A New Monte Carlo Based Algorithm for the Gaussian Process Classification Problem

Gaussian process is a very promising novel technology that has been applied to both the regression problem and the classification problem. While for the regression problem it yields simple exact solutions, this is not the case for the classification problem, because we encounter intractable integrals. In this paper we develop a new derivation that transforms the problem into that of evaluating the ratio of multivariate Gaussian orthant integrals. Moreover, we develop a new Monte Carlo procedure that evaluates these integrals. It is based on some aspects of bootstrap sampling and acceptancerejection. The proposed approach has beneficial properties compared to the existing Markov Chain Monte Carlo approach, such as simplicity, reliability, and speed

A penalized likelihood based pattern classification algorithm

Penalized likelihood is a general approach whereby an objective function is defined, consisting of the log likelihood of the data minus some term penalizing non-smooth solutions. Subsequently, this objective function is maximized, yielding a solution that achieves some sort of trade-off between the faithfulness and the smoothness of the fit. Most work on that topic focused on the regression problem, and there has been little work on the classification problem. In this paper we propose a new classification method using the concept of penalized likelihood (for the two class case). By proposing a novel penalty term based on the K-nearest neighbors, simple analytical derivations have led to an algorithm that is proved to converge to the global optimum. Moreover, this algorithm is very simple to implement and converges typically in two or three iterations. We also introduced two variants of the method by distance-weighting the K-nearest neighbor contributions, and by tackling the unbalanced class patterns situation. We performed extensive experiments to compare the proposed method to several well-known classification methods. These simulations reveal that the proposed method achieves one of the top ranks in classification performance and with a fairly small computation time. © 2009 Elsevier Ltd. All rights reserved

Pattern classification using a penalized likelihood method

Penalized likelihood is a well-known theoretically justified approach that has recently attracted attention by the machine learning society. The objective function of the Penalized likelihood consists of the log likelihood of the data minus some term penalizing non-smooth solutions. Subsequently, maximizing this objective function would lead to some sort of trade-off between the faithfulness and the smoothness of the fit. There has been a lot of research to utilize penalized likelihood in regression, however, it is still to be thoroughly investigated in the pattern classification domain. We propose to use a penalty term based on the K-nearest neighbors and an iterative approach to estimate the posterior probabilities. In addition, instead of fixing the value of K for all pattern, we developed a variable K approach, where the number of neighbors can vary from one sample to another. The chosen value of K for a given testing sample is influenced by the K values of its surrounding training samples as well as the most successful K value of all training samples. Comparison with a number of well-known classification methods proved the potential of the proposed method. © 2010 Springer-Verlag

A modified k-nearest neighbor classifier to deal with unbalanced classes

We present in this paper a simple, yet valuable improvement to the traditional k-Nearest Neighbor (kNN) classifier. It aims at addressing the issue of unbalanced classes by maximizing the class-wise classification accuracy. The proposed classifier also gives the option of favoring a particular class through evaluating a small set of fuzzy rules. When tested on a number of UCI datasets, the proposed algorithm managed to achieve a uniformly good performance

Influence of gender on static balance in healthy community dwelling elderly: a comparison using posturography

Background: Background and need of study- Influence of gender on balance is still controversial. Previous researchers have done studies using traditional methods. These methods may fail to detect subtle changes in balance difference. A tool like posturography which is highly specific may help to for accurate assessment and hence precise conclusion. Aim was to compare balance scores of male and female elderly using modified Clinical Test of Sensory Interaction on Balance (CTSIB).Methods: There were 56 healthy elderly ambulating without an assistive device and free from any neurological and orthopedic problems were assessed for their balance abilities using mCTSIB of balance master(standing on firm surface with eyes open, with eyes closed, standing on foam surface with eyes open and with eyes closed). Sway velocity was assessed using Unpaired t test.Results: There was a no significant difference in scores of modified CTSIB between male and female elderly ( p value>0.005).Conclusions: Gender has no effect on static balance abilities between male and female elderly while performing modified clinical test of sensory interaction on balance

A Green Synthesis of Iron/Copper Nanoparticles as a Catalytic of Fenton-like Reactions for Removal of Orange G Dye

