Important Unresolved Problems Research Articles

Barometric geolocators can reveal unprecedented details about the migratory ecology of small birds

Abstract Knowing the location of migratory birds throughout their annual cycle is fundamental for many questions in ornithology. Technological advances have provided several approaches, with increasing miniaturization allowing deployment on smaller and smaller birds. Here, we examine the strengths and limitations of barometric pressure geolocators (pressure tags), which have recently been shown to be extremely effective in tracking small birds (<25 g). The newly developed geolocation by pressure workflow (GeoPressureR) uses a global weather analysis dataset and hidden Markov movement model to reveal locations more accurately or continuously than can be achieved by other available light-weight devices (e.g., light-level geolocators, automated radio telemetry, and archival GPS tags). Additionally, pressure data can provide altitude information and document generally intractable flight behavior, as well as exact migratory phenologies. This new technology can be applied to important unresolved problems such as altitudinal migration, stopover site use, molt migration, vertical airspace use, and drivers of migratory flight initiation, duration, and direction. We provide an example of a pressure tag on a Swainson’s Warbler (Limnothlypis swainsonii) deployed on its breeding territory in Virginia, USA, revealing the complete story of its migration to and from Cuba, including its refined wintering site, stopover sites, and migration routes, all with precise timing. Studies relying on pressure tags are still subject to biases related to recovery of the devices for data extraction, and application to birds that exhibit extensive aerial movements (e.g., swallows and swifts) remains challenging. Widespread deployment of pressure tags could show unprecedented details of bird migration and other aspects of aerial behavior, which could benefit conservation and greatly enrich our understanding of avian movement ecology.

PROTECTIVE METAL COATINGS MADE OF MOLYBDENUM ON STEEL 12Cr18Ni10Ti FOR FLUORIDE MELTS. OBTAINING, CERTIFICATION, EFFICIENCY

The successful use of molten alkali metal fluorides as an electrolyte for high-temperature devices requires the development of such reactor materials that have high corrosion resistance in melts with compositions characteristic of liquid-salt mixing reactors. This is one of the most important unresolved problems. One of the effective ways to reduce corrosion losses is to create a layer on the surface of the material that protects the metal from the corrosive effects of the environment. In this paper, molybdenum insulating coatings on steel 12Kh18Ni10Ti obtained in molten salts of various compositions and by various methods are considered as protective layers. Experiments were carried out on the electrodeposition of molybdenum coatings on structural materials based on iron (steel 12Cr18Ni10Ti). The coatings obtained by the electrochemical method are inhomogeneous and easily exfoliating. The thickness of molybdenum coatings obtained from molten salts is 8.15 and 20.34 μm on steel in FLiNaK and LiCl–KCl melt, respectively. Corrosion tests have shown the inefficiency of the molybdenum coating obtained from both chloride and fluoride melts. The corrosion rate of 12Cr18Ni10Ti steel in FLiNaK/FLiNaK + 5% CeF3 melts at 650°C and a holding time of 100 hours decreases in the following row: 12Cr18Ni10Ti + Mo (0.75/0.77 mm/year) 12Cr18Ni10Ti (0.45/0.50 mm/year).

Fragments of Oxidized Extracellular DNA Affect the Development of Oxidative Stress in the Peripheral Blood Mononuclear Cells in vitro in Patients with Childhood Autism

