652 research outputs found

    Construction of a 3-Dimensional MDS code

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    In this paper, we describe a procedure for constructing qq--ary [N,3,N−2][N,3,N-2]--MDS codes, of length N≀q+1N\leq q+1 (for qq odd) or N≀q+2N\leq q+2 (for qq even), using a set of non--degenerate Hermitian forms in PG(2,q2)PG(2,q^2).Comment: 8 Pages Minor typesetting changes; dedicatio

    A characterization of Hermitian varieties as codewords

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    It is known that the Hermitian varieties are codewords in the code defined by the points and hyperplanes of the projective spaces PG(r,q2)PG(r,q^2). In finite geometry, also quasi-Hermitian varieties are defined. These are sets of points of PG(r,q2)PG(r,q^2) of the same size as a non-singular Hermitian variety of PG(r,q2)PG(r,q^2), having the same intersection sizes with the hyperplanes of PG(r,q2)PG(r,q^2). In the planar case, this reduces to the definition of a unital. A famous result of Blokhuis, Brouwer, and Wilbrink states that every unital in the code of the points and lines of PG(2,q2)PG(2,q^2) is a Hermitian curve. We prove a similar result for the quasi-Hermitian varieties in PG(3,q2)PG(3,q^2), q=phq=p^{h}, as well as in PG(r,q2)PG(r,q^2), q=pq=p prime, or q=p2q=p^2, pp prime, and r≄4r\geq 4

    An algorithm for constructing some maximal arcs in \PG(2,q^2)

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    In 1974, J. Thas constructed a new class of maximal arcs for the Desarguesian plane of order q2q^2. The construction relied upon the existence of a regular spread of tangent lines to an ovoid in \PG(3,q) and, in particular, it does apply to the Suzuki--Tits ovoid. In this paper, we describe an algorithm for obtaining a possible representation of such arcs in \PG(2,q^2).Comment: 17 page

    Mixed Depression: A Mini-Review to Guide Clinical Practice and Future Research Developments

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    The debate on mixed states (MS) has been intense for decades. However, several points remain controversial from a nosographic, diagnostic, and therapeutic point of view. The different perspectives that have emerged over the years have turned into a large, but heterogeneous, literature body. The present review aims to summarize the evidence on MS, with a particular focus on mixed depression (MxD), in order to provide a guide for clinicians and encourage the development of future research on the topic. First, we review the history of MS, focusing on their different interpretations and categorizations over the centuries. In this section, we also report alternative models to traditional nosography. Second, we describe the main clinical features of MxD and list the most reliable assessment tools. Finally, we summarize the recommendations provided by the main international guidelines for the treatment of MxD. Our review highlights that the different conceptualizations of MS and MxD, the variability of clinical pictures, and the heterogeneous response to pharmacological treatment make MxD a real challenge for clinicians. Further studies are needed to better characterize the phenotypes of patients with MxD to help clinicians in the management of this delicate condition

    ORBIT CODES FROM FORMS ON VECTOR SPACES OVER A FINITE FIELD

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    In this paper we construct different families of orbit codes in the vector spaces of the symmetric bilinear forms, quadratic forms and Hermitian forms on an n-dimensional vector space over the finite field Fq. All these codes admit the general linear group GL(n, q) as a transitive automorphism group

    The association between dyslipidemia and lethality of suicide attempts: A case-control study

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    Evidence supports the existence of an association between dyslipidemia, psychiatric disorders, and suicide risk due to the effects of altered lipid profiles on serotoninergic neuron membranes. The aim of this study was to investigate the differences in c-reactive protein (CRP), thyroid functioning, total cholesterol, high lipoprotein density cholesterol (HDL-c), low-lipoprotein density cholesterol (LDL-c), and triglycerides (TG) serum levels in low lethality (LLSA) vs. high lethality suicide attempters (HLSA) within 24 h fromthe suicide attempt and inpatients who never attempted suicide (NAS). After attempting suicide, subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the section of Psychiatry from 1st August 2013 to 31st July 2018. Socio-demographic and clinical characteristics, serum lipids profile, CRP, and thyroid functioning were collected. The sample consisted of 133 individuals with a HLSA, 299 subjects with LLSA, and 200 patients NAS. HLSA subjects were more likely to be males and diagnosed as having a bipolar disorder. Furthermore, HLSA subgroup showed significantly lower total cholesterol and LDL-c levels and higher CRP serum levels compared to LLSA and control group, respectively. LLSA subgroup showed higher HDL-c levels compared to HLSA subgroup (no differences between HLSA and control group were observed). Additionally, the control group reported higher triglycerides levels compared to patients admitted to psychiatric ward for a suicide attempt. Only male gender, having a diagnosis of bipolar disorder, lower total cholesterol, and higher CRP serum levels predicted HLSA. Investigating the relation between dyslipidemia and the severity of suicide attempts may contribute to reveal the complex determinants underlying at-risk behaviors such as suicide, thus playing a relevant role in the possible prevention of this disabling phenomenon

    The role of seasonality and photoperiod on the lethality of suicide attempts: A case-control study

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    Background: The risk factors related to suicidal behaviors are complex and not yet fully known. Several studies underline how suicide results from the combination of psycho-social, biological, cultural, and environmental factors. The aim of this study was to investigate the potential role of seasonality and photoperiod on high-lethality suicide attempts (HLSA) compared with low-lethality suicide attempts (LLSA) in a sample of psychiatric inpatients. Methods: After attempting suicide, subjects were admitted in the emergency/psychiatric ward of the IRCCS Ospedale Policlinico San Martino from 1st August 2013 to 31st July 2018. Socio-demographic and clinical characteristics were collected. Results: The sample consisted of four hundred thirty-two individuals admitted for suicide attempt. One hundred thirty-three subjects (30.8%) of the sample committed a HLSA. The HLSA group peaked in the months with a higher sunlight exposure (June and July). Bivariate correlation analyses between seasonality/photoperiod in the whole sample and HLSA were positively associated with summer and highest solar intensity period. Limitations: Data were limited to a single hospital, patients’ seasonal environment, meteorological variables and psychological factors. In addition, the presence of acute life-events fostering the suicidal crisis has not been investigated. Conclusions: The current study provides a novel perspective on the questions surrounding the impact of seasonality and daylight exposure on lethality of suicide attempts. further studies are needed to provide deeper understandings on the delicate molecular network that links suicide behaviors, seasonality and daylight in order to develop more effective prevention and treatment strategies in the future

    Maximum temperature and solar radiation as predictors of bipolar patient admission in an emergency psychiatric ward

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    Environmental variables can regulate behavior in healthy subjects. Recently, some authors investigated the role of meteorological variables in bipolar patients with an impact on both the onset and course of bipolar disorder (BD). The aim of this study was to investigate the impact of meteorological variables and other indexes in bipolar hospitalized patients. We examined all patients admitted to the Psychiatric Inpatient Unit of San Luigi Gonzaga Hospital, Orbassano (Turin, Italy) from September 2013 to August 2015, collecting several socio-demographic and clinical characteristics. Seven hundred and thirty patients were included. Compared to the day of admission of control individuals, patients with BD were admitted on a day that presented higher minimum, medium, and maximum temperature, higher maximum humidity, higher solar radiation, and higher hours of sunshine. After logistic regression analysis, admissions to the emergency psychiatric ward due to a primary diagnosis of BD were associated with maximum temperature and solar radiation. The current study provides a novel perspective on the question surrounding seasonal mood patterns in patients with BD. A greater awareness of all possible precipitating factors is needed to inform self-management and psycho-educational programs as well as to improve resilience regarding affective recurrences in the clinical practice
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