bluuebunny/crossref_metadata_2025 huggingface dataset:
The Staphylococcus aureus leucine aminopeptidase is localized to the bacterial cytosol and demonstrates a broad substrate range that extends beyond leucine
Authors: Carroll Ronan K. , Veillard Florian , Gagne Danielle T. , Lindenmuth Jarrod M. , Poreba Marcin , Drag Marcin , Potempa Jan , Shaw Lindsey N.
Published: December 2012

Staphylococcus aureus is a potent pathogen of humans exhibiting a broad disease range, in part due to an extensive repertoire of secreted virulence factors, including proteases. Recently, we identified the first example of an intracellular protease (leucine aminopeptidase, LAP) that is required for virulence in S. aureus. Disruption of pepZ, the gene encoding LAP, had no affect on the growth rate of bacteria; however, in systemic and localized infection models the pepZ mutant had significantly attenuated virulence. Recently, a contradictory report was published suggesting that LAP is an extracellular enzyme and it is required for growth in S. aureus. Here, we investigate these results and confirm our previous findings that LAP is localized to the bacterial cytosol and is not required for growth. In addition, we conduct a biochemical investigation of purified recombinant LAP, identifying optimal conditions for enzymatic activity and substrate preference for hydrolysis. Our results show that LAP has a broad substrate range, including activity against the dipeptide cysteine-glycine, and that leucine is not the primary target of LAP.
Highlight: The physiology and dynamics of cellular microcompartments
Authors: Brandt Roland , Klare Johann , Steinhoff Heinz-Jürgen , Ungermann Christian
Published: December 2012

No abstract available.
High Temperature Tensile Properties of Equal Channel Angular Pressed Al-Zn-Mg-Cu Alloy
Authors: Tekeli Süleyman , Güral Ahmet
Published: December 2012

In this study, ultra fine-grained microstructure was produced in Al–Zn–Mg–Cu alloy by equal channel angular pressing (ECAP) at 200 °C and a pressing speed of 2 mm s−1 using route C. The microstructure of the specimens was characterized by transmission and scanning electron microscopes. The results showed that the mean grain size of the specimens effectively decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 µm, this value decreased to 300 nm after 14 passes. High temperature tensile tests were carried out at a strain rate of 1 × 10− 2 and temperature of 250 °C in the specimens with different pass number. It was seen that the flow stress decreased and the elongation to failure significantly increased with increasing pass number. The highest elongation to failure value of 90% was obtained in the specimen after 14 passes.
Microstructural and Mechanical Properties of Er2O3-ZrO2 Ceramics with Different Er2O3 Contents
Authors: Tekeli Süleyman , Aktaş Bülent , Küçüktüvek Mustafa
Published: December 2012

In this study, the effect of erbium oxide (Er2O3) addition on the microstructure, sinterability and mechanical properties of cubic zirconia (c-ZrO2) was investigated. 0–15 wt% Er2O3 and c-ZrO2 powders were mixed by means of colloidal processing and the specimens were sintered at different temperatures for 1 hour. The XRD results showed the existence of cubic crystal structure in all specimens. The lattice parameter of the specimens decreased with increasing Er2O3 addition up to 10 wt% and remained unchanged after this amount. The grain size of the Er2O3 doped c-ZrO2 specimens dropped up to 5 wt% Er2O3 addition and stayed almost unchanged at higher Er2O3 contents. Both hardness and fracture toughness measurements were done using Vickers hardness tester. The fracture toughness values of the undoped, 1, 5, 10 and 15 wt% Er2O3 doped c-ZrO2specimens were found to be 1.64 MPam1/2, 1.77 MPam1/2, 2.06 MPam1/2, 2.57 MPam1/2 and 2.31 MPam1/2 respectively.
A Simple Method for Synthesis of PbS Nanoparticles Using 2-Mercaptoethanol as the Capping Agent
Authors: Nabiyouni Gholamreza , Boroojerdian Parviz , Hedayati Kambiz , Ghanbari Davood
Published: December 2012

