Separate Intervals Research Articles

Management of breather interactions

We propose theoretically and confirm experimentally a general approach to manage multiple nonlinear interactions of coherent solitary wave structures on an unstable background---breathers. It allows adjusting the initial positions and phases of more than two moving breathers to observe various desired wave states at controllable moments of wave evolution. Our theoretical framework relies on exact multibreather solutions to the one-dimensional focusing nonlinear Schr\"odinger equation and asymptotic expressions describing shifts of breather positions and phases acquired by them in mutual collisions. As proof-of-principle, we consider a couple of separated pairs of breathers initially synchronized in a small-amplitude patterns; meanwhile, our approach can be generalized to other breather types and wave states. We obtain an explicit expression for the separation interval between the pairs so that the interactions of the breathers from the neighboring patterns lead to the formation of an extreme amplitude wave or recurrence to the initial small-amplitude state. Experiments are carried out on a light wave platform with a nearly conservative optical fiber system, which accurately reproduces the predicted dynamics and proves the viability of our nonlinear wave theory.

Fractional Lau effect with binary gratings: A frequency analysis

A theoretical study of the fractional Lau effect is performed for a Lau set-up equipped with binary gratings. The separations between the two gratings are chosen equal to an elementary distance divided by a positive integer. Fourier components of the observed pattern function are calculated for these distances. Also, this study shows that it is sufficient to study the Lau patterns in a restricted interval of the gratings separation. Experimental and simulation results are consistent with the theoretical predictions.

Rectangular multivariate normal prediction regions for setting reference regions in laboratory medicine

ABSTRACT Reference intervals are among the most widely used medical decision-making tools and are invaluable in the interpretation of laboratory results of patients. Moreover, when multiple biochemical analytes are measured on each patient, a multivariate reference region (MRR) is needed. Such regions are more desirable than separate univariate reference intervals since the latter disregard the cross-correlations among variables. Traditionally, assuming multivariate normality, MRRs have been constructed as ellipsoidal regions, which cannot detect componentwise extreme values. Consequently, MRRs are rarely used in actual practice. In order to address the above drawback of ellipsoidal reference regions, we propose a procedure to construct rectangular MRRs under multivariate normality. The rectangular MRR is computed using a prediction region criterion. However, since the population correlations are unknown, a parametric bootstrap approach is employed for computing the required prediction factor. Also addressed in this study is the computation of mixed reference intervals, which include both two-sided and one-sided prediction limits, simultaneously. Numerical results show that the parametric bootstrap procedure is quite accurate, with estimated coverage probabilities very close to the nominal level. Moreover, the expected volumes of the proposed rectangular regions are substantially smaller than the expected volumes obtained from Bonferroni simultaneous prediction intervals. We also explore the computation of covariate-dependent MRRs in a multivariate regression setting. Finally, we discuss real-life applications of the proposed methods, including the computation of reference ranges for the assessment of kidney function and for components of the insulin-like growth factor system in adults.

Prospective Open-Label, Single-Arm, Single-Center Follow-Up Study of the Application of the Advanced Hybrid Closed Loop System in Well-Controlled Children and Adolescents with Type 1 Diabetes.

Background: The aim of this prospective open-label single-arm single-center follow-up study was to analyze glycemic control in children and adolescents with type 1 diabetes treated with the advanced hybrid closed loop (AHCL) system in relation to a sensor-augmented pump with low-glucose suspend (SAP-LGS) or predictive low-glucose suspend (SAP-PLGS). Materials and Methods: The data for 50 children and adolescents (age 5.5-19.6 years) with type 1 diabetes, receiving insulin through an AHCL system after being switched from SAP-LGS/PLGS systems, were included in the analysis. The SAP-LGS/PLGS records from 2 weeks preceding the AHCL connection were compared with the records from the first 4 weeks of AHCL use, represented as two separate 2-week intervals. Results: Significant improvements in most of the parameters, namely time spent in the range of 70-140 mg/dL (from 53.80% ± 12.35% to 61.70% ± 8.42%, P < 0.001) and 70-180 mg/dL (from 76.17% ± 10.28% to 81.32% ± 7.71%, P < 0.001), average sensor glucose (from 138.61 ± 16.66 to 130.02 ± 10.91 mg/dL, P < 0.001), and glucose management indicator (from 6.54% ± 0.45% to 6.27% ± 0.29%, P = 0.001), were observed within 2 weeks of switching to the AHCL. More evident improvements were observed for the parameters monitored at night than during the day. The potential limitations of this study were the short observation time, lack of glycated hemoglobin measurements, and no control arm. Conclusion: The AHCL system can significantly improve glycemic control even in well-controlled children and adolescents with type 1 diabetes by increasing the proportion of time spent in the narrower range of 70-140 mg/dL and decreasing the mean glucose concentration, especially during the night.

