254 research outputs found

    Syzygies of Prym and paracanonical curves of genus 8

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    By analogy with Green's Conjecture on syzygies of canonical curves, the Prym-Green conjecture predicts that the resolution of a general level p paracanonical curve of genus g is natural. The Prym-Green Conjecture is known to hold in odd genus for almost all levels. Probabilistic arguments strongly suggested that the conjecture might fail for level 2 and genus 8 or 16. In this paper, we present three geometric proofs of the surprising failure of the Prym-Green Conjecture in genus 8, hoping that the methods introduced here will shed light on all the exceptions to the Prym-Green Conjecture for genera with high divisibility by 2

    Instability Severity Index Score predicts recurrent shoulder instability after arthroscopic Bankart repair

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    Purpose: The Instability Severity Index (ISI) Score was developed to preoperatively assess the risk of recurrent shoulder instability after an arthroscopic Bankart repair. This study aims to validate the use of ISI Score for predicting the risk of recurrence after an arthroscopic Bankart repair in a heterogeneous population and proposes an appropriate cut-off point for treating patients with an arthroscopic Bankart repair or otherwise. Methods: This study analysed 99 shoulders after a traumatic dislocation that underwent arthroscopic Bankart repair with at least 3 years follow-up. Patients were divided into subcategories based on their respective ISI Score. Recurrence includes either a postoperative dislocation or perceived instability. Results: The overall recurrence rate was found to be 26.3%. A significant correlation was identified between ISI Score and the recurrence rate (odds ratio [OR]: 1.545, 95% confidence interval [CI]: 1.231–1.939, p &lt; 0.001). Furthermore, ISI Score 4–6 (OR: 4.498, 95% CI: 1.866–10.842, p &lt; 0.001) and ISI Score &gt; 6 (OR: 7.076, 95% CI: 2.393–20.924, p &lt; 0.001) both had a significantly higher risk of recurrence compared to ISI Score 0–3. In ISI Score subcategories 0–3, 4–6 and &gt;6, the recurrence rate was, respectively, 15.4%, 40.7% and 71.4%. Conclusion: ISI Score has predictive value in determining the recurrence risk of shoulder instability following an arthroscopic Bankart repair in a heterogeneous population. Based on the findings of this study, we recommend using arthroscopic Bankart repair in patients with ISI Score 0–3. Clinical and shared decision-making are essential in the group with ISI Score 4–6, since the recurrence rate is significantly higher than in patients with ISI Score 0–3. Arthroscopic Bankart repair is not suitable for patients with ISI Score &gt; 6. Level of Evidence: Level III.</p

    Syzygies of torsion bundles and the geometry of the level l modular variety over M_g

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    We formulate, and in some cases prove, three statements concerning the purity or, more generally the naturality of the resolution of various rings one can attach to a generic curve of genus g and a torsion point of order l in its Jacobian. These statements can be viewed an analogues of Green's Conjecture and we verify them computationally for bounded genus. We then compute the cohomology class of the corresponding non-vanishing locus in the moduli space R_{g,l} of twisted level l curves of genus g and use this to derive results about the birational geometry of R_{g, l}. For instance, we prove that R_{g,3} is a variety of general type when g>11 and the Kodaira dimension of R_{11,3} is greater than or equal to 19. In the last section we explain probabilistically the unexpected failure of the Prym-Green conjecture in genus 8 and level 2.Comment: 35 pages, appeared in Invent Math. We correct an inaccuracy in the statement of Prop 2.

    Differences in pain, function and coping in Multidimensional Pain Inventory subgroups of chronic back pain: a one-group pretest-posttest study

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    Contains fulltext : 97819.pdf (publisher's version ) (Open Access)BACKGROUND: Patients with non-specific back pain are not a homogeneous group but heterogeneous with regard to their bio-psycho-social impairments. This study examined a sample of 173 highly disabled patients with chronic back pain to find out how the three subgroups based on the Multidimensional Pain Inventory (MPI) differed in their response to an inpatient pain management program. METHODS: Subgroup classification was conducted by cluster analysis using MPI subscale scores at entry into the program. At program entry and at discharge after four weeks, participants completed the MPI, the MOS Short Form-36 (SF-36), the Hospital Anxiety and Depression Scale (HADS), and the Coping Strategies Questionnaire (CSQ). Pairwise analyses of the score changes of the mentioned outcomes of the three MPI subgroups were performed using the Mann-Whitney-U-test for significance. RESULTS: Cluster analysis identified three MPI subgroups in this highly disabled sample: a dysfunctional, interpersonally distressed and an adaptive copers subgroup. The dysfunctional subgroup (29% of the sample) showed the highest level of depression in SF-36 mental health (33.4 +/- 13.9), the interpersonally distressed subgroup (35% of the sample) a modest level of depression (46.8 +/- 20.4), and the adaptive copers subgroup (32% of the sample) the lowest level of depression (57.8 +/- 19.1). Significant differences in pain reduction and improvement of mental health and coping were observed across the three MPI subgroups, i.e. the effect sizes for MPI pain reduction were: 0.84 (0.44-1.24) for the dysfunctional subgroup, 1.22 (0.86-1.58) for the adaptive copers subgroup, and 0.53 (0.24-0.81) for the interpersonally distressed subgroup (p = 0.006 for pairwise comparison). Significant score changes between subgroups concerning activities and physical functioning could not be identified. CONCLUSIONS: MPI subgroup classification showed significant differences in score changes for pain, mental health and coping. These findings underscore the importance of assessing individual differences to understand how patients adjust to chronic back pain

    Total Joint Replacement in the Past Does Not Relate to a Deteriorated Functional Level and Health Status in the Oldest Old

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    Total hip or knee replacement is effective in improving joint function, quality of life, and pain reduction. The oldest old population with joint replacements (TJR) is underrepresented in current literature. We compared health-related and functional characteristics of oldest olds with and without TJR. Participants (aged 85 years) were divided into a group with and without TJR. Comorbidity, physical and joint functioning, daily living activities, quality of life, and mortality were recorded. Thirty-eight of 599 participants (6.3%) received a TJR in the past. Participants with a TJR had slightly less comorbidities, walked slower (P = 0.006), and complained more about hip-pain (P = 0.007). Mortality of those with a TJR was lower during the first 8-year followup (P = 0.04). All other characteristics were comparable between groups. We conclude that subjects with a TJR performed equally well, besides showing a lower gait speed and a higher frequency of hip-pain. Except for the lower gaitspeed, having a TJR is not associated with poorer health

    Novel Insights Into the Protective Role of Hemoglobin S and C Against Plasmodium falciparum Parasitemia.

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    Although hemoglobin S (HbS) and hemoglobin C (HbC) are well known to protect against severe Plasmodium falciparum malaria, conclusive evidence on their role against infection has not yet been obtained. Here we show, in 2 populations from Burkina Faso (2007-2008), that HbS is associated with a 70% reduction of harboring P. falciparum parasitemia at the heterozygous state (odds ratio [OR] for AS vs AA, 0.27; 95% confidence interval [CI], .11-.66; P = .004). There is no evidence of protection for HbC in the heterozygous state (OR for AC vs AA, 1.49; 95% CI, .69-3.21; P = .31), whereas protection even higher than that observed with AS is observed in the homozygous and double heterozygous states (OR for CC + SC vs AA, 0.04; 95% CI, .01-.29; P = .002). The abnormal display of parasite-adhesive molecules on the surface of HbS and HbC infected erythrocytes, disrupting the pathogenic process of sequestration, might displace the parasite from the deep to the peripheral circulation, promoting its elimination at the spleen level
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