Enhanced insight on the effects of boulders on bedload transport

River morphodynamics and sediment transportMechanics of sediment transpor

In Search of the Criterion Standard Test in Diagnostic Testing

Given a certain technology or procedure for diagnostic testing, different cutoff points produce different sensitivity and specificity rates. The cutoff point that generates highest sensitivity and specificity establishes the Criterion Standard Test (otherwise known as the Gold Standard Test). If, subject to good reason, a new testing technology or procedure emerges, the optimum cutoff point associated with it may generate higher sensitivity and specificity and thus a new improved Criterion Standard Test. Various cutoff selection methodologies have been proposed, all based on Euclidean geometry, involving the so-called Receiver Operating Characteristic (ROC) curve. Our purpose in this paper is to recommend a new selection methodology based on the P-Value associated with the well-known Pearson’s chi-squared test (χ2) – the conventional test utilized when testing for dependence between state of nature (disease present or not present) and evidence (test positive or negative measures). Using a hypothetical numerical example, we demonstrate that the cutoff point associated with the lowest P-Value of the Pearson’s chi-squared test is the one that maximizes sensitivity and specificity, or overall accuracy, thus establishing the Criterion Standard Test. Although the best geometric method (sums of squares) and the proposed method are equally effective in selecting the optimum cutoff point, only the proposed new procedure selects based on statistical significance. Additionally, we propose a simple theoretical benefits / costs linear setting to discuss the importance of net benefits associated with testing accuracy and reference harmful as well as beneficial testing cases found in various literature sources

Conditioned place preference and locomotor activity in response to methylphenidate, amphetamine and cocaine in mice lacking dopamine D4 receptors

Methylphenidate (MP) and amphetamine (AMPH) are the most frequently prescribed medications for the treatment of attention-deficit/hyperactivity disorder (ADHD). Both drugs are believed to derive their therapeutic benefit by virtue of their dopamine (DA)-enhancing effects, yet an explanation for the observation that some patients with ADHD respond well to one medication but not to the other remains elusive. The dopaminergic effects of MP and AMPH are also thought to underlie their reinforcing properties and ultimately their abuse. Polymorphisms in the human gene that codes for the DA D4 receptor (D4R) have been repeatedly associated with ADHD and may correlate with the therapeutic as well as the reinforcing effects of responses to these psychostimulant medications. Conditioned place preference (CPP) for MP, AMPH and cocaine were evaluated in wild-type (WT) mice and their genetically engineered littermates, congenic on the C57Bl/6J background, that completely lack D4Rs (knockout or KO). In addition, the locomotor activity in these mice during the conditioning phase of CPP was tested in the CPP chambers. D4 receptor KO and WT mice showed CPP and increased locomotor activity in response to each of the three psychostimulants tested. D4R differentially modulates the CPP responses to MP, AMPH and cocaine. While the D4R genotype affected CPP responses to MP (high dose only) and AMPH (low dose only) it had no effects on cocaine. Inasmuch as CPP is considered an indicator of sensitivity to reinforcing responses to drugs these data suggest a significant but limited role of D4Rs in modulating conditioning responses to MP and AMPH. In the locomotor test, D4 receptor KO mice displayed attenuated increases in AMPH-induced locomotor activity whereas responses to cocaine and MP did not differ. These results suggest distinct mechanisms for D4 receptor modulation of the reinforcing (perhaps via attenuating dopaminergic signalling) and locomotor properties of these stimulant drugs. Thus, individuals with D4 receptor polymorphisms might show enhanced reinforcing responses to MP and AMPH and attenuated locomotor response to AMPH.Fil: Thanos, P. K.. NIAAA Intramural Program; Estados Unidos. Brookhaven National Laboratory; Estados Unidos. Universidad de Buenos Aires; ArgentinaFil: Bermeo, C.. Brookhaven National Laboratory; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Suchland, K. L.. Oregon Health & Science University; Estados UnidosFil: Wang, G. J.. Brookhaven National Laboratory; Estados UnidosFil: Grandy, David K.. Oregon Health & Science University; Estados UnidosFil: Volkow, N. D.. NIAAA Intramural Program; Estados Unido

Indications and Techniques of Endoscope Assisted Vitrectomy

The popularization of ophthalmic endoscopy has been promoted by recent technological advancements that increase the number of indications for endoscopy. These advancements have improved the endoscope’s capabilities in its two fundamental surgical advantages: (1) bypassing anterior segment opacities, and (2) visualizing anteriorly positioned structures such as the ciliary bodies and sub-iris space. In this article, the current state of the ophthalmic endoscope is reviewed alongside its growing number of applications in glaucoma, vitreoretinal, and ocular trauma surgery. We describe the role of endoscopy in endocyclophotocoagulation for glaucoma, cyclitic membrane peeling in hypotony, retinal detachment surgery, intraocular foreign body removal, severe endophthalmitis, and pediatric traumatic vitreoretinal surgery. This review examines both the pearls and limitations of the ophthalmic application of endoscopy. In doing so, we hope to provide guidelines for using the endoscope and also to highlight applications of endoscopy that merit further study

Decreased dopamine activity predicts relapse in methamphetamine abusers.

