bluuebunny/crossref_metadata_2025 huggingface dataset:
Aqueous phase oxidation of sulphur dioxide by ozone in cloud droplets
Authors: Hoyle C. R. , Fuchs C. , Järvinen E. , Saathoff H. , Dias A. , El Haddad I. , Gysel M. , Coburn S. C. , Tröstl J. , Bernhammer A.-K. , Bianchi F. , Breitenlechner M. , Corbin J. C. , Craven J. , Donahue N. M. , Duplissy J. , Ehrhart S. , Frege C. , Gordon H. , Höppel N. , Heinritzi M. , Kristensen T. B. , Molteni U. , Nichman L. , Pinterich T. , Prévôt A. S. H. , Simon M. , Slowik J. G. , Steiner G. , Tomé A. , Vogel A. L. , Volkamer R. , Wagner A. C. , Wagner R. , Wexler A. S. , Williamson C. , Winkler P. M. , Yan C. , Amorim A. , Dommen J. , Curtius J. , Gallagher M. W. , Flagan R. C. , Hansel A. , Kirkby J. , Kulmala M. , Möhler O. , Stratmann F. , Worsnop D. R. , Baltensperger U.
Published: February 2016

Abstract. The growth of aerosol due to the aqueous phase oxidation of sulfur dioxide by ozone was measured in laboratory-generated clouds created in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN). Experiments were performed at 10 and −10 °C, on acidic (sulfuric acid) and on partially to fully neutralised (ammonium sulfate) seed aerosol. Clouds were generated by performing an adiabatic expansion – pressurising the chamber to 220 hPa above atmospheric pressure, and then rapidly releasing the excess pressure, resulting in a cooling, condensation of water on the aerosol and a cloud lifetime of approximately 6 min. A model was developed to compare the observed aerosol growth with that predicted using oxidation rate constants previously measured in bulk solutions. The model captured the measured aerosol growth very well for experiments performed at 10 and −10 °C, indicating that, in contrast to some previous studies, the oxidation rates of SO2 in a dispersed aqueous system can be well represented by using accepted rate constants, based on bulk measurements. To the best of our knowledge, these are the first laboratory-based measurements of aqueous phase oxidation in a dispersed, super-cooled population of droplets. The measurements are therefore important in confirming that the extrapolation of currently accepted reaction rate constants to temperatures below 0 °C is correct.
Cloud radar with hybrid mode towards estimation of shape and orientation of ice crystals
Authors: Myagkov A. , Seifert P. , Bauer-Pfundstein M. , Wandinger U.
Published: February 2016

Abstract. This paper is devoted to the experimental quantitative characterization of the shape and orientation distribution of ice particles in clouds. The characterization is based on measured and modeled elevation dependencies of the polarimetric parameters differential reflectivity and correlation coefficient. The polarimetric data are obtained using a newly developed 35 GHz cloud radar MIRA-35 with hybrid polarimetric configuration and scanning capabilities. The full procedure chain of the technical implementation and the realization of the setup of the hybrid-mode cloud radar for the shape determination are presented. This includes the description of phase adjustments in the transmitting paths, the introduction of the general data processing scheme, correction of the data for the differences of amplifications and electrical path lengths in the transmitting and receiving channels, the rotation of the polarization basis by 45°, the correction of antenna effects on polarimetric measurements, the determination of spectral polarimetric variables, and the formulation of a scheme to increase the signal-to-noise ratio. Modeling of the polarimetric variables is based on existing back-scattering models assuming the spheroidal representation of cloud scatterers. The parameters retrieved from the model are polarizability ratio and degree of orientation, which can be assigned to certain particle orientations and shapes. The developed algorithm is applied to a measurement of the hybrid-mode cloud radar taken on 20 October 2014 in Cabauw, the Netherlands, in the framework of the ACCEPT (Analysis of the Composition of Clouds with Extended Polarization Techniques) campaign. The case study shows the retrieved polarizability ratio and degree of orientation of ice particles for a cloud system of three cloud layers at different heights. Retrieved polarizability ratios are 0.43, 0.85, and 1.5 which correspond to oblate, quasi-spherical, and columnar ice particles, respectively. It is shown that the polarizability ratio is useful for the detection of aggregation/riming processes. The orientation of oblate and prolate particles is estimated to be close to horizontal while quasi-spherical particles were found to be more randomly oriented.
Changes in nearshore waves during the active sea/land breeze period off Vengurla, central west coast of India
Authors: Amrutha M. M. , Sanil Kumar V. , Singh J.
Published: February 2016

Abstract. A unique feature observed in the tropical and subtropical coastal area is the diurnal sea-breeze/land-breeze cycle. We examined the nearshore waves at 5 and 15 m water depth during the active sea/land breeze period (January–April) in the year 2015 based on the data measured using the waverider buoys moored in the eastern Arabian sea off Vengurla, central west coast of India. Temporal variability of diurnal wave response is examined. Numerical model Delft3D is used to study the nearshore wave transformation. The wave height increased due to the sea breeze and reached its peak at  ∼ 13:00 UTC at 15 m water depth, whereas the peak significant wave height is at 12:00 UTC at 5 m water depth. Due to the influence of the land/sea breeze system, the range of the peak wave period in 1 day varied up to 8 s. Reduction in the wave height of wind-sea is around 20 % and that of the swell is around 10 % from 15 to 5 m water depth.
Extreme N2O accumulation in the coastal oxygen minimum zone off Peru
Authors: Kock A. , Arévalo-Martínez D. L. , Löscher C. R. , Bange H. W.
Published: February 2016

