Quantum Simulation Logic, Oracles, and the Quantum Advantage

Query complexity is a common tool for comparing quantum and classical computation, and it has produced many examples of how quantum algorithms differ from classical ones. Here we investigate in detail the role that oracles play for the advantage of quantum algorithms. We do so by using a simulation framework, Quantum Simulation Logic (QSL), to construct oracles and algorithms that solve some problems with the same success probability and number of queries as the quantum algorithms. The framework can be simulated using only classical resources at a constant overhead as compared to the quantum resources used in quantum computation. Our results clarify the assumptions made and the conditions needed when using quantum oracles. Using the same assumptions on oracles within the simulation framework we show that for some specific algorithms, like the Deutsch-Jozsa and Simon's algorithms, there simply is no advantage in terms of query complexity. This does not detract from the fact that quantum query complexity provides examples of how a quantum computer can be expected to behave, which in turn has proved useful for finding new quantum algorithms outside of the oracle paradigm, where the most prominent example is Shor's algorithm for integer factorization.Comment: 48 pages, 46 figure

Renens fejskador på tall- och contortaplanteringar inom Malå samebys höst- och vinterbetesområden

The effects of Reindeer mechanical damages on the planted regeneration of Pinus sylvestris and Pinus contorta. Semi-domesticated reindeer can damage young trees. In late winter reindeer rub their antlers against young trees. The aim of this study was to quantify those damages. This study covered planted objects from three different areas in northeastern Sweden. The objects should be on private property, be in the Swedish County Forestry Boards database "Kotten", have an average height of maximum 3 m, be planted with Scots pine or Contorta between 1986-1993 and be on mesic or dry sites. 17 objects were chosen randomly for an inventory. A systematic sample plot inventory was done during the summer 2004 with 20 sample plots (r=2.82 m) per objects. The first sample plot was randomly chosen and the rest was located in a quadratic formation adapted to the size of the object. Only main stems were estimated. The number of undamaged main stems, light damaged (capable of development) and seriously damaged (not capable of development) head stems, type and level of damage and occurrence of lichens were recorded on each sample plot. On three objects damages of moose and other causes were investigated together with number of faecal and occurrence of lichens. From the beginning the purpose was also to investigate damages caused when reindeer dig in snow to reach lichens and when they walk in new regenerated areas. A pilot study done in July 2003 indicated the difficulty to identify those types of damages. Antler rubbing occurs on 5 of 17 objects. The average number of seriously damaged main stems on those objects was 14 and light damaged stems were 19 per hectare, corresponding to 0.8 and 0.6 % of vigorous main stems. The number of vigorous main is in average 2232. The damages occur often gathered and are not distributed all over the objects. The possibility to have those kinds of damages is 29 % and 12 % when the damage frequency is at least 1 % of the main stems. Also three objects with a lot of damages reported by the forest owner were investigated with the same method. They have much higher frequency of damages, 39, 18 and 2 % seriously damaged and 9, 19, and 11 % light damaged stems. The number of not damaged stems per hectare is 1676, 1250 and 1454 which is much more than required in the Swedish Forestry Act. The conclusion of this study is that reindeer antler rubbing against small trees is a very small problem for Swedish forestry. But -if this type of damage occurs, the consequence can be serious on a limited area.Renarna kan åstadkomma skador i ungskog genom att under hösten och vårvintern feja sina horn mot plantor och träd. Med syfte att kvantifiera dessa skador och ev samband med avståndet till kusten inventerades 17 objekt (bestånd). Dessa valdes ut genom lottning inom tre områden i Västerbottens län på olika avstånd från kusten, nämligen Ånäset, Bygdsiljum och Rusksele. Av dessa områden ingår två i Malå samebys renbetesområde. Ett område, Bygdsiljum, nyttjas växelvis av två samebyar, men vintern 2003 av Malå sameby. Dessutom inventerades tre objekt kända för skador av ren. Utlottade objekt skulle finnas i skogsvårdsstyrelsens register ”Kotten” (främst privatägd mark), ha ett trädskikt med en medelhöjd på högst 3 m, vara planterade med tall eller contorta åren 1986-1993, och vara belägna på frisk eller torr mark. Inventeringen genomfördes sommaren 2004 som en systematisk cirkelyteinventering med 20 cirkelytor (r=2.82 m) per objekt. Första provytan i varje bestånd lades ut slumpmässigt, medan övriga provytor lades ut i ett kvadratiskt förband anpassat till storleken på resp bestånd. Enbart huvudstammar bedömdes. Antal oskadade huvudstammar, antal lätt skadade (och utvecklingsbara) resp svårt skadade (och ej utvecklingsbara) huvudstammar, typ och grad av skada, samt förekomst av marklav registrerades för varje provyta. På ett objekt per område noterades även spillningshögar av ren resp älg, samt skador av älg och andra orsaker. Ursprungligen var syftet att inventera även de trampskador som renarna åstadkommer under senhösten när de vistas på föryngringsytor, och de grävskador som renarna åstadkommer under vintern när de gräver i snön efter lav. En pilotstudie i två bestånd sommaren 2003 visade dock att dessa skador inte kunde identifieras med tillräcklig säkerhet. Fejskador förekommer på 5 av 17 objekt. På dessa är i medeltal 14 stammar per hektar svårt skadade, och 19 lätt skadade. Antalet utvecklingsbara stammar är i genomsnitt 2232, vilket medför att 0.6 resp 0.8 % av stammarna är svårt resp lätt skadade. Skadorna är dock inte jämnt fördelade över respektive objekt utan samlade till vissa delar av objekten. Risken för att ett objekt drabbas av fejskador är 29 %, att skadorna är minst 1 % av stamantalet är 12 %. De tre objekten som rapporterats skadade har betydligt högre skadegrad, nämligen 39, 18 och 2 % svåra skador respektive 9, 19 och 11 % lätta skador. Antalet oskadade huvudstammar per hektar är 1676, 1250 och 1454 vilket är högt över skogsvårdslagens krav på lägsta antal stammar, och gör att ståndortens virkesproduktionsförmåga nyttjas i hög grad. Slutsatsen av studien är att renarnas fejning enbart är ett marginellt problem för skogsbruket. Uppstår skador kan de dock vara allvarliga inom ett begränsat område