تدرس هذه الورقة البحثية استخدام طريقة صديقة للبيئة وغير مكلفة لإزالة الصبغة البرتقالية G (OG) من المحلول المائي، حيث تم استخدام مستخلص أوراق شجرة الفيكس لغرض التخليق الأخضر لجسيمات الحديد/نحاس ثنائية الفلز النانوية (G-Fe/Cu-NPs). بعد أن تم تحضير G-Fe/Cu-NPs تم تشخيصها باستخدام مجهر الماسح الالكتروني، BET، مجهر القوة الذرية، مطياف الطاقة المشتتة، مطيافية الأشعة تحت الحمراء، و مقياس زيتا. أظهرت نتائج التشخيص بأن شكل G-Fe/Cu-NPs كان مستدير شبه كروي ويتراوح الحجم بين 32-59 نانومتر بينما كانت مساحتها السطحية 4.452 م2/غم. فيما بعد اُستخدمت الجسيمات النانوية الناتجة كعامل مساعد في تفاعلات الأكسدة الشبيهة بالفنتون. حيث أن كفاءة تحلل صبغة OG اعتمدت بشكل كبير على تركيز الهيدروجين بيروكسايد (1.7-5.28 ملي مولاري)، كمية العامل المساعد (0.4-1.6 غم/لتر)، درجة الحامضية (2-7)، تركيز OG الابتدائي (25-75 ملغم/لتر) ودرجة الحرارة (20-50 درجة مئوية). أظهرت التجارب الدفعية أن 94.8% لتركيز 50 ملغم/لتر من صبغة OG تمت ازالته عند الظروف المثلى للهيديروجين بيروكسايد، كمية العامل المساعد، درجة الحامضية، ودرجة الحرارة والتي كانت 3.52 ملي مولاري،1غم/لتر، 3، و 40 درجة مئوية على التوالي خلال زمن مقداره 30 دقيقة. أيضاً أظهرت نتائج دراسة النماذج الحركية بأن ازالة صبغة OG تتبع نموذج  حركي من الدرجة الثانية. أخيراً، تم دراسة الديناميكية الحرارية للتفاعل وخلُصت إلى ان التفاعل ماصاً للحرارة وله طاقة تنشيط مقدارها 29.725 كيلوجول/مول.This research paper studies the use of an environmentally and not expensive method to degrade Orange G dye (OG) from the aqueous solution, where the extract of ficus leaves has been used to fabricate the green bimetallic iron/copper nanoparticles (G-Fe/Cu-NPs). The fabricated G‑Fe/Cu-NPs were characterized utilizing scanning electron microscopy, BET, atomic force microscopy, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy and zeta potential. The rounded and shaped as like spherical nanoparticles were found for G-Fe/Cu‑NPs with the size ranged 32-59 nm and the surface area was 4.452 m2/g. Then the resultant nanoparticles were utilized as a Fenton-like oxidation catalyst. The degradation efficiency of OG dye highly depends on H2O2 concentration (1.7-5.28 mM), catalyst dose (0.4-1.6 g/L), pH (2-7), initial OG concentration (25-75 mg/L), and temperature (20-50 ℃). Batch experiments showed that 94.8 % of 50 mg/L of OG dye was removed within the optimum peroxide concentration, dose, pH and temperature which were 3.52 mM, 1 g/L, 3, and 40℃ respectively along with 30 min contact time. The results of kinetic models showed that OG removal followed the second-order model. Finally, the thermodynamic study of reaction was also examined and concluded to endothermic reaction with 29.725 kJ/mol activation energy

Beyond reach: Do symmetric changes in motor costs affect decision making? A registered report

Executing an important decision can be as easy as moving a mouse cursor or reaching towards the preferred option with a hand. But would we decide differently if choosing required walking a few steps towards an option? More generally, is our preference invariant to the means and motor costs of reporting it? Previous research demonstrated that asymmetric motor costs can nudge the decision-maker towards a less costly option. However, virtually all traditional decision-making theories predict that increasing motor costs symmetrically for all options should not affect choice in any way. This prediction is disputed by the theory of embodied cognition, which suggests that motor behavior is an integral part of cognitive processes, and that motor costs can affect our choices. In this registered report, we investigated whether varying motor costs can affect response dynamics and the final choices in an intertemporal choice task: choosing between a readily available small reward and a larger but delayed reward. Our study compared choices reported by moving a computer mouse cursor towards the preferred option with the choices executed via a more motor costly walking procedure. First, we investigated whether relative values of the intertemporal choice options affect walking trajectories in the same way as they affect mouse cursor dynamics. Second, we tested a hypothesis that, in the walking condition, increased motor costs of a preference reversal would decrease the number of changes-of-mind and therefore increase the proportion of impulsive, smaller-but-sooner choices. We confirmed the hypothesis that walking trajectories reflect covert dynamics of decision making, and rejected the hypothesis that increased motor costs of responding affect decisions in an intertemporal choice task. Overall, this study contributes to the empirical basis enabling the decision-making theories to address the complex interplay between cognitive and motor processes

