Restriction Of Size Research Articles

Six degrees of freedom flight simulation of tilt-rotor aircraft with nacelle conversion

This paper presents six degrees of freedom flight simulation with mode conversion between airplane mode and helicopter mode as an application for realizing Digital Flight of the tiltrotor aircraft. The tiltrotor aircraft has the characteristics of both helicopters and propeller planes with changing the flight mode by tilting the engine nacelles. However, much less work with continuously changing these modes has been done so far. In this paper, the main components such as rotors, engine nacelles, fixed wings and a fuselage are considered. In order to perform large deformations of mesh geometry such as the rotation of the rotor and nacelle as well as the change of the position and attitude of the aircraft, the computational domain is decomposed into multiple domains corresponding to each component. Independently moving these domains makes possible to perform the characteristic behavior of a tiltrotor aircraft. To deal with rotations of multiple decomposed domains, the multi-axis sliding mesh approach is applied. As the solver for simulating unsteady flow driven by complicated moving boundaries, the unstructured Moving-Grid Finite-Volume method is adopted. Based on this solver, the Moving Computational Domain method enables the aircraft to fly in any size of region without restriction of mesh size. The airframe is treated as a rigid body, and the coupled simulations considering interaction with surrounding fluid of the aircraft are demonstrated. The result shows complicated fluid phenomena around the tiltrotor aircraft that occur when it flies with mode change.

Mechanical design and force control algorithm for a robot leg with hydraulic series-elastic actuators

This article presents a mechanical design structure for hydraulic actuators using the principle of series-elastic actuator, considering the restriction of mechanical structure, weight and size, as well as the requirement of high joint torques due to the large payload. An articulated leg was designed to incorporate with two of these elastic elements symmetrically for each joint. Further, for the hydraulic system with a position servo loop, a force control algorithm was particularly proposed and developed for joint torque tracking and Cartesian impedance control. Finally, a number of experiments were carried out on the leg platform, and the experimental results validated the effectiveness of the force control algorithm and the performance of the overall system.

Direct fabrication of inclined thin-walled parts by exploiting inherent overhanging capability of CMT process

PurposeThe purpose of this paper is to develop a build strategy for inclined thin-walled parts by exploiting the inherent overhanging capability of the cold metal transfer (CMT) process, which release wire-arc additive manufacturing from tedious programming work and restriction of producible size of parts.Design/methodology/approachInclined thin-walled parts were fabricated with vertically placed welding torch free from any auxiliary equipment. The inclined features were defined and analyzed based on the geometrical model of inclined parts. A statistical prediction model was developed to describe the dependence of inclined geometrical features on process variables. Based on these models, a build strategy was proposed to plan tool path and output process parameters. After that, the flow work was illustrated by fabricating a vase part.FindingsThe formation mechanism and regulation of inclined geometrical features were revealed by conducting experimental trials. The inclined angle can be significantly increased along with the travel speed and offset distance, whereas the wall width is mainly dependent on the ratio of wire feed speed to travel speed. In contrast to other welding process, CMT has a stronger overhanging capability, which provides the possibility to fabricate parts with large overhanging features directly with high forming accuracy.Originality/valueThis paper describes a novel build strategy for inclined thin-walled parts free from any auxiliary equipment. With the proposed strategy, a complex structural component can be deposited directly in the rectangular coordinates additive manufacturing system, indicating infinite possibilities on the producible size of the parts. Moreover, equipment requirements and tedious program work can also be significantly reduced.

EDUCATIONAL INTERVENTIONS IN IMPROVING QUALITY OF LIFE FOR HYPERTENSIVE PEOPLE: INTEGRATIVE REVIEW

ABSTRACT Objective: to evaluate the effectiveness of educational interventions in improving the quality of life of people with arterial hypertension. Method: an integrative literature review which included studies that conducted educational interventions aimed at the hypertensive public to improve quality of life. The search was performed in the following databases: MEDLINE, LILACS, IBECS, CUMED, BDENF, SciELO and CINAHL, without restriction of language, date and sample size. For this, the following descriptors were crossed: “hipertensão” (hypertension), “educação em saúde” (health education) and “qualidade de vida” (quality of life). 619 articles were retrieved and after the selection and analysis process, a total of 10 made up this review. Data extraction and analysis were performed with the help of validated instruments and the result summarized. Results: Most studies were developed on a quasi-experimental basis, using generic instruments to measure quality of life with significant improvement after educational interventions, with group technology being the most used educational strategy. Just one study used a specific instrument to evaluate hypertensive patients. Conclusion: these results may direct the interventions to be implemented by health professionals in managing arterial hypertension. Further investigations are needed to identify and verify the most effective interventions for hypertensive patients, considering heterogeneous profiles and aiming at improving quality of life.

