bluuebunny/crossref_metadata_2025 huggingface dataset:
Success in Hosted Accommodation: Does Owner Age Matter?
Authors: Weber Paull , Carlsen Jack
Published: July 2012

Recent studies of mature entrepreneurs in Europe, the UK, and North America suggest that, contrary to popular perception, the growing number of small businesses created and operated by mature entrepreneurs have a longer life span and are generally more successful. The literature primarily
attributes this perceived success to various age-related advantages, such as the ability to accrue greater commercial experience, more personal networks and experience, and greater personal financial resources that can be used to fund the venture. In order to investigate the age-related success
of small tourism businesses, this study analyzes 167 responses from a survey of 655 hosted accommodation owner-operators in Western Australia. The relative success of each business venture was evaluated using a number of criteria: longevity of the enterprise, consumer demand (measured via
occupancy rate), and two measures of self-perceived levels of success. The results show that while businesses operated by mature entrepreneurs have a longer life span, every other indicator of success—both objective and subjective—suggests that these owner-operators are actually
less successful than expected. These results contradict the emerging body of evidence elsewhere, and suggest that firms run by older entrepreneurs may in fact be more marginal than has previously been supposed.
Competition, Total Quality Management Practices, and Performance: Evidence from Upscale Hotels
Authors: Patiar Anoop , Davidson Michael C. G. , Wang Ying
Published: July 2012

Hotels operate in a highly competitive market and therefore place a strong emphasis on quality management in order to gain/maintain competitiveness. This research examined the relationship between total quality management (tQM), market competition, and hotel departmental financial and
nonfinancial performance. The data were collected from a sample of Australian and Indian hotels using a self-administered postal survey. the results suggested that while tQM and market competition had a direct interactive effect on hotel departmental nonfinancial performance, the effect on
the financial performance was indirect. It was also suggested that those hotels subscribing to tQM philosophy were more likely to thrive on competition.
All Work and No Play Makes Jack a Dull Boy: An Exploration of Business Travelers' Attendance at Live, Ticketed Entertainment Events
Authors: Bernthal Matthew , Nagel Mark , Harrill Rich , Riner Paul
Published: July 2012

This study explores the factors that influence business travelers' attendance at ticketed live entertainment events while traveling on business. Many ticketed live entertainment events (e.g., concerts, sport events) are held in metropolitan areas that are ripe with large numbers of
business travelers who can be considered a market segment for event promoters. The current study surveyed business travelers in order to gain initial insight into what does and does not motivate them to attend such events. Eesults provide practical benefit to marketers of ticketed live entertainment
events by helping them better understand business travelers as potential customers.
Auction Sales of Hotel Rooms and Airline Seats
Authors: De Kay Frederick , Toh Rex S. , Raven Peter
Published: July 2012

This article provides a primer on the different types of single-item auctions, and then discusses the various combinations of pricing flexibility and opaqueness. It then reveals that whereas 13% of hotel rooms are sold through auction sites, less than 1% of airline seats are auctioned
off. It concludes with plausible reasons for the relative unpopularity of buying airline tickets through auctions.
Marketing Strategies for Casinos: A Case for Australia
Authors: Koo Bon-Ki , Lee Timothy J. , Ahn Tae-Hong
Published: July 2012

The increasing popularity of the gambling industry has prompted casinos to develop strategies to maintain a competitive advantage and accomplish business goals. This study examines the Australian casino operations to provide ideas for potential promotional strategies. Seven such strategies
are identified: advertising; improved public relations; sales promotions; personal selling; branding image; loyalty programs; and pricing and packages. The importance of each is discussed with examples drawn from casinos, and promotional strategies are provided with a critical evaluation in
a broader context. This study provides a method for casino practitioners to monitor and review their promotional strategies to keep stimulating patronage and enhancing overall revenues.
Health Promotion Among Older Cancer Survivors With Prior Disabling Conditions
Authors: Becker Heather , Kang Sook Jung
Published: July 2012

Older cancer survivors, who often cope with multiple disabling conditions, can find health promotion challenging. This study’s purpose was to explore predictors of health promotion for older cancer survivors with a disabling condition that existed prior to their cancer diagnosis. The 92 cancer survivors were predominantly women with preexisting neuromuscular impairments and an average age of 69. Half were breast cancer survivors, and 58% were 6 or more years since their cancer diagnosis. In hierarchical regression analyses, self-efficacy for health promotion and social support were the strongest predictors of total scores on the Health-Promoting Lifestyle Profile II and its subscales. The findings suggest that nursing interventions to assist older cancer survivors with multiple chronic conditions in building their social support and perceived self-efficacy may help them lead healthier lives.
A Path to Greater Inclusivity Through Understanding Implicit Attitudes Toward Disability
Authors: Aaberg Vicki A.
Published: July 2012