The von Economo neurons in frontoinsular and anterior cingulate cortex in great apes and humans

The von Economo neurons (VENs) are large bipolar neurons located in frontoinsular (FI) and anterior cingulate cortex in great apes and humans, but not other primates. We performed stereological counts of the VENs in FI and LA (limbic anterior, a component of anterior cingulate cortex) in great apes and in humans. The VENs are more numerous in humans than in apes, although one gorilla approached the lower end of the human range. We also examined the ontological development of the VENs in FI and LA in humans. The VENs first appear in small numbers in the 36th week post-conception, are rare at birth, and increase in number during the first 8 months after birth. There are significantly more VENs in the right hemisphere than in the left in FI and LA in postnatal brains of apes and humans. This asymmetry in VEN numbers may be related to asymmetries in the autonomic nervous system. The activity of the inferior anterior insula, which contains FI, is related to physiological changes in the body, decision-making, error recognition, and awareness. The VENs appear to be projection neurons, although their targets are unknown. We made a preliminary study of the connections of FI cortex based on diffusion tensor imaging in the brain of a gorilla. The VEN-containing regions connect to the frontal pole as well as to other parts of frontal and insular cortex, the septum, and the amygdala. It is likely that the VENs in FI are projecting to some or all of these structures and relaying information related to autonomic control, decision-making, or awareness. The VENs selectively express the bombesin peptides neuromedin B (NMB) and gastrin releasing peptide (GRP) which are also expressed in another population of closely related neurons, the fork cells. NMB and GRP signal satiety. The genes for NMB and GRP are expressed selectively in small populations of neurons in the insular cortex in mice. These populations may be related to the VEN and fork cells and may be involved in the regulation of appetite. The loss of these cells may be related to the loss of satiety signaling in patients with frontotemporal dementia who have damage to FI. The VENs and fork cells may be morphological specializations of an ancient population of neurons involved in the control of appetite present in the insular cortex in all mammals. We found that the protein encoded by the gene DISC1 (disrupted in schizophrenia) is preferentially expressed by the VENs. DISC1 has undergone rapid evolutionary change in the line leading to humans, and since it suppresses dendritic branching it may be involved in the distinctive VEN morphology

Polyamines: total daily intake in adolescents compared to the intake estimated from the Swedish Nutrition Recommendations Objectified (SNO)

Background: Dietary polyamines have been shown to give a significant contribution to the body pool of polyamines. Knowing the levels of polyamines (putrescine, spermidine, and spermine) in different foods and the contribution of daily food choice to polyamine intake is of interest, due to the association of these bioactive amines to health and disease. Objective: To estimate polyamine intake and food contribution to this intake in adolescents compared to a diet fulfilling the Swedish Nutrition Recommendations. Design: A cross-sectional study of dietary intake in adolescents and an ‘ideal diet’ (Swedish nutrition recommendations objectified [SNO]) list of foods was used to compute polyamine intake using a database of polyamine contents of foods. For polyamine intake estimation, 7-day weighed food records collected from 93 adolescents were entered into dietetic software (Dietist XP) including data on polyamine contents of foods. The content of polyamines in foods recommended according to SNO was entered in the same way. Results: The adolescents’ mean daily polyamine intake was 316±170 µmol/day, while the calculated contribution according to SNO was considerably higher with an average polyamine intake of 541 µmol/day. In both adolescent's intake and SNO, fruits contributed to almost half of the total polyamine intake. The reason why the intake among the adolescents was lower than the one calculated from SNO was mainly due to the low vegetable consumption in the adolescents group. Conclusions: The average daily total polyamine intake was similar to that previously reported in Europe. With an ‘ideal’ diet according to Swedish nutrition recommendations, the intake of this bioactive non-nutrient would be higher than that reported by our adolescents and also higher than that previously reported from Europe