1,377 research outputs found

    Quantum Illumination with a Hetero-Homodyne Receiver and Sequential Detection

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    We propose a hetero-homodyne receiver for quantum illumination (QI) target detection. Unlike prior QI receivers, it uses a cascaded positive operator-valued measurement (POVM) that does not require a quantum interaction between QI's returned radiation and its stored idler. When used without sequential detection its performance matches the 3 dB quantum advantage over optimum classical illumination (CI) that Guha and Erkmen's [Phys. Rev. A 80, 052310 (2009)] phase-conjugate and parametric amplifier receivers enjoy. When used in a sequential detection QI protocol, the hetero-homodyne receiver offers a 9 dB quantum advantage over a conventional CI radar, and a 3 dB advantage over a CI radar with sequential detection. Our work is a significant step forward toward a practical quantum radar for the microwave region, and, more generally, emphasizes the potential offered by cascaded POVMs for quantum radar.Comment: 12 pages, 5 figure

    Nonlinear quantum error correction

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    We introduce a theory of quantum error correction (QEC) for a subclass of states within a larger Hilbert space. In the standard theory of QEC, the set of all encoded states is formed by an arbitrary linear combination of the codewords. However, this can be more general than required for a given quantum protocol which may only traverse a subclass of states within the Hilbert space. Here we propose the concept of nonlinear QEC (NLQEC), where the encoded states are not necessarily a linear combination of codewords. We introduce a sufficiency criterion for NLQEC with respect to the subclass of states. The new criterion gives a more relaxed condition for the formation of a QEC code, such that under the assumption that the states are within the subclass of states, the errors are correctable. This allows us, for instance, to effectively circumvent the no-go theorems regarding optical QEC for Gaussian states and channels, for which we present explicit examples

    Lightweight Process Support with Spreadsheet-Driven Processes: A Case Study in the Finance Domain

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    The use of process management technology constitutes a salient factor for a multitude of business domains as it particularly addresses the flexibility demands of the digital enterprise. Still, spreadsheet applications are more likely to be used in many scenarios in which process management technology appears to be a more appropriate solution. Especially in the context of human-centric and knowledge-intensive processes, spreadsheets are widely used, even if more business-tailored applications exist. For example, financial service providers, like banks or insurers, prefer spreadsheet applications for accomplishing their daily business. However, this kind of usage reveals drawbacks when working collaboratively based on the same spreadsheet document. To remedy these drawbacks, we suggest the use of spreadsheet-driven processes, which shall combine the advantages of traditional process management technology with the ones of spreadsheets. Using a sophisticated scenario from the financial domain, this paper shows how spreadsheet-driven processes improve collaborative work, as required in the context of business processes, significantly. Moreover, a proof-of-concept prototype is presented to evaluate the approach in practice. Altogether, first results indicate that spreadsheet-driven processes may be a promising technical solution for everyday business involving human resources

    Making Reshoring Decisions - the Case of a Norwegian Manufacturing Firm

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    Master's thesis Industrial Economics and Technology Management IND590 - University of Agder 2018Relocating activities to low-cost countries has been, and still is, a prevalent method of reducing production costs for manufacturing companies. In recent years, however, many companies have reconsidered this strategy, and started to move activities back to their home country. Opportunities to reduce labor costs through automation have certainly contributed to this process. The rationale behind the phenomenon, called \reshoring", has been discussed to a large extent in current research literature. How companies make such reshoring decisions, on the other hand, is generally under-researched (Wiesmann, Snoei, Hilletofth, & Eriksson, 2017). This will be the primary focus of this master's thesis, which aims to understand the role of managerial accounting information in reshoring decisions. In order to understand this, we have adopted a single case study methodology. Two embedded cases in a Norwegian manufacturing company have been studied by interviewing key decision-makers. We found that the company had a rather pragmatic approach to decisionmaking. Financial and non- nancial information were integrated by using a multi-criteria analysis method. This approach did not emphasize the quanti cation of qualitative factors, but drew on the experience of decision-makers to weigh qualitative factors. Important factors such as proximity to innovation environments, protection of intellectual property, and e ciency of communication without cultural boundaries had signi cant in uence on the decision. These factors are acknowledged by literature, but this thesis provides more in-depth understanding of how they a ect the reshoring choice. A model of the company's decision-making process is presented, and is found to have a distinct resemblance to the generic purchasing process de ned by van Weele (2014). For this company, reshoring is a special case of sourcing where the best option is in the home country