Individuals with visible disabilities are underrepresented in nursing and have been denied admission to nursing education and discriminated against based on their disability, although nurse educators have been found to hold positive explicit attitudes toward disabled individuals. This study examines nurse educators’ implicitly held attitudes toward individuals with disabilities through the use of the Disability Attitude Implicit Association Test. Findings demonstrated that nurse educators are strongly biased toward individuals without disabilities (
N
= 132, D = 0.76,
SD
= 0.46) and demonstrated a stronger preference than the general population (
N
= 38,544, D = 0.45,
SD
= 0.43). Study results suggest the need for a timely critique of the continuing focus on physical abilities as a prerequisite for admission to nursing programs. In addition, faculty in schools of nursing and practicing nurses must engage in discussions of attitudes toward individuals with visible disabilities for the discipline to be more inclusive.
In Vitro Quantification of the Stiffening Effect of Corneal Cross-linking in the Human Cornea Using Radial Shearing Speckle Pattern Interferometry
Authors: Knox Cartwright Nathaniel E. , Tyrer John R. , Marshall John
Published: July 2012

PURPOSE:

To quantify the magnitude of the stiffening effect of corneal cross-linking (CXL) by studying intact human corneas exposed to physiological pressure transients.

METHODS:

Nine organ-cultured human corneas mounted in artificial anterior chambers were studied. A radial shearing speckle pattern interferometer was used to measure changes in corneal strain following an increase in artificial anterior chamber pressure from 15.0 to 15.5 mmHg before and after treatment. Measurements were taken from all corneas with their epithelium intact before all underwent epithelial debridement. Three specimens were used as controls and did not receive any further treatment; three underwent riboflavin/ultraviolet A (UVA) CXL using 30 minutes of 370-nm irradiation at 3 mW/cm
2
following epithelial removal and saturation with 0.1% riboflavin; and three were fixed with the cross-linking agent 2.5% glutaraldehyde. Strain measurements were repeated after these treatments. Young’s moduli of individual corneas were calculated by mathematical analysis.

RESULTS:

Mean donor age was 81.7 years. Before treatment, the mean Young’s moduli of the control, riboflavin/UVA CXL, and glutaraldehyde-fixed corneas did not differ significantly: 0.46±0.03, 0.48±0.03, and 0.47±0.03 MPa, respectively. Following treatment these values changed to 0.46±0.2, 2.06±0.22, and 3.48±0.41 MPa, respectively. In proportional terms, this was equivalent to an increase in corneal Young’s modulus by a factor of 4.3 (
P
<.05) following riboflavin/UVA CXL and 7.3 (
P
<.05) after glutaraldehyde fixation.

CONCLUSIONS:

Riboflavin-UVA CXL increases the stiffness of organ-cultured corneas by a factor of more than four. This finding quantifies the efficacy of CXL in a physiologic configuration.
Flap Relift for Retreatment After Femtosecond Laser–assisted LASIK
Authors: Santhiago Marcony R. , Smadja David , Zaleski Kelly , Espana Edgar M. , Armstrong Brian K. , Wilson Steven E.
Published: July 2012

PURPOSE:

To analyze the results of LASIK retreatment performed by relifting the original femtosecond laser–created flap.

METHODS:

A retrospective analysis was performed on 1298 eyes from 688 patients treated with LASIK using the femtosecond laser to identify 88 consecutive eyes of 71 patients that underwent attempted flap lift to treat residual refractive error. The eyes were separated in groups in which the flap lift was possible or flap lift was not possible to investigate factors that could make flap lifting more difficult. The main factors evaluated were bed and side-cut energy and time between original surgery and retreatment. In addition, all retreated eyes were studied as a group to evaluate the refractive outcomes of flap lift retreatment.

RESULTS:

In 10 (11.3%) retreated eyes, flap lift was not possible without risk of flap injury due to strong healing of the original femtosecond laser interface. The group of eyes in which the flap could not be relifted had the attempted retreatment performed a longer time period after original LASIK (10.3±3.3 months) compared to the group in which the flap could be re-lifted (5.24±3.14 months) (
P
<.001). No significant differences were found between groups in any other parameters, including bed and side-cut energies. After retreatment, 82% of eyes achieved 20/20 or better uncorrected visual acuity.

CONCLUSIONS:

This study provides clinical evidence that flap lift retreatment after femtosecond laser–assisted LASIK achieves excellent clinical results and is significantly easier to perform in the first 6 to 8 months after primary LASIK.
The effects of a pressure extraction system on quality the parameters of different virgin pistachio (Pistacia vera L. var. Larnaka) oils
Authors: Álvarez-Ortí M. , Quintanilla C. , Sena E. , Alvarruiz A. , Pardo J. E.
Published: July 2012

Pistachios are a good source for oil extraction as they are rich in unsaturated fatty acids and other bioactive components like polyphenols and phenolic compounds. The yield and quality parameters of the oil extracted from four batches of pistachios with different sizes were analyzed. Two different pressure systems (screw press and hydraulic press) were used for oil extraction. The yield was higher when the screw press was used, especially when the highest quality pistachios (larger pistachios) were used to extract the oil (40 ± 2.12%). With the hydraulic press, the yield was around 30% for all pistachio types. The color of the oils extracted with the screw press was darker than the oil extracted with the hydraulic press in all types of pistachios used. No significant differences were found in the acidity, K270, and K232 values when high quality pistachios were used. When lower quality pistachios (smaller pistachios) were used, the values of these three parameters increased in comparison with larger pistachios. On the other hand, oil samples from lower quality pistachios obtained by the screw press showed the highest values. The oxidative stability was higher in the samples of oil from high quality pistachios, with no differences in regard to the extraction system. When lower quality pistachios were used, the oxidative stability was significantly lower.
Carabid beetle communities after 18 years of conservation tillage and crop rotation in a cool humid climate
Authors: Lalonde Olivier , Légère Anne , Stevenson F. Craig , Roy Michèle , Vanasse Anne
Published: July 2012