Background: the etiology and pathogenesis of childhood autism (CA) is one of the important unresolved problems of child psychiatry. It has been shown that the concentration of extracellular DNA (cfDNA) in the blood significantly increases in children with CA, and to the greatest extent in patients with severe CA. Patients with more severe CA also have significantly elevated levels of the oxidized DNA marker 8-OHdG in cfDNA and nuclear DNA samples and the double-strand break marker γH2AX. The aim was to study the effect of oxidized cfDNA fragments on the formation of free radicals, oxidation and breaks of nuclear DNA in the peripheral blood mononuclear cells in vitro in children with CA. Patients and methods: the study involved 13 patients diagnosed with F84.02 according to ICD-10 and 10 conditionally healthy children as a control group. Clinical-psychopathological, molecularbiological, statistical methods were used. Results: oxidized model DNA fragments affect the peripheral blood mononuclear cells of children with CA and conditionally healthy donors in different ways. In the mononuclear cells of conditionally healthy donors, in response to exposure to oxidized DNA fragments, the levels of ROS (reactive oxygen species) (p < 0.05), DNA oxidation (p < 0.05) and chromosome damage (p < 0.05) increase, but within the next 24 hours these indicators return to the previous level. At the same time, in the mononuclear cells of children with CA, the levels of ROS, DNA oxidation, and chromosome damage also increase, but the subsequent decrease occurs more slowly, and the levels of these indicators do not return to their previous values. Conclusion: on the basis of the obtained results, it is possible to put forward a hypothesis about the participation of fragments of oxidized extracellular DNA in the pathogenesis of CA.

Этноним русь и восточногерманское *rauþs ‘красный’: еще раз к обоснованию гипотезы

The author draws attention to a number of important unresolved problems (including those recognized by leading supporters) of the currently dominant variant of the Scandinavian etymology behind of the ethnonym Rus’/русь, He argues a new version of the East Germanic etymology of this ethnonym. Following the explanatory model of “Finno-Germanic militarized groups”, the author believes that for the Roman period we should also assume the existence of such groups (in particular, on Saaremaa, Lanemaa and Virumaa), controlling the sea route along the southern coast of the Baltic — but with the East Germans as the dominant element. East Germanic *rauþs ‘red’ is proposed as the original etymon for русь. Taking into account the phonetic processes characteristic of the East Germanic languages (early contraction of the original Germanic diphthongs and the tendency to increase vowels), a natural stage of evolution of *rauþs ‘red’ should be the form *rōþs. Considering ethnonymic models of the Finnish peoples (and Goths), we should justifiably obtain the form *rōþ (but with the meaning ‘red’) as the original etymon for the Slavic русь.

Некоторые важнейшие отраслевые проблемы стратегии развития образования

The purpose of the work was to identify the most important unresolved industry problems of the education development strategy. Based on the approaches and provisions of economic theory, theory and history of modern economic development, systems theory, it was possible to identify some of the most important problems of education development strategy. One of the most important unresolved problems related to the fact that the strategy should aimed at increasing labor productivity with new technologies that make it possible to replace the labor of those employed in the education sector with technical means. At the same time, it should take into account that the field of education has significant limitations associated with the most important role of creative processes that cannot reproduced by technical means, for example, artificial intelligence systems. Another problem of the education development strategy is associated with the modernization of the content of education, which is necessary in the transition to a post-industrial economy. In order to form the institutions and intellectual climate necessary for economic development and growth, the economically active population must have knowledge in the fields of both natural and social-humanoid sciences. Quality assurance is another critical issue in the education development strategy. Developers of strategies do not have a good enough idea of the essence of the category "quality", do not know the methods and tools for measuring and assessing quality, which determines the ability of a good to satisfy the needs of the consumer. As a result, quality assurance carried out in the form of an archaic command and control system based on the application of orders, standards and control, which, inherited from the industrial economy is ineffective and not competitive in modern conditions.

Unsupervised learning of visual invariant features for person re-identification

The recent successful methods of person re-identification (person Re-ID) involving deep learning have mostly adopted supervised learning algorithms, which require large amounts of manually labelled data to achieve good performance. However, there are two important unresolved problems, dataset annotation is an expensive and time-consuming process, and the performance of recognition model is seriously affected by visual change. In this paper, we primarily study an unsupervised method for learning visual invariant features using networks with temporal coherence for person Re-ID; this method exploits unlabelled data to learn expressions from video. In addition, we propose an unsupervised learning integration framework for pedestrian detection and person Re-ID for practical applications in natural scenarios. In order to prove the performance of the unsupervised person re-identification algorithm based on visual invariance features, the experimental results were verified on the iLIDS-VID, PRID2011 and MARS datasets, and a better performance of 57.5% (R-1) and 73.9% (R-5) was achieved on the iLIDS-VID and MARS datasets, respectively. The efficiency of the algorithm was validated by using BING + R-CNN as the pedestrian detector, and the person Re-ID system achieved a computation speed of 0.09s per frame on the PRW dataset.

