No yield differences occurred in one Torrington experiment. However, yields generally decreased as imazamox application timing was delayed in the other Torrington experiment. Generally, imazamox applied in the fall provided the greatest weed control, caused the least wheat injury, and maximized wheat yield.
Irrigated field experiments were conducted near Torrington, WY, during the 2001 to 2002 (year 1) and 2002 to 2003 (year 2) winter wheat growing seasons to evaluate cultivar response to different imazamox rates, adjuvants, and application timings. Five cultivars were treated postemergence in the early fall (EF), late fall (LF), or early spring (ES) with imazamox at 54 or 108 g ai/ha, including either nonionic surfactant (NIS) at 0.25% or methylated seed oil (MSO) at 1% (v/v) as adjuvants. A 28% urea ammonium nitrate solution at 1% (v/v) was included with all treatments. Spring injury was more severe in year 1 than year 2. Severe spring injury on ‘AP502 CL’, ‘Above’, ‘IMI-Fidel’, ‘IMI-Jagger’, and ‘IMI-Madsen’ was linked to fall application of 108 g/ha imazamox with MSO. Imazamox applied at 108 g/ha plus MSO applied in the fall consistently injured all cultivars more than the same rate with NIS and 54 g/ha imazamox regardless of adjuvant and timing, although severity of injury in the experiments differed between EF and LF timings in years 1 and 2, respectively. Correlation analysis supports injury reduced reproductive tillers per meter of row and wheat yields and increased the number of seeds per spike in year 1. The reduction of reproductive tillers per meter of row in year 1 was likely the result of severe injury caused by 108 g/ha imazamox applied in the EF coupled with little snow cover to protect against cold winter temperatures. Wheat yield in year 1 was reduced by 108 g/ha imazamox applied in the early fall; however, imazamox applied at 54 g/ha with either adjuvant in EF, LF, or ES were safe. Yield parameters and wheat yields in year 2 were not affected by imazamox rate, adjuvant, timing, or interactions of these factors.
Objectives: The aim of this study was to develop a decision support tool to assess the potential benefits and costs of new healthcare interventions.
Methods: The Canadian Partnership Against Cancer (CPAC) commissioned the development of a Cancer Risk Management Model (CRMM)—a computer microsimulation model that simulates individual lives one at a time, from birth to death, taking account of Canadian demographic and labor force characteristics, risk factor exposures, and health histories. Information from all the simulated lives is combined to produce aggregate measures of health outcomes for the population or for particular subpopulations.
Results: The CRMM can project the population health and economic impacts of cancer control programs in Canada and the impacts of major risk factors, cancer prevention, and screening programs and new cancer treatments on population health and costs to the healthcare system. It estimates both the direct costs of medical care, as well as lost earnings and impacts on tax revenues. The lung and colorectal modules are available through the CPAC Web site (www.cancerview.ca/cancerrriskmanagement) to registered users where structured scenarios can be explored for their projected impacts. Advanced users will be able to specify new scenarios or change existing modules by varying input parameters or by accessing open source code. Model development is now being extended to cervical and breast cancers.