Short-term solar energy forecasting: Integrated computational intelligence of LSTMs and GRU

Problems with erroneous forecasts of electricity production from solar farms create serious operational, technological, and financial challenges to both Solar farm owners and electricity companies. Accurate prediction results are necessary for efficient spinning reserve planning as well as regulating inertia and power supply during contingency events. In this work, the impact of several climatic conditions on solar electricity generation in Amherst. Furthermore, three machine learning models using Lasso Regression, ridge Regression, ElasticNet regression, and Support Vector Regression, as well as deep learning models for time series analysis include long short-term memory, bidirectional LSTM, and gated recurrent unit along with their variants for estimating solar energy generation for every five-minute interval on Amherst weather power station. These models were evaluated using mean absolute error root means square error, mean square error, and mean absolute percentage error. It was observed that horizontal solar irradiance and water saturation deficiency had a highly proportional relationship with Solar PV electricity generation. All proposed machine learning models turned out to perform well in predicting electricity generation from the analyzed solar farm. Bi-LSTM has performed the best among all models with 0.0135, 0.0315, 0.0012, and 0.1205 values of MAE, RMSE, MSE, and MAPE, respectively. Comparison with the existing methods endorses the use of our proposed RNN variants for higher efficiency, accuracy, and robustness. Multistep-ahead solar energy prediction is also carried out by exploiting hybrids of LSTM, Bi-LSTM, and GRU.

A simple, sensitive, label-free electrochemical immunosensor based on the chitosan-coated silver/cerium oxide (CS@Ag/CeO2) nanocomposites for the detection of alpha-fetoprotein (AFP)

Metal oxide-based sensors have the benefit of inexpensive, quick response, and high sensitivity in detecting specific biological species. In this article, a simple electrochemical immunosensor was fabricated using antibody-chitosan coated silver/cerium oxide (Ab-CS@Ag/CeO₂) nanocomposites on a gold electrode for sensitive alpha-fetoprotein (AFP) diagnosis in human serum samples. Successfully synthesis of AFP antibody-CS@Ag/CeO₂conjugates was confirmed through Fourier transform infrared spectra of the prototype. The amine coupling bond chemistry was then used to immobilize the resultant conjugate on a gold electrode surface. It was observed that the interaction of the synthesized Ab-CS@Ag/CeO₂nanocomposites with AFP prevented an electron transfer and reduced the voltammetric Fe(CN)₆^3-/4-peak current, which was proportional to the amount of AFP. The linear ranges of AFP concentration were found from 10^-12-10^-6g.ml^-1. The limit of detection was calculated using the calibration curve and came out to be 0.57 pg.ml^-1. The designed label-free immunosensor successfully detected AFP in human serum samples. As a result, the resulting immunosensor is a promising sensor plate form for AFP detection and could be used in clinical bioanalysis.

PCGA: Polynomial collocation genetic algorithm for singular Poisson-Boltzmann equation arising in thermal explosions

Heat generation as a result of the exothermic reaction reaches the environment mainly due to the conduction through the walls of the vessel. The balance between the heat generated and the heat conducted away, resulting in the explosion is described by the Frank-Kamenetzkii (FK) parameter ρ. The critical value of FK for which the explosion occurs depends upon the shape of the vessel, which requires the solution of governing singular nonlinear Poisson-Boltzmann equation. Owing to the exponential nonlinearity and singularity the analytical exact solution for the non-integer k values does not exist. This work focuses on implementing the polynomial collocation by exploiting the global optimization features of the genetic algorithm to solve the Poisson-Boltzmann equation for integer and non-integer shape factors (k). The governing equation was converted into coupled nonlinear algebraic equations and an objective function was formulated. The method was examined for six different configurations of the control parameters of GA to find the best set of parameters. The solution for temperature distribution is obtained for cylindrical (k = 1), parallelepiped (k = 0.438, 0.694), and an arbitrary shape (k = 0.5) respectively. The solution obtained from Polynomial Collocation Genetic Algorithm (PCGA) remained in good agreement with the corresponding analytical results for k = 1, with the minimum absolute error of 10 - 10 . The critical values of the FK are obtained as 1.5 , 1.4 , a n d 1.7 for shape factor k = 0.438 , 0.5 , a n d 0.694 respectively with the convergence of the order of 10 - 6 t o 10 - 5 . The obtained solution is fairly stable over appropriate independent runs with the variation in the fitness value ranging from 10 - 05 t o 10 - 03 . Further simulations were performed to validate the results through statistical error indices. The diminutive errors of the order of 10 - 6 confirm reliable optimum solution, accuracy, and stability.