Vacuum filters

We present vacuum filters, a type of data structures to support approximate membership queries. Vacuum filters cost the smallest space among all known AMQ data structures and provide higher insertion and lookup throughput in most situations. Hence they can be used as the replacement of the widely used Bloom filters and cuckoo filters. Similar to cuckoo filters, vacuum filters also store item fingerprints in a table. The memory-efficiency and throughput improvements are from the innovation of a table insertion and fingerprint eviction strategy that achieves both high load factor and data locality without any restriction of the table size. In addition, we propose a new update framework to resolve two difficult problems for AMQ structures under dynamics, namely duplicate insertions and set resizing. The experiments show that vacuum filters can achieve 25% less space in average and similar throughput compared to cuckoo filters, and 15% less space and >10x throughput compared to Bloom filters, with same false positive rates. AMQ data structures are widely used in various layers of computer systems and networks and are usually hosted in platforms where memory is limited and precious. Hence the improvements brought by vacuum filters can be considered significant.

Semi-supervised learning with summary statistics

Nowadays, the extensive collection and analyzing of data is stimulating widespread privacy concerns, and therefore is increasing tensions between the potential sources of data and researchers. A privacy-friendly learning framework can help to ease the tensions, and to free up more data for research. We propose a new algorithm, LESS (Learning with Empirical feature-based Summary statistics from Semi-supervised data), which uses only summary statistics instead of raw data for regression learning. The selection of empirical features serves as a trade-off between prediction precision and the protection of privacy. We show that LESS achieves the minimax optimal rate of convergence in terms of the size of the labeled sample. LESS extends naturally to the applications where data are separately held by different sources. Compared with the existing literature on distributed learning, LESS removes the restriction of minimum sample size on single data sources.

Four-Dimensional flow magnetic resonance imaging in cardiovascular diseases: Who can benefit?

Four-dimensional flow cardiac magnetic resonance (4D CMR) is an emerging imaging modality for qualitative and quantitative analysis of cardiovascular pathologies. Despite numerous advantages, its distribution and use remain limited suggesting practical or technical difficulties in using this technique routinely. We sought to report our preliminary experience in real life of 4D CMR in unselected children with congenital heart disease (CHD). We focused on its feasibility and ability, compared with adults with CHD as control. We herein report 50 4D CMR examinations over a one-year study period. This modality has been applied as a complementary imaging when conventional imaging modalities were unsatisfactory. Quality was classified according to qualitative and quantitative criteria by two blinded radiologists. This study included 22 children and 28 adults (mean age 29.5 ± 18.5 years old [0.3; 54], mean weight 61.0 ± 22.7 kg [3.8; 105.0], mean height 159.8 ± 5.5 cm [52; 192]). In infant and children mean age was 10.6 ± 6.1 years old [0.3; 18], mean weight was 36.8 ± 24.5 kg [3.8; 105.0], mean height was 149.4 ± 42.1 cm [52; 192]. Clinical indications were 36% of tetralogy of Fallot, 18% of aorta disease, 27% of complex CHD, 9% of ventricular septal defect and 10% of valvulopathy. The feasibility of this examination was excellent, while 100% exams were performed with no need for general anesthesia whatever the indication or patient (infant, child or adult). Average duration of exams were 465 ± 90s [339–610]. The overall quality of exams was satisfactory; 63% of good quality and 23% of medium quality. The evolution of quality over time has shown a progressive improvement which seems to correspond to a 3-month long learning curve. The only predictive factor identified for quality was the experience (X 2 = 4.8; P = 0.03 in CHD). Based on our preliminary experience, 4D Flow has become a complementary imaging modality accessible in current practice and open to all patients, infant, child or adult, without restriction of age, weight, size or pathology. The quality of this examination was satisfactory and seems to require an estimated learning curve of 3 months according to our experience.

Expression of vascular endothelial growth factor as a predictor of complete response for preoperative chemoradiotherapy in rectal cancer.