Evaluation of LFP Battery SOC Estimation Using Auxiliary Particle Filter

State of charge (SOC) estimation of lithium batteries is one of the most important unresolved problems in the field of electric vehicles. Due to the changeable working environment and numerous interference sources on vehicles, it is more difficult to estimate the SOC of batteries. Particle filter is not restricted by the Gaussian distribution of process noise and observation noise, so it is more suitable for the application of SOC estimation. Three main works are completed in this paper by taken LFP (lithium iron phosphate) battery as the research object. Firstly, the first-order equivalent circuit model is adapted in order to reduce the computational complexity of the algorithm. The accuracy of the model is improved by identifying the parameters of the models under different SOC and minimum quadratic fitting of the identification results. The simulation on MATLAB/Simulink shows that the average voltage error between the model simulation and test data was less than 24.3 mV. Secondly, the standard particle filter algorithm based on SIR (sequential importance resampling) is combined with the battery model on the MATLAB platform, and the estimating formula in recursive form is deduced. The test data show that the error of the standard particle filter algorithm is less than 4% and RMSE (root mean square error) is 0.0254. Thirdly, in order to improve estimation accuracy, the auxiliary particle filter algorithm is developed by redesigning the importance density function. The comparative experimental results of the same condition show that the maximum error can be reduced to less than 3.5% and RMSE is decreased to 0.0163, which shows that the auxiliary particle filter algorithm has higher estimation accuracy.

Why Sex? and Why Only in Pairs?

Understanding the purpose of sex remains one of the most important unresolved problems in evolutionary biology. The difficulty is not that there are too few theories of sex, the difficulty is that there are too many and none stand out. To distinguish between theories we suggest the following question: Why are there no triparental species in which an offspring is composed of the genetic material of three individuals? A successful theory should confer an advantage to biparental sex over asexual reproduction without conferring an even greater advantage to triparental sex. We pose our question in the context of two leading theories of sex, the (deterministic) mutational hypothesis that sex reduces the rate at which harmful mutations accumulate, and the red queen hypothesis that sex reduces the impact of parasitic attack by increasing genotypic variability. We show that the mutational hypothesis fails to provide an answer to the question because it implies that triparental sex dominates biparental sex, so the latter should never be observed. In contrast, we show that the red queen hypothesis is able to explain biparental sex without conferring an even greater advantage to triparental sex.

Photo-catalytic or photo-synthetic routes for the decomposition of water – are they realizable dreams?

In a recent report of the ACS publications, there was a question on what is the most important unresolved problems in chemistry? The answer can be varied depending on the specialization one tends t...

Finding zeros of the Riemann zeta function by periodic driving of cold atoms

The Riemann hypothesis, which states that the non-trivial zeros of the Riemann zeta function all lie on a certain line in the complex plane, is one of the most important unresolved problems in mathematics. Inspired by the P\'olya-Hilbert conjecture, we propose a new approach to finding a physical system to study the Riemann zeros, which in contrast to previous examples, is based on applying a time-periodic driving field. This driving allows us to mould the quasienergies of the system (the analogue of the eigenenergies in the absence of driving), so that they are directly governed by the zeta function. We further show by numerical simulations that this allows the Riemann zeros to be measured in currently accessible cold atom experiments.

