The Complexity of Circumscription in DLs

As fragments of first-order logic, Description logics (DLs) do not provide nonmonotonic features such as defeasible inheritance and default rules. Since many applications would benefit from the availability of such features, several families of nonmonotonic DLs have been developed that are mostly based on default logic and autoepistemic logic. In this paper, we consider circumscription as an interesting alternative approach to nonmonotonic DLs that, in particular, supports defeasible inheritance in a natural way. We study DLs extended with circumscription under different language restrictions and under different constraints on the sets of minimized, fixed, and varying predicates, and pinpoint the exact computational complexity of reasoning for DLs ranging from ALC to ALCIO and ALCQO. When the minimized and fixed predicates include only concept names but no role names, then reasoning is complete for NExpTime^NP. It becomes complete for NP^NExpTime when the number of minimized and fixed predicates is bounded by a constant. If roles can be minimized or fixed, then complexity ranges from NExpTime^NP to undecidability.

Conjunctive Query Answering for the Description Logic SHIQ

Conjunctive queries play an important role as an expressive query language for Description Logics (DLs). Although modern DLs usually provide for transitive roles, conjunctive query answering over DL knowledge bases is only poorly understood if transitive roles are admitted in the query. In this paper, we consider unions of conjunctive queries over knowledge bases formulated in the prominent DL SHIQ and allow transitive roles in both the query and the knowledge base. We show decidability of query answering in this setting and establish two tight complexity bounds: regarding combined complexity, we prove that there is a deterministic algorithm for query answering that needs time single exponential in the size of the KB and double exponential in the size of the query, which is optimal. Regarding data complexity, we prove containment in co-NP.

Successful salvage treatment of disseminated cutaneous fusariosis with liposomal amphotericin B and terbinafine after allogeneic stem cell transplantation

Fusarium infections are associated with high mortality after allogeneic stem cell transplantation. We report on successful treatment of a disseminated cutaneous Fusarium proliferatum infection using liposomal amphotericin B and terbinafine. In vitro susceptibility tests of antifungal drugs suggest that terbinafine is a potent additional antifungal drug for disseminated cutaneous fusariosis.

Einstein relation generalized to nonequilibrium

The Einstein relation connecting the diffusion constant and the mobility is violated beyond the linear response regime. For a colloidal particle driven along a periodic potential imposed by laser traps, we test the recent theoretical generalization of the Einstein relation to the nonequilibrium regime which involves an integral over measurable velocity correlation functions.

Survival after reduced-intensity conditioning is not inferior to standard high-dose conditioning before allogeneic haematopoietic cell transplantation in acute leukaemias

To assess the role of allogeneic stem cell transplantation (SCT) after reduced-intensity conditioning (RIC) in acute leukaemias, we retrospectively compared 25 patients with acute lymphoblastic leukaemia or acute myelogenous leukaemia after RIC to a historical group of 50 matched controls after high-dose conditioning. Engraftment, acute GvHD and severe infections were comparable in both groups. During the observation period, 1/25 patients (4%) after RIC and 14/50 (28%) after standard SCT died due to transplant-related causes; cumulative nonrelapse mortality (NRM) was 4% after RIC and 24% after standard SCT (P=0.029). In total, 15/25 patients (60%) relapsed after RIC and 20/50 (40%) after standard SCT; probability of disease-free survival (DFS) at 3 years was 43% after RIC and 49% after standard SCT (NS). Overall survival (OS) was 40% after RIC and 37% after standard SCT (NS). Stage of disease, cytogenetic risk profile, acute and chronic GvHD, chimerism status at day 90 and severe infections after transplantation were risk factors with significant impact on DFS and/or OS. In retrospective analysis, patients with acute leukaemias who receive RIC because of contraindications against standard SCT have a comparable outcome to standard SCT, but the higher relapse rate warrants further studies.