Biomarkers that predict tumor response before surgical treatment are necessary to help select patients for preoperative chemoradiotherapy for rectal cancer. However, no definite predictive biomarker has been established. This study explored programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), p-signal transducer and activator of transcription 3 (p-STAT3), and death-domain associated protein as predictive biomarkers with regard to preoperative chemoradiotherapy in rectal cancer.Formalin-fixed paraffin-embedded cancer tissues from pretreatment biopsies from 31 patients who underwent preoperative chemoradiotherapy were studied. The biomarkers were evaluated by immunohistochemistry.PD-L1 positivity was found in 22.6% of 31 patients and complete response (CR) showed 33.3% and non-CR showed 18.2%. EGFR positivity was found in 71.0% of 31 patients and CR showed 88.9% and non-CR showed 73.6%. VEGF positivity was found in 83.9% of 31 patients and CR showed 88.9% and non-CR showed 81.8%. p-STAT3 positivity was found in 80.6% of 31 patients and CR showed 88.9% and non-CR showed 77.3%. On multiple logistic regression analysis, only VEGF expression was found to be a significant predictive factor for CR (P = .001). VEGF expression in pretreatment biopsies might be a predictive marker for CR after preoperative chemoradiation in rectal cancer.Although there is a restriction of small sample size, our finding suggested that this study can be foundation for a larger further study for biomarkers which can predict neoadjuvant therapy response of specimens obtained for diagnosis before surgery.

Simulation of turbulence mixing in the atmosphere boundary layer and analysis of fractal dimension

In the first part of this paper, a flow model for numerical simulation of turbulent parameters in atmospheric boundary layer (ABL), based on finite volume method and large-eddy simulation is introduced. This model consists of balance equations for mass, momentum and energy (for potential temperature) equations. The Lagrangian dynamic model of Smagorinsky with restriction of size for the coefficient Cs was used for sub grid turbulent viscosity. The second part of this paper is devoted to the numerical aspects of flow model using proper orthogonal decomposition (POD) method. In the final part of this paper, results from numerical studies on flow in ABL for the neutral and stable case and analysis of fractal dimensions are presented. These results constitute important tests for the assessment of the predictive capacity for the stratified flow model in hand. ImaCalc program was used to study the fractal parameter and structure functions. We calculated the maximum value of fractal dimension D selected among all of the velocity intensity and vorticity modules which was a good indicator of flow’s complexity. The data of evolution of D(t) in the middle section of the domain of the multifractal spectra along the main downstream axis were also calculated. The reduction in the maximum value of the fractal dimension for intermediate velocity and vorticity values is consistent with laboratory experiments and with wind wane measurements.

Ultra-deep adsorptive removal of thiophenic sulfur compounds from FCC gasoline over the specific active sites of CeHY zeolite

Abstract Adsorption desulfurization performance of NaY, HY and CeHY zeolites is evaluated in a miniature fixed-bed flow by model gasoline containing with thiophene, tetrahydrothiophene, 2-methylthiophene, benzothiophene or mixed sulfur compounds. The structural properties of adsorbents are characterized by XRD, N2-adsorption and XPS techniques. Adsorption desulfurization mechanisms of these sulfur compounds over the specific active sites of adsorbents as a major focus of this work, have been systematically investigated by using in situ FT-IR spectroscopy with single and double probing molecules. Desulfurization experimental results show that the CeHY adsorbent exhibits superior adsorption sulfur capacity at breakthrough point of zero sulfur for ultra-deep removal of each thiophenic sulfur compound, especially in the capture of aromatic 2-methylthiophene (about ca. 28.6 mgS/gadsorbent). The results of in situ FT-IR with single probing molecule demonstrate an important finding that high oligomerization ability of thiophene or 2-methylthiophene on the CeHY can promote the breakthrough adsorption sulfur capacity, mainly resulting from the synergy between Bronsted acid sites and Ce(III) hydroxylated species active sites located in the supercages of CeHY. Meanwhile, the result of in situ FT-IR with double probing molecules further reveals the essence of oligomerization reactions of thiophene and 2-methylthiophene molecules on those specific active sites. By contrast, the oligomerization reaction of benzothiophene molecules on the active sites of CeHY cannot occur due to the restriction of cavity size of supercages, but they can be adsorbed on the Bronsted acid sites via protonation, and on Ce(III) hydroxylated species and extra-framework aluminum hydroxyls species via direct “S-M” bonding interaction. As to the tetrahydrothiophene, adsorption mechanism is similar to that of benzothiophene, except in the absence of protonation. The paper can provide a new design idea of specific adsorption active sites in excellent desulfurization adsorbents for elevating higher quality of FCC gasoline in the future.