Abstract. Depth profiles of nitrous oxide (N2O) were measured during six cruises to the upwelling area and oxygen minimum zone (OMZ) off Peru in 2009 and 2012/2013, covering both the coastal shelf region and the adjacent open ocean. N2O profiles displayed a strong sensitivity towards oxygen concentrations. Open ocean profiles with distances to the shelf break larger than the first baroclinic Rossby radius of deformation showed a transition from a broad maximum close to the Equator to a double-peak structure south of 5° S where the oxygen minimum was more pronounced. Maximum N2O concentrations in the open ocean were about 80 nM. A linear relationship between ΔN2O and apparent oxygen utilization (AOU) could be found for measurements within the upper oxycline, with a slope similar to studies in other oceanic regions. In contrast, N2O profiles close to the shelf revealed a much higher variability, and N2O concentrations higher than 100 nM were often observed. The highest N2O concentration measured at the shelf was  ∼  850 nM. Due to the extremely sharp oxygen gradients at the shelf, N2O maxima occurred in very shallow water depths of less than 50 m. In the coastal area, a linear relationship between ΔN2O and AOU could not be observed as extremely high ΔN2O values were scattered over the full range of oxygen concentrations. The data points that showed the strongest deviation from a linear ΔN2O ∕ AOU relationship also showed signals of intense nitrogen loss. These results indicate that the coastal upwelling at the Peruvian coast and the subsequent strong remineralization in the water column causes conditions that lead to extreme N2O accumulation, most likely due to the interplay of intense mixing and high rates of remineralization which lead to a rapid switching of the OMZ waters between anoxic and oxic conditions. This, in turn, could trigger incomplete denitrification or pulses of increased nitrification with extreme N2O production.
Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters
Authors: Zhu Wenjuan , Xiang Wenhua , Pan Qiong , Zeng Yelin , Ouyang Shuai , Lei Pifeng , Deng Xiangwen , Fang Xi , Peng Changhui
Published: February 2016

Abstract. Leaf area index (LAI) is an important parameter related to carbon, water and energy exchange between canopy and atmosphere, and is widely applied in the process models to simulate production and hydrological cycle in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have not been fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (i.e. Pinus massoniana – Lithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaber – Cyclobalanopsis glauca evergreen broadleaved forests) during period from April, 2014 to January, 2015. Spatial heterogeneity of LAI and its controlling factors were analysed by using geostatistics method the generalised additive models (GAMs), respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for three forests measured in January and for the L. glaber – C. glauca forest in April, July and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stand basal area, crown coverage, crown width, proportion of deciduous species on basal area basis and forest types affected the spatial variations in LAI values in January, while species richness, crown coverage, stem number and forest types affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.
The early Spörer Minimum – a period of extraordinary climate and socio-economic changes in Western and Central Europe
Authors: Camenisch Chantal , Keller Kathrin M. , Salvisberg Melanie , Amann Benjamin , Bauch Martin , Blumer Sandro , Brázdil Rudolf , Brönnimann Stefan , Büntgen Ulf , Campbell Bruce M. S. , Fernández-Donado Laura , Fleitmann Dominik , Glaser Rüdiger , González-Rouco Fidel , Grosjean Martin , Hoffmann Richard C. , Huhtamaa Heli , Joos Fortunat , Kiss Andrea , Kotyza Oldřich , Lehner Flavio , Luterbacher Jürg , Maughan Nicolas , Neukom Raphael , Novy Theresa , Pribyl Kathleen , Raible Christoph C. , Riemann Dirk , Schuh Maximilian , Slavin Philip , Werner Johannes P. , Wetter Oliver
Published: February 2016

Abstract. Throughout the last millennium, mankind was affected by prolonged deviations from the climate mean state. While periods like the Maunder Minimum in the 17th century have been assessed in greater detail, earlier cold periods such as the 15th century received much less attention due to the sparse information available. Based on new evidence from different sources ranging from proxy archives to model simulations, it is now possible to provide an end-to-end assessment about the climate state during an exceptionally cold period in the 15th century, the role of internal, unforced climate variability and external forcing in shaping these extreme climatic conditions, and the impacts on and responses of the medieval society in Central Europe. Climate reconstructions from a multitude of natural and human archives indicate that, during winter, the period of the early Spörer Minimum (1431–1440 CE) was the coldest decade in Central Europe in the 15th century. The particularly cold winters and normal but wet summers resulted in a strong seasonal cycle that challenged food production and led to increasing food prices, a subsistence crisis, and a famine in parts of Europe. As a consequence, authorities implemented adaptation measures, such as the installation of grain storage capacities, in order to be prepared for future events. The 15th century is characterised by a grand solar minimum and enhanced volcanic activity, which both imply a reduction of seasonality. Climate model simulations show that periods with cold winters and strong seasonality are associated with internal climate variability rather than external forcing. Accordingly, it is hypothesised that the reconstructed extreme climatic conditions during this decade occurred by chance and in relation to the partly chaotic, internal variability within the climate system.
A global scale mechanistic model of photosynthetic capacity (LUNA V1.0)
Authors: Ali A. A. , Xu C. , Rogers A. , Fisher R. A. , Wullschleger S. D. , Massoud E. C. , Vrugt J. A. , Muss J. D. , McDowell N. G. , Fisher J. B. , Reich P. B. , Wilson C. J.
Published: February 2016