Agricultural practices affect the biotic and abiotic conditions that determine food and shelter for carabid beetles (Coleoptera: Carabidae). We hypothesised that carabid communities would respond differently to 18 years of contrasted cropping practices in cereal-based rotations. We measured the effects of tillage (MP: moldboard plough; CP: chisel plough; NT: no-till) and previous crop sequence (cereal monoculture versus cereal–forage/cereal–oilseed rotation) on carabid beetle activity density, diversity, and community structure in corn (Zea maysLinnaeus, Poaceae) at La Pocatière, Québec, Canada. Carabid beetles were sampled monthly from May to September 2006, using pitfall traps. Although 19 carabid species were observed, assemblages were dominated byHarpalus rufipes(De Geer), particularly in the second half of the season. Multivariate analyses indicated a strong affinity of carabid species for the NT treatment throughout the season. Crop sequence and tillage had no effect on diversity (Shannon'sH′ ≤ 1.3) and evenness of carabid assemblage, but species richness and activity density were greater in NT than in tilled systems. Peak activity density of dominant species occurred at different times during the season, generally in accordance with preferred breeding season. Many species had greater activity density in NT than in tilled treatments. Because of their granivorous feeding habit, carabid populations such as that ofH. rufipescould be an important asset to NT, given the limited weed management options available for this system.
Management of Luteal Phase Defect in Adolescent Girls
Authors: Dutta Indranil , Dutta Dilip Kumar
Published: July 2012

Objective

To find out the effect of dydrogesterone drug on menstral cycle of adolescent girl.

Study design

A total of 50 adolescent girl (16-19 years) who were suffering from irregular menstruation were recruited for this study from April 2008 to February 2009, at JNM Hospital, Kalyani, West Bengal, India.

Results

Menstrul cycle was found to be regular within 6 months of treatment along with the reduction of endometrial thickness.

Conclusion

Dydrogesterone was found to be safest drug to regularize menstrual cycle of adolescent girl suffering from menstrual irregularity due to luteal phase defect.

How to cite this article

Dutta DK, Dutta I. Management of Luteal Phase Defect in Adolescent Girls. J South Asian Feder Obst Gynae 2012;4(1):10-11.
Fertility Promoting Laparoscopic Surgery: Our Experience
Authors: Chatterjee Alokendu , Chatterjee Siddhartha , Chowdhury Rajib Gon , Dey Sandip , Ganguly Debidas
Published: July 2012

Aim and objective

This study was to find out optimal laparoscopic surgical procedures for fertility promotion and to compare its pregnancy outcome with in vitro fertilization (IVF) procedure.

Design and setting

Laparoscopic surgical procedures were performed under one consultant in a tertiary fertility set-up.

Materials and methods

Between January 1994 and December 2008, 3,982 cases of fertility promoting laparoscopic surgery (FPLS) were performed in our center. The procedures were related to uterus and appendages and especially endometriosis.

Results

The pregnancy rate following the surgical correction of minor tubal defects, ovarian cyst and uterine fibroids was between 25 and 30%, major tubal defects (5.7%) and severe endometriosis 18.5%. But the assisted reproductive technology (ART) outcome for the former was 30% and for the latter too, was between 25 and 30%.

Conclusion

Laparoscopic surgical corrections for minor tubal defects yield comparable results to ART, but for other two conditions, the latter is superior to the former.

How to cite this article

Chatterjee S, Chatterjee A, Chowdhury RG, Dey S, Ganguly D. Fertility Promoting Laparoscopic Surgery: Our Experience. J South Asian Feder Obst Gynae 2012;4(1):12-16.
Cervical Length Measurement by Transvaginal Ultrasound at 20 to 24 Weeks Gestation and the Timing and Mode of Delivery
Authors: Agarwal Shonali , Arora Payal , Maitra Nandita K
Published: July 2012

Objective

To study the relationship between midtrimester cervical length measurement on transvaginal ultrasonography and timing and mode of delivery.

Materials and methods

A total of 200 asymptomatic antenatal women at 20 to 24 weeks gestation were recruited. Cervical assessment with transvaginal ultrasound was performed using a 5 MHz transvaginal probe. Findings of cervical assessment were then correlated with the timing and mode of delivery. Chisquare test and Odd's ratios with 95% confidence intervals were used.

Results

Sixteen percent women delivered preterm. A cervical length of ≤ 30 mm had good specificity and NPV. At the cut-off value of 25 mm or less, sensitivity was 31.3%, specificity was 100%, PPV was also 100% and NPV was 88.4%. Increased cervical length on TVS (>40 mm) was associated with higher rate of cesarean section as compared to <40 mm (66% vs 34%) and this observation was statistically significant.

