bluuebunny/crossref_metadata_2025 huggingface dataset:
A serosurvey of bluetongue and epizootic haemorrhagic disease in a convenience sample of sheep and cattle herds in Zimbabwe
Authors: Gordon Stuart J.G. , Bolwell Charlotte , Rogers Chris W. , Musuka Godfrey , Kelly Patrick , Guthrie Alan , Mellor Philip S. , Hamblin Chris
Published: November 2017

A convenience sample of sheep and cattle herds around the cities of Harare, Kwekwe and Bulawayo, located in the Highveld region of Zimbabwe, was used to estimate the seroprevalence and sero-incidence of bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV) antibodies. A competitive enzyme-linked immunosorbent assay was used to identify serum antibodies against BTV and EHDV across three rainy seasons. The median sero-prevalence of BTV and EHDV antibodies in cattle was 62% (interquartile range [IQR]: 30–89) and 56% (IQR: 5–77), respectively. In sheep, the median sero-prevalence of BTV and EHDV was 41% (IQR: 19–63) and 0% (IQR: 0–21), respectively. Median sero-incidences of BTV and EHDV antibodies in cattle of 43% (IQR: 22–67) and 27% (IQR: 9–57) respectively were recorded. The median sero-incidence of BTV in sheep was 14% (IQR: 6–23). Based on these preliminary findings, animal health workers in Zimbabwe should continue to monitor the exposure rates of cattle and sheep to BTV and consider the possibility of strains emerging with increased pathogenicity. There are no previous published reports of antibodies against EHDV in Zimbabwe so the possibility of epizootic haemorrhagic disease existing in domestic livestock should now be considered by Zimbabwean animal health officials. Seroconversions to BTV and EHDV occurred predominantly at the end of each rainy season (March and April), which generally corresponds to high numbers of the Culicoides vectors. BTV isolations were made from three individual cows in two of the sentinel herds and all three were identified as serotype 3. This is the first time BTV serotype 3 has been recorded in Zimbabwe, although its presence in neighbouring South Africa is well documented.
Serum Concentrations of F2-Isoprostanes and 4-Hydroxynonenal in Hemodialysis Patients in Relation to Inflammation and Renal Anemia
Authors: Wiswedel Ingrid , Peter Daniela , Gardemann Andreas , Carluccio Francesco , Hampl Hannelore , Siems Werner
Published: November 2017

Background

Patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) are apparently exposed to enhanced oxidative stress and to inflammation. It was the aim of this study to characterize the state of systemic oxidative stress of ESRD patients before and following HD using highly specific biomarkers, F2-isoprostanes and 4-hydroxynonenal (HNE). Furthermore the question should be answered, if there are associations between inflammation and systemic oxidative stress and/or between systemic oxidative stress and renal anemia, which is more or less typical for HD patients.

Patients and methods

Concentrations of F2-isoprostanes, HNE, C-reactive protein (CRP) as marker of inflammation, and hemoglobin were measured in serum samples of patients with ESRD before and after HD and of healthy control persons for comparison. Total (esterified plus free) F2-isoprostanes were quantified by highly sensitive gas chromatography/mass spectrometry technique, HNE by thin layer chromatography and HPLC/UV detection, CRP by immunoturbidimetry and hemoglobin by clinico-chemical routine assay.

Results

1. HD patients showed significantly higher serum concentrations of F2-isoprostanes and HNE than healthy human control subjects. 2. Total (esterified plus free) F2-isoprostane levels before HD were not significantly different from those after HD, whereas HNE levels were significantly decreased in patients after HD. 3. F2-isoprostane concentrations in HD patients correlated with the levels of CRP, whereas HNE concentrations inversely correlated with the content of hemoglobin.

Conclusion

Both, F2-isoprostanes and HNE serum concentrations are useful oxidative stress parameters in ESRD patients undergoing HD. Whereas HNE strongly correlates with the severity of renal anemia, leading to left heart insufficiency, F2-isoprostanes (sum of free plus esterified) highly correlate with the degree of inflammation.
Excision Repair Cross-Complementation Group 1 Enzyme as a Molecular Determinant of Responsiveness to Platinum-Based Chemotherapy for non Small-Cell Lung Cancer
Authors: Mountzios Giannis , Dimopoulos Meletios-Athanasios , Papadimitriou Christos
Published: November 2017

Although platinum-based chemotherapy remains the “standard” in advanced non small-cell lung cancer, not all patients derive clinical benefit from such a treatment. Hence, the development of predictive biomarkers able to identify lung cancer patients who are most likely to benefit from cisplatin-based chemotherapy has become a scientific priority. Among the molecular pathways involved in DNA damage control after chemotherapy, the nucleotide excision repair (NER) is a critical process for the repair of DNA damage caused by cisplatin-induced DNA adducts. Many reports have explored the role of the excision repair cross-complementation group 1 enzyme (ERCC1) expression in the repair mechanism of cisplatin-induced DNA adducts in cancer cells.