Studies in methamphetamine (METH) abusers showed that the decreases in brain dopamine (DA) function might recover with protracted detoxification. However, the extent to which striatal DA function in METH predicts recovery has not been evaluated. Here we assessed whether striatal DA activity in METH abusers is associated with clinical outcomes. Brain DA D2 receptor (D2R) availability was measured with positron emission tomography and [(11)C]raclopride in 16 METH abusers, both after placebo and after challenge with 60 mg oral methylphenidate (MPH) (to measure DA release) to assess whether it predicted clinical outcomes. For this purpose, METH abusers were tested within 6 months of last METH use and then followed up for 9 months of abstinence. In parallel, 15 healthy controls were tested. METH abusers had lower D2R availability in caudate than in controls. Both METH abusers and controls showed decreased striatal D2R availability after MPH and these decreases were smaller in METH than in controls in left putamen. The six METH abusers who relapsed during the follow-up period had lower D2R availability in dorsal striatum than in controls, and had no D2R changes after MPH challenge. The 10 METH abusers who completed detoxification did not differ from controls neither in striatal D2R availability nor in MPH-induced striatal DA changes. These results provide preliminary evidence that low striatal DA function in METH abusers is associated with a greater likelihood of relapse during treatment. Detection of the extent of DA dysfunction may be helpful in predicting therapeutic outcomes

Can developmental trauma disorder be distinguished from posttraumatic stress disorder? A symptom-level person-centred empirical approach