Local and non-local properties of the entanglement Hamiltonian for two disjoint intervals

We consider free-fermion chains in the ground state and the entanglement Hamiltonian for a subsystem consisting of two separated intervals. In this case, one has a peculiar long-range hopping between the intervals in addition to the well-known and dominant short-range hopping. We show how the continuum expressions can be recovered from the lattice results for general filling and arbitrary intervals. We also discuss the closely related case of a single interval located at a certain distance from the end of a semi-infinite chain and the continuum limit for this problem. Finally, we show that for the double interval in the continuum a commuting operator exists which can be used to find the eigenstates.

Peripheral-Free Calibration Method for Redundant IMUs Based on Array-Based Consumer-Grade MEMS Information Fusion.

The MEMS array-based inertial navigation module (M-IMU) reduces the measurement singularities of MEMS sensors by fusing multiple data processing to improve its navigation performance. However, there are still existing random and fixed errors in M-IMU navigation. The calibration method calibrates the fixed error parameters of M-IMU to further improve navigation accuracy. In this paper, we propose a low-cost and efficient calibration method to effectively estimate the fixed error parameters of M-IMU. Firstly, we manually rotate the M-IMU in multiple sets of different attitudes (stationary), then use the LM-calibration algorithm to optimize the cost function of the corresponding sensors in different intervals of the stationary-dynamic filter separation to obtain the fixed error parameters of MEMS, and finally, the global fixed error parameters of the M-IMU are calibrated by adaptive support fusion of the individual MEMS fixed error parameters based on the benchmark conversion. A comparison of the MEMS calibrated separately by the fusion-calibration algorithm and the LM-calibration algorithm verified that the calibrated MEMS array improved the measurement accuracy by about 10 db and reduced the dispersion of the output data by about 8 db compared to the individual MEMS in a multi-dimensional test environment, indicating the robustness and feasibility of the fusion calibration algorithm.

Low-Cost Millimeter Wave Frequency Scanning Based Synthesis Aperture Imaging System for Concealed Weapon Detection

In this article, a novel low-cost frequency scanning-based synthetic aperture radar (F-SAR) system is proposed for high-resolution imaging. F-SAR scheme is demonstrated for personal screening for the first time. A hybrid scanning model is presented to illuminate the human body, namely, frequency control beam steering in cross-track and mechanical scanning in along-track. A frequency scanning-based tomographic SAR focusing algorithm is proposed. Accordingly, a power spectrum estimation algorithm in cross-track and synthetical aperture processing in along-track are compounded in the signal processing framework. Unlike a variety of multiple input multiple output (MIMO) array imaging which illuminates the object by switching different channels sequentially over separate time intervals, the F-SAR concept sweeps across all swaths over each chirp by employing a frequency scanned beam. Herein imaging time and hardware cost can be significantly cut down by dimensionality reduction from the MIMO system to a single input single output (SISO) system. Furthermore, to fulfill the particular scheme of the F-SAR system, a novel combo antenna module, leaky-wave slotted waveguide combined with a cylindrical lens, is proposed and achieved at 78–92-GHz band, by which a steering fan-beam focused at the object under test (OUT) plane is radiated. The radiation beam is focalized by the cylindrical lens accompanied by frequency sweeping, while is diffused in along-track. The frequency-controlled beam-steering concept and the fan-beam focusing mechanism are verified by the chamber measurements. The measured scanning range is 23°. Beamwidth of 11–16 mm is obtained at the focal plane. Beam steering in cross-track together with mechanical scanning in along-track can attain a field of view (FoV) of 0.54 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{2}$ </tex-math></inline-formula> . Through-clothes imaging of person-borne concealed objects and the real-time capability are demonstrated by experiments. Resolutions in both along-track and cross-track can reach 5 mm.