Lead sulfide nanoparticles were synthesized at room temperature via a simple chemical reaction. In this synthesis, 2-mercaptoethanolwas used as the capping agent and sodium sulfide was used as a sulfur source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy Electron microscopy study showed that without using a capping agent the bulk PbS is obtained, while adding the mercaptoethanol leads to production of nanoparticles. We found that the electronic absorption spectra as well as the particle sizes depend on the used capping agents. Two exitonic peaks with a large blue shift were observed when mercaptoethanol was used.
Effect of Ag on the Hot Corrosion of NiAl Intermetallic Compound
Authors: Liu S.N. , Su W. , Lv W.Y. , Wei Z.F. , Zeng C.L.
Published: December 2012

The low ambient tensile ductility and inadequate high temperature strength and creep resistance have limited the applications of intermetallic compound NiAl as a structure material at high temperatures. A small addition of Ag could increase the strength of NiAl. In this study, hot corrosion behavior of NiAl and NiAl-Ag containing 1 and 5%Ag (in weight percent), respectively, in molten (Na,K)﻿2SO4 at 1173 K has been examined by thermogravimetry and physical analysis techniques. The experimental results indicated that the corrosion rates of NiAl and NiAl-Ag tended to increase with exposure time, accompanied with the formation of nodules. Fast localized corrosion is the typical feature of the corrosion of both NiAl and NiAl-Ag. The addition of Ag to NiAl accelerated its corrosion, with a higher corrosion rate observed for the 5%Ag addition. The two-phase microstructure of NiAl-Ag alloys accelerated the formation of nodules in the regions close to Ag phases.
Comparison between neurological examination and computerized test of attention for suspected ADHD: implications for assessment of a common childhood disability
Authors: Diamond Gary , Badir Moad , Sevilla Patty , Inbar Dov , Gadoth Natan
Published: December 2012

The aim of this study was to determine the role of the Test of Variables of Attention (TOVA), a computer-based continuous performance test (CPT), in assessing suspected attention-deficit/hyperactivity disorder (ADHD), a pervasive cause of disability in children and adolescents.

One hundred and fifty children and adolescents referred to a community-hospital-based neurology clinic for suspected ADHD underwent a comprehensive clinical evaluation by a pediatric neurologist in addition to the TOVA test. Retrospective chart data were analyzed separately for children aged 6–12 years (n=101) and adolescents (13–18 years) (n=49). Parents and teachers completed

The correlation between the neurologist’s impression of the presence of attention deficit and the TOVA scores was good in the younger group (r=0.28, p≤0.001) and weaker in the older group (r=0.29, p≤0.05). On nonparametric analysis, the neurological evaluation did not distinguish between low and high TOVA scorers in the older group. The neurologist’s impression correlated more closely with the DSM-IV parents ratings (r=0.29, p≤0.01) than the teachers’ (r=0.08, p≤0.05).

The TOVA correlated well with clinical assessment of ADHD and has added value in the evaluation of ADHD in adolescents, for whom standardized rating scales are lacking. In younger children, an experienced clinician can usually reach an accurate diagnosis based on accepted clinical criteria, including parent and teacher reports.
The 392 Problem
Authors: Meyerowitz Aaron , Selfridge John
Published: December 2012

Suppose that
Explicit Solutions of Certain Systems of Pell Equations
Authors: Ribenboim Paulo
Published: December 2012

We show how to obtain the solutions of families of systems of two Pell equations; these families are parameterized by the prime numbers.
Protective role of ferulic acid on carbon tetrachloride-induced hyperlipidemia and histological alterations in experimental rats
Authors: Marimuthu Srinivasan , Adluri Ram Sudheer , Rajagopalan Rukkumani , Menon Venugopal Padmanabhan
Published: December 2012

Background: The present study aimed to evaluate the antihyperlipidemic effect of ferulic acid (FA) on carbon tetrachloride (CCl4)-treated rats.

Methods: Female albino rats of the Wistar strain were used in the present study. The rats were divided into four groups: groups 1 and 4 received physiological saline (3 mL/kg body weight/week) by subcutaneous injection, whereas groups 2 and 3 received a subcutaneous injection of CCl4 (3 mL/kg body weight/week) for a total period of 12 weeks. In addition, groups 3 and 4 were administered FA (20 mL/kg body weight) every day for the last 90 days.

