2,036 research outputs found
Consumer responses to the H5N1 Avian Influenza: the case of Turkey
Using the case of the 2005-2006 Avian Influenza crisis also experienced in Turkey, we present its impacts on consumers' concerns on the pandemic. Based on our cross-sectional dataset derived from a household survey, results from our probit estimations imply that the negative impact of the pandemic on the poultry sector could have been alleviated by informing consumers about it. Frequent users, older consumers, and females are derived to be more concerned about the pandemic. Campaigns, especially through the efficient use of media channels, can target to minimize demand shocks and help poultry demand return to pre-outbreak levels. Using these results, policies can be designed to decrease the negative impacts of future food scares.
Update or Wait: How to Keep Your Data Fresh
In this work, we study how to optimally manage the freshness of information
updates sent from a source node to a destination via a channel. A proper metric
for data freshness at the destination is the age-of-information, or simply age,
which is defined as how old the freshest received update is since the moment
that this update was generated at the source node (e.g., a sensor). A
reasonable update policy is the zero-wait policy, i.e., the source node submits
a fresh update once the previous update is delivered and the channel becomes
free, which achieves the maximum throughput and the minimum delay.
Surprisingly, this zero-wait policy does not always minimize the age. This
counter-intuitive phenomenon motivates us to study how to optimally control
information updates to keep the data fresh and to understand when the zero-wait
policy is optimal. We introduce a general age penalty function to characterize
the level of dissatisfaction on data staleness and formulate the average age
penalty minimization problem as a constrained semi-Markov decision problem
(SMDP) with an uncountable state space. We develop efficient algorithms to find
the optimal update policy among all causal policies, and establish sufficient
and necessary conditions for the optimality of the zero-wait policy. Our
investigation shows that the zero-wait policy is far from the optimum if (i)
the age penalty function grows quickly with respect to the age, (ii) the packet
transmission times over the channel are positively correlated over time, or
(iii) the packet transmission times are highly random (e.g., following a
heavy-tail distribution)
Pre-service Chemistry Teachers’ Expectations and Experiences in the School Experience Course
The purpose of this study is to investigate prospective chemistry teachers’ expectations and experiences of teaching practice. Six (four females and two males) pre-service chemistry teachers taking a School Experience II course participated in the study. A case study design was employed. The data were collected from multiple sources including observations, lesson plans, and semi-structured interviews before and after the school experience course. Pre-service teachers’ expectations and experiences were categorized regarding the faculty, placement school, and teaching practice. It was found that school experience courses are crucial for pre-service teachers in deciding whether to continue in the teaching profession. It is also concluded that the harmony between pre-service teachers’ expectations of and experiences in the school experience course had an influence on their opinions related to the teaching profession
Recent advances in signal integration mechanisms in the unfolded protein response [version 1; peer review: 2 approved]
Since its discovery more than 25 years ago, great progress has been made in our understanding of the unfolded protein response (UPR), a homeostatic mechanism that adjusts endoplasmic reticulum (ER) function to satisfy the physiological demands of the cell. However, if ER homeostasis is unattainable, the UPR switches to drive cell death to remove defective cells in an effort to protect the health of the organism. This functional dichotomy places the UPR at the crossroads of the adaptation versus apoptosis decision. Here, we focus on new developments in UPR signaling mechanisms, in the interconnectivity among the signaling pathways that make up the UPR in higher eukaryotes, and in the coordination between the UPR and other fundamental cellular processes
Physical Properties of Kraft PULP From Four-Year-Old Aspen Hybrids and Crosses
Short-rotation forestry and species hybridization offer acceptable raw materials for pulp and paper production. Poplars (Populus spc.) are the most promising materials because of their fast growth rates and their suitability for pulp. The objectives of this study were to determine the kraft pulp properties of three new aspen hybrids and crosses and to compare these properties with those of other poplars. We used Populus alba X Populus tremula, Populus alba X Populus alba Bolleana, and Populus alba X Populus grandidentata. Results indicated that the P. alba X P. trernula hybrid was most suitable for pulp production. Handsheets made from the P. alba X P. tremula hybrid had greater burst and tear strengths and a comparable tensile index compared with those of the kraft pulps of other juvenile poplars. Results suggest that P. alba X P. tremula is a promising hybrid for pulp production
Longitudinal associations between conflict monitoring and emergent academic skills: An event‐related potentials study
Identifying the links between specific cognitive functions and emergent academic skills can help determine pathways to support both early academic performance and later academic achievement. Here, we investigated the longitudinal associations between a key aspect of cognitive control, conflict monitoring, and emergent academic skills from preschool through first grade, in a large sample of socioeconomically diverse children (N = 261). We recorded event‐related potentials (ERPs) during a Go/No‐Go task. The neural index of conflict monitoring, ΔN2, was defined as larger N2 mean amplitudes for No‐Go versus Go trials. ΔN2 was observed over the right hemisphere across time points and showed developmental stability. Cross‐lagged panel models revealed prospective links from ΔN2 to later math performance, but not reading performance. Specifically, larger ΔN2 at preschool predicted higher kindergarten math performance, and larger ΔN2 at kindergarten predicted higher first‐grade math performance, above and beyond the behavioral performance in the Go/No‐Go task. Early academic skills did not predict later ΔN2. These findings provided electrophysiological evidence for the contribution of conflict monitoring abilities to emergent math skills. In addition, our findings suggested that neural indices of cognitive control can provide additional information in predicting emergent math skills, above and beyond behavioral task performance.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149228/1/dev21809.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149228/2/dev21809_am.pd