Developing understanding of the fate and behaviour of silver in fresh waters and waste waters

The Windermere Humic Aqueous Model (WHAM) is often used for risk assessment of metals; WHAM can be used to estimate the potential bioavailability of dissolved metals, where metals complexed to dissolved organic matter (DOM) are expected to be less toxic than ionic forms. Silver is a potential metal of concern but WHAM has not been rigorously tested against experimental measurements. This study compares WHAM predictions to measured ionic silver during fixed pH (4, 8 or 10) argentometric titrations of DOM from diverse origins. There were almost two orders of magnitude variation in free silver between sources but, within model uncertainty, WHAM captured this variability. This agreement, between measurements and models, suggests that WHAM is an appropriate tool for silver risk assessment in surface receiving waters when DOM is predominantly in the form of humic/fulvic acids. In sewage samples WHAM dramatically underestimated silver binding by approximately 3 orders of magnitude. Simulations with additional specific strong silver binding sulphide-like binding sites could explain Ag binding at low loadings, but not at higher loadings. This suggests the presence of additional intermediate strength binding sites. These additional ligands would represent components of the raw sewage largely absent in natural waters unimpacted by sewage effluents. A revised empirical model was proposed to account for these sewage-specific binding sites. Further, it is suspected that as sewage organic matter is degraded, either by natural attenuation or by engineered treatment, that sewage organic matter will degrade to a form more readily modelled by WHAM; i.e., humic-like substances. These ageing experiments were performed starting from raw sewage, and the material did in fact become more humic-like, but even after 30 days of aerobic incubation still showed greater Ag⁺ binding than WHAM predictions. In these incubation experiments it was found that silver (up to 1000 μg/L) had minimal impact on ammonia oxidation kinetics.

Magnetothermoelectric transport in modulated and unmodulated graphene

We draw motivation from recent experimental studies and present a comprehensive study of magnetothermoelectric transport in a graphene monolayer within the linear response regime. We employ the modified Kubo formalism developed for thermal transport in a magnetic field. Thermopower as well as thermal conductivity as a function of the gate voltage of a graphene monolayer in the presence of a magnetic field perpendicular to the graphene plane is determined for low magnetic fields (∼1 T) as well as high fields (∼8 T). We include the effects of screened charged impurities on thermal transport. We find good qualitative and quantitative agreement with recent experimental work on the subject. In addition, in order to analyze the effects of modulation, which can be induced by various means, on the thermal transport in graphene, we evaluate the thermal transport coefficients for a graphene monolayer subjected to a periodic electric modulation in a magnetic field. The results are presented as a function of the magnetic field and the gate voltage.

Thermodynamic properties of a weakly modulated graphene monolayer in a magnetic field

Theoretical investigation of thermodynamic properties of an electrically modulated graphene monolayer in the presence of a perpendicular magnetic field B is presented. This work is aimed at determining the modulation-induced effects on the thermodynamic properties of graphene. The results obtained are compared with those of conventional two-dimensional electron gas (2DEG) systems realized in semiconductor heterostructures. The one-dimensional periodic potential, due to electric modulation lifts the degeneracy of the Landau levels and converts them into bands whose width oscillates as a function of B. We find commensurability (Weiss) oscillations for small values of B and de Haas-van Alphen (dHvA)-type oscillations at larger values of B. We find that the modulation-induced effects on the thermodynamic properties are enhanced and less damped with temperature in graphene compared with conventional 2DEG systems. Furthermore, we have derived analytic asymptotic expressions which allow us to determine the critical temperature and critical magnetic field for the damping of magnetic oscillations in the thermodynamic quantities considered here.

Microdeletion/duplication at 15q13.2q13.3 among individuals with features of autism and other neuropsychiatric disorders

BACKGROUND

Segmental duplications at breakpoints (BP4-BP5) of chromosome 15q13.2q13.3 mediate a recurrent genomic imbalance syndrome associated with mental retardation, epilepsy, and/or electroencephalogram (EEG) abnormalities.