Results: The results showed significantly (p≤0.05) elevated levels of cholesterol, triglycerides (TG), and free fatty acids (FFA) in the liver and kidney of CCl4-treated rats as compared with those of the controls. In addition, the levels of cholesterol, FFA, phospholipids (PL), and TG were elevated significantly in the circulation. Administration of FA effectively reduced these levels of lipids in the plasma, liver, and kidney of CCl4-treated rats. The PL level was significantly decreased in the liver and kidney of CCl4-treated rats and was positively modulated by FA treatment. Our histopathological observations were also in correlation with the biochemical parameters.

Conclusions: From the results obtained, we could conclude that FA effectively protects the system against hyperlipidemia and may be an effective therapeutic agent for the treatment of this disorder.
The structure of non-nilpotent CTI-groups
Authors: Mousavi Hamid , Rastgoo Tahereh , Zenkov Viktor
Published: December 2012

A subgroup
Degeneration and orbits of tuples and subgroups in an abelian group
Authors: Calvert Wesley , Dutta Kunal , Prasad Amritanshu
Published: December 2012

A tuple (or subgroup) in a group is said to degenerate to another if the latter is an endomorphic image of the former. In a countable reduced abelian group, it is shown that if tuples (or finite subgroups) degenerate to each other, then they lie in the same automorphism orbit. The proof is based on techniques that were developed by Kaplansky and Mackey in order to give an elegant proof of Ulm's theorem. Similar results hold for reduced countably-generated torsion modules over principal ideal domains. It is shown that the depth and the description of atoms of the resulting poset of orbits of tuples depend only on the Ulm invariants of the module in question (and not on the underlying ring). A complete description of the poset of orbits of elements in terms of the Ulm invariants of the module is given. The relationship between this description of orbits and a very different-looking one obtained by Dutta and Prasad for torsion modules of bounded order is explained.
Baumslag's big powers in metabelian groups
Authors: Gaglione Anthony M. , Lipschutz Seymour , Spellman Dennis
Published: December 2012

Let
Cybersecurity Policy-Making at the Local Government Level: An Analysis of Threats, Preparedness, and Bureaucratic Roadblocks to Success
Authors: Caruson Kiki , MacManus Susan A. , McPhee Brian D.
Published: December 2012

Cybersecurity is a serious and complex problem that is escalating at all levels, yet little research has examined the issue at the local government level. This probative study, based on an extensive e-survey of Florida county officials, focuses on: (1) the incidence of cyber attacks – type, source (internal vs. external), and severity (major, minor); (2) perceived threats to agency operations – internally and externally from utility and telecommunications companies, financial institutions, hospitals, and schools; (3) the current status of cybersecurity planning; (4) the urgency of unmet preparedness-related needs; and (5) the degree to which financial, personnel, and organizational roadblocks have deterred the development of comprehensive cybersecurity plans. Controls are made for agency size and type of position held. The study finds that the knowledge or awareness gap between IT professionals and generalist and specialist public administrators is even wider at the local than at the federal (or state) levels. Preparedness lags because of this knowledge gap. There is little sense of urgency, partially because many non-IT officials have little understanding of newer, more dangerous cyber threats and cyber crime.
Limited-angle cone-beam computed tomography image
reconstruction by total variation minimization and piecewise-constant modification
Authors: Zeng Li , Guo Jiqiang , Liu Baodong
Published: December 2012

Because of x-ray dose considerations or practical
mechanical restrictions, it may be interesting for some applications to
perform limited-angle scanning. So the limited-angle problem is of practical
significance in computed tomography (CT). Furthermore, it is an ill-posed
problem. Total variation minimization (TVM) and projection on convex sets
(POCS) based iterative reconstruction algorithm is comparatively valid for
this undersampling CT reconstruction problem and can obtain comparatively
good performance. But the reconstruction images have artifacts with gradual
change gray nearby edges. In this paper, a simple but efficient method to
eliminate such artifacts during the reconstruction is proposed. Based on the
same assumption of the TVM algorithm, for the object whose density distribution
is approximate piecewise-constant, we develop and investigate an
improved iterative reconstruction algorithm for volume image reconstruction
from limited-angle cone-beam scan, which is referred to as
piecewise-constant modification TVM-POCS (PM-TVM-POCS) algorithm. The grays
of voxels with gradually changed gray artifacts are modified in the TVM-POCS
iteration process by the piecewise-constant modification algorithm which is
regarded as a “collapse” process, and gradually approaches the true
piecewise-constant image. The results of simulation experiments show that
the presented modification algorithm can improve the quality of the
reconstructed image obviously and it is steady to noise. This modification
algorithm can also be applied to other reconstruction problems which have
artifacts with gradual change gray.
Material parameter estimation and hypothesis testing on a 1D viscoelastic stenosis model: Methodology
Authors: Banks H. Thomas , Hu Shuhua , Kenz Zackary R. , Kruse Carola , Shaw Simon , Whiteman John R. , Brewin Mark P. , Greenwald Steve E. , Birch Malcolm J.
Published: December 2012