Dimension-reduced generalized likelihood ratio detection based on sampling of normal modes in deep ocean

In this paper, two generalized likelihood ratio (GLR) detectors are presented for the case of multiple snapshots of test data to detect the presence of an underwater acoustic source in the deep ocean. The two GLR detectors are termed the eigenvalue detector (EVD) and the constant false alarm rate eigenvalue detector (CFAR EVD), respectively. Theoretical analysis and numerical results show that for a given input signal-to-noise ratio (SNR) of the array, the GLR detectors achieve higher output SNRs when the spatial dimension of test data decreases. To further enhance the detection performances of the GLR detectors, we propose a dimension-reduced (DR-GLR) method based on array sampling of modal information. This DR-GLR method combines the characteristics of sound propagation and array receiving. According to normal mode theory, acoustic signals emitted from the acoustic source lie in the modal space spanned by the sampled modal information of the array. Resulting from the restriction of the array size, it often occurs in deep ocean when the dimension of " effective modal subspace” is less than that of the test data which is equivalent to the number of hydrophones. Based on this phenomenon, we reconstruct the modal information by merely retaining the " effective modal subspace” to formulate the dimension reduction matrix. The DR-GLR test statistics is deduced by employing the dimension reduction matrix when using the vertical linear array (VLA) and the horizontal linear array (HLA), respectively. The DR-GLR detectors when using an HLA require more computational amount than when using a VLA. Simulation experiments are conducted to analyze the detection performances of the two GLR detectors, and verify the performance improvement effects of DR-GLR detectors. The numerical results show that the CFAR EVD presents good robustness to the uncertainty of the noise power and the DR-GLR detectors outperform the GLR detectors in detection performance. It also turns out the acoustic signals received by the HLA lie in a lower-dimensional " effective modal subspace” than by the VLA, and thus when using an HLA the DR-GLR detectors present higher detection probabilities than using a VLA. Moreover, the smaller the dimension of the " effective modal subspace”, the better the performance improvement of the DR-GLR detectors will be. The dimension of the " effective modal subspace” increases with hydrophone spacing and/or the source frequency increasing.

Assessment of Serum Electrolytes in Sudanese Hypertensive Patients in Khartoum State-Sudan

Background: Hypertension increases the risk of heart failure and kidney failure [1]. Worldwide, hypertension is estimated to cause (7.5) million deaths, about (12.8%) of the total of all deaths. In Africa, however, more than (40%) (And up to 50%) of adults in many countries are estimated to have hypertension [2]. The aim of this study was to assess the association between hypertension and serum electrolytes (sodium, potassium, magnesium and calcium) in hypertensive Sudanese males and females in Khartoum State. Material and Methods: Study Approach is A quantitative approach was used to measure Na+, K+, Mg2+ and Ca2+ in hypertensive Sudanese patients in period from March to Augustus 2018. The study was designed as prospective, hospitals/laboratory based study, this study was performed in different hospitals at Khartoum State. This study was include 30 blood samples collected from patients with hypertension, the restriction of the sample size to (30) subjects is due to lack of financial support. Data was collected using questionnaire. Two and half ml from venous blood sample was collected in heparin container, by using sterile disposable plastic syringes and aseptic condition, vein puncture technique was applied. The sample was centrifuged at (3500 rpm) for (5 minute), and reading. A quantitative method can be used to measuring Ca2+ and Mg2+ concentration by used semi automation method by used spectrophotometer instrument, and the level of Na+ and K+ is determined by methodology is based on the selective electrode measurement (SLE) principle to precisely determine measurement values. Results: This study presented that there were non-significant correlations between levels of (sodium, potassium, magnesium and calcium) of hypertensive patients compared to normal range. The illustrated that there were non-significant correlations between age, duration, social status, gander, job, education status of hypertensive tested group. The study revealed that there was a finding referring to significant correlation between level of (magnesium) and economic status of test group, but non-significant in (sodium, potassium, magnesium). Conclusion: Based on the results of the study was demonstrated the non-significant correlation between serum electrolyte and hypertension tested group compared with normal range. Also the study was not finding any correlation or effect of age, gender, duration of disease and education status of hypertensive patients on serum electrolytes levels, but depended on the finding of results study was presented prevailed significant correlation with economic status of tested group and level of magnesium serum. From this study concluded there was non physiological alteration in electrolytes balance in patients of hypertension.