Using immunohistochemistry in resected tumors from patients included in the International Adjuvant Lung Cancer Trial, the study of important biomarkers showed that high ERCC1 protein expression was associated with improved survival in chemo-naïve patients. On the contrary, the benefit of adjuvant cisplatin-based chemotherapy was more profound in patients with low ERCC1 expression. In a prospective cohort studying mRNA expression in tumor biopsies from patients receiving customized therapy with cisplatin and gemcitabine depending on the molecular profile of the tumour, results showed that patients with low ERCC1 mRNA expression had a longer median survival compared to those with high expression. These data suggest the potent use of ERCC1 as a molecular predictor of clinical resistance to platinum-based chemotherapy in the adjuvant setting of NSCLC. Nevertheless, optimization of methodology, including standardization of technical procedures, as well as validation of ERCC1 protein expression in large prospective cohorts, seem necessary before any routine immunohistochemical validation of ERCC1 can be implemented in daily practice.
Biomarkers of Ovarian Reserve
Authors: Roudebush William E. , Kivens Wendy J. , Mattke Jessica M.
Published: November 2017

The primary function of the female ovary is the production of a mature and viable oocyte capable of fertilization and subsequent embryo development and implantation. At birth, the ovary contains a finite number of oocytes available for folliculogenesis. This finite number of available oocytes is termed “the ovarian reserve”. The determination of ovarian reserve is important in the assessment and treatment of infertility. As the ovary ages, the ovarian reserve will decline. Infertility affects approximately 15%–20% of reproductive aged couples. The most commonly used biomarker assay to assess ovarian reserve is the measurement of follicle stimulating hormone (FSH) on day 3 of the menstrual cycle. However, anti-müllerian hormone and inhibin-B are other biomarkers of ovarian reserve that are gaining in popularity since they provide direct determination of ovarian status, whereas day 3 FSH is an indirect measurement. This review examines the physical tools and the hormone biomarkers used to evaluate ovarian reserve.
Elevated CAIX Expression is Associated with an Increased Risk of Distant Failure in Early-Stage Cervical Cancer
Authors: Kirkpatrick John P. , Rabbani Zahid N. , Bentley Rex C. , Hardee Matt E. , Karol Seth , Meyer Jeffrey , Oosterwijk Egbert , Havrilesky Laura , Secord Angeles Alvarez , Vujaskovic Zeljko , Dewhirst Mark W. , Jones Ellen L.
Published: November 2017

Tumor hypoxia is associated with adverse outcome in many malignancies. The goal of this study was to determine if elevated expression of carbonic anhydrase IX (CAIX), a biomarker of hypoxia, predicts for recurrence in early-stage cervical cancer. The charts of all patients with early-stage cervical cancer, primarily FIGO IB, treated by radical hysterectomy at our institution from 1988–2001 were reviewed. Adequate pathologic specimens from patients who recurred or who had at least three years follow-up and remained disease-free were stained for CAIX. An immunohistochemical score (IHC) was generated from the extent/intensity of staining. Outcome, as measured by freedom from recurrence (FFR), distant metastases (FFDM) and local recurrence (FFLR), was analyzed as a function of age, IHC, lymph node status (LN) and histology. Forty-two relapsing patients and 76 non-relapsing patients were evaluated. In univariate analysis, +LN, though not IHC or histology, was a significant predictor of any recurrence. Both +LN and higher IHC were associated with decreased FFDM but not FFLR. Patients with both +LN and elevated IHC more frequently exhibited distant metastases as first site of failure (5-year FFDM 50%) than patients with only +LN, elevated IHC or neither feature (70, 85 and 95%, respectively, p = 0.0004). In multivariable analysis, only +LN was significantly associated with poorer FFDM (hazard ratio 4.6, p = 0.0015) though there was a strong trend with elevated CAIX expression (p = 0.069). Elevated CAIX expression is associated with more frequent distant metastases in early-stage cervical cancer, suggesting that patients with this characteristic may benefit from more aggressive treatment.
FTIR Microspectroscopy Coupled with Two-Class Discrimination Segregates Markers Responsible for Inter- and Intra-Category Variance in Exfoliative Cervical Cytology
Authors: Walsh Michael J. , Singh Maneesh N. , Stringfellow Helen F. , Pollock Hubert M. , Hammiche Azzedine , Grude Olaug , Fullwood Nigel J. , Pitt Mark A. , Martin-Hirsch Pierre L. , Martin Francis L.
Published: November 2017

Infrared (IR) absorbance of cellular biomolecules generates a vibrational spectrum, which can be exploited as a “biochemical fingerprint” of a particular cell type. Biomolecules absorb in the mid-IR (2–20 μm) and Fourier-transform infrared (FTIR) microspectroscopy applied to discriminate different cell types (exfoliative cervical cytology collected into buffered fixative solution) was evaluated. This consisted of cervical cytology free of atypia (i.e. normal; n = 60), specimens categorised as containing low-grade changes (i.e. CIN1 or LSIL; n = 60) and a further cohort designated as high-grade (CIN2/3 or HSIL; n = 60). IR spectral analysis was coupled with principal component analysis (PCA), with or without subsequent linear discriminant analysis (LDA), to determine if normal versus low-grade versus high-grade exfoliative cytology could be segregated. With increasing severity of atypia, decreases in absorbance intensity were observable throughout the 1,500 cm–1 to 1,100 cm–1 spectral region; this included proteins (1,460 cm–1), glycoproteins (1,380 cm–1), amide III (1,260 cm–1), asymmetric (νas) PO2– (1,225 cm–1) and carbohydrates (1,155 cm–1). In contrast, symmetric (νs) PO2–(1,080 cm–1) appeared to have an elevated intensity in high-grade cytology. Inter-category variance was associated with protein and DNA conformational changes whereas glycogen status strongly influenced intra-category. Multivariate data reduction of IR spectra using PCA with LDA maximises inter-category variance whilst reducing the influence of intra-class variation towards an objective approach to class cervical cytology based on a biochemical profile.
A Rapid and Simple Bioassay Method for Herbicide Detection
Authors: Li Xiu-Qing , Ng Alan , King Russell , Durnford Dion G.
Published: November 2017