Background: Developmental Trauma Disorder (DTD) is a proposed childhood psychiatric diagnosis for psychopathological and developmental sequela of victimization and attachment trauma extending beyond posttraumatic stress disorder (PTSD). Objective: To determine whether a sub-group of trauma-impacted children is characterized by symptoms of DTD that extend beyond, or co-occur with, the symptoms of PTSD. Method: Person-centred Latent Class Analyses (LCA) were done with data from 507 children (ages 7–18 years, (M = 12.11, SD = 2/92); 49% female) referred to the study by mental health or paediatric clinicians. Results: A four class solution was optimal (LMR = 398.264, p \u3c .001; Entropy = .93): (1) combined DTD + PTSD (n = 150); (2) predominant DTD (n = 156); (3) predominant PTSD (n = 54); (4) minimal symptoms (n = 147). Consistent with prior research, the DTD + PTSD class was most likely to have experienced traumatic emotional abuse and neglect (X2(3) = 16.916 and 28.016, respectively, p \u3c .001), and had the most psychiatric comorbidity (F(3, 502) = 3.204, p \u3c .05). Predominant DTD class members were most likely to meet criteria for Oppositional Defiant Disorder (ODD) (X2(3) = 84.66, p \u3c .001). Conclusion: Symptoms of DTD may occur with, or separately from, PTSD symptoms. Children with high DTD|+PTSD symptoms had extensive psychiatric comorbidity, while those with high DTD symptoms and minimal PTSD symptoms were highly likely to meet criteria for ODD. In clinical and research assessment and treatment of children with complex psychiatric comorbidity or disruptive behaviour problems, symptoms of DTD should be considered, both along with, and in the absence of, PTSD symptoms. - Antecedentes: El trastorno traumático del desarrollo (DTD en su sigla en inglés) es un diagnóstico psiquiátrico infantil propuesto para las secuelas psicopatológicas y del desarrollo de la victimización y el trauma del apego que se extiende más allá del trastorno de estrés postraumático (TEPT). Objetivo: Determinar si un subgrupo de niños afectados por un trauma se caracteriza por síntomas de DTD que se extienden más allá o coexiste con los síntomas del trastorno de estrés postraumático (TEPT). Método: Se realizaron análisis de clase latente (LCA en su sigla en inglés) centrados en la persona con datos de 507 niños (de 7 a 18 años de edad, (M = 12.11, DS = 2/92); 49% mujeres) remitidos al estudio por médicos pediátricos o de salud mental. Resultados: Una solución de cuatro clases fue óptima (LMR = 398.264, p \u3c .001; Entropía = .93): (1) combinado DTD + TEPT (n = 150); (2) DTD predominante (n = 156); (3) TEPT predominante (n = 54); (4) síntomas mínimos (n = 147). De acuerdo con investigaciones previas, la clase DTD + TEPT tenía más probabilidades de haber experimentado abuso emocional traumático y negligencia (X2(3) = 16.916 y 28.016, respectivamente, p \u3c .001), y tenía la mayor comorbilidad psiquiátrica (F(3, 502) = 3.204, p \u3c .05). Los miembros de la clase DTD predominante tenían más probabilidades de cumplir los criterios para el trastorno oposicionista desafiante (ODD en su sigla en inglés) (X2(3) = 84.66, p \u3c .001). Conclusión: Los síntomas de DTD pueden ocurrir con, o por separado de, los síntomas de TEPT. Los niños con síntomas de DTD + TEPT altos tenían una comorbilidad psiquiátrica extensa, mientras que aquellos con síntomas de DTD altos y síntomas mínimos de TEPT tenían muchas probabilidades de cumplir con los criterios para ODD. En la evaluación y tratamiento clínico y de investigación de niños con comorbilidad psiquiátrica compleja o problemas de comportamiento disruptivo, se deben considerar los síntomas de DTD, tanto junto con, como en ausencia de, síntomas de TEPT. - 背景：发育性创伤障碍 (DTD) 是一种倡议的儿童精神病学诊断，用于治疗超出创伤后应激障碍 (PTSD) 受害程度和依恋创伤的精神病和发育后遗症。 目的：确定一个受创伤影响的儿童亚组是否具有超出创伤后应激障碍 (PTSD) 症状或与之并发的 DTD 症状。 方法：对 507 名转诊到心理健康或儿科医生的儿童（年龄 7-18 岁，（平均年龄 = 12.11，标准差 = 2/92）；49% 女性）的数据进行了以人分类的潜在类别分析 (LCA)。 结果：四类解决方案是最佳的（LMR = 398.264，p \u3c .001；熵 = .93）：（1）DTD + PTSD 组合（n = 150）； (2) 主要 DTD (n = 156); (3) 主要的 PTSD (n = 54); (4) 轻微症状 (n = 147)。与先前研究一致，DTD + PTSD 类最有可能经历过创伤性情绪虐待和忽视（分别地，X2(3) = 16.916 和 28.016，p \u3c .001），并且有最多的精神并发症（F(3, 502) = 3.204, p \u3c .05)。主要的 DTD 类人群最有可能符合对立违抗障碍 (ODD) 的标准 (X2(3) = 84.66, p \u3c .001)。 结论：DTD 症状可能与 PTSD 症状同时出现，或与 PTSD 症状分开出现。高 DTD|+PTSD 症状的儿童具有广泛的精神并发症，而高 DTD 症状和少 PTSD 症状的儿童很可能符合 ODD 标准。在对患有复杂精神并发症或破坏性行为问题的儿童进行临床和研究评估和治疗时，无论是否存在 PTSD 症状，都应考虑 DTD 的症状

Skin rash associated with intravitreal bevacizumab in a patient with macular choroidal neovascularization

Ioannis D Ladas, Marilita M Moschos, Thanos D Papakostas, Athanasios I Kotsolis, Ilias Georgalas, Michail ApostolopoulosDepartment of Ophthalmology, “G. Gennimatas” Hospital of Athens, University of Athens, Athens, GreecePurpose: The purpose of this observational case report is to describe a case of skin rash after intravitreal use of bevacizumab.Methods: A 50-year-old man with choroidal neovascularization in the right eye due to age-related macular degeneration was treated with three intravitreal injections of bevacizumab.Results: Twelve days after the first injection, the patient developed a maculopapular rash on his forehead and on both temporal regions around his eyes. The rash disappeared eight days after treatment with topical corticosteroids. A skin rash with the same distribution reappeared 14 days after the second and 10 days after the third injection. Similarly, it disappeared five and seven days after the use of the same treatment. The follow-up period was 15 months after the third injection. During the follow-up period the rash did not reappear.Conclusion: This case report may initiate further investigation of similar cases to support this observation, as there are a lack of reports of skin rash after intravitreal administration of bevacizumab.Keywords: skin rash, bevacizumab, age-related macular degeneratio