Analytical forecasting of the optimal trajectory of mobile robot

The purpose of the research, the results of which are presented in the article, is the analytical synthesis of the law of control of a wheeled mobile robot while it moves along a trajectory specified by reference points on the surface in an inertial coordinate system. The analysis of the existing various approaches to the formation of a given trajectory of movement of a mobile robot, based on a different mathematical formulation of the problem, is carried out. To achieve this goal, the trajectory of motion is considered to consist of separate intervals, at each of which the control optimization problem is solved. The optimization criterion in general form and its representation in the form of a minimized quadratic quality functional, convenient for analytical synthesis of control, are substantiated. As components of the functional, the parameters of the deviation of the trajectory of the mobile robot from the given points in space are considered, as well as the predicted parameters of the velocity vector and the controlling normal acceleration of the mobile robot mass center. In this case, at each given point in space, the trajectory direction to the next point is taken into account, which ensures the optimal curvature of the trajectory at a given flight speed of the aircraft. As a result of analytical synthesis, mathematical dependences were obtained to determine the control acceleration, which allow in the robot control system to obtain a given optimal control law in the form of the rotation angle of the velocity vector, which ultimately ensures the minimum energy consumption by the mobile robot for various conditions of its use. The validity of the proposed theoretical provisions is confirmed by an illustrative example, in which, for a simplified mathematical formulation of the problem, the optimal laws of changing the direction of the velocity vector and the parameters of the trajectory of a mobile robot are calculated by means of computer modeling. The illustrations show the trajectories of the robot through various given points in space and the law of changing the direction of the velocity vector.

Plasma von Willebrand Factor Antigen Levels and Its Relation with ABO Blood Group, Age and Sex

Background: The ABO blood antigens may influence the levels of vWF: Ag and put individuals at risk of coagulopathies. This study assessed the plasma vWF: Ag and its relation with ABO blood antigens among healthy adults in northern Ghana. Methods: This cross-sectional study recruited 84 blood donors, aged 18–50 years, at Tamale Teaching Hospital. Blood groups were determined using the standard tube method, and a complete blood count was measured with an automated haematology analyzer. Sandwich ELISA was used to assess plasma vWF: Ag levels. The data obtained were analyzed using SPSS version 22. Results: The frequencies of O, A, B, and AB blood groups were 34 (40.5%), 25 (29.8%), 20 (23.8%), and 5 (6.0%), respectively. vWF: Ag levels were higher among the non-O than group O individuals (p = 0.008). Plasma vWF: Ag levels were lower in group O compared to AB (p = 0.015) and A (p = 0.013) individuals. Males had higher vWF: Ag levels than females (p = 0.002). A moderately positive correlation was observed between age and vWF levels (r = 0.497, p&lt;0.001). Blood group O participants had lower absolute neutrophil counts (p = 0.039), but higher RDW-SD (p = 0.045). Conclusion: The predominant blood group was O, followed by other groups in the order: O&gt;A&gt;B&gt;AB. Plasma vWF: Ag levels were higher in non-group O compared with group O individuals. Males had higher vWF: Ag levels, and a positive correlation between age and vWF: Ag was observed. Again, blood group O participants had lower neutrophil counts, but higher RDW-SD. The relationship between ABO blood phenotypes and plasma vWF: Ag should be considered in clinical practice. The establishment of separate reference intervals of vWF: Ag for the various phenotypes of ABO is recommended. Also, the study recommends further multicenter studies to assess the link between ABO phenotypes and all the endothelial cell parameters. Doi: 10.28991/SciMedJ-2022-04-02-02 Full Text: PDF