    Effectiveness of adjuvant radiotherapy in patients with oropharyngeal and floor of mouth squamous cell carcinoma and concomitant histological verification of singular ipsilateral cervical lymph node metastasis (pN1-state) - A prospective multicenter randomized controlled clinical trial using a comprehensive cohort design

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    <p>Abstract</p> <p>Background</p> <p>Modern radiotherapy plays an important role in therapy of advanced head and neck carcinomas. However, no clinical studies have been published addressing the effectiveness of postoperative radiotherapy in patients with small tumor (pT1, pT2) and concomitant ipsilateral metastasis of a single lymph node (pN1), which would provide a basis for a general treatment recommendation.</p> <p>Methods/Design</p> <p>The present study is a non-blinded, prospective, multi-center randomized controlled trial (RCT). As the primary clinical endpoint, overall-survival in patients receiving postoperative radiation therapy vs. patients without adjuvant therapy following curative intended surgery is compared. The aim of the study is to enroll 560 adult males and females for 1:1 randomization to one of the two treatment arms (irradiation/no irradiation). Since patients with small tumor (T1/T2) but singular lymph node metastasis are rare and the amount of patients consenting to randomization is not predictable in advance, all patients rejecting randomization will be treated as preferred and enrolled in a prospective observational study (comprehensive cohort design) after giving informed consent. This observational part of the trial will be performed with maximum consistency to the treatment and observation protocol of the RCT. Because the impact of patient preference for a certain treatment option is not calculable, parallel design of RCT and observational study may provide a maximum of evidence and efficacy for evaluation of treatment outcome. Secondary clinical endpoints are as follows: incidence and time to tumor relapse (locoregional relapse, lymph node involvement and distant metastatic spread), Quality of life as reported by EORTC (QLQ-C30 with H&N 35 module), and time from operation to orofacial rehabilitation. All tumors represent a homogeneous clinical state and therefore additional investigation of protein expression levels within resection specimen may serve for establishment of surrogate parameters of patient outcome.</p> <p>Conclusion</p> <p>The inherent challenges of a rare clinical condition (pN1) and two substantially different therapy arms would limit the practicality of a classical randomized study. The concept of a Comprehensive Cohort Design combines the preference of a randomized study, with the option of careful data interpretation within an observational study.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: NCT00964977</p

    Recurrent osteomyelitis with proliferative periostitis after segmental resection and reconstruction of the mandible: a case report

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    A 50-year-old patient presented with a two-year history of chronic osteomyelitis of the left mandibular body. It was treated by wide segmental resection of the left hemimandible and reconstruction with a free vascularized fibular graft. Six months after surgery, the patient returned with pain, swelling, and moth-like lesions in the transplant in combination with appositional bone formation surrounding the ossified fibular bone. Radiographic and histological examination led to the diagnosis of a recurrent osteomyelitis with proliferative periostitis affecting the resected and reconstructed mandible. Application of ibandronate led to a significant symptom decrease

    The importance of high quality real-life social interactions during the COVID-19 pandemic

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    The coronavirus pandemic has brought about dramatic restrictions to real-life social interactions and a shift towards more online social encounters. Positive social interactions have been highlighted as an important protective factor, with previous studies suggesting an involvement of the amygdala in the relationship between social embeddedness and well-being. The present study investigated the effect of the quality of real-life and online social interactions on mood, and explored whether this association is affected by an individual’s amygdala activity. Sixty-two participants of a longitudinal study took part in a one-week ecological momentary assessment (EMA) during the first lockdown, reporting their momentary well-being and their engagement in real-life and online social interactions eight times per day (N ~ 3000 observations). Amygdala activity was assessed before the pandemic during an emotion-processing task. Mixed models were calculated to estimate the association between social interactions and well-being, including two-way interactions to test for the moderating effect of amygdala activity. We found a positive relationship between real-life interactions and momentary well-being. In contrast, online interactions had no effect on well-being. Moreover, positive real-life social interactions augmented this social affective benefit, especially in individuals with higher amygdala being more sensitive to the interaction quality. Our findings demonstrate a mood-lifting effect of positive real-life social interactions during the pandemic, which was dependent on amygdala activity before the pandemic. As no corresponding effect was found between online social interactions and well-being, it can be concluded that increased online social interactions may not compensate for the absence of real-life social interactions