Chlamydomonas reinhardtii, a unicellular green alga, has been used in bioassay detection of a variety of toxic compounds such as pesticides and toxic metals, but mainly using liquid culture systems. In this study, an algal lawn–-agar system for semi-quantitative bioassay of herbicidal activities has been developed. Sixteen different herbicides belonging to 11 different categories were applied to paper disks and placed on green alga lawns in Petri dishes. Presence of herbicide activities was indicated by clearing zones around the paper disks on the lawn 2–3 days after application. The different groups of herbicides induced clearing zones of variable size that depended on the amount, mode of action, and chemical properties of the herbicides applied to the paper disks. This simple, paper-disk-algal system may be used to detect the presence of herbicides in water samples and act as a quick and inexpensive semi-quantitative screening for assessing herbicide contamination.
Serum and Ascitic Fluid Superoxide Dismutase and Malondialdehyde Levels in Patients with Cirrhosis
Authors: Ozenirler Seren , Sancak Banu , Coskun Ugur
Published: November 2017

Serum and ascitic fluid superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured in 43 patients with cirrhosis and in a 10 healthy control group.

Compensated cirrhotic patients had no clinically detectable ascites, but decompensated patients had massive ascites. Cirrhotic patients were divided into three groups: patients with compensated cirrhosis (n = 16), patients with decompensated cirrhosis with Spontaneous bacterial peritonitis (SBP) (n = 14), and patients with decompensated cirrhosis without SBP (n = 13).

All cirrhotic patients in the experimental group had significantly higher serum SOD (p < 0.001) and MDA levels (p < 0.01) than those in the control group. There were no significant differences with respect to serum SOD and MDA levels among the three different groups of patients. There was no remarkable difference in ascitic fluid SOD and MDA levels between decompensated cirrhotic patients with and without SBP (p > 0.05).

These results suggest that the increase in serum SOD and MDA levels are not related to the presence of SBP and the status of liver cirrhosis. To sum up, clarifying the impact of increased serum SOD and MDA levels in cirrhotic patients needs further investigation.
Comparison of the Calibration Standards of Three Commercially Available Multiplex Kits for Human Cytokine Measurement to WHO Standards Reveals Striking Differences
Authors: Nechansky Andreas , Grunt Susanne , Roitt Ivan M. , Kircheis Ralf
Published: November 2017

Serum parameters as indicators for the efficacy of therapeutic drugs are currently in the focus of intensive research. The induction of certain cytokines (or cytokine patterns) is known to be related to the status of the immune response e.g. in regulating the TH1/TH2 balance. Regarding their potential value as surrogate parameters in clinical trials and subsequently for the assignment of treatment efficacy, the accurate and reliable determination of cytokines in patient serum is mandatory. Because serum samples are precious and limited, test methods–-like the xMAP multiplex technology–-that allow for the simultaneous determination of a variety of cytokines from only a small sample aliquot, can offer great advantages.

We here have compared multiplex kits from three different manufactures and found striking differences upon standardizing using WHO standards for selected cytokines. We therefore extended our xMAP multiplex measurements investigations to an ex-vivo situation by testing serum samples and found that the cytokine amounts measured was critically influenced by the actual kit used. The presented data indicate that statements regarding the quantitive determination of cytokines–-and therefore their use as biomarkers–-in serum samples have to be interpreted with caution.
Tracking Differential Gene Expression in MRL/MpJ versus C57BL/6 Anergic B Cells: Molecular Markers of Autoimmunity
Authors: Clark Amy G. , Mackin Katherine M. , Foster Mary H.
Published: November 2017

Background

Anergy is a key mechanism controlling expression of autoreactive B cells and a major site for failed regulation in autoimmune diseases. Yet the molecular basis for this differentiated cell state remains poorly understood. The current lack of well-characterized surface or molecular markers hinders the isolation of anergic cells for further study. Global gene profiling recently identified transcripts whose expression differentiates anergic from naïve B cells in model mouse systems. The objective of the current study was to evaluate the molecular and cellular processes that differentiate anergic cells that develop in the healthy C57BL/6 (B6) milieu from those that develop in the autoimmune-prone MRL/MpJ (MRL) background. This approach takes advantage of B6 and MRL mice bearing an anti-laminin Ig transgene with a well characterized anergic B cell phenotype.