PATIENTS

DNA samples from 1445 unrelated patients submitted consecutively for clinical array comparative genomic hybridisation (CGH) testing at Children's Hospital Boston and DNA samples from 1441 individuals with autism from 751 families in the Autism Genetic Resource Exchange (AGRE) repository.

RESULTS

We report the clinical features of five patients with a BP4-BP5 deletion, three with a BP4-BP5 duplication, and two with an overlapping but smaller duplication identified by whole genome high resolution oligonucleotide array CGH. These BP4-BP5 deletion cases exhibit minor dysmorphic features, significant expressive language deficits, and a spectrum of neuropsychiatric impairments that include autism spectrum disorder, attention deficit hyperactivity disorder, anxiety disorder, and mood disorder. Cognitive impairment varied from moderate mental retardation to normal IQ with learning disability. BP4-BP5 covers approximately 1.5 Mb (chr15:28.719-30.298 Mb) and includes six reference genes and 1 miRNA gene, while the smaller duplications cover approximately 500 kb (chr15:28.902-29.404 Mb) and contain three reference genes and one miRNA gene. The BP4-BP5 deletion and duplication events span CHRNA7, a candidate gene for seizures. However, none of these individuals reported here have epilepsy, although two have an abnormal EEG.

CONCLUSIONS

The phenotype of chromosome 15q13.2q13.3 BP4-BP5 microdeletion/duplication syndrome may include features of autism spectrum disorder, a variety of neuropsychiatric disorders, and cognitive impairment. Recognition of this broader phenotype has implications for clinical diagnostic testing and efforts to understand the underlying aetiology of this syndrome.

The Currarino syndrome--hereditary transmitted syndrome of anorectal, sacral and presacral anomalies. Case report and review of the literature

The Currarino triad is a hereditary transmitted syndrome, originally defined by Currarino as ASP-association, consisting of an anorectal malformation, a sacral bony defect and a presacral mass. In most cases autosomal dominant transmission is suggested. In family members one or two features of the syndrome may be missing, indicating an incomplete form of this complex. We describe two unrelated girls at the age of 8 and 9 months respectively with ASP-association. Family screening in both patients showed 8 additional cases with a complete or incomplete Currarino triad, four of them being asymptomatic. A review of the literature up to 1991 revealed 48 patients with ASP-association. In more than 80% of cases, this complex is diagnosed in the first decade, whereas incomplete Currarino syndrome is diagnosed predominantly in adults. Most frequently the presacral mass in ASP-association was reported to be an anterior meningocele (47%) and a benign teratoma (40%). The number of patients with Currarino syndrome has been underestimated so far. We recommend anorectal examination, pelvic ultrasound and pelvic x-rays in all patients with a history of chronic constipation since early childhood. Positive findings should lead to further investigations such as barium enema, MRI, myelography and family screening. Close cooperation between pediatric surgeons and neurosurgeons is required to ensure adequate surgical treatment, considering both the risk of malignant degeneration as well as the risk of intraoperative nerve damage. Thus, radical excisional surgery is not obligatory in every case of Currarino syndrome.

The value of sonography in the detection of osteomyelitis

PURPOSE

A retrospective study was carried out in order to determine the role of sonography in establishing the diagnosis in extremity osteomyelitis.

MATERIALS AND METHODS

The imaging documents of 24 infants and children aged from 2 weeks to 13 years with osteomyelitis (acute 21, chronic 3) were reviewed. Sonograms and conventional radiographs were available in all patients. Additional skeletal scintigraphy had been performed in 13 patients and MRI in only 3. Special emphasis was put on the different ultrasound findings and their onset in the course of disease.

RESULTS

Intra-articular fluid collections (in 15 cases) and/or subperiosteal abscess formation (in 12) were the most frequent early sonographic findings, and preceded any radiographic changes by several days in 11 of these cases. Together with positive clinical signs of inflammation, they were usually sufficient to establish the correct diagnosis. In selected cases, fluid or abscess puncture for immediate microscopic and later bacteriological studies was carried out under sonographic control. In addition, sonography was also able to detect superficial cortical erosion and even an intramedullary focus in a very young patient.

CONCLUSION

Ultrasonography is a very helpful tool for establishing the correct diagnosis in osteomyelitis and reducing the frequency of additional imaging studies.