Gerçeküstü Kodlar Üzerinden Reha Erdem Sinemasına Bakmak
Gerçeküstücü akım önce sanatta ve ardından sinemada, modernizmin boşa çıkan vaatlerinin etkisiyle gelişen bir akımdır. Gerçekliğin çizgisel ilerleme nosyonuna başkaldıran gerçeküstücü sanatçılar, gerçeğin sistem tarafından belirlenmiş tanımlarına değil, insanın varlık itibariyle hiçbir denetim olmaksızın sahip olduğu duyguları ve düşünceleri ortaya çıkarmakla ilgilenmiştir. Gerçeküstücü sinema, Bunuel’in etkisiyle tüm dünyada sinemayı etkisi altına almıştır ve gerçeküstücülük akımının öne çıkan temsilcileri Andre Breton, Louis Aragon, Paul Eluard ve Pierre Unik olarak bilinir. Bugün hala pek çok yönetmenin filmlerinde gerçeküstücü akımın izlerini görmek mümkündür. Bu çalışmada gerçeküstücü akımın ortak kodları üzerinden Reha Erdem sineması ele alınmıştır. Bu çalışmanın Reha Erdem’in sinemasını gerçeküstücü olarak ele alma iddiası bulunmamaktadır. Çalışma, Reha Erdem filmlerinde gerçeküstü öğelerin saptanması ve bu öğelerin özgün bir anlatı içinde nasıl yapılandığını incelemektedir. Reha Erdem’in yönettiği uzun metrajlı filmlerden yedi tanesi amaçlı örneklem olarak seçilmiş ve bu filmler üzerinden gerçeküstü sinemanın sıklıkla kullandığı ögelerin Reha Erdem sinemasında nasıl yer bulduğu sorusunun yanıtları aranmış, seçilen filmlerde gerçeküstü kodların okunması ve saptanması hedeflenmiştir
Comparison of active vs. expectant management of the third stage of labor in women with low risk of postpartum hemorrhage: a randomized controlled trial
Objectives: To compare the ‘strictly’ active management protocol in women with low risk of postpartum hemorrhage using the expectant management protocol with respect to changes in hematologic parameters, uterotonics, blood transfusions, or additional interventions.
Material and methods: A randomized controlled prospective trial in which 934 singleton parturients enrolled; 654 were randomly assigned to the active and mixed management groups. The primary outcome parameter was the reduction in hemoglobin concentrations due to delivery, and the secondary outcome parameters were changes in hemoglobin of more than 3 g/dL (ΔHb ≥ 3 g/dL), durations of the third stage of labor, need for additional uterotonic agents, blood transfusions, manual removal of the placenta, and surgical evacuation of retained products of conception.
Results: The mean postpartum hemoglobin concentration was significantly higher (P = 0.04) in the active management group with a significantly lower reduction (P = 0.03). Falls of hemoglobin levels of more than 3 g/dL (ΔHb ≥ 3g/dL) were less common in the active management group though not significantly (P = 0.32). The mean duration of the third stage of labor was significantly (P < 0.001) shorter in the active management group. There was no significant difference between the two groups with regard to the need for additional uterotonic agents, uterine atony, blood transfusion, manual removal of the placenta, surgical evacuation of retained products of conception, and prolonged third stage of labor.
Conclusions: Although active management of the third stage of labor was associated with higher postpartum hemoglobin levels, it did not influence the risk of ‘severe postpartum hemorrhage’ in women with low risk of postpartum hemorrhage
Experimental study of a TLP offshore floating wind turbine
Tank testing in a wind and wave environment is a key part of the design process for the development of an offshore floating wind turbine. The current paper describes an extensive experiment campaign carried out at the Kelvin Hydrodynamics Laboratory at the University of Strathclyde to determine the hydrodynamic performance of the Iberdrola TLPWIND offshore floating wind turbine with the NREL 5MW reference turbine over a range of environmental conditions. Tests were carried out for 70m water depth and the deployment area selected as off Aberdeen, North Sea. The campaign included free oscillation tests, tests in regular waves and irregular waves, and additionally examined failure and accidental load cases
Small inhibitor of Bcl-2, HA14-1, selectively enhanced the apoptotic effect of cisplatin by modulating Bcl-2 family members in MDA-MB-231 breast cancer cells
Inhibition or downregulation of Bcl-2 represents a new therapeutic approach to by-pass chemoresistance in cancer cells. Therefore, we explored the potential of this approach in breast cancer cells. Cisplatin and paclitaxel induced apoptosis in a dose-dependent manner in MCF-7 (drug-sensitive) and MDA-MB-231 (drug-insensitive) cells. Furthermore, when we transiently silenced Bcl-2, both cisplatin and paclitaxel induced apoptosis more than parental cells. Dose dependent induction of apoptosis by drugs was enhanced by the pre-treatment of these cells with HA14-1, a Bcl-2 inhibitor. Although the effect of cisplatin was significant on both cell lines, the effect of paclitaxel was much less potent only in MDA-MB-231 cells. To further understand the distinct role of drugs in MDA-MB-231 cells pretreated with HA14-1, caspases and Bcl-2 family proteins were studied. The apoptotic effect of cisplatin with or without HA14-1 pre-treatment is shown to be caspase-dependent. Among pro-apoptotic Bcl-2 proteins, Bax and Puma were found to be up-regulated whereas Bcl-2 and Bcl-x(L) were down-regulated when cells were pretreated with HA14-1 followed by paclitaxel or cisplatin. Enforced Bcl-2 expression in MDA-MB-231 cells abrogated the sensitizing effect of HA14-1 in cisplatin induced apoptosis. These results suggest that the potentiating effect of HA14-1 is drug and cell type specific and may not only depend on the inhibition of Bcl-2. Importantly, alteration of other pro-apoptotic or anti-apoptotic Bcl-2 family members may dictate the apoptotic response when HA14-1 is combined with chemotherapeutic drugs
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