Complete right- and left-sided thoracic ducts associated with aberrant left vertebral artery: unreported case with surgical implications

Anatomy is the keystone to an appropriate understanding of surgical and radiological sciences. Here the authors report on a rare case of complete right- and left-sided thoracic ducts (TDs) associated with aberrant left-vertebral artery (LVA) arising from the aortic arch. The TDs originated from right and left cisterna chyli and terminated separately close to the left venous angle. Superior to the aortic arch, the TDs showed different relationships to the LVA; the right TD was ventral, while the left was dorsal in position. This report is associated with other variations detailed below, and may have important implications in cervicothoracic surgery. (Folia Morphol 2018; 77, 1: 156–160)

Understanding guests' intention to visit green hotels

The purpose of this study was to expand existing knowledge of hotel consumers' green behaviours by merging value-belief-norm theory and the theory of planned behaviour into one theoretical framework to understand comprehensively consumers' decision-making processes with respect to their intentions to visit a green hotel. Data collected from 757 respondents were analysed. The results indicate that our integrated framework demonstrates a favorable level of prediction power for guests' behavior, which verified the superiority of the suggested framework. Furthermore, its findings from fuzzy-set qualitative comparative analysis (fsQCA) indicate that: (1) attitude toward green hotels, perceived behavioural control, sense of obligation, and corporate image are key drivers of guests' intentions to visit green hotels; (2) three distinct configurations of guests' intention drivers are likely to result in a high degree of intentions among customers to visit green hotels. The three solutions all contain the conditions of high attitude, corporate image, biospheric value, and green activities, which means that these conditions are vital components of a high intention among customers to visit green hotels. This study contributes to the growing literature on sustainability in marketing and practice by providing useful insights about the determinants of guests' behaviour to use green hotels in the Egyptian hospitality context. It is one of the first empirical studies examining factors affecting guests' behavior to use green hotels in the Egyptian hospitality context

Theoretical analysis of the spatial variability in tillage forces for fatigue analysis of tillage machines

This paper presents a new theoretical model to describe the spatial variability in tillage forces for the purpose of fatigue analysis of tillage machines. The proposed model took into account both the variability in tillage system parameters (soil engineering properties, tool design parameters and operational conditions) and the cyclic effects of mechanical behavior of the soil during failure ahead of tillage tools on the spatial variability in tillage forces. The stress-based fatigue life approach was used to determine the life time of tillage machines, based on the fact that the applied stress on tillage machines is primarily within the elastic range of the material. Stress cycles with their mean values and amplitudes were determined by the rainflow algorithm. The damage friction caused by each cycle of stress was computed according to the Soderberg criterion and the total damage was calculated by the Miner's law. The proposed model was applied to determine the spatial variability in tillage forces on the shank of a chisel plough. The equivalent stress history resulted from these forces were calculated by means of a finite element model and the Von misses criterion. The histograms of mean stress and stress amplitude obtained by the rainflow algorithm showed significant dispersions. Although the equivalent stress is smaller than the yield stress of the material, the failure by fatigue will occur after a certain travel distance. The expected distance to failure was found to be df=0.825×106km. It is concluded that the spatial variability in tillage forces has significant effect on the life time of tillage machines and should be considered in the design analysis of tillage machines to predict the life time. Further investigations are required to correlate the results achieved by the proposed model with field tests and to validate the proposed assumptions to model the spatial variability in tillage force

An Observational Pursuit for Population III Stars in a Ly_alpha Emitter at z=6.33 through HeII Emission

We present a very deep near-infrared spectroscopic observation of a strong Ly_alpha emitter at z=6.33, SDF J132440.6+273607, which we used to search for HeII 1640. This emission line is expected if the target hosts a significant number of population III stars. Even after 42 ksec of integration with the Subaru/OHS spectrograph, no emission-line features are detected in the JH band, which confirms that SDF J132440.6+273607 is neither an active galactic nucleus nor a low-$z$ emission-line object. We obtained a 2sigma upper-limit of 9.06e-18 ergs/s/cm^2 on the HeII 1640 emission line flux, which corresponds to a luminosity of 4.11e42 ergs/s. This upper-limit on the HeII 1640 luminosity implies that the upper limit on population III star-formation rate is in the range 4.9--41.2 M_sun/yr if population III stars suffer no mass loss, and in the range 1.8--13.2 M_sun/yr if strong mass loss is present. The non-detection of HeII in SDF J132440.6+273607 at z=6.33 may thus disfavor weak feedback models for population III stars.Comment: 13 pages, 3 figures, to appear in The Astrophysical Journal Letter

Does #Tamojunto alter the dynamic between drug use and school violence among youth?: Secondary analysis from a large cluster-randomized trial

The present study investigated how intervention might alter the relationship between perpetrating violence and later drug use. A cluster-randomized controlled trial design involving 72 schools (38 intervention, 34 control) and 6390 students attending grades 7 and 8 was employed in Brazil. Drug use and violence were assessed at three points. A random-intercept cross-lagged panel model examined the reciprocal association between drug use and school violence domains across the three data collection waves. For both groups, we found that the cross-lagged effect of perpetration on further drug use in adolescents was stronger than the reverse, but the interrelationship was not statistically significant between #Tamojunto and control schools. The carry-over effects of drug use and violence were also not significantly different between groups. There is a lack of evidence showing that #Tamojunto can modify the dynamics between drug use and school violence across the 21-month period. The direction of the causal effect (i.e., the more perpetration behavior, the more subsequent drug use behavior) is present, but weak in both groups. The trial registration protocol at the national Brazilian Register of Clinical Trials (REBEC) is #RBR-4mnv5g.publishedVersio