[Ultrasound of extremity lesions caused by birth trauma]

With regard to injuries of the extremities caused by birth trauma, ultrasound allows simultaneous direct evaluation of the surface of osseous elements and of cartilaginous and soft-tissue structures as well. Thus, not only fractures, but also concomitant articular fluid collections, respectively haematomas and/or dislocation of an epiphysis are demonstrated in their initial extent and in their course of healing. Additionally, closed repositions, for instance of a displaced epiphysis, can be exactly monitored by ultrasound. A reduced number of roentgenograms as well as renunciation of other imaging modalities are the consequence. Own experiences in 4 patients with birth trauma to the humerus confirm the high validity of ultrasound in this area as well.

US-guided hydrostatic reduction of intussusception in children

Over a period of 3 3/4 years, hydrostatic reduction of ileocolic intussusception was performed under sonographic guidance in 47 cases (a total of 41 consecutive patients). The enema consisted of a mixture of isotonic electrolyte solution and water-soluble contrast medium (9:1 ratio) and was given at a hydrostatic pressure of 80-100 cm water. Reduction was successful in 83% of cases (n = 39). Even initially remaining ileo-ileal intussusception could finally be reduced in two cases. No complications were observed. Since, in comparison with other conservative methods of reduction, the success rate was not substantially worse (versus that of pneumatic reduction) or was even higher (versus that of barium enema reduction), the method described can be recommended for wider use because of the substantial reduction in radiation exposure.

Hyperechoic lesions in the basal ganglia: an incidental sonographic finding in neonates and infants

Cerebral ultrasound (US) imaging was performed as a screening procedure in approximately 3,600 neonates and infants over a period of 18 months. Hyperechoic lesions in the basal ganglia and thalamic region were detected incidentally in 15 of these patients. Clinical diagnoses included cytomegalovirus infection, asphyxia, rotavirus infection, prematurity, amniotic infection, dysmorphic stigmata, hyperbilirubinemia, congenital heart disease, and diabetic fetopathia. Lesions showed a single punctate (n = 5), multiple punctate (n = 8), or stripe-like pattern (n = 2), with no disease-specific distribution. Computed tomography performed in two of the 15 patients was normal. Lesions resolved within four to seven months in four of eleven cases who had follow-up studies, whereas echogenicities persisted in the remaining seven patients over a period of observation ranging between one to 15 months. Our results indicate that hyperechoic lesions in the basal ganglia and thalamic region may be associated with congenital infections and asphyxia, but could indicate some other unknown pathology. No correlation was found between the morphology of foci and both clinical diagnosis and results of follow-up studies.

Choroid plexus cysts: a normal finding on ultrasound

Within a period of 2.5 years, cystic structures in the choroid plexus were encountered at cerebral sonography in 70 neonates and babies (45 male, 25 female; 18 premature babies). Their prevalence in patients examined during the first 4 weeks of life (n = 55) was 3%. The size of the cysts ranged from 1-4 and, rarely, up to 7 mm. They were mostly solitary and unilateral. Follow-up sonograms over periods up to 13 months showed that most of the cysts persisted unchanged. A few disappeared (n = 7), while distinct increase in size was observed in 1 case. Since no additional sonographic changes were observed and none of the patients displayed any neurological abnormalities and no association existed with any other, particularly chromosomal, disease, such plexus cysts are postulated to represent a normal sonographic finding and do not require follow-up.

[Deterioration of clinical findings in hip joint follow-ups in neonatal screening]

6 per cent out of 4290 hips checked by neonatal ultrasound screening could be reexamined later on. 7 of 200 hips (i.e. 4 per cent), primarily categorized as type IIa, showed an unexpected severe deterioration to type D (n = 3) or even to type IIIa (n = 4) after a mean-time of 9 weeks. Additional 5 cases with similar unfavourable courses from IIa to IIc, D or IIIa, and even 3 initially normal hips, changing to type IIa, were seen in another screening material (not yet systematically analyzed). Reasons for possible initial misinterpretation (purely visual evaluation in most cases, uncertainties in measuring suboptimal sonographic cuts, deficiencies in technical equipment and documentation), equivocal classification of border-line sonograms as well as possible influence of additional risk factors are discussed. Routine sonographic re-examinations after 6 (to 12) weeks are recommended as obligatory for all hips.