A Class of Recursive Optimal Stopping Problems with Applications to Stock Trading

In this paper, we introduce and solve a class of optimal stopping problems of recursive type. In particular, the stopping payoff depends directly on the value function of the problem itself. In a multidimensional Markovian setting, we show that the problem is well posed in the sense that the value is indeed the unique solution to a fixed point problem in a suitable space of continuous functions, and an optimal stopping time exists. We then apply our class of problems to a model for stock trading in two different market venues, and we determine the optimal stopping rule in that case.

Bacterial aerosol, particulate matter, and microclimatic parameters in the horse stables in Poland

Keeping horses in good condition requires providing them with living conditions that meet welfare requirements. These animals should be accommodated with suitable space, access to high nutritional fodder and water, and a suitable microclimate in their shelters. When it comes to the environment in the stables, a serious problem is created by particulate matter (PM), which consists of bacteria. PM concentration may be responsible for developing multiple lower respiratory tract diseases in horses, including allergies and recurrent airway obstruction (RAO). In turn, these ailments may lead to decreasing equine physical and mental fitness. Additionally, people who spend time in the stables are exposed to the same harmful factors. The study was conducted in Udórz Stud Farm located in the southern region of Poland. The study was carried out in 2 different types of stables: 3 runners (a type of stable where horses are housed together and occasionally linked up, e.g., for feeding or grooming) and 2 box stables. The research continued for 2 years and the samples were collected in each season. The bioaerosol samples were collected using a six-stage Andersen-Graseby cascade impactor to assess size distribution and concentrations of airborne bacteria. PM concentration was analyzed using the DustTrak™ II Aerosol Monitor 8530, while microclimate parameters were measured using the Kestrel 5000 Weather Meter. There are almost no studies concerning size distribution of airborne bacteria, individual PM fractions, and the impact of everyday handling on the changes in the bioaerosol and PM concentration. This preliminary study provided basic information on this subject. We have revealed a strong correlation between high PM and bacterial aerosol concentrations. Higher contamination levels were recorded in runners, as compared to box stables. The highest bacterial aerosol level was detected in the spring. The analysis of the fractions of the bacterial aerosol in the stables indicated the highest share of ultra-fine fraction (0.65–2.1 µm), while respirable fraction (below 4.7 µm) exceeded 75%. It was established that the concentration of the bacterial aerosol inside the stables was many times higher than outside. It depended significantly on everyday activities undertaken in the stables, like feeding or cleaning. Taking the above into account, a different cleaning system should be developed (a wet cleaning system, with the use of water) and excrement should be removed more frequently.

L’affidamento familiare: le strategie educative elaborate dagli affidatari

Foster care is a condition of welcoming children with families in serious difficulty, legally regulated, aimed at guaranteeing to minors a suitable space for growth, and to families of origin the possibility of overcoming the problems so as to consent the return of the children. It is a challenging educational condition, to be deepened with research. The complexity of the backgrounds of origin and the co-presence of multiple risk factors in fact generate in children and young people in foster care, important difficulties in development, which foster families have to cope with, also with the support of specialists, services and associations. However, the skills that caregivers come to build over the years are valuable, deserving of pedagogical insights, so that good practices of positive parenting can be valued and shared. In this paper we will report the results of a survey, carried out with a national sample of 323 foster families. The study makes it possible to investigate the reasons for the custody prevision, the relationships with families of origin, the difficult life trajectories of the children in foster care (transitions, placements, discontinuities, years of foster care, continuation of relationships after foster care). In this way it is possible to identify the needs highlighted by the minors, the relevant problems that emerge and the promising strategies adopted by the foster families.

A neonatal ward strengthening program improves survival for neonates treated with CPAP at district hospitals in Malawi

Introduction: From 2013-2015, a CPAP quality improvement program (QIP) was implemented to introduce and monitor CPAP usage and outcomes in the neonatal wards at all government district and central hospitals in Malawi. In 2016 the CPAP QIP was extended into healthcare facilities operated by the Christian Health Association of Malawi. Although clinical outcomes improved, ward assessments indicated that many rural sites lacked other essential equipment and a suitable space to adequately treat sick neonates, which likely limited the impact of improved respiratory care. The aim of this study was to determine if a ward strengthening program improved outcomes for neonates treated with CPAP. Methods: To address the needs identified from ward assessments, a ward strengthening program was implemented from 2017-2018 at rural hospitals in Malawi to improve the care of sick neonates. The ward strengthening program included the distribution of a bundle of equipment, supplemental training, and, in some cases, health facility renovations. Survival to discharge was compared for neonates treated with CPAP at 12 rural hospitals for one year before and for one year immediately after implementation of the ward strengthening program. Results: In the year prior to ward strengthening, 189 neonates were treated with CPAP; in the year after, 232 neonates received CPAP. The overall rate of survival for those treated with CPAP improved from 46.6% to 57.3% after ward strengthening (p=0.03). For the subset of neonates with admission weights between 1.00-2.49 kg diagnosed with respiratory distress syndrome, survival increased from 39.4% to 60.3% after ward strengthening (p=0.001). Conclusion: A ward strengthening program including the distribution of a bundle of equipment, supplemental training, and some health facility renovations, further improved survival among neonates treated with CPAP at district-level hospitals in Malawi.