Results

Global gene expression was evaluated in purified transgenic B cells using Operon version 3.0 oligonucleotide microarray assaying > 31,000 oligoprobes. Genes with a 2-fold expression difference in B6 as compared to MRL anergic B cells were identified. Expression of selected genes was confirmed using quantitative RT-PCR. This approach identified 43 probes corresponding to 37 characterized genes, including Ptpn22, CD74, Birc1f/Naip, and Ctla4, as differentially expressed in anergic B cells in the two strains. Gene Ontology classification identified differentiation, cell cycle, proliferation, development, apoptosis, and cell death as prominently represented ontology groups. Ingenuity Pathway Analysis identified two major networks incorporating 27 qualifying genes. Network 1 centers on beta-estradiol and TP53, and Network 2 encompasses RB1, p38 MAPK, and NFkB cell growth, proliferation, and cell cycle signaling pathways.

Conclusion

Using microarray analysis we identified 37 characterized genes and two functional pathways engaged in maintenance of B cell anergy for which expression is distorted by underlying autoimmune genetic susceptibility. This approach identifes a new biological role for multiple genes and potential new therapeutic targets in autoimmunity.
Prevention of Preeclampsia: Is it Still a Disappointment?
Authors: Eddib Abeer , Yeh John
Published: November 2017

Preeclampsia is a major cause of maternal mortality worldwide, with many preventive strategies tested. In this review we intend to provide a synthesis of available studies of these strategies that have been tested, including systematic reviews. We will not be performing systematic review of the studies here. Of these strategies tested only low dose acetyl salicylic acid (ASA) and calcium can be considered helpful for prevention at this time. A recent meta-analysis showed a benefit of low dose ASA for both high (RR 0.75, 95% CI 0.66 to 0.85) and moderate risk groups (RR 0.86, 95% CI 0.79 to 0.95). Therefore, low dose ASA in high risk groups may be useful, with a possible smaller benefit in moderate to low risk women. Another meta-analysis looking at calcium shows benefit for both high and low risk groups with an overall reduction in the risk of preeclampsia (RR 0.48, 95% CI 0.33 to 0.69). As a result, prenatal supplementation of calcium may be beneficial for the prevention of preeclampsia. However, vitamins C and E, zinc, fish oil, and magnesium supplementation have been discounted as potential preventive strategies. Nitric oxide, folic acid, and antithrombotics have not been well studied and there is insufficient data for reliable conclusions to be made. Areas of ongoing research that appear promising in the prevention of preeclampsia include modifiable metabolic factors, angiogenic proteins, angiotensin receptor antibodies, and syncytiotrophoblast microparticles. Strategies targeting these areas may provide opportunities for therapeutic interventions.
Competency Assessment in Family Medicine Residency: Observations, Knowledge-Based Examinations, and Advancement
Authors: Mainous Arch G. , Fang Bo , Peterson Lars E.
Published: November 2017

Background 

The Family Medicine (FM) Milestones are competency-based assessments of residents in key dimensions relevant to practice in the specialty. Residency programs use the milestones in semiannual reviews of resident performance from the time of entry into the program to graduation.

Objective 

Using a national sample, we investigated the relationship of FM competency-based assessments to resident progress and the complementarity of milestones with knowledge-based assessments in FM residencies.

Methods 

We used midyear and end-of-year milestone ratings for all FM residents in Accreditation Council for Graduate Medical Education–accredited programs during academic years 2014–2015 and 2015–2016. The milestones contain 22 items across 6 competencies. We created a summative index across the milestones. The American Board of Family Medicine database provided resident demographics and in-training examination (ITE) scores. We linked information to the milestone data.

Results 

The sample encompassed 6630 FM residents. The summative milestone index increased, on average, for each cohort (postgraduate year 1 [PGY-1] to PGY-2 and PGY-2 to PGY-3) at each assessment. The correlation between the milestone index that excluded the medical knowledge milestone and ITE scores was r = .195 (P < .001) for PGY-1 to PGY-2 cohort and r = .254 (P < .001) for PGY-2 to PGY-3 cohort. For both cohorts, ITE scores and composite milestone assessments were higher for residents who advanced than for those who did not.

Conclusions 

Competency-based assessment using the milestones for FM residents seems to be a viable multidimensional tool to assess the successful progression of residents.
La enseñanza del Derecho en aulas masivas. El caso de una Facultad de Derecho argentina.
Authors: Gapel Redcozub Guillermo
Published: November 2017

Este trabajo analiza el efecto de la masificación de la matrícula sobre las prácticas docentes en una Facultad de Derecho perteneciente a una Universidad Pública argentina. Describe el contexto general del fenómeno y detalla sus principales consecuencias sobre las prácticas áulicas. Luego reflexiona sobre el proceso enseñanza-aprendizaje en la Facultad de Derecho en su estado actual, caracterizando la perspectiva epistemológica subyacente, la teoría del aprendizaje implícita, el enfoque didáctico predominante y el plan de estudios de la carrera. A continuación, evalúa el efecto de la universalización del acceso a la educación superior sobre el proyecto educativo de la institución. Concluye ofreciendo una propuesta alternativa para alcanzar los objetivos educativos institucionales en un contexto de masificación.