Conclusion

Cervical length measured by TVS at midtrimester is a useful and significant predictor of the gestational age at delivery and the mode of delivery. The high negative predictive value avoids unnecessary interventions, such as tocolysis or cerclage in high-risk pregnancies.

How to cite this article

Arora P, Maitra NK, Agarwal S. Cervical Length Measurement by Transvaginal Ultrasound at 20 to 24 Weeks Gestation and the Timing and Mode of Delivery. J South Asian Feder Obst Gynae 2012;4(1):22-24.
Second Trimester Abortion with Vaginal Misoprostol: Is There Any Advantage with Prior Mifepristone Priming? A Comparative Study
Authors: Mukhopadhyay Partha , Bag Tara Sankar , Kyal Amit , Bhuniya Anup , Saha Tushar Kanti
Published: July 2012

Objective

Second trimester medical termination of pregnancy (MTP) can be done by surgical or nonsurgical methods or by various combinations of the two. Every method has its advantages and disadvantages. An ideal method would be one which was safe, quick and 100% effective, inexpensive and without any immediate or late side-effects. However, in the absence of such, various methods in synergistic combinations have been tried to come close to an ideal method. The successes of medical method now appear to be useful in MTP even in second trimester of pregnancy. Our objective is to investigate the effectiveness of only vaginal misoprostol and compare with oral mifepristone plus vaginal misoprostol in second-trimester induction abortions (≥12 and ≤20 weeks).

Methods

The patients are selected after careful examination and necessary investigations were divided into group A (n = 62) which received 400 μg of vaginal misoprostol followed by 200 μg vaginal misoprostol 4 hourly till expulsion of fetus or a maximum dose of 2000 μg and group B (n = 60) which received 200 mg of oral mifepristone followed 48 hours later by vaginal misoprostol as in group A. Main outcomes measured were efficacy, blood loss, induction-abortion interval and complication.

Results

The present study showed that the both methods were effective in 2nd trimester MTP. Average blood loss was lesser in group B (131.66 ml) compared to group A (150 ml). Induction abortion interval was shorter in group B (6.62 hours) than in group A (12.19 hours). Ninty percent of group B and 80.7% of group A had no complications. Success rate was higher in group B.

Conclusion

Therefore, in our study, pretreatment mifepristone followed by misoprostol was found to be a very effective regimen for 2nd trimester abortion with lesser complications and higher efficacy.

How to cite this article

Mukhopadhyay P, Bag TS, Kyal A, Bhuniya A, Saha TK. Second Trimester Abortion with Vaginal Misoprostol: Is There Any Advantage with Prior Mifepristone Priming? A Comparative Study. J South Asian Feder Obst Gynae 2012;4(1):25-27.
Predictability of Fetal Birth Weight from Measurement of Fetal Thigh Circumference by Two-dimensional Ultrasound: A Prospective Study
Authors: Dasgupta Shyamal , Ghosh Tarun Kumar , Mukherjee Amitava , Sanyal Poushali , Karim Rezaul , Das Anita
Published: July 2012

Objective

The aim of this study was to compare the predictability of the Vintzileos’ formula with the Hadlock's formula in estimating the fetal weight nearest to the actual birth weight.

Methods

It was a prospective observational study conducted with 138 antenatal mothers with single viable fetus and no major congenital abnormalities. A two-dimensional ultrasound scan was performed between 38 and 40 weeks gestation, which measured the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and thigh circumference (TC) at the level of midthigh, and incorporated them to estimate fetal weight using the Hadlock's and the Vintzileos’ formulae.

Results

For the majority of the study population (63.04%), the mean fetal weight estimated by the Vintzileos’ formula was nearer to the mean actual birth weight compared to the Hadlock's formula. There was strong correlation (Karl Pearson's correlation coefficient r = 0.98, p-value <0.05) between the sonologically estimated and the neonatal thigh circumference.

Conclusion

The results of this study show that the fetal thigh circumference, if incorporated with other standard biometric parameters in estimating fetal weight by ultrasound, improves the predictability of birth weight estimation, and can predict intrauterine growth restriction.

How to cite this article

Sanyal P, Ghosh TK, Dasgupta S, Karim R, Mukherjee A, Das A. Predictability of Fetal Birth Weight from Measurement of Fetal Thigh Circumference by Twodimensional Ultrasound: A Prospective Study. J South Asian Feder Obst Gynae 2012;4(1):35-38.
Knowledge and Awareness about Preventive Health Seeking Behavior and Acceptability of Cervical Cancer Vaccine in Urban Women in Comparison with School Students
Authors: Divakar Hema
Published: July 2012

Background

In India, cervical cancer is the single largest killer of middle-aged women, followed by breast cancer. Though the effective screening test is available, most of the women in developing and underdeveloped countries do not have access to Pap (papanicolou) smear screening due to poor literacy and low level of awareness both early detection and screening remain a major area of concern for health care persons.

Objective

To explore knowledge and awareness about preventive health seeking behavior and acceptability of cervical cancer vaccine in urban women in comparison with school students.

Materials and methods

This was a prospective study conducted to compare the awareness between 236 urban women attending the antenatal, gynaec and postdelivery outpatients and inpatients and 132 students aged between 12 to 14 years. A questionnaire was designed to tap the information about cervix-related questions, cancer cervix awareness and also about the Pap test and HPV vaccine.