Analysing Mathematical Abilities of High School Graduates

In this paper we are trying to differentiate the level of mathematical abilities of high school graduates in Bahrain schools. The mathematical abilities that we are trying to analyse are conceptual understanding, content knowledge and problemsolving skills. content understanding focusses on performing algorithms, while conceptual understanding focus on comprehending the concepts and relations. Problem solving needs both. We will prepare test items to measure graduates on different mathematics content domains. This research will try to identify students’ weaknesses in mathematical and suggest ways to improve the understanding in mathematics.     Keywords: Conceptual understanding; content knowledge; problem solving

Does #Tamojunto alter the dynamic between drug use and school violence among youth? Secondary analysis from a large cluster-randomized trial

The present study investigated how intervention might alter the relationship between perpetrating violence and later drug use. A cluster-randomized controlled trial design involving 72 schools (38 intervention, 34 control) and 6390 students attending grades 7 and 8 was employed in Brazil. Drug use and violence were assessed at three points. A random-intercept cross-lagged panel model examined the reciprocal association between drug use and school violence domains across the three data collection waves. For both groups, we found that the cross-lagged effect of perpetration on further drug use in adolescents was stronger than the reverse, but the interrelationship was not statistically significant between #Tamojunto and control schools. The carry-over effects of drug use and violence were also not significantly different between groups. There is a lack of evidence showing that #Tamojunto can modify the dynamics between drug use and school violence across the 21-month period. The direction of the causal effect (i.e., the more perpetration behavior, the more subsequent drug use behavior) is present, but weak in both groups. The trial registration protocol at the national Brazilian Register of Clinical Trials (REBEC) is #RBR-4mnv5g

Evolution of low-mass metal-free stars including effects of diffusion and external pollution

We investigate the evolution of low-mass metal-free Population III stars. Emphasis is laid upon the question of internal and external sources for CNO-elements, which - if present in sufficient amounts in the hydrogen-burning regions - lead to a strong modification of the stars' evolutionary behavior. For the production of carbon due to nuclear processes inside the stars, we use an extended nuclear network, demonstrating that hot pp-chains do not suffice to produce enough carbon or are less effective than the triple3-alpha-process. As an external source of CNO-elements we test the efficiency of pollution by a nearby massive star combined with particle diffusion. For all cases investigated, the additional metals fail to reach nuclear burning regions before deep convection on the Red Giant Branch obliterates the previous evolution. The surface abundance history of the polluted Pop III stars is presented. The possibilities to discriminate between a Pop II and a polluted Pop III field star are also discussed.Comment: Accepted for publication in Ap

The detection of extragalactic 15^{15}N: Consequences for nitrogen nucleosynthesis and chemical evolution

Detections of extragalactic $^{15}$N are reported from observations of the rare hydrogen cyanide isotope HC$^{15}$N toward the Large Magellanic Cloud (LMC) and the core of the (post-) starburst galaxy NGC 4945. Accounting for optical depth effects, the LMC data from the massive star-forming region N113 infer a $^{14}N/^{15}$N ratio of 111 $\pm$ 17, about twice the $^{12}C/^{13}$C value. For the LMC star-forming region N159HW and for the central region of NGC 4945, $^{14}N/^{15}$N ratios are also $\approx$ 100. The $^{14}N/^{15}$N ratios are smaller than all interstellar nitrogen isotope ratios measured in the disk and center of the Milky Way, strongly supporting the idea that $^{15}$N is predominantly of `primary' nature, with massive stars being its dominant source. Although this appears to be in contradiction with standard stellar evolution and nucleosynthesis calculations, it supports recent findings of abundant $^{15}$N production due to rotationally induced mixing of protons into the helium-burning shells of massive stars.Comment: 15 pages including one postscript figure, accepted for publication by ApJ Letter, further comments: please contact Yi-nan Chi

A photometric survey for Lyalpha-HeII dual emitters: Searching for Population III stars in high-redshift galaxies

We present a new photometric search for high-z galaxies hosting Population III (PopIII) stars based on deep intermediate-band imaging observations obtained in the Subaru Deep Field (SDF), by using Suprime-Cam on the Subaru Telescope. By combining our new data with the existing broad-band and narrow-band data, we searched for galaxies which emit strongly both in Ly_alpha and in HeII 1640 (``dual emitters'') that are promising candidates for PopIII-hosting galaxies, at 3.93<z<4.01 and 4.57<z<4.65. Although we found 10 ``dual emitters'', most of them turn out to be [OII]-[OIII] dual emitters or H_beta-(H_alpha+[NII]) dual emitters at z<1, as inferred from their broad-band colors and from the ratio of the equivalent widths. No convincing candidate of Ly_alpha-HeII dual emitter of SFR_PopIII > 2 Msun/yr was found by our photometric search in 4.03 x 10^5 Mpc^3 in the SDF. This result disfavors low feedback models for PopIII star clusters, and implies an upper-limit of the PopIII SFR density of SFRD_PopIII < 5 x 10^-6 Msun/yr/Mpc^3. This new selection method to search for PopIII-hosting galaxies should be useful in future narrow-band surveys to achieve the first observational detection of PopIII-hosting galaxies at high redshifts.Comment: 24 pages, 10 figures, accepted for publication in Ap