2-D Elastodynamic Scattering from a Finite Closed Crack

In the present paper the problem of 2-D elastodynamic scattering of horizontally polarized transverse waves from a finite planar or nonplanar closed crack is studied. The boundary conditions on the flaw are of a type which incorporate restoring forces (as well as energy dissipation), and this enables the modelling of a crack which is partly closed under a static background pressure. Given an incident plane wave and the crack geometry we calculate the backscattered far field in the time-harmonic case. In this study there are also a numerical comparison between two well known theoretical methods for 2-D scattering of ultrasonic sound by flaws in elastic solids. The methods are the GTD (Geometrical Theory of Diffraction) method that gives an asymptotic solution for high frequencies and the nullfield approach that yields an “exact” numerical solution. The boundary conditions for the partly closed crack are proposed by Boström and Wickham [1]. For a thorough description of the details of the GTD method as applied to scattering problems in elastodynamics, the reader is referred to the book by Achenbach, Gautesen, and McMaken [2]. The nullfield approach has previously been used for treating 3-D planar and nonplanar cracks with similar boundary conditions [3], the same ideas will here be used in the treatment of the 2-D case. The backscattered far field amplitude is numerically calculated and compared between the two methods

A comparative framework: how broadly applicable is a 'rigorous' critical junctures framework?

The paper tests Hogan and Doyle's (2007, 2008) framework for examining critical junctures. This framework sought to incorporate the concept of ideational change in understanding critical junctures. Until its development, frameworks utilized in identifying critical junctures were subjective, seeking only to identify crisis, and subsequent policy changes, arguing that one invariably led to the other, as both occurred around the same time. Hogan and Doyle (2007, 2008) hypothesized ideational change as an intermediating variable in their framework, determining if, and when, a crisis leads to radical policy change. Here we test this framework on cases similar to, but different from, those employed in developing the exemplar. This will enable us determine whether the framework's relegation of ideational change to a condition of crisis holds, or, if ideational change has more importance than is ascribed to it by this framework. This will also enable us determined if the framework itself is robust, and fit for the purposes it was designed to perform — identifying the nature of policy change

Male gynecomastia and risk for malignant tumours – a cohort study

BACKGROUND: Men with gynecomastia may suffer from absolute or relative estrogen excess and their risk of different malignancies may be increased. We tested whether men with gynecomastia were at greater risk of developing cancer. METHODS: A cohort was formed of all the men having a histopathological diagnosis of gynecomastia at the Department of Pathology, University of Lund, following an operation for either uni- or bilateral breast enlargement between 1970–1979. All possible causes of gynecomastia were accepted, such as endogenous or exogenous hormonal exposure as well as cases of unknown etiology. Prior to diagnosis of gynecomastia eight men had a diagnosis of prostate carcinoma, two men a diagnosis of unilateral breast cancer and one had Hodgkin's disease. These patients were included in the analyses. The final cohort of 446 men was matched to the Swedish Cancer Registry, Death Registry and General Population Registry. RESULTS: At the end of the follow up in December 1999, the cohort constituted 8375.2 person years of follow-up time. A total of 68 malignancies versus 66.07 expected were observed; SIR = 1.03 (95% CI 0.80–1.30). A significantly increased risk for testicular cancer; SIR = 5.82 (95% CI 1.20–17.00) and squamous cell carcinoma of the skin; SIR = 3.21 (95% CI 1.71–5.48) were noted. The increased risk appeared after 2 years of follow-up. A non-significantly increased risk for esophageal cancer was also seen while no new cases of male breast cancer were observed. However, in the prospective cohort, diagnostic operations for gynecomastia may substantially have reduced this risk CONCLUSIONS: There is a significant increased risk of testicular cancer and squamous cell carcinoma of the skin in men who have been operated on for gynecomastia

Sex Differences in Sand Lizard Telomere Inheritance: Paternal Epigenetic Effects Increases Telomere Heritability and Offspring Survival

To date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve.Here, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g. males vs. females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations.TL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival

Loss of circadian rhythm of blood pressure following acute stroke

BACKGROUND: Epidemiology of acute stroke in developing countries differs from that in the developed world, for example, the age at stroke, risk factors, subtypes of stroke and prognosis. Hypertension remains a dominant risk factor and prognostic indicator in patients with stroke in all communities. The risk of stroke is directly related to elevations of blood pressure. A number of clinical studies have shown that the control of hypertension leads to a reduction in the incidence of stroke in a community. However there is still considerable controversy surrounds the changes in blood pressure in various subtypes of strokes and problem of management of elevated BP after stroke. We studied the circadian rhythm of blood pressure in patients following acute stroke. METHODS: To study the circadian rhythm of blood pressure, fifty consecutive patients with an acute stroke who were admitted to medical emergency within 120 hours of onset were included in the study. After a detailed history and clinical examination, a continuous blood pressure monitor (Spacelab 90207) was attached on the side ipsilateral to intracranial lesion (unaffected arm). The blood pressure was recorded for 24 hours at 15 minutes interval during daytime (6.00 am–6.00 pm) and 20 minutes interval overnight (6 pm to 6 am). RESULTS: Risk factors for stroke in 50 patients included hypertension in 31(62%), diabetes mellitus in 4 (8%), smoking in 13 (26%) and previous history of transient ischemic attack in 7 (14%) patients. Mean systolic pressure and diastolic pressure at admission were higher in patients with hemorrhagic stroke -29 patients (177 ± 24 mmHg and 105 ± 19 mmHg respectively) compared to patients with ischemic strokes-21 patients (150 ± 36 mm Hg and 89 ± 18 mm Hg respectively, p value <0.01 in both comparisons). The normal diurnal variation in blood pressure (night time dipping of more than 10%) was abolished in 44 (88%) of patients. Out of 44 nondippers, 29 patients showed reverse dipping i.e. rise of BP during night time compared to day time levels. None of the risk factors, clinical or laboratory variables, type of stroke or blood pressure changes differed significantly between these two groups. CONCLUSIONS: Therefore, we showed a pathologically reduced or abolished circadian BP variation after stroke. Absence of normal dipping results in a higher 24 hour blood pressure load and may have more target organ damage than those with normal diurnal variation of blood pressure

