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The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
Additive manufacturing (AM) has made long strides in the recent past and rapidly evolved into a promising alternative in specific applications. The aircraft industry is not an exception to this. The true just-intime production possibility is critical for the aircraft maintenance industries, though the lack of material freedom is a major hurdle. Several fire-retardant materials were investigated for AM in the aerospace context, but mainly for fused deposition modeling (FDM). The material consolidation constraints in FDM led to the expansion to the use of selective laser sintering (SLS) to some extent. Nevertheless, the material options are still limited, proprietary, and lack scientific insights into the material consolidation mechanics. Attempts are made in this paper to fill this gap, evaluating a new fire-retardant material for processing by SLS. Experiments conducted to ascertain the material, process, structure, and consolidation relationships indicated energy density levels 0.062–0.070 J/mm2 with laser power 13 W and scan speed varied slightly around 390 mm/s to give the best laser sintering and mechanical property results in polyetherimide powders.
This chapter summarizes the findings of 32 years of research from all of our longitudinal studies to date, conducted in 36 school districts in 16 U.S. states, more than 7.5 million student records analyzed, following English learners (of all language backgrounds) as far as Grades K–12. These studies are very generalizable to all regions and contexts of the United States and have been replicated in other countries, answering questions regarding program effectiveness for policymakers in education. We have shown that English-only and transitional bilingual programs of short duration only close about half of the achievement gap between English learners and native English speakers, while high-quality, long-term bilingual programs close all of the gap after 5–6 years of schooling through the students’ first and second languages (L1 and L2). In addition, our studies answer the linguistic question of how long it takes student groups to reach grade-level achievement in their L2, and we have developed and refined our theoretical Prism model by collecting and analyzing program effectiveness data, basing the Prism model on our empirical findings.
In this paper, we report on a multifunctional battery assembly, which possesses a
balanced combination of energy storage capability and resistance to electrical
failure under mechanical impact loading. The Granular Battery Assembly (GBA)
presented here exhibits a mechanical response that emerges from features of
granular and cellular media. We demonstrate that for the specific GBA embodiment
considered in the present study, the electrical reliability following a
mechanical loading event is substantively increased compared to that of plain
battery cells. The increased reliability is due to the sacrificial material
elements interspersed between the battery units, attributing energy absorption
and local stress limiting.
There are few areas in medicine which have changed as much in the past ten to 20 years as the management of the severely traumatised patient, driven for the most part by the complexity and severity of the trauma in recent military conflicts. Few patients offer a greater challenge than the critically injured patient. The acuity and uncertainty of the extent of the injuries require the anaesthetist to be both vigilant and methodical as the case progresses. Rapid changes in the patient’s condition occur commonly and constant communication between anaesthetist, surgeon and the rest of the team is vital. The anaesthetist should take an active lead in the operating theatre, in combination with the senior surgeon present, as he/she has the greatest situational awareness and needs to be aware of the resources at his/her disposal. Therefore, the traditional metaphorical ‘blood brain barrier’ or physical drape that still exists between the surgeon and anaesthetist in some elective surgery has been replaced by constant communication, supporting an integrated damage-control philosophy. There are three central tenets to the damage-control philosophy: permissive hypotension, damage-control or haemostatic resuscitation, and damage-control surgery.
The damage-control philosophy was initially conceived as a surgical approach to the multiply injured patient when it was realised that such patients lacked the physiological reserve to survive complex reconstructive surgery and restoration of anatomy. Damage-control surgery is confined to that surgery which is necessary to control haemorrhage and limit contamination. Temporary cavity closure further abbreviates the surgery and the patient is then normalised physiologically in the intensive care unit before definitive anatomical repair 24 to 72 hours later. However, such an approach to a severely traumatised patient cannot be used in isolation. Haemostatic resuscitation and permissive hypotension also contribute to the philosophy of damage control in an effort to limit the development of the ‘lethal triad’. An institutional massive transfusion protocol for trauma is also required.