Validation of Transverse Instability Damping Computations for Rocket Engines

The reliable numerical evaluation of thermoacoustic stability is one of the most important unresolved problems in the development of liquid rocket engines. To provide data for code validation, a transonic cold-flow test facility was built, which comprises a rocket engine model for acoustic measurements. It consists of a cylindrical chamber with inflow through a perforated plate representing the faceplate and a choked nozzle at the exit. The flow is excited with a siren and complex eigenfrequencies, and the nozzle admittances for the most critical first-transverse mode are extracted from dynamic pressure measurements. These data are used to benchmark three stability assessment tools of widely varying numerical complexity. Results obtained with one- and three-dimensional methods based on the solution of the linearized Euler equations and results from nonlinear Navier–Stokes computations (unsteady Reynolds-averaged Navier–Stokes) are compared with the experimental data. All three codes reproduce the measured first-transverse-mode frequency, but only the two linearized Euler equation methods provide satisfactory values for first-transverse-mode damping and nozzle admittance. The nozzle admittances calculated from the unsteady Reynolds-averaged Navier–Stokes results exhibit large scatter, but the average of the data from 11 monitor points is close to the measured values and mode decomposition during data analysis is expected to reduce scatter further. However, the employed unsteady Reynolds-averaged Navier–Stokes method overpredicts nozzle damping.

Quantum models for psychological measurements: an unsolved problem.

There has been a strong recent interest in applying quantum theory (QT) outside physics, including in cognitive science. We analyze the applicability of QT to two basic properties in opinion polling. The first property (response replicability) is that, for a large class of questions, a response to a given question is expected to be repeated if the question is posed again, irrespective of whether another question is asked and answered in between. The second property (question order effect) is that the response probabilities frequently depend on the order in which the questions are asked. Whenever these two properties occur together, it poses a problem for QT. The conventional QT with Hermitian operators can handle response replicability, but only in the way incompatible with the question order effect. In the generalization of QT known as theory of positive-operator-valued measures (POVMs), in order to account for response replicability, the POVMs involved must be conventional operators. Although these problems are not unique to QT and also challenge conventional cognitive theories, they stand out as important unresolved problems for the application of QT to cognition. Either some new principles are needed to determine the bounds of applicability of QT to cognition, or quantum formalisms more general than POVMs are needed.

Quality assurance of Chinese herbal medicines: Procedure for multiple‐herb extraction

A quality assurance (QA) procedure for multiple‐herb extraction, which takes into account the existence of common chemical markers and multiple‐herb‐extraction effects, has been developed for producing Chinese herbal medicines (CHMs) of consistent quality. The experimental method for determining related correlation function of the multiple‐herb‐extraction effect was designed. A systematic solution strategy was also developed to appropriately decompose the multiple‐herb extraction system into several subsystems for obtaining solution(s) and determining the overall behavior of the system. An example of QA of Danshen–Gegen (DG) decoction was used to demonstrate the QA procedure. An H9c2 cell assay was used to test the efficacy of consistent quality DG decoctions prepared by different herb combinations with different material costs of herbs. It was observed that a multiple‐herb‐extraction effect was present in the aqueous extraction of Danshensu and this effect was depended on the extraction solvent. The possible mechanism of this multiple‐herb‐extraction effect in the aqueous DG extraction was speculated to be the change of initial pH value of the aqueous extraction solvent by an unknown component from Gegen. The experimental chemical marker concentrations fell within ±10% of the specified chemical marker compositions by using the amount of herb from each herb class as predicted by the QA model. Furthermore, an H9c2 cell assay was used to test the efficacy of three consistent quality DG extracts, which were produced by different herb combinations with different material costs of herbs. The results showed that the three DG extracts provided consistent biological efficacy against menadione‐induced toxicity. This study extended a recently developed QA procedure of single‐herb extraction to multiple‐herb extraction. It provides a solution of QA in extraction, which is one of the most important unresolved problems in the modernization of traditional Chinese medicines. With this modified model and the companion experiments, the amount of herbs needed from different quality classes to produce a multiple‐herb formula CHM product decoction with consistent quality can be exactly determined. © 2014 American Institute of Chemical Engineers AIChE J 60: 4014–4026, 2014

Anxiety, post-traumatic stress disorder and social supports among parents of premature and full-term infants.