Global and regional externalities of the Ukrainian energy sector

PurposeThe purpose of this paper is to develop a methodology for assessing the effects of global and regional externalities that create traditional power generation industries and to propose a transition to a tariff strategy taking into account these consequences. The main purpose of the research is to analyze the current wholesale electricity tariffs in the energy market of Ukraine and propose their assessment taking into account external effects for other sectors of the economy.Design/methodology/approachAt the first stage, according to observations for 2004–2019 on the amount of pollution and the cost of agricultural products in some regions of Ukraine, which is provided in 2010 prices, the impact of hazardous emissions on the cost of agricultural products was analyzed in each region. The use of panel regression allowed to combine spatial and temporal studies (12 separate areas and time interval 2004–2019). To assess the external effects of heat generation, panel regression was used, which made it possible to combine spatial and temporal data on the impact of pollution on the efficiency of agricultural production and add regional losses of agricultural business to the cost of heat generation. This paper uses optimization models to maximize the function of public utility of electricity generation, making allowances for externalities.FindingsThis research assesses the negative externalities of Ukraine's energy and confirms the need for a global transition to a low-carbon economy primarily through climate finance. The analysis revealed the presence of various influences of the factor of regional air pollution and time. The hypothesis of the existence of a negative impact of local air pollution on agricultural production has been confirmed. An increase in emissions by 1,000 tons leads to an average decrease in regional agricultural production by UAH 84 million (at the prices of 2010).Originality/valueThe optimization problem of the ratio of different types of generation is set on the basis of maximizing the function of social utility of electricity generation, taking into account external effects. The authors presented an optimization model of electricity generation, which corresponded to the state of the energy market for 2019, provides an opportunity to assess the contribution of the inverse external effects of each electricity sector and to estimate external tariffs for each electricity generation sector.

Reference interval of antithrombin, protein C, and protein S activities in healthy adults in Iran, the effect of age, sex, oral contraceptive intake, and menopause.

Antithrombin (AT), protein C (PC), and protein S (PS) are natural anticoagulant proteins that deficiency in each of them is associated with an increased risk of venous thromboembolism.The overlapping of plasma levels of AT, PC, and PS between healthy individuals and heterozygote carriers poses significant challenges in precise diagnosis. This study aimed to evaluate the effect of most influencing variables on plasma levels of these proteins and propose specific reference intervals to improve the interpretation of the laboratory results. This study was conducted on 1464 individuals who were referred to Massoud medical laboratory, Tehran, Iran, from 2019 to 2020. AT and PC were measured through chromogenic assay and PS plasma level with the clot-based assay. A multivariable linear regression model was performed to evaluate the effect of sex, age, oral contraceptive (OCP) intake, and menopause state. Normal deviate z value was used for different subgroups to justify the need for a separate reference interval. 1200 verified healthy individuals (434males and 766 females), aged between 18 and 69years were included in the study. The mean±SD age of the participants was 39.78±11.79years. The age-related effects for AT were found in men. In females, increasing age was associated with a rise in AT, PC, and PS plasma levels. No sex difference was found in AT plasma level. OCP-taking is associated with a decrease in AT and an increase in PC plasma levels. This is the largest study ever conducted on healthy individuals in the Iranian population, using specific reference interval results in accurate diagnosis of true AT, PC, and PS deficiency.

Nonlinear eigenvalue topology optimization for structures with frequency-dependent material properties

Eigenvalue topology optimization problem has been a hot topic in recent years for its wide applications in many engineering areas. In the previous studies, the applied materials are usually assumed as elastic, and the resulting structural eigenfrequencies are obtained by solving a linear eigenvalue problem. However, many engineering materials, such as viscoelastic materials, have frequency-dependent modulus, which results in a more complicated nonlinear eigenvalue problem. This paper presents a systematic study on the nonlinear eigenvalue topology optimization problem with frequency-dependent material properties. The nonlinear eigenvalue problem is solved by a continuous asymptotic numerical method based on the homotopy algorithm and perturbation expansion technique, which involves higher-order differentiation of the nonlinear term and shows a fast convergence. Several schemes are proposed to improve the computational accuracy, applicability, and robustness of the method for the application in topology optimization, including Faà di Bruno's theorem, bisection method, and inverse iteration based eigenvector modification method. Three optimization problems are solved to demonstrate the effectiveness of the developed methods, including the maximization of the fundamental frequency, the eigenfrequency separation interval between two adjacent eigenfrequencies of given orders, and the eigenfrequency separation interval at a given frequency. Numerical examples show the large influence of the frequency-dependent material properties on the optimized results and validate the effectiveness of the developed method.

Comparison of Summative Temporal Bone Dissection Scales Demonstrate Equivalence.