Results

Overall 29.55% and urban women 19.07% did not know about the cervix. Overall, 79.55% students and 74.15% of urban women did not know about symptomatology of cervical cancer. Overall, 34.09% of students and 38.98% of women did not know about prevention of cervical cancer. Out of the total participants, 35.61% of students and 44.07% of women knew that death will happen, if cancer cervix was not treated or controlled for a long period.

Conclusion

Attempts to educate parents/peers and students themselves would intensify the awareness and improve the usage of the HPV vaccines in the desired cohort.

How to cite this article

Divakar H. Knowledge and Awareness about Preventive Health Seeking Behavior and Acceptability of Cervical Cancer Vaccine in Urban Women in Comparison with School Students. J South Asian Feder Obst Gynae 2012;4(1): 47-53.
Aerosol lifetime and climate change
Authors: Roelofs G.-J.
Published: July 2012

Abstract. The dominant removal mechanism for atmospheric aerosol is activation of particles to cloud droplets and subsequent wet deposition in precipitation. The atmospheric lifetime of aerosol is thus closely coupled to the atmospheric cycling time of water vapor. Changes of hydrological cycle characteristics resulting from climate change therefore directly affect aerosol lifetime, and thus the radiative forcing exerted by aerosol. This study expresses the coupling between water vapor and aerosol lifetimes and their temperature sensitivities in fundamental equations and in terms of the efficiency of processing of air by precipitating clouds. Based on climate model simulations these temperature sensitivities are estimated to be on the order of +5.3% K−1, but this may be an overestimation. Generally, shifting spatial and temporal patterns of aerosol (precursor) emissions and precipitation, and changes in aerosol activation efficiency probably influence aerosol lifetimes more than climate change itself, resulting in a wide range of simulated aerosol lifetime sensitivities between aerosol-climate models. It is possible that the climate sensitivity of models plays a role. It can be argued that climate sensitivity is intrinsically coupled with the simulated (temperature sensitivity of the) aerosol lifetime through the distribution of water vapor and aerosol between the lower and upper troposphere. This implies a fundamental relation between various feedback forcings (water vapor, lapse rate, cloud) and the aerosol forcing, illustrating the key role of the hydrological cycle in different aspects of the climate system.
Strato-mesospheric ClO observations by SMILES: error analysis and diurnal variation
Authors: Sato T. O. , Sagawa H. , Kreyling D. , Manabe T. , Ochiai S. , Kikuchi K. , Baron P. , Mendrok J. , Urban J. , Murtagh D. , Yasui M. , Kasai Y.
Published: July 2012

Abstract. Chlorine monoxide (ClO) is the key species for anthropogenic ozone loss in the middle atmosphere. We observed the ClO diurnal variation using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station which has a non sun-synchronous orbit. This is the first global observation of the ClO diurnal variation from the stratosphere up to the mesosphere. The SMILES observation reproduced the diurnal variation of stratospheric ClO, an enhancement during a daytime, as observed by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite (UARS/MLS). Mesospheric ClO has shown a different diurnal behavior with an enhancement during nighttime. The ClO enhancement was found at a pressure of 0.02 hPa (about 70 km) with an amplitude of about 100 pptv and reached up to 0.01 hPa (80 km) in the zonal mean of 50° N–65° N in January–February 2010. The observation of mesospheric ClO was possible due to the 10–20 times better signal-to-noise ratio of the spectra than those of past microwave/submillimeter-wave limb-emission sounders. We performed a quantitative error analysis for the strato- and mesospheric ClO of the Level-2 research (L2r) product version 2.1.5 taking into account all possible error contributions; i.e. errors due to spectrum noise, smoothing and uncertainties in the radiative transfer model and instrument function. The SMILES L2r v2.1.5 ClO data are useful over the range 0.01 and 100 hPa with a total error of 10–30 pptv (about 10%) with averaging of 100 profiles. The vertical resolution is 3–5 km and 5–8 km for the stratosphere and mesosphere, respectively. The performance of the SMILES observation opens the new opportunity to investigate ClO up to the mesopause.
Production of oceanic nitrous oxide by ammonia-oxidizing archaea
Authors: Löscher C. R. , Kock A. , Könneke M. , LaRoche J. , Bange H. W. , Schmitz R. A.
Published: July 2012