On backward problem for fractional spherically symmetric diffusion equation with observation data of nonlocal type

The main target of this paper is to study a problem of recovering a spherically symmetric domain with fractional derivative from observed data of nonlocal type. This problem can be established as a new boundary value problem where a Cauchy condition is replaced with a prescribed time average of the solution. In this work, we set some of the results above existence and regularity of the mild solutions of the proposed problem in some suitable space. Next, we also show the ill-posedness of our problem in the sense of Hadamard. The regularized solution is given by the fractional Tikhonov method and convergence rate between the regularized solution and the exact solution under a priori parameter choice rule and under a posteriori parameter choice rule.

Territorial Distribution of Maritime Symbols in Public Spaces of Klaipėda City

The geographical location of Klaipeda city determined that a suitable space for the formation of maritime culture was created here. There are a number of exceptional objects of small and large architecture in the public spaces of the city, some of which are related to the sea. However, it must be stated that the city still lacks objects that glorify famous personalities who have contributed to the fostering of maritime culture and the promotion of Lithuania as a maritime country. Methods used in the research: observation, object photography, cartographic, expert surveys. The study analyzes the diversity of maritime symbols and their territorial distribution in the public spaces of Klaipeda city. Trends in the renewal and further development of maritime elements are also presented in order to form the image of the city and foster maritime culture. This research should expand the boundaries of cognition of maritime culture and contribute to the strengthening of the maritime image of Klaipeda city. Keywords: Klaipeda city, maritime symbols, maritime themes, public spaces.

Prediction of nodes mobility in 3-D space

<span>Recently, mobility prediction researches attracted increasing interests, especially for mobile networks where nodes are free to move in the three-dimensional space. Accurate mobility prediction leads to an efficient data delivery for real time applications and enables the network to plan for future tasks such as route planning and data transmission in an adequate time and a suitable space. In this paper, we proposed, tested and validated an algorithm that predicts the future mobility of mobile networks in three-dimensional space. The prediction technique uses polynomial regression to model the spatial relation of a set of points along the mobile node’s path and then provides a time-space mapping for each of the three components of the node’s location coordinates along the trajectory of the node. The proposed algorithm was tested and validated in MATLAB simulation platform using real and computer generated location data. The algorithm achieved an accurate mobility prediction with minimal error and provides promising results for many applications.</span>

Establishment and Management Of COVID-19 Testing Molecular Laboratory in Minimal Resource Setting, Challenges and Issues Reported From Birgunj, Nepal – An Experience of Pathologist

The Coronavirus pandemic is recording numerous deaths worldwide. The temporal distribution and burden of the disease varies from setting to setting based on economic status, demography and geographic location. Nepal reported the first COVID-19 case on January 23, 2020. A rapid increase in the number of COVID-19 cases was being reported in Nepal as of June 2020. Limited molecular laboratory capacity in resource limited settings is a challenge in the diagnosis of the ever-increasing cases and the overall management of the disease. In this article, we share the experience, challenges and prospects in the rapid establishment of COVID-19 testing laboratory in Birgunj from available resources. We provide empirical evidence from Parsa district, as this is one of the SARS-CoV-2 transmission hotspots in Nepal and it is likely generalizable to other similar settings in the country. The first step in establishing the COVID-19 molecular testing laboratory were i) identifying a suitable space ii) renovating it and iii) mobilizing materials including consumables, mainly from the hospital store and administration. A chain of experimental design was set up with distinct laboratories to standardize the extraction of samples, preparation of the master mix and detection. At the commencement of sample reception and testing, laboratory contamination was among the primary challenges faced. The source of the contamination was identified in the master mix room and resolved. In summary, the established COVID-19 testing lab (Narayani PCR Lab) has tested more than 40,000 samples (January 2021) and is now the preferred setting for CoVID-19 testing. The lessons learnt may benefit the further establishment of testing laboratories for COVID-19 and/or other epidemic/pandemic diseases in resource-limited settings.

Evidence for competition and cannibalism in wormlions

Trap-building predators, such as web-building spiders and pit-building antlions, construct traps to capture their prey. These predators compete over sites that either enable the construction of suitable traps, are prey rich, or simply satisfy their abiotic requirements. We examined the effect of intraspecific competition over suitable space in pit-building wormlions. As expected, the ability of wormlions to select their favorable microhabitats—shaded or deep sand over lit or shallow sand—decreased with increasing density. Favorable microhabitats were populated more frequently by large than by small individuals and the density of individuals in the favorable microhabitat decreased with their increase in body mass. The advantage of large individuals in populating favorable microhabitats is nevertheless not absolute: both size categories constructed smaller pits when competing over a limited space compared to those constructed in isolation. The outcome of competition also depends on the type of habitat: deep sand is more important for large wormlions than small ones, while shade is similarly important for both size classes. Finally, in contrast to previous reports, cannibalism is shown here to be possible in wormlions. Its prevalence however is much lower compared to that documented in other trap-building predators. Our findings show that the advantage of large individuals over small ones should not be taken for granted, as it can depend on the environmental context. We present suggestions for the relative lack of competitive advantage of large wormlion individuals compared to other trap-building predators, which may stem from the absence of obvious weaponry, such as sharp mandibles.

Nonexistence results of Caputo-type fractional problem

In this paper, we deal with Caputo-type fractional differential inequality where there is a low-order fractional derivative with the term polynomial source. We investigate the nonexistence of nontrivial global solutions in a suitable space via the test function technique and some properties of fractional integrals. Finally, we demonstrate three examples to illustrate our results. The presented results are more general than those in the literature, which can be obtained as particular cases.