Non-invasive detection, localization and characterization of an arterial stenosis (a blockage or partial blockage in the artery) continues to be an important problem in medicine. Partial blockage stenoses are known to generate disturbances in blood flow which generate shear waves in the chest cavity. We examine a one-dimensional viscoelastic model that incorporates Kelvin–Voigt damping and internal variables, and develop a proof-of-concept methodology using simulated data. We first develop an estimation procedure for the material parameters. We use this procedure to determine confidence intervals for the estimated parameters, which indicates the efficacy of finding parameter estimates in practice. Confidence intervals are computed using asymptotic error theory as well as bootstrapping. We then develop a model comparison test to be used in determining if a particular data set came from a low input amplitude or a high input amplitude; this we anticipate will aid in determining when stenosis is present. These two thrusts together will serve as the methodological basis for our continuing analysis using experimental data currently being collected.
Mode of delivery in a subsequent pregnancy following previous instrumental delivery
Authors: Lurie Samuel , Steinberg Netanel , Tannus Samer , Golan Abraham , Sadan Oscar
Published: December 2012

Objective: To assess mode of subsequent delivery in women with previous instrumental vaginal delivery.

Study design: In this retrospective longitudinal study we followed women who underwent instrumental delivery. The study group included all consecutive parturient women who underwent an instrumental vaginal delivery during a 24-month period (1996–1999). We then identified women who had a subsequent delivery in our center until the end of the year 2010. The control group included women who had a spontaneous vaginal delivery from the same time.

Results: During the index period we had 349 consecutive successful instrumental vaginal deliveries. Of those, 125 women had a subsequent delivery in our center (35.8%). In subsequent pregnancies, the spontaneous vaginal delivery rate was 76.8% and 90.4%; the instrumental delivery rate was 8.8% and 1.6%; and the cesarean rate was 14.4% and 8.0%, in the instrumental delivery, and spontaneous vaginal delivery groups, respectively (P<0.05). The odds ratio for a woman to undergo either an instrumental delivery or a cesarean after having an instrumental delivery in a previous pregnancy was 2.8 (95% confidence interval 1.4–5.9, P<0.05).

Conclusion: Women with a previous instrumental delivery are at an increased risk of requiring either an instrumental delivery or a cesarean section in a subsequent pregnancy compared with women with a previous spontaneous vaginal delivery.
Prenatal maternal stress predicts cord-blood ferritin concentration
Authors: Armony-Sivan Rinat , Aviner Shraga , Cojocaru Lutzy , Fytlovitch Shlomo , Ben-Alon Dora , Eliassy Anat , Babkoff Harvey , Lozoff Betsy , Anteby Eyal
Published: December 2012

Aim: To examine the relationship between maternal stress in early pregnancy and cord-blood ferritin concentration.

Methods: The sample consisted of 140 pregnant women who lived in a region that was under rocket attack during a military operation (December 2008 to January 2009). Mothers in the stress group (n=63) were in their first trimester during this period. Mothers in the control group (n=77) became pregnant 4–5 months after the attacks ended. Maternal subjective stress was reported retrospectively. Cord-blood ferritin concentration was compared between stress and control groups, and was the dependent variable in a hierarchical multiple regression analysis.

Results: The mean cord-blood ferritin concentration was lower in the stress group compared to the control group (145.7±62.0 vs. 169.3±85.4 ng/mL, P<0.05). The cumulative distribution of cord-blood ferritin showed a shift to the left for the stress group. Hierarchical multiple regression analysis revealed that maternal subjective stress was a predictor for cord-blood ferritin concentration (hierarchical regression: β=–0.18, P<0.05), especially in the stress group (simple slope analysis: β=–0.32, P<0.01).