Background:Premature birth is one of the most important unresolved reproductive health problems. Premature birth is often traumatic and a source of distress for parents. Increased parental stress during the first year of their infant's life is a risk factor for later behavioral problems in infants.Objectives:This study was designed to compare anxiety, post-traumatic stress, and social supports in parents of premature and mature infants.Patients and Methods:This was a comparative descriptive study conducted at healthcare centers of Qom city, in 2012. In this study, 82 couples (164 parents) divided into two groups including parents who have preterm and term infants. Questionnaires including items such as demographic characteristics, obstetric and post-traumatic stress disorders, Spielberger anxiety and Multidimensional Scale of Perceived Social Support were completed two months after childbirth. Data were analyzed using χ2 test, Fisher’s exact test, Mann-Whitney test, independent t-test, and regression logistic using SPSS18 software.Results:The levels of anxiety was not significantly different in mothers and fathers in the two groups, but the trait anxiety level of mothers (P < 0.001) and fathers who had preterm infants (P = 0.01) was significantly greater than the parents of full-term infants. Post-traumatic stress disorder was significantly greater in mothers of preterm infants than those of term infants (P = 0.03), but this amount was not significantly different between the two groups of fathers. Mothers' social support did not differ significantly (P = 0.08), however, it was significantly different in fathers (P = 0.01).Conclusions:Premature infants' parents are more at risk of mental disorders than term infants' parents. This result shows the need of interventions, so these parents can better deal with the problems of premature infants.

‘Rabone’ and four unresolved problems in mental health law

SummaryIn a landmark decision, the Supreme Court of the UK ruled that the state has a special operational duty to protect the right to life in informal psychiatric in-patients (‘Rabone case'), in sharp distinction to general medical or surgical patients. We will argue that the significance of this case is general, not just local, and that it exposes four important unresolved problems in mental health law: the place of decision-making capacity; the meaning of ‘informal’ admission; parity between mental and physical health; and the accuracy of risk assessment.

Multiterm Extended Kantorovich Method for Three-Dimensional Elasticity Solution of Laminated Plates

In an article recently published in this journal, the powerful single-term extended Kantorovich method (EKM) originally proposed by Kerr in 1968 for two-dimensional (2D) elasticity problems was further extended by the authors to the three-dimensional (3D) elasticity solution for laminated plates. The single-term solution, however, failed to predict accurately the stress field near the boundaries; thus limiting its applicability. In this work, the method is generalized to the multiterm solution. The solution is developed using the Reissner-type mixed variational principle that ensures the same order of accuracy for displacements and stresses. An n-term solution generates a set of 8n algebraic-ordinary differential equations in the in-plane direction and a similar set in the thickness direction for each lamina, which are solved in close form. The problem of large eigenvalues associated with higher order terms is addressed. In addition to the composite laminates considered in the previous article, results are also presented for sandwich laminates, for which the inaccuracy in the single-term solution is even more prominent. It is shown that considering just one or two additional terms in the solution (n = 2 or 3) leads to a very accurate prediction and drastic improvement over the single-term solution (n = 1) for all entities including the stress field near the boundaries. This work will facilitate development of near-exact solutions of many important unresolved problems involving 3D elasticity, such as the free edge stresses in laminated structures under bending, tension and torsion.