Abstract. Although plant photosynthetic capacity as determined by the maximum carboxylation rate (i.e., Vc, max25) and the maximum electron transport rate (i.e., Jmax25) at a reference temperature (generally 25 °C) is known to vary considerably in space and time in response to environmental conditions, it is typically parameterized in Earth system models (ESMs) with tabulated values associated with plant functional types. In this study, we have developed a mechanistic model of leaf utilization of nitrogen for assimilation (LUNA) to predict photosynthetic capacity at the global scale under different environmental conditions. We adopt an optimality hypothesis to nitrogen allocation among light capture, electron transport, carboxylation and respiration. The LUNA model is able to reasonably capture the measured spatial and temporal patterns of photosynthetic capacity as it explains  ∼  55 % of the global variation in observed values of Vc, max25 and  ∼  65 % of the variation in the observed values of Jmax25. Model simulations with LUNA under current and future climate conditions demonstrate that modeled values of Vc, max25 are most affected in high-latitude regions under future climates. ESMs that relate the values of Vc, max25 or Jmax25 to plant functional types only are likely to substantially overestimate future global photosynthesis.
Quantifying the impact of sub-grid surface wind variability on sea salt and dust emissions in CAM5
Authors: Zhang Kai , Zhao Chun , Wan Hui , Qian Yun , Easter Richard C. , Ghan Steven J. , Sakaguchi Koichi , Liu Xiaohong
Published: February 2016

Abstract. This paper evaluates the impact of sub-grid variability of surface wind on sea salt and dust emissions in the Community Atmosphere Model version 5 (CAM5). The basic strategy is to calculate emission fluxes multiple times, using different wind speed samples of a Weibull probability distribution derived from model-predicted grid-box mean quantities. In order to derive the Weibull distribution, the sub-grid standard deviation of surface wind speed is estimated by taking into account four mechanisms: turbulence under neutral and stable conditions, dry convective eddies, moist convective eddies over the ocean, and air motions induced by mesoscale systems and fine-scale topography over land. The contributions of turbulence and dry convective eddy are parameterized using schemes from the literature. Wind variabilities caused by moist convective eddies and fine-scale topography are estimated using empirical relationships derived from an operational weather analysis data set at 15 km resolution. The estimated sub-grid standard deviations of surface wind speed agree well with reference results derived from 1 year of global weather analysis at 15 km resolution and from two regional model simulations with  3 km grid spacing.The wind-distribution-based emission calculations are implemented in CAM5. In terms of computational cost, the increase in total simulation time turns out to be less than 3 %. Simulations at 2° resolution indicate that sub-grid wind variability has relatively small impacts (about 7 % increase) on the global annual mean emission of sea salt aerosols, but considerable influence on the emission of dust. Among the considered mechanisms, dry convective eddies and mesoscale flows associated with topography are major causes of dust emission enhancement. With all the four mechanisms included and without additional adjustment of uncertain parameters in the model, the simulated global and annual mean dust emission increase by about 50 % compared to the default model. By tuning the globally constant dust emission scale factor, the global annual mean dust emission, aerosol optical depth, and top-of-atmosphere radiative fluxes can be adjusted to the level of the default model, but the frequency distribution of dust emission changes, with more contribution from weaker wind events and less contribution from stronger wind events. In Africa and Asia, the overall frequencies of occurrence of dust emissions increase, and the seasonal variations are enhanced, while the geographical patterns of the emission frequency show little change.
Estimating evaporation with thermal UAV data and two-source energy balance models
Authors: Hoffmann H. , Nieto H. , Jensen R. , Guzinski R. , Zarco-Tejada P. , Friborg T.
Published: February 2016