Abstract. The recent finding that microbial ammonia oxidation in the ocean is performed by archaea to a greater extent than by bacteria has drastically changed the view on oceanic nitrification. The numerical dominance of archaeal ammonia-oxidizers (AOA) over their bacterial counterparts (AOB) in large parts of the ocean leads to the hypothesis that AOA rather than AOB could be the key organisms for the oceanic production of the strong greenhouse gas nitrous oxide (N2O) that occurs as a by-product of nitrification. Very recently, enrichment cultures of marine ammonia-oxidizing archaea have been reported to produce N2O. Here, we demonstrate that archaeal ammonia monooxygenase genes (amoA) were detectable throughout the water column of the eastern tropical North Atlantic (ETNA) and eastern tropical South Pacific (ETSP) Oceans. Particularly in the ETNA, comparable patterns of abundance and expression of archaeal amoA genes and N2O co-occurred in the oxygen minimum, whereas the abundances of bacterial amoA genes were negligible. Moreover, selective inhibition of archaea in seawater incubations from the ETNA decreased the N2O production significantly. In studies with the only cultivated marine archaeal ammonia-oxidizer Nitrosopumilus maritimus SCM1, we provide the first direct evidence for N2O production in a pure culture of AOA, excluding the involvement of other microorganisms as possibly present in enrichments. N. maritimus showed high N2O production rates under low oxygen concentrations comparable to concentrations existing in the oxycline of the ETNA, whereas the N2O production from two AOB cultures was comparably low under similar conditions. Based on our findings, we hypothesize that the production of N2O in tropical ocean areas results mainly from archaeal nitrification and will be affected by the predicted decrease in dissolved oxygen in the ocean.
Breakdown of the coral-algae symbiosis: towards formalising a linkage between warm-water bleaching thresholds and the growth rate of the intracellular zooxanthellae
Authors: Wooldridge S. A.
Published: July 2012

Abstract. Impairment of the photosynthetic machinery of the algal endosymbiont ("zooxanthellae") is the proximal trigger for the thermal breakdown of the coral-algae symbiosis ("coral bleaching"). Yet, the primary site of thermal damage is not well resolved. In this perspective essay, I consider further a recent hypothesis which proposes an energetic disruption to the carbon-concentrating mechanisms (CCMs) of the coral host, and the resultant onset of CO2-limitation within the photosynthetic "dark reactions", as a unifying cellular mechanism. The hypothesis identifies the enhanced retention of photosynthetic carbon for zooxanthellae (re)growth following an initial irradiance-driven expulsion event as the cause of the energetic disruption. If true, then it implies that the onset of the bleaching syndrome and setting of upper thermal bleaching limits are emergent attributes of the coral symbiosis that are ultimately underpinned by the characteristic growth profile of the intracellular zooxanthellae; which is known to depend not just on temperature, but also external (seawater) nutrient availability and zooxanthellae genotype. Here, I review this proposed bleaching linkage at a variety of observational scales, and find it to be parsimonious with the available evidence. This provides a new standpoint to consider the future prospects of the coral symbiosis in an era of rapid environmental change, including the now crucial importance of reef water quality in co-determining thermal bleaching resistance.
Mapping uncertainties through the POM-SAT model of climate reconstruction from borehole data
Authors: Bartlett M. G.
Published: July 2012

Abstract. Borehole temperature-depth profiles contain information about the ground surface temperature (GST) history of a locale and can be employed in climate reconstruction. The borehole method of climate reconstruction assumes that the dominant heat transport mechanism in the upper few hundred meters of the earth's crust is conduction; mathematically, conduction is a compressive (information losing) mapping from the temperature-time space of GST to the temperature-depth profile (T−z). Because the mapping is compressive, multiple GST histories can map into the same T−z profile; the solution suffers from non-uniqueness. One means of dealing with the non-uniqueness problem is to limit the number of parameters sought in the solution space. However, even when only a single parameter (the pre-observation mean GST, or POM) is sought in the inversion, a certain amount of a priori information must be introduced prior to inverting for a GST history. In the POM-SAT method, a priori information introduced includes the surface-air temperature history (SAT), the thermal diffusivity of the conductive medium, and the reducing parameter used to remove the background (non-climatic) heat flux. I perform a set of Monte Carlo analyses to investigate how uncertainties in these a priori model parameters are mapped into the solution space of the POM-SAT method of climate reconstruction. Results indicate that uncertainties in the thermal diffusivity are generally reduced by an order of magnitude when mapped to the POM. Uncertainties in the SAT time series are approximately equivalent in magnitude to their projection onto the POM. However, uncertainties in the adjustment for the background (non-climatic) thermal regime are magnified by an order of magnitude in the POM solution-space. These results suggest a degree of prudence should be exercised in interpreting surface temperature histories from reduced borehole data.
Mass transport of contaminated soil released into surface water by landslides (Göta River, SW Sweden)
Authors: Göransson G. , Larson M. , Bendz D. , Åkesson M.
Published: July 2012