Conclusion: Maternal stress during the first trimester of pregnancy is associated with lower cord-blood ferritin concentration.
Expectant management in type II selective intrauterine growth restriction and abnormal chord insertion in monochorionic twins
Authors: Visentin Silvia , Macchi Veronica , Grumolato Francesca , Porzionato Andrea , De Caro Raffaele , Cosmi Erich
Published: December 2012

Objective: To assess perinatal outcome in type II monochorionic (MC) diamniotic twin pregnancies (DA) affected by selective intrauterine growth restriction (sIUGR) and abnormal cord insertion managed expectantly.

Methods: A prospective longitudinal study from June 2008 and July 2011 on 24 MCDA sIUGR twins. sIUGR was defined as estimated fetal weight below the 10th percentile in one twin and was classified into three groups based on umbilical artery (UA) Doppler diastolic flow (I: presence; II: constantly absent/reverse (AEDF/ARED); III: intermittently absent or reverse). Marginal cord insertion was defined as insertion within 2 cm of the placental disc edge, and velamentous insertion as a cord insertion into the fetal membranes. Expectant management was chosen in these twins, and absent or reverse A wave in the ductus venosus (DV) was a criterion for delivery. Neonatal outcome was available for all twins delivered. Pathological examination and vascular cast of placentas were performed in all cases.

Results: Fourteen twin pregnancies were type II sIUGR, and ten presented an abnormal umbilical cord insertion. Median gestational age (GA) at diagnosis of sIUGR was 18 weeks’ gestation (range 16–20 weeks), and all sIUGR co-twins showed AEDF of UA at a median gestational age of 20 weeks (range 18–22 weeks). Median gestational age at delivery was 30 weeks (range 28–34 weeks) with a median birth weight of 1285 g (range 307–1725 g). pH at birth and base excess (BE) were normal in all IUGR co-twin (pH>7.10, median BE 5.5); Apgar score at 5 min was >7. Perinatal outcome was favorable in all cases. Placental pathological examination confirmed the marginal insertion of the umbilical cord and the absence of anastomosis between the two portions of umbilical insertion.

Conclusions: This study highlights that expectant management for sIUGR type II twins with or without an abnormal cord insertion should be a valid option to time delivery for these fetuses as shown by the favorable neonatal outcome.
Hyperoxic resuscitation after hypoxia-ischemia induces cerebral inflammation that is attenuated by tempol in a reporter mouse model with very young mice
Authors: Døhlen Gaute , Antal Ellen-Ann , Castellheim Albert , Thaulow Erik , Kielland Anders , Saugstad Ola Didrik
Published: December 2012

Background: Oxygen supplementation is still part of international resuscitation protocols for premature children. Mechanisms for tissue damage by hypoxia/ischemia in the extreme premature involve inflammation.

Aim and method: To study cerebral inflammation after hypoxia/ischemia and oxygen treatment in the premature, we measured NF-κB activity in 5-day-old transgenic reporter mice in response to experimental hypoxia/ischemia. Results were correlated to cerebral histological evaluation and plasma cytokine levels. A treatment strategy with the antioxidant tempol was tested.

Results: One day after hypoxia/ischemia NF-κB activation was increased compared to controls [mean difference: 10.6±4.6% (P=0.03)]. Exposure to 100% oxygen after hypoxia/ischemia further increased NF-κB activation compared to hypoxia/ischemia alone [mean difference: 15.0±5.5% (P=0.01)]. Histological changes in the brain were positively correlated with NF-κB activity (P<0.001), but we found no significant difference in tissue damage between resuscitation with air and resuscitation with pure oxygen. Administration of tempol reduced NF-κB activation [mean difference: 14.6±5.0% (P=0.01)] and the plasma level of cytokines; however, the histological damage score was not affected.

Conclusion: Cerebral inflammatory response after hypoxia/ischemia in a mouse model with immature brain development corresponding to human prematurity prior to 32 weeks’ gestation was influenced by administration of oxygen. Tempol treatment attenuated inflammation but did not reduce the extent of histological cerebral damage.
Puerperal curettage after cesarean section delivery
Authors: Almansa Cristina , Camaño Isabel , Villar Olga , Montañez Dolores , Vallejo Paloma , García-Burguillo Antonio
Published: December 2012

Objective: To analyze the clinical situations that leads us to carry out curettage after cesarean section, the ultrasound prior surgery, intraoperative, and pathological findings.