Abstract. Estimating evaporation is important when managing water resources and cultivating crops. Evaporation can be estimated using land surface heat flux models and remotely sensed land surface temperatures (LST), which have recently become obtainable in very high resolution using lightweight thermal cameras and Unmanned Aerial Vehicles (UAVs). In this study a thermal camera was mounted on a UAV and applied into the field of heat fluxes and hydrology by concatenating thermal images into mosaics of LST and using these as input for the two-source energy balance (TSEB) modelling scheme. Thermal images are obtained with a fixed-wing UAV overflying a barley field in western Denmark during the growing season of 2014 and a spatial resolution of 0.20 m is obtained in final LST mosaics. Two models are used: the original TSEB model (TSEB-PT) and a dual-temperature-difference (DTD) model. In contrast to the TSEB-PT model, the DTD model accounts for the bias that is likely present in remotely sensed LST. TSEB-PT and DTD have already been well tested, however only during sunny weather conditions and with satellite images serving as thermal input. The aim of this study is to assess whether a lightweight thermal camera mounted on a UAV is able to provide data of sufficient quality to constitute as model input and thus attain accurate and high spatial and temporal resolution surface energy heat fluxes, with special focus on latent heat flux (evaporation). Furthermore, this study evaluates the performance of the TSEB scheme during cloudy and overcast weather conditions, which is feasible due to the low data retrieval altitude (due to low UAV flying altitude) compared to satellite thermal data that are only available during clear-sky conditions. TSEB-PT and DTD fluxes are compared and validated against eddy covariance measurements and the comparison shows that both TSEB-PT and DTD simulations are in good agreement with eddy covariance measurements, with DTD obtaining the best results. The DTD model provides results comparable to studies estimating evaporation with similar experimental setups, but with LST retrieved from satellites instead of a UAV. Further, systematic irrigation patterns on the barley field provide confidence in the veracity of the spatially distributed evaporation revealed by model output maps. Lastly, this study outlines and discusses the thermal UAV image processing that results in mosaics suited for model input. This study shows that the UAV platform and the lightweight thermal camera provide high spatial and temporal resolution data valid for model input and for other potential applications requiring high-resolution and consistent LST.
Long-term variability of the southern Adriatic circulation in relation to North Atlantic Oscillation
Authors: Shabrang L. , Menna M. , Pizzi C. , Lavigne H. , Civitarese G. , Gačić M.
Published: February 2016

Abstract. The interannual variability of the South Adriatic Gyre and its relation to the wind vorticity and the large-scale climatic pattern (North Atlantic Oscillation – NAO) was studied using the time series of satellite altimetric data and ocean surface wind products. The cyclonic circulation observed in the southern Adriatic area was partly sustained by the local wind forcing, as suggested by the positive correlation between the rate of change of the current vorticity and the wind-stress vorticity. Nevertheless, the influence of vorticity advection from the adjacent area (northern Ionian Sea) cannot be ignored and it is more significant during the anticyclonic phase of Adriatic–Ionian Bimodal Oscillation System. The geostrophic current vorticities of the southern Adriatic and northern Ionian seas are correlated with a time lag of 14 months, which approximately corresponds to an advection speed of  ∼  1 cm s−1. The different wind patterns observed during two NAO phases in the winter revealed a stronger positive vorticity during the negative NAO phase. Conversely, during the wintertime positive NAO phase the wind vorticity is characterized by lower positive or slightly negative values. Despite a statistically significant negative correlation between the NAO index and the wind vorticity, no unequivocal relationship between large climatic system and the interannual variability of the South Adriatic Gyre intensity was found due to additional effects of the vorticity advection from the Ionian. This can be explained by the fact that the Ionian circulation mode does not depend on the NAO variations. Therefore, the main result of this study is that the interannual variability of the southern Adriatic cyclonic circulation is a result of the combined influence of the vorticity advection from the Ionian and the local wind-curl effect.
Effect of the North Equatorial Counter Current on the generation and propagation of internal solitary waves off the Amazon shelf (SAR observations)
Authors: Magalhaes J. M. , da Silva J. C. B. , Buijsman M. C. , Garcia C. A. E.
Published: February 2016

Abstract. Synthetic aperture radar (SAR) imagery from the Amazon shelf break region in the tropical west Atlantic reveals for the first time the two-dimensional horizontal structure of an intense Internal Solitary Wave (ISW) field, whose first surface manifestations are detected several hundred kilometres away from the nearest forcing bathymetry. Composite maps and an energy budget analysis (provided from the Hybrid Coordinate Ocean Model – HYCOM) help to identify two major ISW pathways emanating from the steep slopes of a small promontory (or headland) near 44° W and 0° N, which are seen to extend for over 500 km into the open ocean. Further analysis in the SAR reveals propagation speeds above 3  m  s−1, which are amongst the fastest ever recorded. The main characteristics of the ISWs are further discussed based on a statistical analysis, and seasonal variability is found for one of the ISW sources. This seasonal variability is discussed in light of the North Equatorial Counter Current. The remote appearance of the ISW sea surface manifestations is explained by a late disintegration of the internal tide (IT), which is further investigated based on the SAR data and climatological monthly means (for stratification and currents). Acknowledging the possibility of a late disintegration of the IT may help explain the remote-sensing views of other ISWs in the world's oceans.
A harmonic projection and least–squares method for quantifying Kelvin wave activity
Authors: Delman Andrew , Sprintall Janet , McClean Julie , Talley Lynne
Published: February 2016