Introduction Temporal bone surgery is a unique and complicated surgical skill that requires extensive training. There is an educational requirement to maximize trainee experience and provide effective feedback. Objective We evaluate three temporal bone dissection scales for efficacy, reliability, and accuracy in identifying resident skill during temporal bone surgery. Methods Residents of various skill levels performed a mastoidectomy with posterior tympanotomy on identic 3D-printed temporal bone models. Four blinded otologic surgeons evaluated each specimen at two separate intervals using three separate dissection scales: the Welling Scale (WS), the Iowa Temporal Bone Assessment Tool (ITBAT), and the CanadaWest Scale (CWS). Scores from each scale were compared in their ability to accurately separate residents by skill level, inter- and intrarater reliability, and efficiency in application. Results Nineteen residents from 9 postgraduate programs participated. Assessment was clustered into junior (postgraduate year or PGY 1, 2), intermediate (PGY 3) and senior resident (PGY 4, 5) cohorts. Analysis of variance (ANOVA) found significant differences between cohort performance ( p < 0.05) for all 3 scales considering the PGY level and the subjective account of temporal bone surgical experience. The inter-rater reliability was consistent across each scale. The intrarater reliability was comparable between the CWS (0.711) and the WS (0.713), but not the ITBAT (0.289). Time (in seconds) to complete scoring for each scale was also comparable between the CWS (42.7 ± 16.8), the WS (76.6 ± 14.5), and the ITBAT (105.6 ± 38.9). Conclusion All three scales demonstrated construct validity and consistency in performance, and consideration should be given to judicious use in training.

Anomalous mobility edges in one-dimensional quasiperiodic models

Mobility edges, separating localized from extended states, are known to arise in the single-particle energy spectrum of disordered systems in dimension strictly higher than two and certain quasiperiodic models in one dimension. Here we unveil a different class of mobility edges, dubbed anomalous mobility edges, that separate energy intervals where all states are localized from energy intervals where all states are critical in diagonal and off-diagonal quasiperiodic models. We first introduce an exactly solvable quasi-periodic diagonal model and analytically demonstrate the existence of anomalous mobility edges. Moreover, numerical multifractal analysis of the corresponding wave functions confirms the emergence of a finite energy interval where all states are critical. We then extend the sudy to a quasiperiodic off-diagonal Su-Schrieffer-Heeger model and show numerical evidence of anomalous mobility edges. We finally discuss possible experimental realizations of quasi-periodic models hosting anomalous mobility edges. These results shed new light on the localization and critical properties of low-dimensional systems with aperiodic order.

Emergence of kinematic space from quantum modular geometric tensor

We generalize the Quantum Geometric Tensor by replacing a Hamiltonian with a modular Hamiltonian. The symmetric part of the Quantum Geometric Tensor provides a Fubini-Study metric, and its anti-symmetric sector gives a Berry curvature. Our generalization dubbed Quantum Modular Geometric Tensor gives the metric and curvature of a Kinematic Space. We also use the result of the identity Virasoro block to relate the connected correlator of two Wilson lines to the two-point function of a modular Hamiltonian. This relation realizes a novel holographic entanglement formula for two intervals of a general separation. This result also provides a new interpretation to the connected correlators as the mutual information. Our study remains valid at the quantum level. Hence it provides an opportunity to explore the Kinematic Space in a generic case without conformal symmetry.

The Influence of Synthesis Method on Characteristics of Buffer and Organic Solutions of Thermo- and pH-Responsive Poly(N-[3-(diethylamino)propyl]methacrylamide)s.

Thermo- and pH-responsive poly(N-[3-(diethylamino)propyl]methacrylamide)s were synthesized by free radical polymerization and RAFT polymerization. The molar masses of the samples were 33,000–35,000 g∙mol−1. Investigations of the dilute solutions showed that the prepared samples were flexible chain polymers. The behavior of the synthesized polymers in the buffer solutions was analyzed by turbidity and light scattering at a pH range of 7–13 and a concentration range of 0.0002–0.008 g·cm−3. When the concentrated solutions were at a low temperature, there were macromolecules and aggregates, which were formed due to the interaction of hydrophobic units. For the investigated samples, the lower critical solution temperatures were equal. The phase separation temperatures decreased as pH increased. The influence of polydispersity index on the characteristics of the samples in the solutions was analyzed. The radii of molecules of poly(N-[3-(diethylamino)propyl]methacrylamide) obtained by RAFT polymerization at this temperature at the onset and end of the phase separation interval were lower than ones for samples synthesized by conventional free radical polymerization.

