Влияние ледового сжатия на составляющие скорости движения жидкости под ледяным покровом в бегущей периодической изгибно-гравитационной волне конечной амплитуды

Методом многих масштабов с точностью до величин третьего порядка малости получены асимптотические разложения, определяющие составляющие скорости движения жидкости под плавающим ледяным покровом при распространении периодической поверхностной изгибногравитационной волны конечной амплитуды в условиях ледового сжатия. Рассмотрена зависимость распределений составляющих скорости вдоль профиля волны от величины сжимающего усилия и характеристик начальной гармоники. Показано, что с увеличением сжимающего усилия происходит уменьшение амплитудных значений составляющих скорости и отставание фазы колебаний.Методом багатьох масштабів з точністю до величин третього порядку малості отримані асимптотичні розкладання, які визначають складові швидкості руху рідини під плаваючим льодяним покривом при розповсюдженні періодичної поверхневої згинально-гравітаційної хвилі кінцевої амплітуди в умовах льодяного стиснення. Розглянуто залежність розподілів складових швидкості вздовж профілю хвилі від величини стискаючого зусилля та характеристик початкової гармоніки. Показано, що із збільшенням стискаючого зусилля відбувається зменшення амплітудних значень складових швидкості та відставання фази коливань.Using the method of multiple scales, the asymptotic expansions are obtained up to the values of the third order. The expansions condition the components of fluid movement velocity under floating ice cover at propagation of periodic surface flexural-gravity wave of finite amplitude in the condition of ice compression. Dependence of distribution of velocity components along the wave profile upon the compressive force value and the initial harmonic characteristics is considered. It is shown that rise of compressive force is accompanied by decrease of amplitude values of velocity components and lag of oscillations’ phase

Threat of an influenza pandemic: family physicians in the front line

<p>Abstract</p> <p>Background</p> <p>The chance of an influenza pandemic is real and clinicians should keep themselves informed about the rationale and science behind preventive and therapeutic principles relating to an (impending) influenza pandemic.</p> <p>Discussion</p> <p>Vaccination is considered the best prevention in case of a pandemic threat and first choice to contain the impact of a pandemic. Pending the availability of an effective pandemic vaccine, antivirals are likely the only effective agents for prevention and treatment. When an influenza pandemic is impending, all interventions aim to prevent people becoming infected and to suppress replication and transmission of the virus as much as possible. Antivirals will be prescribed to patients with laboratory confirmed pre-pandemic influenza as well as to their contacts (post-exposure prophylaxis) which may delay development of or even prevent a pandemic. During a manifest influenza pandemic, however, there is large-scale spreading of the influenza virus. Therefore, preventive use of antivirals is less efficient to prevent transmission. Delaying the pandemic is then important in order to prevent exhausting public health resources and disruption of society. Thus, during a manifest pandemic everyone with influenza symptoms should receive antivirals as quickly as possible, regardless of virological confirmation. To ensure optimal effectiveness of antivirals and to minimize development of drug resistant viral strains, the use of antivirals for annual influenza should be restrictive. The crucial position of family physicians during an (impending) influenza pandemic necessitates the development of primary health care guidelines on this topic for all countries.</p> <p>Summary</p> <p>Family physicians will play a key role in assessing and treating victims of a new influenza virus, and in reassuring the worried well. We outline various possible interventions in the event of an impending and a manifest influenza pandemic, such as non-medial measures, prescription of antivirals, and vaccination, and emphasize the need for pandemic influenza preparedness.</p

The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390]

BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life. The results of PHN treatment are rather disappointing. Epidural injection of local anaesthetics and steroids in the acute phase of HZ is a promising therapy for the prevention of PHN. Since randomised trials on the effectiveness of this intervention are lacking, the PINE (Prevention by epidural Injection of postherpetic Neuralgia in the Elderly) study was set up. The PINE study compares the effectiveness and cost-effectiveness of a single epidural injection of local anaesthetics and steroids during the acute phase of HZ with that of care-as-usual (i.e. antivirals and analgesics) in preventing PHN in elderly patients. METHODS / DESIGN: The PINE study is an open, multicenter clinical trial in which 550 elderly (age ≥ 50 yr.) patients who consult their general practitioner in the acute phase of HZ (rash < 7 days) are randomised to one of the treatment groups. The primary clinical endpoint is the presence of HZ-related pain one month after the onset of the rash. Secondary endpoints include duration and severity of pain, re-interventions aiming to treat the existing pain, side effects, quality of life, and cost-effectiveness. CONCLUSION: The PINE study is aimed to quantify the (cost-) effectiveness of a single epidural injection during the acute phase of HZ on the prevention of PHN