Abstract. A new method for isolating the equatorial and coastal Kelvin wave signal from alongtrack satellite altimetry data is presented and applied to sea level anomaly (SLA) observations in the tropical Indian Ocean. The method consists of sequential projections onto the SLA data, starting with meridional or cross-shore Kelvin wave profiles derived from shallow water theory (y-projections). Next, Fourier basis functions in x-t (along-waveguide distance and time respectively) space with the phase speed ranges of Kelvin and Rossby waves are projected onto the y-projections. After projections in all three dimensions have been carried out, least-squares methods are applied to optimize the non-orthogonal basis function coefficients and minimize the misfit of their along-waveguide forcing and dissipation. Lastly, the westward-propagating (Rossby wave-related) signals are removed, generating a Kelvin wave coefficient K that represents Kelvin wave activity. Along the Indian Ocean equatorial-coastal waveguide, Hovmöller diagrams of K show reduced high-wavenumber noise compared to analogous diagrams of pre-processed sea level anomaly. Results from a Monte Carlo simulation demonstrate that Kelvin wave signals generated a priori can be effectively recovered even when superimposed with strong Rossby waves; the signs of all but the weakest waves are diagnosed correctly in over 90 % of cases. When the method is applied to 21 years of satellite observations and the SLA signal associated with K is removed, the large residual in the equatorial SLA signal has a spatial distribution consistent with wind-forced Rossby waves. The equatorial SLA variability in the western part of the basin is poorly correlated with the SLA field associated with K, as the superimposed SLA profile of Rossby waves can distort the true origin locations of Kelvin waves in the raw SLA field. Therefore, this method offers improved tracking of Kelvin waves compared to the raw SLA dataset, and may provide the opportunity to study weakly nonlinear aspects of these waves by comparison with linear models.
Small-scale disturbances in the stratigraphy of the NEEM ice core: observations and numerical model simulations
Authors: Jansen D. , Llorens M.-G. , Westhoff J. , Steinbach F. , Kipfstuhl S. , Bons P. D. , Griera A. , Weikusat I.
Published: February 2016

Abstract. Disturbances on the centimetre scale in the stratigraphy of the North Greenland Eemian Ice Drilling (NEEM) ice core (North Greenland) can be mapped by an optical line scanner as long as the ice has visual layering, such as, for example, cloudy bands. Different focal depths allow, to a certain extent, a three-dimensional view of the structures. In this study we present a detailed analysis of the visible folds, discuss their characteristics and frequency, and present examples of typical fold structures. We also analyse the structures with regard to the deformation boundary conditions under which they formed. The structures evolve from gentle waves at about 1500 m to overturned z folds with increasing depth. Occasionally, the folding causes significant thickening of layers. Their similar fold shape indicates that they are passive features and are probably not initiated by rheology differences between alternating layers. Layering is heavily disturbed and tracing of single layers is no longer possible below a depth of 2160 m. C axes orientation distributions for the corresponding core sections were analysed, where available, in addition to visual stratigraphy. The data show axial-plane parallel strings of grains with c axis orientations that deviate from that of the matrix, which shows a single maximum fabric at the depth where the folding occurs. Numerical modelling of crystal viscoplastic deformation and dynamic recrystallisation was used to improve the understanding of the formation of the observed structures during deformation. The modelling reproduces the development of bands of grains with a tilted-lattice orientation relative to the single maximum fabric of the matrix, and also the associated local deformation. We conclude from these results that the observed folding can be explained by formation of these tilted-lattice bands.
Relationship between Problem Solving Approaches and Academic Performance: A Case of Kakamega Municipality, Kenya
Authors: Matemba Collins K. , Awinja Jane , Otieno Kenneth O.
Published: February 2016

The problem of poor performance of students in public secondary schools in the national examination continues unabated despite numerous efforts and resources put into education development. The study sought to determine the relationship between problem solving approach and academic performance and to establish gender differences in the problem solving approaches among secondary school students in Kakamega Municipality. Correlation research design was adopted for the study. Using stratified sampling, six schools consisting of one boys school, one girls school, three public co-educational schools and one private co-educational school were sampled. Proportionate and simple random sampling was used to select a total of 200 students comprising of 113 boys and 87 girls. Questionnaires, observation check lists and Focus Group discussions were used to collect data. Quantitative data collected in the field was analysed using descriptive and inferential statistics, while qualitative data from Focus Group Discussion was analysed qualitatively. The differences between groups on studied variables were tested using t-test while correlation was used to test the null hypothesises at a significance level of .05. There was no significant relationship between problem solving approaches and academic performance while gender had no affect on problem solving. It was recommended that counsellors and secondary school teachers should train students in positive problem solving skills and an ideal environment should be created for students to acquire positive problem solving skills.
Legal Framework as a Determinant of Implementation of Occupational Health and Safety Programmes in the Manufacturing Sector in Kenya.
Authors: Ndegwa Priscilla Wanjiku , Guyo Wario , Orwa George , Ng’ang’a Robert , Murigi Elishba Muthoni
Published: February 2016