Implantation of the Freehand System during initial rehabilitation using minimally invasive techniques

STUDY DESIGN

Series of four single subjects with and without intervention design.

OBJECTIVES

To describe a minimally invasive surgical technique used to implant the Freehand System during initial spinal cord injury (SCI) rehabilitation and to report rehabilitation outcomes of four recently injured adolescents using the Freehand System.

SETTING

Nonprofit children's hospital specializing in orthopedic and SCI care.

METHODS

Four subjects with C5 tetraplegia between 13 and 16 years of age and between 9 and 16 weeks following traumatic SCI underwent implantation of the Freehand System using minimally invasive surgical techniques. Outcomes on muscle strength, pinch force, hand function, performance of activities of daily living and satisfaction with and without the Freehand System were collected.

RESULTS

Each subject was successfully implanted with the Freehand System without perioperative complications and employed the Freehand System during therapy services and ad lib on the rehabilitation floor. At the last follow-up, every subject remained a motor candidate for the Freehand System. With the Freehand System, average lateral and palmar pinch force was 1.8 and 1.6 kg respectively; average pinch force without functional electrical stimulation (FES) was 0.29 kg. With the Freehand System, three subjects improved their rate of performance on The Upper Extremity Capabilities Questionnaire. All subjects increased their level of independence on The Quadriplegia Index of Function. On the Canadian Occupational Performance Measure (COPM) with the Freehand System, average performance and satisfaction scores improved for every patient. Three of the four subjects continued to use the system at home.

CONCLUSION

This case series demonstrates that the Freehand System can vastly improve hand function and performance of rehabilitation activities within days after a minimally invasive implant procedure during initial SCI rehabilitation. Satisfaction with the Freehand System beyond initial rehabilitation is evidenced by continued use at home.

Long-term results of high tibial osteotomy for medial osteoarthritis of the knee

We reviewed retrospectively the results in patients who had undergone one hundred and four high tibial lateral osteotomies. The operations were all performed between 1985 and 1993. Each one of fifty men and forty nine women demonstrated a varus deformity of the knee with a coexistent medial osteoarthritis. Results were reviewed in 49 patients (62 knees) with an average follow-up of 10.2 years (range 6-14 years). Of the remaining 42 patients, 8 were lost to follow-up, 10 had died, and 24 were subsequently treated with total knee arthroplasty at an average 4.7 years after having had a high tibial osteotomy. Clinical results were evaluated using the Hospital for Special Surgery Score (HSS) and the Knee Society Score. Radiographs were systematically analysed to evaluate osteoarthritis and leg axis. Forty four (90 per cent) of the forty nine patients stated the results met their expectations and given the same circumstances, they would have the operation once again. In these patients the knee score results were excellent. The same patients had excellent HSS and Knee Society Scores. Five patients (10 per cent) had a poor result and twenty four patients were treated later by total knee arthroplasty because of pain. The following factors set these patients apart from those with more favorable results: previous arthroscopic debridement, obesity, lateral knee osteoarthritis, insufficient valgus correction, and an age of more than 55 years. High tibial valgus osteotomy provides good pain relief and improved function in carefully selected patients. Our results support this conclusion.

Intradiscal electrothermal therapy (IDET) for treatment of chronic lumbar discogenic pain: a minimum 2-year clinical outcome study

OBJECTIVE

To determine the long-term efficacy of IDET in the treatment of chronic lumbar discogenic pain.

DESIGN

Prospective case series clinical outcome study.

METHODS

IDET was performed on 62 consecutive patients with chronic discogenic pain of greater than 6 months duration and consecutively enrolled in a non-randomized prospective case series outcome study. Outcome measures included visual numeric pain scale (VNS) for low back (LB) and lower extremity (LE) pain, Roland-Morris disability scale (RM), and North American Spine Society (NASS) patient satisfaction index. Outcome success was defined as a change of more than 2 points on VNS and RM as well as a positive NASS satisfaction response. Data were collected at baseline and post-procedure at 1, 3, and 6 months and then annually for up to 4 years.