Assessment of low-dose cisplatin as a model of nausea and emesis in beagle dogs, potential for repeated administration

Cisplatin is a highly emetogenic cancer chemotherapy agent, which is often used to induce nausea and emesis in animal models. The cytotoxic properties of cisplatin also cause adverse events that negatively impact on animal welfare preventing repeated administration of cisplatin. In this study, we assessed whether a low (subclinical) dose of cisplatin could be utilized as a model of nausea and emesis in the dog while decreasing the severity of adverse events to allow repeated administration. The emetic, nausea-like behavior and potential biomarker response to both the clinical dose (70 mg/m2) and low dose (15 mg/m2) of cisplatin was assessed. Plasma creatinine concentrations and granulocyte counts were used to assess adverse effects on the kidneys and bone marrow, respectively. Nausea-like behavior and emesis was induced by both doses of cisplatin, but the latency to onset was greater in the low-dose group. No significant change in plasma creatinine was detected for either dose groups. Granulocytes were significantly reduced compared with baseline (P = 0.000) following the clinical, but not the low-dose cisplatin group. Tolerability of repeated administration was assessed with 4 administrations of an 18 mg/m2 dose cisplatin. Plasma creatinine did not change significantly. Cumulative effects on the granulocytes occurred, they were significantly decreased (P = 0.03) from baseline at 3 weeks following cisplatin for the 4th administration only. Our results suggest that subclinical doses (15 and 18 mg/m2) of cisplatin induce nausea-like behavior and emesis but have reduced adverse effects compared with the clinical dose allowing for repeated administration in crossover studies

The integrated care pathway reduced the number of hospital days by half: a prospective comparative study of patients with acute hip fracture

BACKGROUND: The incidence of hip fracture is expected to increase during the coming years, demanding greater resources and improved effectiveness on this group of patients. The aim of the present study was to evaluate the effectiveness of an integrated care pathway (ICP) in patients with an acute fracture of the hip. METHODS: A nonrandomized prospective study comparing a consecutive series of patients treated by the conventional pathway to a newer intervention. 112 independently living patients aged 65 years or older admitted to the hospital with a hip fracture were consecutively selected. Exclusion criteria were pathological fracture and severe cognitive impairment. An ICP was developed with the intention of creating a care path with rapid pre-operative attention, increased continuity and an accelerated training programme based on the individual patient's prerequisites and was used as a guidance for each patient's tailored care in the intervention group (N = 56) The main outcome measure was the length of hospital stay. Secondary outcomes were the amount of time from the emergency room to the ward, to surgery and to first ambulation, as well as in-hospital complications and 30-day readmission rate. RESULTS: The intervention group had a significantly shorter length of hospital stay (12.2 vs. 26.3 days; p < 0.000), a shorter time to first ambulation (41 vs. 49 h; p = 0.01), fewer pressure wounds (8 vs. 19; p = 0.02) and medical complications (5 vs. 14; p = 0.003) than the comparison group. No readmissions occurred within 30 days post-intervention in either group. CONCLUSION: Implementing an ICP for patients with a hip fracture was found to significantly reduce the length of hospital stay and improve the quality of care

Geographical variation in radiological services: a nationwide survey

BACKGROUND: Geographical variation in health care services challenges the basic principle of fair allocation of health care resources. This study aimed to investigate geographical variation in the use of X-ray, CT, MRI and Ultrasound examinations in Norway, the contribution from public and private institutions, and the impact of accessibility and socioeconomic factors on variation in examination rates. METHODS: A nationwide survey of activity in all radiological institutions for the year 2002 was used to compare the rates per thousand of examinations in the counties. The data format was files/printouts where the examinations were recorded according to a code system. RESULTS: Overall rates per thousand of radiological examinations varied by a factor of 2.4. The use of MRI varied from 170 to 2, and CT from 216 to 56 examinations per 1000 inhabitants. Single MRI examinations (knee, cervical spine and head/brain) ranged high in variation, as did certain other spine examinations. For examination of specific organs, the counties' use of one modality was positively correlated with the use of other modalities. Private institutions accounted for 28% of all examinations, and tended towards performing a higher proportion of single examinations with high variability. Indicators of accessibility correlated positively to variation in examination rates, partly due to the figures from the county of Oslo. Correlations between examination rates and socioeconomic factors were also highly influenced by the figures from this county. CONCLUSION: The counties use of radiological services varied substantially, especially CT and MRI examinations. A likely cause of the variation is differences in accessibility. The coexistence of public and private institutions may be a source of variability, along with socioeconomic factors. The findings represent a challenge to the objective of equality in access to health care services, and indicate a potential for better allocation of overall health care resources. PREVIOUS PUBLICATION: The data applied in this article was originally published in Norwegian in: Børretzen I, Lysdahl KB, Olerud HM: Radiologi i Noreg – undersøkingsfrekvens per 2002, tidstrendar, geografisk variasjon og befolkningsdose. StrålevernRapport 2006:6. Østerås: The Norwegian Radiation Protection Authority. The Norwegian Radiation Protection Authority has given the authors permission to republish the data