Methods: A retrospective study of all cases of postpartum curettage after cesarean section in a level 3 maternity unit.

Results: There were 42 curettages to women with cesarean sections (1.6% of all cesarean sections). The indications for curettage were: fever: 21, methrorraghia: 11, and residual trophoblastic tissue: 10. In the previous ultrasound, all indicated curettages for retained trophoblastic tissue showed it, and in a lower proportion those indicated for fever (66.6%) or methrorraghia (22.2%). A total of fourteen curettages (35%) were performed without suspect image of retained tissue, and in all cases the surgeon described to obtain small amount of tissue. From material submitted to pathologic evaluation trophoblastic tissue was found in 64.7%, and there were no differences as curettage indication.

Conclusions: When the previous ultrasound do not showed retained tissue, the surgeon did not remove retained material. When extracted there were always in small amounts. Therefore, it could be concluded that after cesarean section the curettage should be indicated only in the presence of evident ultrasound image of retained products.
Bariatric surgery and pregnancy: the magical solution?
Authors: Willis Kent , Sheiner Eyal
Published: December 2012

The obesity epidemic is a problem of global importance with a profound impact on maternal-fetal health. Currently, 1 in 5 women, worldwide, are obese at time of conception. Normalizing pregravid weight may significantly reduce obstetrical complications and alter the long-term weight status of mother and child. Bariatric surgery is the most efficient form of weight loss in severely obese women. Surgery has the exciting potential to treat obesity in women of reproductive age and to prevent obesity-related reproductive complications. Pregnancy after bariatric surgery appears to be safe and is effective in reducing complications such as gestational diabetes mellitus, gestational hypertensive disorders and fetal macrosomia, but may result in an increase in neonates born small-for-gestational-age.
Observation of successful mobbing of an insectivorous bat, Taphozous nudiventris (Emballonuridae), on an avian predator, Tyto alba (Tytonidae)
Authors: Lučan Radek K. , Šálek Martin
Published: December 2012

Mobbing in animals is an aggressive behaviour performed cooperatively towards a potential predator. In bats, the existence of mobbing is based on both intra- and interspecific behavioural responses of freely flying individuals to distress calls emitted by live bats or playbacked by researchers. In this note, we describe the mobbing behaviour of free-living naked-bellied tomb bats
Enhanced nonlinearities using plasmonic nanoantennas
Authors: Chen Pai-Yen , Argyropoulos Christos , Alù Andrea
Published: December 2012

In this paper, we review and discuss how nanoantennas may be used to largely enhance the nonlinear response of optical materials. For single nanoantennas, there have been tremendous advancements in understanding how to exploit the local field enhancement to boost the nonlinear susceptibility at the surface or sharp edges of plasmonic metals. After an overview of the work in this area, we discuss the possibility of controlling the optical nonlinear response using nanocircuit concepts and of significantly enhancing various nonlinear optical processes using planar arrays of plasmonic nanoantennas loaded with χ(2) or χ(3) nonlinear optical materials, forming ultrathin, nanometer-scale nonlinear metasurfaces, as optical nanodevices. We describe how this concept may be used to boost the efficiency of nonlinear wave mixing and optical bistability, due to the large local field enhancement at the nonlinear nanoloads associated with the plasmonic features of suitably tailored nanoantenna designs. We finally discuss three exciting applications of the proposed nonlinear metasurface: dramatically-enhanced frequency conversion efficiency, efficient phase-conjugation for super-resolution imaging and large optical bistabilities.
Review Label-free detection with high-Q microcavities: a review of biosensing mechanisms for integrated devices
Authors: Vollmer Frank , Yang Lan
Published: December 2012