MIL-PVDF blend ultrafiltration membranes with ultrahigh MOF loading for simultaneous adsorption and catalytic oxidation of methylene blue.

Multifunctional ultrafiltration membranes need to be further developed with ultrafiltration performance and high multifunctional decontamination efficiency. Here, the MIL-PVDF multifunctional ultrafiltration membrane with ultrahigh MIL loading was demonstrated by a new blending method of predispersion in acetone and thermally induced phase separation. Due to the improved dispersity and restriction of pore size, the MIL-53(Fe) mass loading was as high as approximately 61%. The new membrane showed high performance for methylene blue (MB) removal and maintained high permeability and ultrafiltration efficiency. The characteristics of the membranes were analyzed to explain the above advantages. Meanwhile, compared to the traditional blend ultrafiltration membrane, the 67-MIL-PVDF membrane showed an 9-fold increase in effective treatment volume for more than 75% MB removal. The contribution and efficiency of adsorption and catalytic oxidation were analyzed and explained. The relationship between them was confirmed as being independent, and the reasons for this independence were proposed. Additionally, the mechanism of multifunctional decontamination and permeability by MIL-PVDF membranes was proposed. Moreover, the 67-MIL-PVDF membrane was also suitable for long-term run and real wastewaters treatment. In conclusion, this study sheds new light on the preparation strategy for multifunctional blend ultrafiltration membranes with ultrahigh particles loading displaying high decontamination and permeability performance.

A multi-objective optimization of PV/ST-GSHP system based on office buildings

Solar thermal heaters (STs), photovoltaics (PVs) and ground source heat pumps (GSHPs) are widely used nowadays due to their advantages of environmental protection and energy saving. The combination of solar thermal, photovoltaic and GSHP can achieve an even better performance and such a system is referred to as PV/ST-GSHP in this study. The overall efficiency of the PV/ST-GSHP system is highly dependent on the capacity size which is large or small would affect the overall efficiency and the power of PVs and STs affects the efficiency as well. This paper established an optimization model for a PV/ST-GSHP system based on the environment, energy and economy criteria. The model focused on the optimal planning of PV and ST under the restriction of a limited size of area and of the practical loads of heat and cooling, for which the rated capacity of GSHP is included. Genetic algorithm is employed to solve the optimization problem. After optimization, the multi-objective value is 26.88%.

Adaptive Modal Filters Based on Artificial and Spectral Viscosity Techniques

In this work, we adapt techniques of artificial and spectral viscosities [especially those presented in Klockner et al. (Math Model Nat Phenom 6(03):57–83, 2011) and Tadmor and Waagan (SIAM J Sci Comput 34(2):A993–A1009, 2012)] to develop adaptive modal filters for Legendre polynomial bases and demonstrate their application in a shock-capturing discontinuous Galerkin method. While traditional artificial viscosities can impose additional stability restrictions on the time step size, we show that our filtering methods can achieve a similar shock-capturing capability without additional restriction of the time step size. We further demonstrate that the accuracy of the artificial viscosity filter can be significantly improved upon with a hybrid spectral viscosity-artifical viscosity filter, which we also develop and demonstrate. We show that we can achieve computational efficiency with an analytical time integration technique similar to one presented in Moura et al. (Diffusion-based limiters for discontinuous galerkin methods-part I: one-dimensional equations, 2013). We consider several 1D numerical examples for the linear advection, scalar wave, Burgers’, and Euler equations to demonstrate the accuracy and uniform stability of our methods.

THE ANALYSIS OF OPERATION MODES OF ENERGY STORES IN AUTONOMOUS HYBRID POWER PLANTS WITH RENEWABLE ENERGY RESOURCES

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.

Event-triggered resilient control for cyber-physical systems under asynchronous DoS attacks

In this paper, a novel event-triggered control strategy is proposed for cyber-physical systems (CPSs) with disturbance and measurement noise under two channels asynchronous denial-of-service (DoS) attacks. Two different event-triggering mechanisms for the sensor-to-controller (S-C) channel and controller-to-actuator (C-A) channel are designed, and the relationship amongst the event-triggering coefficients is obtained. Then sufficient conditions on the duration and frequency of the DoS attacks are proposed to guarantee the input-to-state stability of the closed-loop system under DoS attacks based on an observer-based control framework. In contrast to the existing studies where the synchronous DoS attacks on the S-C and C-A channels or attacks only on one channel are considered, the coupling problem for the two interconnected channels under asynchronous DoS attacks is solved. Furthermore, the condition for removing the restriction of the buffer size is obtained. Finally, a numerical simulation is given to illustrate the efficiency and the feasibility of the proposed strategy.