Recent trends in the organization of work have increased the risk of occupational safety and health (OSH) in Kenyan industries through exposure to hazardous substances, work related accidents and increased stress-related illnesses. According to International lab our organization (ILO) everyone is entitled to the right to safe and healthy working conditions and therefore the corpus of law in Kenya dealing with occupational safety and health should be embedded in the international OSH legal instruments. Specifically the occupational health and safety Act (2007) is expected to provide for safety, health and welfare of workers and all persons lawfully present at workplaces. The purpose of this study therefore was to investigate legal framework as a determinant of implementation of occupational health and safety programmes in the manufacturing sector in Kenya. It focused on six legal areas predicted as affecting implementation of OSH. These factors were national OSH policy, OSHA (occupational safety and health Act) familiarity with OSHA, government OSH inspections and audits, ease of implementation of OSHA, Government support in the implementation of OSH and OSHA implement ability. The study adopted descriptive cross-sectional survey design but however intended to gather both qualitative and quantitative data. A self administered questionnaire was used to collect data from 257 OSH officers drawn randomly from 735 manufacturing industries registered by Kenya manufacturers association. 252 questionnaires were received back and analyzed with the help of SSPS window version 21. Both correlation and regression analysis were conducted and the results showed that there was a positive significant relationship between legal framework and implementation of OSH programmes.
Collective Bargaining Worker Union of Fspsi Surabaya: Study on Concept and Practice of Industrial Relation
Authors: Sridadi Ahmad Rizki
Published: February 2016

The purpose of this paper is to examine collective bargaining (negotiation) exercised by worker union as the attempt to arrange collective agreement from the aspect of: concept and approach, Indonesia regulation, and practices by working unit official (PUK) under all indonesia worker union (SPSI) in Surabaya. This paper applies qualitative exploratory method with case study approach by which data collection was implemented through structured interview, obeservation and literature review. The implication of this paper is its contribution in literatur riching concerning principles, techniques, approaches, and process of collective bargaining both in conceptual and empirical side. Besides, practical implication is for company and working unit official as learning material  in subsequent collective bargaining. This paper reveals variations among practices and its concordance with the relevant concept and implementing regulations.
Adherence to European Society for Cataract and Refractive Surgery Recommendations among Italian Cataract Surgeons: A Survey
Authors: Grosso Andrea , Pertile Grazia , Marchini Giorgio , Scarpa Giuseppe , Ceruti Piero , Prigione Guido , Romano Mario R. , Bert Fabrizio , Gili Renata , Panico Claudio , Siliquini Roberta , Engelbert Michael
Published: February 2016

Purpose

To survey the surgical routines with regards to prophylactic strategies in a sample of Italian hospitals and compare these with European Society for Cataract and Refractive Surgery (ESCRS) guidelines.

Methods

Six private and 18 public hospitals were included in this clinical-based retrospective study. The overall volume of cataract operations in the 24 centers in 2013 was 43,553. Main outcome measure was incidence of endophthalmitis per 1,000. An incidence of less than 0.13% was considered acceptable.

Results

Our study provides the first Italian data on the use of intracameral antibiotics in cataract surgery as recommended by the ESCRS. Thirteen centers (54%) used intracameral cefuroxime at the end of surgery. Of the 13 centers that used cefuroxime, 8 (62%) had an incidence of endophthalmitis less than 0.13%. Of the 7 (29%) centers that did not use intracameral cefuroxime, all had an endophthalmitis rate of greater than 0.13%. This difference was statistically significant (p<0.05). Among the 4 centers not included, 2 used vancomycin in the infusion bottle, 1 a fluoroquinolone, and the last a combination of antibiotics. The majority of surgeons (71%) used preoperative antibiotic eyedrops, but this measure was not shown to be significantly protective.

Conclusions

Slightly more than half of the centers surveyed in this study adhered to the recommendations of the ESCRS and routinely employed prophylactic intracameral cefuroxime. An incidence of endophthalmitis greater than 0.13% was encountered significantly more frequently among centers that did not employ intracameral cefuroxime.
Selecting Fuchs Patients for Drug Trials Involving Endothelial Cell Proliferation
Authors: Shearer Thomas R. , Chamberlain Winston D. , Fujii Atsuko , Azuma Mitsuyoshi
Published: February 2016

Purpose

Fuchs endothelial corneal dystrophy (FECD) might be managed by drug treatment before becoming severe enough to require surgery. For a clinical trial of such a drug, we hypothesize that selecting an adequate number of patients with FECD with only moderately compromised cell densities will be challenging. Thus, the purpose of the present study was to measure the prevalence of patients with FECD exhibiting moderately decreased corneal cell densities.

Methods

A retrospective data mining study (cross-sectional study) was performed on patient charts presenting at a large US northwestern academic health center by searching for diagnosis ICD-9 code 371.57 and Fuchs corneal dystrophies, including those with prior cataract surgeries and/or existing glaucoma. Patients with prior corneal transplants were excluded. Noncontact specular photomicroscopic data (Topcon 2000) were obtained from the central region whenever possible, and individual eyes were grouped according to cell density (cells/mm2): severe (<800), moderate (800-1,500), and mild (>1,500).

Results

The values for 98 eyes from 61 patients with FECD were as follows (mean ± SD): corneal thickness 573 ± 59 μm, cell size 627 ± 336 μm2/cell, coefficient of variation 23 ± 7, and density 1,883 ± 703 cells/mm2. The moderate subgroup with cell density values averaging 1,184 ± 212 (26) comprised 27% of the total FECD patient pool.