    Alternatives to free flap surgery for maxillofacial reconstruction: focus on the submental island flap and the pectoralis major myocutaneous flap

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    Background Microvascular tissue transfer (MTT) has been established as the gold standard in oral- and maxillofacial reconstruction. However, free flap surgery may be critical in multimorbid elderly patients and after surgery or radiotherapy, which aggravate microsurgery. This study evaluates indications and outcome of the submental island flap (SMIF) and the pectoralis major myocutaneous flap (PMMF) as alternatives to the free radial forearm flap (RFF). Methods This retrospective study included 134 patients who had undergone resection and reconstruction with SMIF, PMMF, or RFF at our department between 2005 and 2020. The level of comorbidity was measured with the Age-adjusted Charlson comorbidity index (ACCI). Primary outcome variables were flap success, complications, wound dehiscence, surgery duration, as well as time at the ICU and the ward (hospitalization). Chi-square tests, t-tests, and ANOVA were performed for statistics. Results 24 SMIFs, 52 RFFs, and 58 PMMFs were included in this study. The flap types did not significantly differ in terms of flap success, complications, and healing disorders. The SMIF presented a success rate of 95.8% and was significantly more often used in elderly patients (mean age = 70.2 years; p < 0.001) with increased comorbidities than the PMMF (p < 0.01) and RFF (p < 0.001). SMIF reconstruction reduced surgery duration (p < 0.001) and time at the ICU (p = 0.009) and the ward (p < 0.001) more than PMMF and RFF reconstructions. PMMF reconstruction was successful in 91.4% of patients and was more frequently used after head and neck surgery (p < 0.001) and radiotherapy (p < 0.001) than SMIF and RFF reconstructions. Patients undergoing PMMF reconstruction more frequently required segmental jaw resection and had presented with advanced tumor stages (both p < 0.001). Nicotine and alcohol abuse was more frequent in the RFF and PMMF groups (both p < 0.001) than in the SMIF group. Conclusions The pedicled SMIF represents a valuable reconstructive option for elderly patients with increased comorbidity because of the shorter duration of surgery and hospitalization. On the other hand, the PMMF serves as a solid backup solution after head and neck surgery or radiotherapy. The rates of flap success, complications, and healing disorders of both pedicled flaps are comparable to those of free flap reconstruction

    Influence of Radiotherapy on Ossification of Vascularized Osseous Reconstruction of the Jaw: A Radiological Retrospective Cohort Study Based on Panoramic Radiographs

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    Background: The aim of this study was to evaluate the impact of irradiation and time of irradiation on the ossification of jaws reconstructed with free bone grafts. Methods: In total, 100 reconstructions of the jaw were retrospectively evaluated for ossification between bone segments by two raters based on postoperative panoramic radiographs (immediate postOP, approximately 6, 12 and 24 months follow-up). Three subgroups were divided according to the time of irradiation: preoperative radiation therapy (n = 41), postoperative radiation therapy (n = 26) and patients without any radiation therapy (n = 33) as the control group. Ossification time and influencing factors were documented. Results: The fastest ossification with a median of 304 ± 37 days was observed (p < 0.001) in the nonirradiated control group. No significant difference (p = 0.087) in ossification was found between the pre- (447 ± 136 days) and postoperative (510 ± 112 days) radiation groups. Ossification between two graft segments (336 ± 38 days) showed significantly (p < 0.001) faster ossification than between the original and grafted bone (448 ± 85 days). Moreover, closer initial contact between the segments resulted in faster ossification (p < 0.001). When analyzing cofactors, tobacco consumption was the only negative factor aggravating ossification (p = 0.006). Conclusion: Head and neck radiation corresponded with the impaired and prolonged ossification of jaw reconstructions with free bone grafts. There was no difference in ossification if radiotherapy was performed before or after reconstructive surgery. A close bony contact was particularly important for ossification between the original and grafted bone
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