Eating disorders - knowledge, attitudes, management and clinical experience of Norwegian dentists

Background The purpose of this study was to investigate knowledge, attitudes and clinical experience with regard to patients with eating disorders (ED) among Norwegian dentists. Methods In 2010, a questionnaire was sent to all dentists in Norway (N = 4282) comprising 33 questions related to demographics of the participating dentists, their knowledge of ED (general and oral health aspects), clinical experience, attitudes and perceived management preferences. Results The participation rate was 40 % (47 % women and 53 % men). Their knowledge about ED was often retrieved from common media sources and the greater part of the participants reported they had seen very few patients with ED during their professional career. Female dentists reported superior knowledge about ED compared to males, but the former experienced greater difficulties to inform about the condition. Referrals of the patient to other health facilities were significantly more common among female compared to male dentists. The majority of dentists (76 %) reported a need of more education related to ED management. Conclusions The Norwegian dentists in this study reported limited clinical experience and insufficient knowledge regarding ED. There is therefore a need to increase both undergraduate and continuing education in this field, which can improve preventive and management measures that a dentist can provide for ED patients.publishedVersio

Leveraging network and traffic measurements for content distribution and interpersonal communication services with sufficient quality

In this paper, we discuss research problems for enabling content distribution and supporting real-time interpersonal communication services (e.g. voice and video) over best effort networks with sufficient quality. We take a practical view of content distribution and quality, and this is the reason for the term “sufficient”. We argue that the understanding of quality as perceived by the user is a key factor in this context, but also that the understanding of context dependence is a key factor for delivering services which are “good enough” to make the user satisfied. We base our assumptions upon results from the Celtic TRAMMS project, and we describe how to leverage upon the framework for traffic measurements that was built up in that project. Moreover, we identify key technological components that are common for optimization of content delivery and real-time interpersonal communication services such as VoIP and videoconferencing. We also describe how the research problems stated will be tackled in the newly started IPNQSIS project

The Ringloc liner compared with the Hexloc liner in total hip arthroplasty

The aim of this study was to compare the 10-year survival rate, pelvic osteolysis frequency and linear head penetration rate of the Hexloc and Ringloc liners used together with a partially threaded porous and hydroxyapatite coated cup and the Bi-Metric uncemented femoral stem. The 15-year results for the cup with the Hexloc liner are also reported. We included 332 consecutive hips (166 Hexloc and 166 Ringloc) on 281 patients in the study. Revisions of prosthesis components were recorded and pelvic osteolytic lesions were assessed using radiographs and computed tomography. The linear head penetration rate was measured using the Martell method. The 10-year survival rate of the liner with revision due to liner wear and/or osteolysis as endpoint was 88% for the Hexloc liner and 98% for the Ringloc liner. The 15-year survival rate of the Hexloc liner was 67%. Pelvic osteolysis was found in 27% of the Hexloc and 19% of the Ringloc hips. After 15 years, 53% of the Hexloc hips had developed an osteolytic lesion. The linear head penetration rate was 0.16 mm/year for the Hexloc liner and 0.12 mm/year for the Ringloc liner. This paper is the first to describe the rapidly deteriorating survival up to 15 years with the old generation gamma-in-air sterilized polyethylene used in Hexloc liners. The newer Ringloc liner with the ArCom™ polyethylene has superior clinical results but a linear wear rate and frequency of osteolytic lesions that is higher than expected

Comparison of a high and a low intensity smoking cessation intervention in a dentistry setting in Sweden – a randomized trial

<p>Abstract</p> <p>Background</p> <p>Tobacco is still the number one life style risk factor for ill health and premature death and also one of the major contributors to oral problems and diseases. Dentistry may be a potential setting for several aspects of clinical public health interventions and there is a growing interest in several countries to develop tobacco cessation support in dentistry setting. The aim of the present study was to assess the relative effectiveness of a high intensity intervention compared with a low intensity intervention for smoking cessation support in a dental clinic setting.</p> <p>Methods</p> <p>300 smokers attending dental or general health care were randomly assigned to two arms and referred to the local dental clinic for smoking cessation support. One arm received support with low intensity treatment (LIT), whereas the other group was assigned to high intensity treatment (HIT) support. The main outcome measures included self-reported point prevalence and continuous abstinence (≥ 183 days) at the 12-month follow-up.</p> <p>Results</p> <p>Follow-up questionnaires were returned from 86% of the participants. People in the HIT-arm were twice as likely to report continuous abstinence compared with the LIT-arm (18% vs. 9%, p = 0.02). There was a difference (not significant) between the arms in point prevalence abstinence in favour of the HIT-protocol (23% vs. 16%). However, point prevalence cessation rates in the LIT-arm reporting additional support were relatively high (23%) compared with available data assessing abstinence in smokers trying to quit without professional support.</p> <p>Conclusion</p> <p>Screening for willingness to quit smoking within the health care system and offering smoking cessation support within dentistry may be an effective model for smoking cessation support in Sweden. The LIT approach is less expensive and time consuming and may be appropriate as a first treatment option, but should be integrated with other forms of available support in the community. The more extensive and expensive HIT-protocol should be offered to those who are unable to quit with the LIT approach in combination with other support.</p> <p>Trial Registration</p> <p>Trial registration number: NCT00670514</p