 
Curriculum XXI. Lo esencial de la educación para un mundo en cambio
Authors: Cantón Mayo Isabel
Published: November 2017

Recensión del libro CURRICULUM XXI. Lo esencial de la educación para un mundo en cambio, de Heidi Hayes Jacobs.
Consideraciones sobre una experiencia en Orientación en la Facultad de Ingeniería - Universidad Nacional de Entre Ríos
Authors: Perassi Marisol , Doval Temporelli Azul
Published: November 2017

Este trabajo presenta diferentes instancias y dispositivos de Orientación que se han implementado en una institución universitaria pública argentina durante diez años, y analiza los temas que aparecen como más significativos y que se abordan allí.
En el Área de Asesoría Pedagógica y Orientación Vocacional actualmente trabajan profesionales de Educación y de Psicología, y colaboran activamente docentes, egresados, autoridades y administrativos de la institución.
En el ámbito de la universidad, la Orientación Vocacional (OV) es una potente herramienta para trabajar con los estudiantes (particularmente al ingreso y egreso), cuestiones que subyacen y se relacionan con sus elecciones vocacionales. En la Universidad, además de la formación, también se hace posible el intercambio social, y por eso se considera importante colaborar en la construcción de espacios que favorezcan el encuentro con otros, y que posibiliten el apoyo para resolver cuestiones comunes que preocupan.
Las instancias y dispositivos que se presentan aquí son: jornadas de orientación para futuros ingresantes, ambientación universitaria, encuestas vocacionales a ingresantes, tutoría entre pares, talleres destinados a estudiantes de los primeros años, talleres destinados a estudiantes avanzados, cuestionarios breves sobre la situación vocacional y entrevistas personales. También se realiza una referencia a encuentros informales y casuales, por considerarse que éstos muchas veces posibilitan que los estudiantes se expresen respecto de su situación particular.
Esta experiencia permite ver que hay muchos modos de abordar la OV en la Universidad y esto es así principalmente porque las elecciones vocacionales siempre están en construcción, y esa construcción no se realiza de manera lineal.
Practicum y simulación clínica en el Grado de Enfermería, una experiencia de innovación docente
Authors: Leal Costa César , Díaz Agea José Luis , Rojo Rojo Andrés , Juguera Rodríguez Laura , López Arroyo María José
Published: November 2017

Se ha implantado la simulación clínica avanzada en la Facultad de Enfermería de la UCAM como método complementario de aprendizaje y evaluación, dentro de los diferentes Practicum Clínicos. Utilizar la simulación como método de aprendizaje y evaluación por competencias en enfermería así como integrar la metodología científica que ofrece el proceso de enfermería con la práctica asistencial simulada han sido los principales objetivos para llevar a cabo esta experiencia. Se utilizan simuladores a escala real (SER) que reproducen de manera realista un paciente con diversos problemas de salud. La metodología de aprendizaje/evaluación se basa en la reproducción de casos clínicos basados en la práctica asistencial en entornos clínicos simulados y controlados. Mediante diferentes sesiones los alumnos escenifican los procedimientos y cuidados en la sala de simulación. Estas sesiones son grabadas en un sistema de vídeo y visionadas en tiempo real por otro grupo de alumnos. Posteriormente se analiza la situación de manera reflexiva por el grupo y el instructor (Debriefing). En las sesiones de evaluación se evalúan, por parte del instructor y del resto de alumnos, las competencias asociadas al Practicum Clínico correspondiente mediante simulación. La simulación clínica es una metodología complementaria útil, tanto para el aprendizaje como para la evaluación por competencias en los diferentes Practicum Clínicos replicando escenarios reales en entornos simulados con alumnos de Grado de Enfermería.
Long-term chemical analysis and organic aerosol source apportionment at nine sites in central Europe: source identification and uncertainty assessment
Authors: Daellenbach Kaspar R. , Stefenelli Giulia , Bozzetti Carlo , Vlachou Athanasia , Fermo Paola , Gonzalez Raquel , Piazzalunga Andrea , Colombi Cristina , Canonaco Francesco , Hueglin Christoph , Kasper-Giebl Anne , Jaffrezo Jean-Luc , Bianchi Federico , Slowik Jay G. , Baltensperger Urs , El-Haddad Imad , Prévôt André S. H.
Published: November 2017

Abstract. Long-term monitoring of organic aerosol is important for epidemiological studies, validation of atmospheric models, and air quality management. In this study, we apply a recently developed filter-based offline methodology using an aerosol mass spectrometer (AMS) to investigate the regional and seasonal differences of contributing organic aerosol sources. We present offline AMS measurements for particulate matter smaller than 10 µm at nine stations in central Europe with different exposure characteristics for the entire year of 2013 (819 samples). The focus of this study is a detailed source apportionment analysis (using positive matrix factorization, PMF) including in-depth assessment of the related uncertainties. Primary organic aerosol (POA) is separated in three components: hydrocarbon-like OA related to traffic emissions (HOA), cooking OA (COA), and biomass burning OA (BBOA). We observe enhanced production of secondary organic aerosol (SOA) in summer, following the increase in biogenic emissions with temperature (summer oxygenated OA, SOOA). In addition, a SOA component was extracted that correlated with an anthropogenic secondary inorganic species that is dominant in winter (winter oxygenated OA, WOOA). A factor (sulfur-containing organic, SC-OA) explaining sulfur-containing fragments (CH3SO2+), which has an event-driven temporal behaviour, was also identified. The relative yearly average factor contributions range from 4 to 14 % for HOA, from 3 to 11 % for COA, from 11 to 59 % for BBOA, from 5 to 23 % for SC-OA, from 14 to 27 % for WOOA, and from 15 to 38 % for SOOA. The uncertainty of the relative average factor contribution lies between 2 and 12 % of OA. At the sites north of the alpine crest, the sum of HOA, COA, and BBOA (POA) contributes less to OA (POA / OA  =  0.3) than at the southern alpine valley sites (0.6). BBOA is the main contributor to POA with 87 % in alpine valleys and 42 % north of the alpine crest. Furthermore, the influence of primary biological particles (PBOAs), not resolved by PMF, is estimated and could contribute significantly to OA in PM10.
Laser ablation aerosol particle time-of-flight mass spectrometer
(LAAPTOF): Performance, reference spectra and classification of
atmospheric samples
Authors: Shen Xiaoli , Ramisetty Ramakrishna , Mohr Claudia , Huang Wei , Leisner Thomas , Saathoff Harald
Published: November 2017

