The g-modes of white dwarfs

The neutral g-modes of a degenerate fluid at zero temperature are analyzed. The g-modes of a degenerate fluid at finite but small temperatures are then expanded in terms of those of the zero temperature fluid. For nonrelativistic degenerate fluids it is found that (1) the g-eigenvalues are proportional to T mu(6)sub e mu(-1)sub i, where T is the internal temperature of the fluid, mu sub e and mu sub i are the mean molecular weights of electrons and ions, respectively; (2) the ion pressure is solely responsible for driving the g-modes. For white dwarfs of about a solar mass, the periods of the g-oscillations are in the range of a few hundredths of seconds

Вeta1-Adrenoreceptors of the CA1 Area Mediate Morphine Modified State-Dependent Memory in Rat

In our study, we investigated the effects of intra­CA1 microinjections of a selective b1­ adrenoreceptor antagonist, betaxolol, on state­dependent memory induced by morphine. A step­through passive avoidance task was used to assess memory retrieval. Male Wistar rats were bilaterally implanted with chronic cannulas in the CA1 regions of the dorsal hippocampus by stereotaxic surgery seven days before training. Each animal was tested 24 h after training to measure the step­through latency and the time spent in a dark chamber of the apparatus. Post-training intra-CA1 administrations of different doses of morphine (5 and 7.5 mg/kg, s.c.) decreased memory retrieval in the retention test (morphine­induced amnesia). The effect of post­training injections of 7.5 mg/kg morphine on retrieval was reversed by pre­test injection of the same dose of morphine. This phenomenon is named morphine state­dependent memory. The results also showed that pre-test intra-CA1 microinjection of ineffective low doses of betaxolol (0.125 and 0.25 mg/rat) inhibited morphine­induced state­dependent memory retrieval. Taken together, our results suggest that the CA1 may be potentially critical for morphine state­dependent memory, and the b1­adrenergic receptor mechanism(s) interact with the opioidergic system in the modulation of this type of memory in the CA1.У нашій роботі ми досліджували впливи мікроін’єкцій селективного антагоніста b1­адренорецепторів бетаксололу в ділянку CA1 гіпокампа на формування залежної від стану пам’яті, індукованої ін’єкціями морфіну. Для оцінки ефективності здобування пам’ятних слідів використовували тест пасивного уникання. Самцям щурів лінії Вістар стереотаксично імплантували канюлі в ділянку CA1 дорсального гіпокампа за сім днів до тренування. Кожну тварину тестували через 24 год після тренування з вимірюванням латентного періоду уникання та тривалості перебування у темному відсіку тест­установки. Підшкірне введення 5 або 7.5 мг/кг морфіну після тренування послаблювало збереження пам’ятних слідів у відповідному тесті (індукована морфіном амнезія). Ефекти ін’єкцій 7.5 мг/кг морфіну після тренувань спотворювалися внаслідок ін’єкцій морфіну в тій самій дозі, виконаних перед тестом. Цей феномен кваліфікується як модифікація залежної від стану пам’яті під впливом морфіну. Як показали результати наших дослідів, мікроін’єкції в ділянку CA1 малих (неефективних) кількостей бетаксололу (0.125 або 0.25 мкг на тварину) послаблювали збереження індукованих морфіном модифікацій залежної від стану пам’яті. У цілому наші результати дозволяють вважати, що ділянка CA1 є критичною для формування модифікованої морфіном залежної від стану пам’яті і що b1­адренергічні рецепторні механізми взаємодіють із опіоїдергічною системою в перебігу модуляції пам’яті цього типу у щурів

Innovation Adoption in Robotic Surgery - A Surgical Innovation Framework using Royal Bournemouth Hospital

Robotic Surgery is studied as an innovative surgical procedure and we examine the way Robotic Surgery is adopted by healthcare professionals in Royal Bournemouth Hospital. This research aims to develop a Surgical Innovation Framework (SIF) that incorporates the broader adoption of surgical innovation for the National Health Service (NHS) in the United Kingdom. The aim of the framework is to assist the NHS in its determination and adoption of surgical innovation. The framework is developed taking into consideration The recent reports by the Department of Health and Social Care, NHS, NICE and existing body of knowledge. The proposed model considers unique characteristics of Robotic Surgery, NHS as the host organization, healthcare professionals as adopters and other elements such as communication channels. An end-to-end communication pathway is developed for the robotic surgery team to identify stakeholders involved in this process

A novel underdetermined source recovery algorithm based on k-sparse component analysis

Sparse component analysis (SCA) is a popular method for addressing underdetermined blind source separation in array signal processing applications. We are motivated by problems that arise in the applications where the sources are densely sparse (i.e. the number of active sources is high and very close to the number of sensors). The separation performance of current underdetermined source recovery (USR) solutions, including the relaxation and greedy families, reduces with decreasing the mixing system dimension and increasing the sparsity level (k). In this paper, we present a k-SCA-based algorithm that is suitable for USR in low-dimensional mixing systems. Assuming the sources is at most (m−1) sparse where m is the number of mixtures; the proposed method is capable of recovering the sources from the mixtures given the mixing matrix using a subspace detection framework. Simulation results show that the proposed algorithm achieves better separation performance in k-SCA conditions compared to state-of-the-art USR algorithms such as basis pursuit, minimizing norm-L1, smoothed L0, focal underdetermined system solver and orthogonal matching pursuit

Troublesome trade-offs: balancing urban activities and values when securing a city-centre governmental quarter

Background Homeland security measures increasingly affect urban life and activities. Standoff distance, which prevents unscreened vehicles from approaching within a certain distance of a building, is a widely applied measure when protecting buildings against attacks with vehicle-borne improvised explosive devices. This measure both is rather inexpensive and has few negative externalities when implemented in rural areas. Unfortunately, sites with protection needs often are situated in city centres. Methods We apply the so-called Security Function Framework to illuminate the externalities or the ‘troublesome trade-offs’ between protecting a high-value site against vehicle-borne improvised explosive devices and protecting other urban values. Results This paper demonstrates that standoff creates challenges for other important values, such as functional office spaces for all employees, deliveries and emergency vehicle access. Simultaneously, standoff creates opportunities for reinforcing social-responsibility requirements, such as accessibility for pedestrians and environmental considerations. Conclusions Security measures can have both negative and positive externalities and planning might alleviate some of the negative ones