Complexing the hydraulic fracturing simulation results when hybrid acid-propant treatment performing and with the simultaneous hydraulic fracture initiation in separated intervals

The purpose of the work is to substantiate and formulate the principles of data generation with multiple results of hydraulic fracturing (HF) modeling. Qualitative data for assessment, intercomparison and subsequent statistical analysis are characterized by a single numerical value for each considered hydraulic fracturing parameter. For a number of hydraulic fracturing technologies, uncertainty may arise due to obtaining several values for the parameter under consideration. The scientific novelty of the work lies in the substantiation of a new approach for evaluating the obtained data series during hydraulic fracturing modeling. A number of data can be obtained both during the formation and modeling of several hydraulic fractures, and for one fracture when calculating in different modules of the simulator. As a result, an integration technique was developed that allows forming a uniform data array regardless of the number of elements in the hydraulic fracturing modeling results. Keywords: hydraulic fracturing; acid-proppant hydraulic fracturing; hydraulic fracturing of layered rocks; hydraulic fracturing modeling; pseudo-three-dimensional fracture model; data preparation; statistical analysis.

Functional Model of Communication Network of Microwave Link Stations with Adaptive Modulation and Package Switching

The article describes the model of the communication network functioning, which consist of microwave link stations with adaptive modulation and packet switching. Mathematical expressions are presented, which allow to calculate particular indicators of stability and throughput of microwave link intervals, lines and communication directions, as well as generalized quality indicators of the communication network as a whole, taking into account the peculiarities of the functioning of microwave link stations with adaptive modulation and packet switching under the fading conditions at separate microwave link intervals.

Role of Bisphenol A in Regulation of Arrival of Sexual Maturity and Fertility in Male Albino Rats

Reproductive toxicity during prepubertal and pubertal period causes significant alterations in sexual maturation and fertility. Bisphenol A has been associated with decreased sperm production, damaged testicular cells, perturbed hormone levels and reduced fertility. Its role in sexual maturity and duration before first successful mating is still elusive. The present study aimed to investigate BPA induced alteration in testicular development and fertility at critical period of peri-adolescence, adolescence and adulthood. Male albino rats were administered with 5, 25, and 50 mg/kg body weight/day (Group II, III and IV) for three separate time intervals 42-63, 42-91, and 42-105 postnatal days (PND). Body and testicular weight were measured and polynomial regression was applied to predict associations between variables. Fertility test was observed at every 7 days interval for each dose at investigated time intervals. Histological observations were carried out to examine parallels between results of fertility test. Results of each parameter was compared with respective sham control (Group I). A consistent decline in testicular weight gain was observed in BPA treated groups (p&lt;0.05). Strong relatedness between body and testicular weight variables was evident (R2³0.9). Initial successful mating was delayed significantly in BPA administered rats. Group IV showed maximum delay in first successful mating. Histological observations indicated interferences at various stages during spermatogenesis along with presence of tubular vacuolization, indicative of cellular toxicity. Higher doses of BPA inflicted more damage, likewise, longer duration amplified severity of adverse activity. BPA administration at critical period of reproductive development in male rats can adversely affect testicular functions leading to delayed and reduced fertility.

Biochemical reference intervals in broiler chickens according to age and strain

Abstract. The objective of the research was to study the physiological pattern of biochemical variables and to obtain reference intervals for young (less than 1 month) and adult (more than 1 month) broiler chickens of 2 strains. From the jugular vein, blood for analysis was collected, separated, and then immediately analyzed. The influence of age was significant for the majority of the investigated variables in the 2 groups. In Isa15 strain, a significant age-related decrease in plasma uric acid, glucose, cholesterol, triglycerides, phosphorus, potassium and iron was established. Also, a significant age-related increase in plasma calcium and ASAT was obtained in the same broiler strain. In Arbor Acres Plus strain, a significant age-related decrease in plasma glucose, cholesterol, triglycerides and phosphorus was observed. A significant age-related increase in plasma total protein, calcium and ASAT has also been reported in this broiler strain. A significant difference between the two strains was reported for plasma uric acid, glucose, cholesterol, phosphorus, magnesium and iron (p&lt;0.05). For most estimated parameters in the 2 strains, calculation of separate reference intervals for young and adult animals was appropriate. Except for potassium in young Isa15 strain, and phosphorus in young Arbor Acres Plus strain, all variables did not follow a normal distribution. Reference intervals are presented for both ages using non-parametric or robust method. 90% confidence intervals for both groups were calculated non-parametrically, or by the bootstraping method. The established reference intervals will be a useful guide for interpreting plasma biochemical variables in different strains of broiler chickens raised in Algeria, and reared in a mild Mediterranean climate.