Abstract. The laser ablation aerosol particles time-of-flight mass spectrometer (LAAPTOF, Aeromegt GmbH) is able to identify the chemical composition and mixing state of individual aerosol particles, and thus is a tool for elucidating their impacts on human health, visibility, ecosystem and climate. The overall detection efficiency (ODE) of the instrument we use was determined to range from ~(0.01 ± 0.01) % to ~(6.57 ± 2.38) % for polystyrene latex (PSL), ammonium nitrate (NH4NO3), and sodium chloride (NaCl) particles in the size rage of 200 to 2000 nm. Reference mass spectra of 32 different particle types relevant for atmospheric aerosol (e.g. pure compounds NH4NO4, K2SO4, NaCl, oxalic acid, pinic acid, and pinonic acid; internal mixtures of e.g. salts, secondary organic aerosol, and metallic core-organic shell particles; more complex particles such as soot and dust particles) were determined. Our results show that internally mixed aerosol particles can result in spectra with new clusters of ions, rather than simply a combination of the spectra from the single components. An exemplary one-day ambient data set was analysed by classical Fuzzy-clustering leading to six different particle classes. Correlating these particle classes with the reference spectra as well as direct comparison of the ambient data with the reference spectra has proven how useful they are for the interpretation of field measurements, for e.g. grouping data, and identifying special particle types and potential sources.
Climatology and modeling of ionospheric scintillations and irregularity zonal drifts at the equatorial anomaly crest region
Authors: Muella Marcio T. A. H. , Duarte-Silva Marcelo H. , Moraes Alison O. , de Paula Eurico R. , de Rezende Luiz F. C. , Alfonsi Lucilla , Affonso Bruno J.
Published: November 2017

Abstract. In this study the climatology of ionospheric scintillations and the zonal drift velocities of scintillation-producing irregularities are depicted for a station located under the southern crest of the equatorial ionization anomaly. Then, the α − μ ionospheric fading model is used for the first- and second-order statistical characterization of amplitude scintillations. In the statistical analyzes, data are used from single-frequency GPS receivers acquired during ∼ 17 years (September 1997–November 2014) at Cachoeira Paulista (22.4° S; 45.0° W), Brazil. The results reveal that the nocturnal occurrence of scintillations follows the seasonal distribution of plasma bubble irregularities observed in the longitudinal sector of eastern South America. In addition to the solar cycle dependence, the results suggest that the occurrence climatology of scintillations is also modulated by the secular variation in the dip latitude of Cachoeira Paulista, since the maximum occurrence of scintillations during the peak of solar cycle 24 was ∼ 20 % lower than that observed during the maximum of solar cycle 23. The dynamics of the irregularities throughout a solar cycle, as investigated from the estimates of the mean zonal drift velocities, presented a good correlation with the EUV and F10.7 cm solar fluxes. Meanwhile, the seasonal behavior showed that the magnitude of the zonal drift velocities is larger during the December solstice months than during the equinoxes. In terms of modeling, the results for the α − μ distribution fit quite well with the experimental data and with the temporal characteristics of fading events independently of the solar activity level.
Seasonal variability of the inorganic carbon system in a large coastal plain estuary
Authors: Joesoef Andrew , Kirchman David L. , Sommerfield Christopher K. , Cai Wei-Jun
Published: November 2017