Gene transfer to skeletal muscle by site-specific delivery of electroporation and ultrasound

Transfecting foreign genes into target cells require certain vectors and specific techniques. With more new genes and gene targets for gene therapy are continually being discovered, which provide useful clues for the study of gene function and gene therapy for human disease. However, there still remain a number of important unresolved problems associated with the use of viral and non viral vectors or techniques, such as secondary toxicity, immune response, or low gene transfer efficiency. Therefore, efficient and safe approaches of gene delivery in vivo still need to be found for medical applications. Electroporation or ultrasound (US), which involving electrical pulses or a US field to increase cell membrane permeability, has shown to be an efficient, safe and simple non viral physical method of DNA delivery in vivo and alternative technique in the field of gene therapy. However, the high field strength or energy often required for electroporation or US can result in tissue damage, thus limit their widely clinical applications. In recent years, site-specific gene delivery by electroporation or US has aroused much attention, because of optimized protocols and novel devices using a lower field strength than conventional methods, which has shown high transfection efficiency with minimal tissue damage. In this paper, we reviewed the advancement in the field of electroporation and US for gene delivery, particularly by site-specific delivery into skeletal muscle for gene therapy and their applications in Alzheimer’s disease (AD)’s treatment.

The efficacy of withdrawal therapy in subjects with chronic daily headache and medication overuse following prophylaxis with topiramate and amitriptyline

Management of patients affected by chronic daily headache (CDH) with medication overuse constitutes one of the most important unresolved problems. The uncertainty regarding the classification and the prophylaxis are a remarkable part of this problem. Objectives are to: (1) to evaluate the efficacy of withdrawal therapy following prophylaxis with topiramate and amitriptyline in a population affected by CDH and medication overuse with follow-up at 1 (T1), 3 (T2) and 6 (T3) months; (2) to identify which group of the Silberstein's CDH classification (1994) may benefit from this protocol. Inclusion criteria are patients with CDH (headache for more >15 days/month for at least 3 consecutive months) and medication overuse according with IHS second edition (8.2 group); exclusion criteria are patients with secondary headache. All patients included in the study were hospitalized for 1 week. Type of overuse: combination of medications, 38%; analgesics, 29%; triptans, 29%; opioids, 2%; ergotamines, 2%. During hospitalization the following protocol was applied: desametasone 4 mg i.v./day for 1 week, diazepam 6 mg/day for 10 days and prophylaxis with amitriptylin plus topiramate. This prophylaxis was protracted for at least 6 months. The dosages assumed ranged for amitriptylin from 10 to 20 mg/day and for topiramate from 50 to 100 mg/day. In the last 4 years 105 patients with CDH (age 24-89 years; f 96; m 9) were admitted to the hospital. The protocol was applied in 52 patients (age, 29-65 years; f 49; m 3). At T1, 89% of the patients did not fall again into medication overuse; at T2, 64%; and at T3,45% of the patients remained free from overuse. According to the Silberstein' proposal at T1, 93% of the subjects was affected by transformed migraine; and 7% by tension-type headache. At T3, all the patients free from overuse were affected by transformed migraine. Our data suggest that the patients affected by CDH and medication overuse benefit from withdrawal therapy performed during hospitalization plus prophylaxis with amitriptyline plus topiramate. This combination seems a good pharmacological solution to reduce the risk of relapse.

Power and behavioral approach orientation in existing power relations and the mediating effect of income

AbstractA large number of authors have observed that the experience of power increases behavioral approach tendencies. There are however some important unresolved problems. Predominantly, the literature relies on lab manipulations, priming, and student populations. This has resulted in low face validity. Also, it is unclear what process underlies this effect. A large‐scale survey (N = 3082) reliably measures power among real low‐ and high‐power employees in existing organizations and finds strong support for the effect of power on behavioral approach. Consistent with expectations, this effect is mediated by increased access to resources. We also discuss findings that suggest the shape of this power‐approach effect might be quadratic. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Fitness and its role in evolutionary genetics

Although the operation of natural selection requires that genotypes differ in fitness, some geneticists may find it easier to understand natural selection than fitness. Partly this reflects the fact that the word 'fitness' has been used to mean subtly different things. In this Review I distinguish among these meanings (for example, individual fitness, absolute fitness and relative fitness) and explain how evolutionary geneticists use fitness to predict changes in the genetic composition of populations through time. I also review the empirical study of fitness, emphasizing approaches that take advantage of recent genetic and genomic data, and I highlight important unresolved problems in understanding fitness.