Optical microcavities that confine light in high-Q resonance promise all of the capabilities required for a successful next-generation microsystem biodetection technology. Label-free detection down to single molecules as well as operation in aqueous environments can be integrated cost-effectively on microchips, together with other photonic components, as well as electronic ones. We provide a comprehensive review of the sensing mechanisms utilized in this emerging field, their physics, engineering and material science aspects, and their application to nanoparticle analysis and biomolecular detection. We survey the most recent developments such as the use of mode splitting for self-referenced measurements, plasmonic nanoantennas for signal enhancements, the use of optical force for nanoparticle manipulation as well as the design of active devices for ultra-sensitive detection. Furthermore, we provide an outlook on the exciting capabilities of functionalized high-Q microcavities in the life sciences.
Nanotechnology Reviews
Authors: Grossmann Alexander , Sora Karin
Published: December 2012

No abstract available.
The Organization of Political Violence by Insurgencies
Authors: Haer Roos
Published: December 2012

A range of theories have attempted to explain the variation in civilian abuse of warring parties. Most of these theories have been focused on the strategic environment in which these acts take place. Less attention is devoted to the perpetrators of these human right abuses themselves: the armed groups. This study tries to fill this niche by using the organizational process theory in which it is assumed that armed groups, like every organization, struggles for survival. The leader tries to ensure the maintenance of her armed group by increasing her control over her troops. The relationship between the level of control and the perpetrated civilian abuse is examined with a new dataset on the internal structure of more than 70 different armed groups around the world. With the help of a Bayesian Ordered Probit model, this new dataset on civilian abuse is analyzed. The results show that especially particular incentives play an important role.
Partitioning Ethnic Groups and their Members: Explaining Variations in Satisfaction with Democracy in Africa
Authors: Gold Valentin
Published: December 2012

This article examines the conditions that influence citizens’ satisfaction with democracy in Africa. In the analysis, individual, ethnic group, and national context determinants are combined in a multilevel model allowing a comparative analysis over time, countries, ethnic groups, and individuals. Using Afrobarometer survey data along with ethnic group-level and national-level data, I show that factors shaping citizens’ satisfaction can be found on each contextual level. To a large extent, perceived economic and political inequalities between ethnic groups explain variations in citizens’ satisfaction.
Cooperation beats Deterrence in Cyberwar
Authors: Schutte Sebastian
Published: December 2012

This brief article argues for a narrow definition of cyberwar and a technology-centric approach to understanding its strategic implications. Based on a review of the underlying technologies, approaches to facilitating peace in this rather new form of confrontation will be derived. This brief discussion already shows that Cold War era strategies such as credible deterrence through retaliation are ill-suited to serve peace in the digital domain. Generally, building offensive capabilities for cyberwar does not increase an actor’s security. Instead, geographically unrestricted security communities (Deutsch et al., 1957) of nationstates that employ similar technologies seem to serve individual security best.
Gold and Civil Conflict Intensity: evidence from a spatially disaggregated analysis
Authors: Balestri Sara
Published: December 2012

This research is aimed at investigating whether the presence of available extractive resources, in particular gold, interacts with civil conflict intensity, accounting for sub-country level data through the use of Geographic Information System (GIS) techniques. By a spatially disaggregated and specific resource analysis, I found that gold, gemstones and hydrocarbons productions within the conflict areas tend to increase conflict intensity. The analysis is carried out by applying a Zero-Truncated Negative Binomial model. Data for gold resource are extracted from an original dataset - GOLDATA - which provides a comprehensive list of gold deposits throughout the world completed of geographic coordinates, temporal information and characteristics. The overall finding is that the presence of exploitable gold resource tends to increase conflict intensity and that resources’ lootability and accessibility in wartime can largely determine to what extent revenues can be appropriated and misused during conflict events.
Human Rights “Naming & Shaming” and Civil War Violence
Authors: Ruggeri Andrea , Burgoon Brian
Published: December 2012

The aim of this PEPS Letter is to clarify the effects of human rights “Naming and Shaming” by international actors, such as IOs, NGOs and the international media, on the intensity of violence in domestic conflict. The note carries out, evaluates and proposes empirical strategies to study such effects. We find that a classic panel-year data structure is insufficient to disentangle and assess possible mechanisms. Though the UN-labeled attempts to “name and shame” seem to decrease the level of violence, this and other results cannot be defended as robust and coherent in light of likely endogeneity bias. Results based on just lagged explanatory variables differ in the sign and significance of relationships with results based on instrumented-variable estimation. We highlight the value and necessity of collecting and analyzing data that is more disaggregated with respect to time and target levels. Only such further steps will allow full study the role of “naming and shaming” on domestic conflict dynamics.
Effect of solvents and thermal annealing on the morphology development of a novel block copolymer ionomer: a case study of sulfonated polystyrene-block-fluorinated polyisoprene
Authors: Hosoda Tomonori , Gido Samuel P. , Mays Jimmy W. , Huang Tianzi , Park Chong Rae , Yamada Toshiro
Published: December 2012