Abstract. Carbonate geochemistry research in large estuarine systems is limited. More work is needed to understand how changes in land-use activity influence watershed export of organic and inorganic carbon, acids, and nutrients to the coastal ocean. To investigate the seasonal variation of the inorganic carbon system in the Delaware Estuary, one of the largest estuaries along the US east coast, dissolved inorganic carbon (DIC), total alkalinity (TA), and pH were measured along the estuary from June 2013 to April 2015. In addition, DIC, TA, and pH were periodically measured from March to October 2015 in the nontidal freshwater Delaware, Schuylkill, and Christina rivers over a range of discharge conditions. There were strong negative relationships between river TA and discharge, suggesting that changes in HCO3− concentrations reflect dilution of weathering products in the drainage basin. The ratio of DIC to TA, an understudied but important property, was high (1.11) during high discharge and low (0.94) during low discharge, reflecting additional DIC input in the form of carbon dioxide (CO2), most likely from terrestrial organic matter decomposition, rather than bicarbonate (HCO3−) inputs due to drainage basin weathering processes. This is also a result of CO2 loss to the atmosphere due to rapid water transit during the wet season. Our data further show that elevated DIC in the Schuylkill River is substantially different than that in the Delaware River. Thus, tributary contributions must be considered when attributing estuarine DIC sources to the internal carbon cycle versus external processes such as drainage basin mineralogy, weathering intensity, and discharge patterns. Long-term records in the Delaware and Schuylkill rivers indicate shifts toward higher alkalinity in estuarine waters over time, as has been found in other estuaries worldwide. Annual DIC input flux to the estuary and export flux to the coastal ocean are estimated to be 15.7 ± 8.2  ×  109 mol C yr−1 and 16.5 ± 10.6  ×  109 mol C yr−1, respectively, while net DIC production within the estuary including inputs from intertidal marshes is estimated to be 5.1  ×  109 mol C yr−1. The small difference between riverine input and export flux suggests that, in the case of the Delaware Estuary and perhaps other large coastal systems with long freshwater residence times, the majority of the DIC produced in the estuary by biological processes is exchanged with the atmosphere rather than exported to the sea.
The sensitivity of the Greenland ice sheet to glacial-interglacial oceanic forcing
Authors: Tabone Ilaria , Blasco Javier , Robinson Alexander , Alvarez-Solas Jorge , Montoya Marisa
Published: November 2017

Abstract. Observations suggest that during the last decades the Greenland Ice Sheet (GrIS) has experienced a gradually accelerating mass loss, in part due to the observed acceleration of several of Greenland’s marine-terminating glaciers. Recent studies directly attribute this to increasing North Atlantic temperatures, which have triggered melting of the GrIS outlet glaciers, grounding-line retreat and enhanced ice discharge into the ocean, contributing to an acceleration of sea level rise. Reconstructions suggest that the influence of the ocean has been of primary importance in the past as well. This was the case not only in interglacial periods, when warmer climates led to a rapid retreat of the GrIS to land above sea level, but also in glacial periods, when the GrIS expanded as far as the continental shelf break, and was thus more directly exposed to ocean changes. However, the GrIS response to paleo oceanic variations has not been investigated from a modelling perspective so far. In this work the evolution of the GrIS over the past two glacial cycles has been studied using a three-dimensional hybrid ice-sheet/ice-shelf model. We assess the effect of the variation of oceanic temperatures on the GrIS evolution on glacial-interglacial timescales through changes in submarine melting. The results show a very high sensitivity of the GrIS to the changing oceanic conditions. Oceanic forcing is found to be the dominant driver of the GrIS expansion in glacial times and retreat in interglacial periods. If switched off, paleo atmospheric variations alone are not able to yield a reliable glacial configuration of the GrIS. This work therefore suggests that considering the ocean as an active forcing should become standard in paleo ice sheet modelling.
Comparison of spatial downscaling methods of general circulation models to study climate variability during the Last Glacial Maximum
Authors: Latombe Guillaume , Burke Ariane , Vrac Mathieu , Levavasseur Guillaume , Dumas Christophe , Kageyama Masa , Ramstein Gilles
Published: November 2017

Abstract. The extent to which climate conditions influenced the spatial distribution of hominin populations in the past is highly debated. General Circulation Models (GCMs) and archaeological data have been used to address this issue. Most GCMs are not currently capable of simulating past surface climate conditions with sufficiently detailed spatial resolution to distinguish areas of potential hominin habitat, however. In this paper we propose a Statistical Downscaling Methods (SDM) for increasing the resolution of climate model outputs in a computationally efficient way. Our method uses a generalized additive model (GAM), calibrated over present-day data, to statistically downscale temperature and precipitation from the outputs of a GCM simulating the climate of the Last Glacial Maximum (19–23 000 BP) over Western Europe. Once the SDM is calibrated, we first interpolate the coarse-scale GCM outputs to the final resolution and then use the GAM to compute surface air temperature and precipitation levels using these interpolated GCM outputs and fine resolution geographical variables such as topography and distance from an ocean. The GAM acts as a transfer function, capturing non-linear relationships between variables at different spatial scales. We tested three different techniques for the first interpolation of GCM output: bilinear, bicubic, and kriging. The results were evaluated by comparing downscaled temperature and precipitation at local sites with paleoclimate reconstructions based on paleoclimate archives (archaeozoological and palynological data). Our results show that the simulated, downscaled temperature and precipitation values are in good agreement with paleoclimate reconstructions at local sites confirming that our method for producing fine-grained paleoclimate simulations suitable for conducting paleo-anthropological research is sound. In addition, the bilinear and bicubic interpolation techniques were shown to distort either the temporal variability or the values of the response variables, while the kriging method offers the best compromise. Since climate variability is an aspect of their environment to which human populations may have responded in the past this is an important distinction.
Including Effects of Watershed Heterogeneity in the Curve Number
Method Using Variable Initial Abstraction
Authors: Santikari Vijay P. , Murdoch Lawrence C.
Published: November 2017