Conclusions

Only approximately 1 out of 4 patients with FECD will show moderately compromised corneal cell densities. A moderate level of damage may be optimal for clinical trials for testing topical drugs on endothelial cell viability. Thus, investigators will need to initially screen a fourfold excess of all patients with FECD.
Modular Neck Total HIP Arthroplasty – A Perfect Storm
Authors: Humadi Ali , Jamieson Richard , Chao Tat , Tacey Mark , Khoury Elie
Published: February 2016

Purpose

This study was aimed to highlight neck notching as a potential cause of failure in modular neck total hip arthroplasty. It aimed to identify both the combination of modular components that place patients at greatest risk of failure and the potential mechanism for failure.

Methods

This study involved a retrospective review of 301 total hip arthroplasties (THA) using Kinectiv modular neck Technology (Zimmer, Warsaw, Indiana). The primary outcome was the presence of neck notching requiring revision. Patient records, operative notes and postoperative radiographs were reviewed. A statistical analysis was performed.

Results

A total of 301 THA were performed on 290 patients. There were 7 failures (2.3%). All 7 failures involved a modular combination of an anteverted neck, extended offset and length code -8 (failure rate of 36.8%, p<0.001).

Conclusions

We identified femoral neck notching as a potential cause of failure in modular neck THA. The combination of an anteverted neck, extended offset and length code -8 was associated with a high rate of neck notching using the Kinectiv modular neck Technology (Zimmer, Warsaw, Indiana). Based on our experience with this prosthesis we advise caution when using this particular combination of implants.
Debridement, Antibiotics and Implant Retention in Early Periprosthetic Joint Infection
Authors: Bergkvist Magnus , Mukka Sebastian S. , Johansson Lars , Ahl Torbjörn E. , Sayed-Noor Arkan S. , Sköldenberg Olof G. , Eisler Thomas
Published: February 2016

Introduction

Periprosthetic joint infection (PJI) is a devastating complication in hip arthroplasty surgery. Debridement, antibiotics (AB) and implant retention (DAIR) is recommended in early PJI in association with stable implants. The aim of this study was to evaluate the success rate of DAIR in early PJI (<4 weeks) and to identify factors predicting the outcome.

Methods

This cohort study included a consecutive series of 35 patients (median age 74 years, 25 women, 26 primary arthroplasties) treated with DAIR for an early PJI in a regional hospital.

Results

28 patients (80%) had their infection eradicated. DAIR-only eradicated the PJI in 22 (63%) patients with a median follow-up of 50 (24-84) months. In 17 (49%) patients, oral AB had been given prior to intraoperative cultures, which delayed first debridement with average 6 days and delayed hospital stay. Primary surgery for a hip fracture increased the risk of DAIR-failure. Surgical experience did not affect the outcome. 17% (n = 6) of the patients sustained a secondary infection during their hospital stay; the majority was beta-lactam resistant coagulase negative Staphylococcus aureus.

Conclusions

The success rate of DAIR was inferior to pervious controls from experienced revision centers. Hip fracture patients should be informed about the increased risk of DAIR treatment failure. In order not to delay surgery, empirically based oral AB should not be administered prior to deep cultures.

Trial registration

ClinicalTrials.gov Identifier: NCT02087020.
Clinical and Radiographic Outcomes after Femoral Varus Derotation Osteotomy for Legg-Calvé-Perthes Disease at 25 Years Follow-Up: What are the Determinants of Outcome in the Long Term?
Authors: Aydin Bahattin K. , Sofu Hakan , Konya Mehmet N. , Er Turgay , Sahin Vedat
Published: February 2016

Objective

The main purposes of the present study were to analyse the long-term clinical and radiographic results of femoral varus derotation osteotomy performed in a group of patients with the diagnosis of Legg-Calvé-Perthes (LCP) disease and to compare the effects of age, lateral pillar classification, radiographic stage according to Waldenström's classification, and the amount of varisation obtained on long-term results.

Design

The study group consisted of 21 hips. The mean postoperative follow-up time was 25.1 years. The effect of age at the time of surgery, preoperative lateral pillar classification, Waldenström's classification, and the amount of varisation on Merle d'Aubigne score, Stulberg class, and presence of degenerative arthritis of the hip joint were assessed at the final follow-up.

Results

Better clinical and radiographic outcomes were detected in patients operated younger than 10 years. The hips with lateral pillar group C involvement preoperatively were found to be significantly associated with worse clinical scores, worse radiographic outcome, and higher rate of degenerative arthritis. The overall rate of the hips with good radiologic outcome was 52.4%. 7 hips had degenerative arthritis at the final follow-up.

Conclusions

Femoral varus derotation osteotomy revealed a congruent joint in half of the operated hips and arthritis-free hip joint in 2/3 at 25 years follow-up. Age at the time of surgery and preoperative lateral pillar classification were the main determinants of the radiographic outcome whereas the factors significantly correlated with progression to degenerative arthritis were determined preoperative lateral pillar classification and Stulberg group at maturity.
Comparison of Nafamostat Mesilate and Unfractionated Heparin as Anticoagulants during Continuous Renal Replacement Therapy
Authors: Makino Shohei , Egi Moritoki , Kita Hiroshi , Miyatake Yuji , Kubota Kenta , Mizobuchi Satoshi
Published: February 2016

Purpose

Nafamostat mesilate (NM) can be used as a regional anticoagulant for continuous renal replacement therapy (CRRT). The primary aim of this study was to assess the association of the use of NM with risk of bleeding complications and compare it with the use of unfractionated heparin (UFH).