Formulating marine sanctuary designation for sustainable management of blue swimming crab in Lancang Island, Kepulauan Seribu

Lancang Island is the center of fisheries of blue swimming crab in Kepulauan Seribu, Jakarta. Most of the inhabitants in this island are fishermen, and blue swimming crab is the main target without considering the stocks. One of the management effort of blue swimming crab by the government is the restriction of catchment size. To support the government policy and to maintain the population stocks and the sustainability of blue swimming crab around Lancang Island, we need another effort such us proposing area of Marine Sanctuary. The analysis of possibility area of the marine sanctuary was performed with simulated annealing using Marxan. The datasets were used in analysis included geomorphic model of habitat (sea floor), coastal ecosystems, blue swimming crab catches (sample size, location, and fishing pressure). The results obtained three possibility locations of the marine sanctuary, which is around of Laki Island, Southern, and Southeastern of Lancang Island. From the possibility locations, we recommend the first location as the Marine Sanctuary with considering the more diverse of features represented.

Signatures of Microevolutionary Processes in Phylogenetic Patterns.

Phylogenetic trees are representations of evolutionary relationships among species and contain signatures of the processes responsible for the speciation events they display. Inferring processes from tree properties, however, is challenging. To address this problem, we analyzed a spatially-explicit model of speciation where genome size and mating range can be controlled. We simulated parapatric and sympatric (narrow and wide mating range, respectively) radiations and constructed their phylogenetic trees, computing structural properties such as tree balance and speed of diversification. We showed that parapatric and sympatric speciation are well separated by these structural tree properties. Balanced trees with constant rates of diversification only originate in sympatry and genome size affected both the balance and the speed of diversification of the simulated trees. Comparison with empirical data showed that most of the evolutionary radiations considered to have developed in parapatry or sympatry are in good agreement with model predictions. Even though additional forces other than spatial restriction of gene flow, genome size, and genetic incompatibilities, do play a role in the evolution of species formation, the microevolutionary processes modeled here capture signatures of the diversification pattern of evolutionary radiations, regarding the symmetry and speed of diversification of lineages.

Expected numbers of embryos to transfer in in vitro fertilization: what affects?

Introduction: Increased multiple pregnancy rate and resultant complications are some of the greatest concerns for in vitro fertilization (IVF) due to the practice of multiple embryo transfer. Although in some countries elective single embryo transfer has already been mandatory, in majority of other countries, clinical counsel still plays very important role to affect expected number of embryos transferred (ENET). Here we aim to explore the impact factors for ENET of IVF patients in order to provide scientific suggestions for clinical counsel before ET. Methods: We performed a survey of impact factors on ENET using a self-designed questionnaire in a total of 1154 IVF couples. Questions about policy change, medical concerns, and social-cultural information were included. Results: When the policy for restriction of family size was lifted, the percentages for double embryos transferred (77.8% vs. 63.7%) and multiple embryos transferred (8.0% vs. 3.9%) decreased significantly, while more tended to choose single embryo transfer (SET) (14.2% vs. 32.4%, P<0.01). Patients of more advanced age were more likely to choose SET (12.9% for 18–24 y, 11.8% for 25–29 y, 12.0% for 30–34 y, 22.4% for 35–39 y, and 28.6% for over 40 y, P=0.01). More subjects with previous labor preferred SET than those without (23.3% vs. 12.4%, P<0.01). In addition, the proportion of SET choice was significantly decreased with infertility duration prolonged (1 vs. 2 y vs. 3 vs. ≥4 y: 24.2% vs. 14.9% vs. 11.1% vs. 11.2%, P<0.01). On the basis of further investigation for reasons of ENET, specific formula including individual weighted policy, medical, and social-cultural factors was derived. Conclusions: Collectively, ENET for IVF patients is a complex, multi-factorial decision. The heterogeneity between patients due to differential policy restriction, medical concerns, and social-cultural background should be fully considered in clinical counsel about ENET.