RESULTS

Fifty-one out of 62 patients (82%) were available for a minimum of 2-year follow-up. Average age was 41.4 years; average symptom duration was 46 months; and average follow-up was 34 months. Overall, there was statistically significant improvement in LB-VNS, RM, and LE pain scores of 3.2, 6.6, and 2.3 (p<0.001), respectively. Twenty-seven of 51 (53%) patients demonstrated clinically significant VNS and RM improvements of greater than 2. On NASS index, 63% (32/51) responded positively. Neither the number of disc levels treated nor the insurance status of patients made any difference in outcome.

CONCLUSION

IDET appears to be an effective treatment for chronic lumbar discogenic pain in a well-selected group of patients with favorable long-term outcome.

Treatment of chronic lumbar diskogenic pain with intradiskal electrothermal therapy: a prospective outcome study

OBJECTIVE

To determine the clinical efficacy of intradiskal electrothermal annuloplasty in treating patients with chronic constant lumbar diskogenic pain who have not responded to at least 6 months of aggressive nonoperative care.

DESIGN

Prospective case series.

SETTING

Academic-affiliated private physiatry practice.

PARTICIPANTS

Thirty-three patients with chronic constant lumbar diskogenic pain of more than 6 months in duration diagnosed with history and physical examination, with concordant pain on provocative pressure-controlled lumbar diskography, and with symptomatic annular tears and/or protrusions less than 5mm, who did not respond to aggressive nonoperative care.

INTERVENTION

Intradiskal electrothermal annuloplasty.

MAIN OUTCOME MEASURES

Visual analog scale (VAS) pain scores for the back and for the lower extremity, the Roland-Morris Disability Questionnaire (RMDQ), and the North American Spine Society Patient Satisfaction Index.

RESULTS

A total of 33 patients, with mean age of 40 years and a mean duration of symptoms of 46 months, were observed with a mean follow-up of 15 months. Relief of pain and improvement in physical function were associated with a mean change in the VAS score of 3.9 (P<.001), a mean change in the lower-extremity VAS score of 3.7 (P<.001), and a mean change in the RMDQ of 7.3 (P<.001). For patient satisfaction, 75.7% reported that they would undergo the same procedure for the same outcome. Complete pain relief was achieved in 24% of the patients, and partial pain relief in 46% of the patients.

CONCLUSIONS

Intradiskal electrothermal annuloplasty offers a safe, minimally invasive treatment option for carefully selected patients with chronic lumbar diskogenic pain who have not responded to aggressive nonoperative care.

Fusions of Description Logics and Abstract Description Systems

Fusions are a simple way of combining logics. For normal modal logics, fusions have been investigated in detail. In particular, it is known that, under certain conditions, decidability transfers from the component logics to their fusion. Though description logics are closely related to modal logics, they are not necessarily normal. In addition, ABox reasoning in description logics is not covered by the results from modal logics. In this paper, we extend the decidability transfer results from normal modal logics to a large class of description logics. To cover different description logics in a uniform way, we introduce abstract description systems, which can be seen as a common generalization of description and modal logics, and show the transfer results in this general setting.

Cognitive complexity and the validity of clinicians' judgments

Efforts to explain why some neuropsychologists are more accurate than others have been unsuccessful. In the present study, the relation between the cognitive complexity of clinicians and the validity of their judgments was investigated. Forty-two neuropsychologists completed a measure of cognitive complexity. The hypothesis that neuropsychologists who are high in cognitive complexity will be more accurate than those who are low in cognitive complexity was not supported. It is not clear why cognitive complexity was not significantly related to the validity of diagnostic ratings: One explanation is that the measure of cognitive complexity used in this study was inadequate but another possibility is that neuropsychologists who are low in cognitive complexity may still be able to achieve high levels of accuracy if they attend to normative data when they interpret test results.