Methods

We conducted a single-center retrospective observational study. We included adult patients who required CRRT in our intensive care unit from 2011 to 2013. The primary outcome was the risk of bleeding complications during CRRT and the secondary outcome was filter life for the first filter of CRRT.

Results

We included 101 patients (76 with NM, 25 with UFH). Among the 101 patients, use of NM tended to be associated with lower risk of bleeding complications (6.6% vs. 16%; odds ratio, 0.37; p = 0.16). Propensity score matching generated 30 patients with NM and 15 patients with UFH with well-balanced baseline characteristics. Among the propensity score-matched cohorts, use of NM was significantly associated with decreased risk of bleeding complications (3.3% vs. 27%; odds ratio, 0.09; p = 0.04). In multivariate logistic analysis using the inverse probability of treatment weighting for sensitive analysis, the use of NM was independently associated with reduced risk of bleeding complications (p = 0.02). The median filter life was not significantly different for patients with NM and patients with UFH (25.5 hours vs. 30.5 hours, p = 0.16).

Conclusions

In our retrospective analysis, the use of NM as an anticoagulant during CRRT was associated with decreased incidence of bleeding complications compared with the use of UFH.
Morphometric Analysis of the Infraorbital Foramen, Canal and Groove Using Cone Beam CT: Considerations for Creating Artificial Organs
Authors: Orhan Kaan , Misirli Melis , Aksoy Secil , Hincal Umut Seki Evren , Ormeci Tugrul , Arslan Ahmet
Published: February 2016

Purpose

The aim of this study was to examine the anatomy and variations of the infraorbital foramen and its surroundings via morphometric measurements using cone beam computed tomography (CBCT) scans derived from a 3D volumetric rendering program.

Methods

354 sides of CBCT scans from 177 patients were examined in this study. DICOM data from these images were exported to Maxilim® software in order to generate 3D surface models. The morphometric measurements were done for infraorbital foramen (IOF), infraorbital groove (IOG) and infraorbital canal (IOC). All images were evaluated by 1 radiologist. To assess intra-observer reliability, the Wilcoxon matched-pairs signed rank test was used. Differences between sex, side, age and measurements were evaluated using chi-square and paired t-test and measurements were evaluated using 1-way ANOVA tests. Differences were considered significant when p<0.05.

Results

The most common shape was oval for IOF and parallel for IOC without any accessory foramen. The results showed that females have smaller dimensions for the measurements between the two foramen rotundum (FR), FR-IOF, sella-FR, center of the IOF (cIOF)-nasion (N), cIOF-NB (nasion-B) (p>0.05). No significant difference was found according to age groups (p>0.05).

Conclusions

These results provide detailed knowledge of the anatomical characteristics in this particular area. CBCT imaging with lower radiation dose and thin slices can be a powerful tool for anesthesia procedures like infra orbital nerve blocks, for surgical approaches like osteotomies and neurectomies and also for generating artificial prostheses.
HOTAIR in Relation to Epithelial-Mesenchymal Transition and Cancer Stem Cells in Molecular Subtypes of Endometrial Cancer
Authors: Łuczak Agata , Supernat Anna , Łapińska-Szumczyk Sylwia , Jachimowicz Daniel , Majewska Hanna , Gulczyński Jacek , Żaczek Anna J.
Published: February 2016

Background

Endometrial cancer (EC) is a hormone-related disease, showing highly diverse features of ER/PR/HER2 status-based molecular subtypes. Long noncoding RNA (lncRNA) HOX antisense intergenic RNA (HOTAIR) has recently emerged as a key molecule in many cancers, triggering epithelial-mesenchymal transition (EMT)–mediated cancer stem cell (CSC) formation, but little is known about its significance in EC. Thus, we aimed to investigate the clinical significance of HOTAIR itself in different molecular subtypes of EC and possible links between HOTAIR, EMT and CSC-related markers.

Methods

The study group included 156 consecutive, stage I-IV EC patients treated between 2000 and 2010. ER, PR and HER2 protein expression were examined by immunohistochemistry (IHC) on tissue microarrays. RT-qPCR was used to analyze the expression levels of HOTAIR, EMT-related genes – SNAIL and SLUG – and the CSCs marker CD133.

Results

Molecular subtypes, defined as ER/PR+HER2+, ER/PR+HER2-, ER-PR-HER2+ and ER-PR-HER2-, occurred in 40.2%, 52.3%, 4.7% and 1.9% of cases, respectively. The expression of HOTAIR did not differ between the subtypes, but high HOTAIR expression correlated with shorter overall survival (p = 0.04) in the entire group. The expression levels of HOTAIR, SNAIL, SLUG and CD133 were similar in defined EC molecular subtypes.

Conclusions

Our data do not confirm the role of HOTAIR in EMT-mediated CSC formation in EC. Neither does the diversity of EC molecular subtypes influence these processes. But HOTAIR expression could serve as an independent prognostic factor in EC. The clinical importance of the above discoveries requires further studies.