Abstract. Landslides of contaminated soil into surface water represent an overlooked exposure pathway that has not been addressed properly in existing risk analysis for landslide hazard, contaminated land, or river basin management. A landslide of contaminated soil into surface water implies an instantaneous exposure of the water to the soil, dramatically changing the prerequisites for the mobilisation and transport of pollutants. In this study, an analytical approach is taken to simulate the transport of suspended matter released in connection with landslides into rivers. Different analytical solutions to the advection-dispersion equation (ADE) were tested against the measured data from the shallow rotational, retrogressive landslide in clayey sediments that took place in 1993 on the Göta River, SW Sweden. The landslide encompassed three distinct events, namely an initial submerged slide, followed by a main slide, and a retrogressive slide. These slides generated three distinct and non-Gaussian peaks in the online turbidity recordings at the freshwater intake downstream the slide area. To our knowledge, this registration of the impact on a river of the sediment release from a landslide is one of few of its kind in the world and unique for Sweden. Considering the low frequency of such events, the data from this landslide are highly useful for evaluating how appropriate the ADE is to describe the effects of landslides into surface water. The results yielded realistic predictions of the measured variation in suspended particle matter (SPM) concentration, after proper calibration. For the three individual slides it was estimated that a total of about 0.6% of the total landslide mass went into suspension and was transported downstream. This release corresponds to about 1 to 2% of the annual suspended sediment transport for that river stretch. The studied landslide partly involved an industrial area, and by applying the analytical solution to estimate the transport of metals in the sediments, it was found that landslides may release a significant amount of pollutants if large contaminated areas are involved. However, further studies are needed to develop more detailed descriptions of the transport processes. There is also a need to increase the knowledge on possible environmental consequences in the near and far field, in a short- and long-time perspective. In summary, the release of pollutants should not be neglected in landslide risk assessments.
Assessing the impact of uncertainty on flood risk estimates with reliability analysis using 1-D and 2-D hydraulic models
Authors: Altarejos-García L. , Martínez-Chenoll M. L. , Escuder-Bueno I. , Serrano-Lombillo A.
Published: July 2012

Abstract. This paper addresses the use of reliability techniques such as Rosenblueth's Point-Estimate Method (PEM) as a practical alternative to more precise Monte Carlo approaches to get estimates of the mean and variance of uncertain flood parameters water depth and velocity. These parameters define the flood severity, which is a concept used for decision-making in the context of flood risk assessment. The method proposed is particularly useful when the degree of complexity of the hydraulic models makes Monte Carlo inapplicable in terms of computing time, but when a measure of the variability of these parameters is still needed. The capacity of PEM, which is a special case of numerical quadrature based on orthogonal polynomials, to evaluate the first two moments of performance functions such as the water depth and velocity is demonstrated in the case of a single river reach using a 1-D HEC-RAS model. It is shown that in some cases, using a simple variable transformation, statistical distributions of both water depth and velocity approximate the lognormal. As this distribution is fully defined by its mean and variance, PEM can be used to define the full probability distribution function of these flood parameters and so allowing for probability estimations of flood severity. Then, an application of the method to the same river reach using a 2-D Shallow Water Equations (SWE) model is performed. Flood maps of mean and standard deviation of water depth and velocity are obtained, and uncertainty in the extension of flooded areas with different severity levels is assessed. It is recognized, though, that whenever application of Monte Carlo method is practically feasible, it is a preferred approach.
Quantifying different sources of uncertainty in hydrological projections at the catchment scale
Authors: Dobler C. , Hagemann S. , Wilby R. L. , Stötter J.
Published: July 2012

Abstract. Many studies have investigated potential climate change impacts on regional hydrology; less attention has been given to the components of uncertainty that affect these scenarios. This study quantifies uncertainties resulting from (i) General Circulation Models (GCMs), (ii) Regional Climate Models (RCMs), (iii) bias-correction of RCMs, and (iv) hydrological model parameterization using a multi model framework. This consists of three GCMs, three RCMs, three bias-correction techniques, and sets of hydrological model parameters. The study is performed for the Lech watershed (~1000 km2), located in the Northern Limestone Alps, Austria. Bias-corrected climate data are used to drive the hydrological model HQsim to simulate runoff under present (1971–2000) and future (2070–2099) climate conditions. Hydrological model parameter uncertainty is assessed by Monte Carlo sampling. The model chain is found to perform well under present climate conditions. However, hydrological projections are associated with large uncertainty, mainly due to the choice of GCM and RCM. Uncertainty due to bias-correction is found to have greatest influence on projections of extreme river flows and the choice of method(s) is an important consideration in snowmelt systems. Overall, hydrological model parameterization is least important. The study also demonstrates how an improved understanding of the physical processes governing future river flows can help focus attention on the scientifically tractable elements of the uncertainty.
Modelling canopy and litter interception in commercial forest plantations in South Africa
Authors: Bulcock H. H. , Jewitt G. P. W.
Published: July 2012

Abstract. There is a gap in the knowledge of both canopy and litter interception in South African forest hydrology. Interception is typically considered to constitute only a small portion of the total evaporation and in some models is disregarded. Interception is a threshold process, as a certain amount of water is required before successive processes can take place. Therefore an error introduced in modelling interception, especially disregarding it, will automatically introduce errors in the calibration of subsequent models/processes. Field experiments to assess these processes, viz. canopy and litter interception were established for the three main commercial forestry genera in South Africa, namely, Pinus, Acacia and Eucalyptus. Drawing on both field and laboratory data, the "variable storage Gash" model for canopy interception and an idealised drying curve litter interception model were developed to represent these processes. It was found that canopy and litter interception can account for as much as 26.6% and 13.4% of gross precipitation, respectively, and are therefore important hydrological processes. The models developed were able to adequately represent these interception processes and provide a way forward for more representative water resources planning modelling.
Change of extreme rainfall indexes at Ebro River Basin
Authors: Valencia J. L. , Tarquis A. M. , Saá-Requejo A. , Gascó J. M.
Published: July 2012