Abstract. The curve number (CN) method was developed more than half a century ago and is still used in many watershed/water quality models to estimate direct runoff from a rainfall event. Despite its popularity, the method is plagued by a conceptual problem where CN is assumed to be constant for a given set of watershed conditions, but many field observations show that CN decreases with event rainfall (P). Recent studies indicate that heterogeneity within the watershed is the cause of this behavior, but the governing mechanism remains poorly understood. This study shows that heterogeneity in initial abstraction, Ia, can be used to explain how CN varies with P. By conventional definition, Ia is equal to the cumulative rainfall before the onset of runoff, and is assumed to be constant for a given set of watershed conditions. Our analysis shows that the total storage in Ia (IaT) is constant, but the effective Ia varies with P, and is equal to the filled portion of IaT, which we call IaF. CN calculated using IaF varies with P similar to published field observations. This motivated modifications to the CN method, called Variable Ia Models (VIMs), which replace Ia with IaF. VIMs were evaluated against Conventional Models CM0.2 (λ = 0.2) and CMλ (calibrated λ) in their ability to predict runoff data generated using a distributed parameter CN model. The performance of CM0.2 was the poorest whereas those of the VIMs were the best in predicting overall runoff and watershed heterogeneity. VIMs also predicted the runoff from smaller events better than the CMs, and eliminated the false prediction of zero-runoffs, which is a common shortcoming of the CMs. We conclude that including variable Ia accounts for heterogeneity and improves the performance of the CN method while retaining its simplicity.
A trusted cryptocurrency scheme for secure and verifiable digital transactions
Authors: Baldi Marco , Chiaraluce Franco
Published: November 2017

Decentralized digital currency systems known as cryptocurrencies are a breakthrough in electronic payments: the absence of a central authority can avoid the risk that a not fully reliable government seizes assets or causes hyperinflation, very small transactions can be made without incurring high costs and transactions can be traced, thus providing a tool to counter laundering and tax evasion. Furthermore, decentralization provides robustness against many attacks. Despite these advantages, cryptocurrencies have still not become mainstream solutions, because of scarce users’ inclination to adopt them as a privileged payment tool. This is mostly due to the absence of a structured form of control, which also prevents from having some credit insurance. Moreover, some present and future attacks, like quantum computer-based attacks, may threaten their security. In this paper we define new technical solutions to allow cryptocurrencies to become trusted tools for secure and verifiable digital transactions, and also for deposits, while preserving decentralization and users’ privacy. Based on a thorough security analysis, a new cryptocurrency model is first defined, exploiting a set of secure and post-quantum cryptographic primitives. Then, a secure supervision and authentication network is designed, which allows to control transactions, while guaranteeing users’ privacy. A robust reputation system for this context is also proposed, which helps to increase users’ trust and to reduce misconduct.
Wikipedia: An opportunity to rethink the links between sources' credibility, trust, and authority
Authors: Sahut Gilles , Tricot André
Published: November 2017

The Web and its main tools (Google, Wikipedia, Facebook, Twitter) deeply raise and renew fundamental questions, that everyone asks almost every day: Is this information or content true? Can I trust this author or source? These questions are not new, they have been the same with books, newspapers, broadcasting and television, and, more fundamentally, in every human interpersonal communication. This paper is focused on two scientific problems on this issue. The first one is theoretical: to address this issue, many concepts have been used in library and information sciences, communication and psychology. The links between these concepts are not clear: sometimes two concepts are considered as synonymous, sometimes as very different. The second one is historical: sources like Wikipedia deeply challenge the epistemic evaluation of information sources, compared to previous modes of information production. This paper proposes an integrated and simple model considering the relation between a user, a document and an author as human communication. It reduces the problem to three concepts: credibility as a characteristic granted to information depending on its truth-value; trust as the ability to produce credible information; authority when the power to influence of an author is accepted, i.e., when readers accept that the source can modify their opinion, knowledge and decisions. The model describes also two kinds of relationships between the three concepts: an upward link and a downward link. The model is confronted with findings of empirical research on Wikipedia in particular.
How geopolitical conflict shapes the mass-produced online map
Authors: Quinn Sterling D. , Tucker Doran A.
Published: November 2017

Cartographers have always grappled with the question of how to depict spaces of conflict where place names or boundaries are disputed. We examine how these conflicts are represented in mass-produced online maps with a worldwide audience, focusing on both commercial maps produced by tech giants such as Google, and crowdsourced efforts such as OpenStreetMap. Producers of these maps occasionally publish policies on conflict resolution, emphasizing the mapping of ground truth and conformance to internationally recognized specifications. In practice, the makers of these maps violate their own appeals to neutrality and ground truth by (1) producing customized versions of the map tailored to local laws or expectations; and, (2) introducing ambiguity through the selective addition or omission of information in sensitive locations. We provide examples of these customization and ambiguity practices in commercial and crowdsourced maps. We demonstrate how commercial maps can appear in any number of versions to satisfy disputing parties, and crowdsourced maps can undergo “rogue customizations” for varying time periods as irredentist or separatist contributors seek for avenues to express their causes to a worldwide audience. We reflect on the long-term viability of customization and ambiguity as cartographic practices, commenting on ways that they shape — and are shaped by — the conflict on the ground and power of involved actors. Behind the seamless navigation of the Web 2.0 world map lies a patchwork of contributor motives and worldviews that complicates an understanding of ground truth and warrants interpretation through the lens of critical cartography.