The effects of wet (canned) or dry (kibbled) diets on faecal bacterial populations in the cat were investigated in eight domestic short-haired cats (four males and four females; averaging 6 years of age and 3·4 kg) in a nested design. The cats were fed ad libitum a commercially available wet diet (moisture 82·0 %, crude protein 51·7 %, fat 28·9 %, carbohydrate (CHO) 8·9 % and ash 10·6 % DM) for 5 weeks. On the fifth week, individual feed intakes and faecal outputs were determined. Fresh faecal samples were collected twice daily, mixed for homogeneity, subsampled and stored at − 85°C until analysis. The cats were then switched to a commercially available dry diet (moisture 8·5 %, crude protein 33·0 %, fat 11·0 %, CHO 49·4 % and ash 6·6 % DM) for 5 weeks, and fresh faeces were sampled as described previously. Energy intake tended to be higher in cats fed dry diets (P < 0·10), but body weight was similar between the two feeding periods (P>0·05). Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes amplified from DNA extracted from faeces was performed. The unweighted pair group method with arithmetic mean cluster analysis of bacterial community profiles using Pearson's correlation revealed diet-specific clustering when the same cats were fed on either a dry or a wet diet (dissimilarity between the groups, 88·6 %; P < 0·001). Subsequent cloning and sequencing of five selected distinct DGGE bands indicated that members of the Pelomonas and Fusobacteriaceae were influenced by a short-term change in diet format. This suggests that 5-week dietary exposure is sufficient to alter gastrointestinal microflora.
The terrorist attacks in the USA on 11 September 2001 affected suicide rates in two European countries, whereas overall US rates remained stable. The effect on attack site rates, however, has not been studied.
To examine post-attack suicide rates in areas surrounding the three airline crash sites.
Daily mortality rates were modelled using time series techniques. Where rate change was significant, both duration and geographic scope were analysed.
Around the World Trade Center, post-attack 180-day rates dropped significantly (t = 2.4, P = 0.0046), whereas comparison condition rates remained stable. No change was observed for Pentagon or Flight 93 crash sites.
The differential effect by site suggests that proximity may be less important that other event characteristics. Both temporal and geographic aspects of rate fluctuation after sentinel events appear measurable and further analyses may contribute valuable knowledge about how sociological forces affect these rates.
Development during approximately 200 years of agricultural activity in Alaska has been varied and generally inadequate. Four stages are here identified. During the period from Russian and early American colonization to the late 1880s production was largely for personal consumption. From 1898 to World War II federal intervention stimulated local commercial agriculture, and from the late 1940s to the late 1960s commercial production expanded. Since then a state- supported strategy to develop an export-based agriculture has been tried, but implementation has not been completed. Alaska remains a frontier which has yet to find a workable manner in which to implement a strategy for its agriculture.
Field studies were established at two Missouri locations in 2004 and 2005 to evaluate the effects of fall and early spring herbicide applications on soil temperature, soil moisture content, and insect injury in no-till corn production systems. Both experiments received applications of simazine plus 2,4-D, rimsulfuron plus thifensulfuron plus 2,4-D, and glyphosate plus 2,4-D in the fall, 45 d prior to planting (45 d EPP), 30 d prior to planting (30 d EPP), and 7 d prior to planting (7 d EPP). During a period from April 1 to April 14, simazine plus 2,4-D applied 45 d EPP resulted in higher soil temperatures at a 5-cm depth compared to the untreated control. However, there were few differences in soil temperature present from April 15 to May 1. Soil moisture readings taken during this same time period correlated with soil temperature readings. Measurements of soil moisture taken at 1 and 3 wk after planting (WAP) revealed significantly lower soil moisture readings in the untreated compared to herbicide treated plots. This lower soil moisture content allowed untreated plots to warm up more rapidly and thereby eliminated any negative impacts that dense stands of winter annual weeds may have had on soil temperature. Evaluations of corn flea beetle and lepidopteron injury taken at the V2, V4, and V6 corn leaf stages revealed significant differences in injury as a result of these treatments. When dense stands of winter and summer annual weeds were left uncontrolled, corn flea beetle injury was significantly lower than in plots treated with a herbicide. However, when a post herbicide application was made to remove all weed species prior to the V6 sampling date, differences in corn flea beetle injury between the untreated and herbicide treated plots were eliminated. Additionally, removal of all weed species led to higher lepidopteron injury in the untreated.