Abstract. Extreme rainfall events are a serious concern for regional hydrology and agriculture in the Ebro River Basin. Repeated anomalous rainfall in recent decades has had a devastating impact on this region, both socially and economically. Some studies developed in Italy and USA have shown that there is a change in seasonal patterns and an increasing frequency of extreme rainfall events, whereas other studies have pointed out that no global behaviour could be observed in monthly trends due to high climatic variability. The aim of this work is to test which of these scenarios is the case for the Ebro River Basin. For this purpose, 14 meteorological stations were selected based on the length of the rainfall series and the climatic classification to obtain a representative untreated dataset from the river basin. Daily rainfall series from 1957 to 2002 were obtained from each meteorological station. First, classical climatic indexes were analysed with an autoregressive test to study possible trends in rainfall. The results can be explained following the evolution of the NAO and WeMO indexes, which indicate that the initial period should be subdivided in two periods (1957–1979 and 1980–2002) to assume stationarity and to analyse the rainfall distribution functions. The general results obtained in this study for both sub-periods, through the generalised Pareto distribution (GPD) parameters and the maximum expected return values, do not support the results previously obtained by other authors that affirm a positive trend in extreme rainfall indexes and point to a slight reduction indicated by others. Three extreme precipitation indexes show negative statistical significant trends. GPD-scale parameters decrease except for only one rain gauge, although this decrease is only statistically significant for two rain gauges. Another two locations show statistical significance decreased for maximum expected return values.
On the chemical dynamics of extracellular polysaccharides in the high Arctic surface microlayer
Authors: Gao Q. , Leck C. , Rauschenberg C. , Matrai P. A.
Published: July 2012

Abstract. The surface microlayer (SML) represents a unique system of which the physicochemical characteristics may differ from those of the underlying subsurface seawater (SSW). Within the Arctic pack ice area, the SML has been characterized as enriched in small colloids of biological origin, resulting from extracellular polymeric secretions (EPS). During the Arctic Summer Cloud Ocean Study (ASCOS) in August 2008, particulate organic matter (POM, with size range > 0.22 μm) and dissolved organic matter (DOM, < 0.22 μm, obtained after filtration) samples were collected and chemically characterized from the SML and the corresponding SSW at an open lead centered at 87.5° N and 5° E. Total organic carbon was persistently enriched in the SML with a mean enrichment factor (EF) of 1.45 ± 0.41, whereas sporadic depletions of dissolved carbohydrates and amino acids were observed. Monosaccharide compositional analysis reveals that EPS in the Arctic lead was formed mainly of distinctive heteropolysaccharides, enriched in xylose, fucose and glucose. The mean concentrations of total hydrolysable neutral sugars in SSW were 94.9 ± 37.5 nM in high molecular weight (HMW) DOM (> 5 kDa) and 64.4 ± 14.5 nM in POM. The enrichment of polysaccharides in the SML appeared to be a common feature, with EFs ranging from 1.7 to 7.0 for particulate polysaccharides and 3.5 to 12.1 for polysaccharides in the HMW DOM fraction. A calculated monosaccharide yield suggests that polymers in the HMW DOM fraction were scavenged, without substantial degradation, into the SML. Bubble scavenging experiments showed that newly aggregated particles could be formed abiotically by coagulation of low molecular weight nanometer-sized gels. Aerosol particles, artificially generated by bubbling experiments, were enriched in polysaccharides by factors of 22–70, relative to the source seawater. We propose that bubble scavenging of surface-active polysaccharides could be one of the possible mechanisms for the enrichment of polysaccharides in the high Arctic open lead SML.
Segmentation of the Izu-Bonin and Mariana plates based on the analysis of the Benioff seismicity distribution and regional tomography results
Authors: Jaxybulatov K. , Koulakov I. , Dobretsov N. L.
Published: July 2012

Abstract. We present a new model of P- and S-velocity anomalies in the mantle down to 1300 km depth beneath the Izu-Bonin and Mariana (IBM) arcs. This model is derived based on tomographic inversion of global travel time data from the revised ISC catalogue. The results of inversion are thoroughly verified using a series of different tests. The obtained model is generally consistent with previous studies of different authors. We also present the distribution of relocated deep events projected to the vertical surface along the IBM arc. Unexpectedly, the seismicity form elongated vertical clusters instead of horizontal zones indicating phase transitions in the slab. We propose that these vertical seismicity zones mark zones of intense deformation and boundaries between semi-autonomous segments of the subducting plate. The P- and S-seismic tomography models consistently display the slab as prominent high-velocity anomalies coinciding with the distribution of deep seismicity. Based on joint consideration of the tomography results and the seismicity distribution we propose a scenario of the subduction evolution in the IBM zone during the recent time. We can distinguish at least four segments which subduct differently. The northernmost segment of the Izu-Bonin arc has the gentlest angle of dipping which is explained by backward displacement of the trench. In the second segment, the trench stayed at the same location, and we observe the accumulation of the slab material in the transition zone and its further descending to the lower mantle. In third segment, the trench is moving forward that causes steepening of the slab. Finally, for the Mariana segment, despite the backward displacement of the arc, the subducting slab is nearly vertical. We propose that it might be due to the high density of the slab which is responsible for turning any inclined subduction to the vertical position. Between the Izu-Bonin and Mariana arcs we clearly observe a gap which is traced down to about 400 km depth.