The morphologies of sulfonated polystyrene-block-fluorinated polyisoprene (s-PS-b-f-PI) were studied as functions of different kinds of solvents and thermal annealing, using transmission electron microscope microscopy (TEM), small angle X-ray scattering (SAXS) and intermediate angle X-ray diffraction (IMAXD). The film of the block copolymer ionomer with an acid form [sulfonated PS-b-fluorinated PI (sH-PS-b-f-PI)], which was cast from anhydrous tetrahydrofuran (THF), developed a well-ordered cylindrical morphology of the f-PI domains in the sH-PS matrix. The morphology was explained by the solubility parameter and the Bjerrum length. The morphology changed to that of a no long-range ordered structure, through thermal annealing. The result was different from the usual behavior of uncharged diblock copolymers and could have been due to the ionic cluster formation. The solution casting films of the block copolymer ionomer with a cesium neutralized form (sCs-PS-b-f-PI) were obtained from the mixed solvent of THF/water (98/2, wt/wt) and DMSO. The ionic cluster formation in the film cast from the mixed solvent was hardly changed by annealing. The promotion of the ionic cluster formation by annealing was clearly observed in the film cast from DMSO. However, hindrance of microphase separation by the promotion of the ionic cluster formation was not confirmed in this study.
Investigation of rapid manufacturing technology with ABS material for wind tunnel models fabrication
Authors: Daneshmand Saeed , Aghanajafi Cyrus , Shahverdi Hossein
Published: December 2012

Nowadays, several procedures are used for manufacturing wind tunnel models. These methods include machining, casting, molding and rapid prototyping. Raw materials such as metals, ceramics, composites and plastics are used in making these models. Dimension accuracy, surface roughness and material strength are significant parameters which are effective in wind tunnel manufacturing and testing. Wind tunnel testing may need several models. Traditional methods for constructing these models are both costly and time consuming. In this research, a study has been undertaken to determine the suitability of models constructed using rapid manufacturing (RM) methods for use in wind tunnel testing. The aim of this research is to improve the surface roughness, dimensional accuracy and material strength of rapid manufacturing models for testing in wind tunnels. Consequently, the aerodynamic characteristics of three models were investigated and compared. The first model is made of steel, the second model from FDM-M30, and the third model is a hybrid model. Results show that metal models can be replaced by hybrid models in order to measure aerodynamic characteristics, reduce model fabrication time, save fabrication cost and also to verify the accuracy of aerodynamic data obtained in aerospace industry.
Nanocrystallites in urine and their relationship with the formation of kidney stones
Authors: Ouyang Jian-Ming , Xia Zhi-Yue , Zhang Guang-Na , Chen He-Qun
Published: December 2012

Kidney stones are mainly composed of inorganic crystals such as calcium oxalate (CaOxa). At present, kidney stones can be detected only after their formation, which causes great suffering for patients. If kidney stones can be detected prior to their formation, they can be effectively prevented, which presents great commercial value. In this paper, we review the differences in urine nanocrystallites between stone-forming patients and healthy controls, as well as the relationship between nanocrystallites in urine and the formation of kidney stones. These differences are microcrystalline morphology, aggregation, size and distribution, chemical composition, Zeta potential and stability. The results showed that the formation of kidney stones is closely related to the nature of nanocrystallites. Through the regulation of the physical and chemical properties of nanocrystallites, the formation and recurrence of kidney stones are possibly inhibited.
Platinum organometallic compounds: classification and analysis of crystallographic and structural data. Monomeric Pt compounds with PtC2AB, PtA2BC and PtABCD compositions
Authors: Melnik Milan , Sprusansky Ondrej , Holloway Clive Eduard , Mikus Peter
Published: December 2012

This review covers almost 350 four-coordinated monomeric organoplatinum complexes with PtC2AB, PtA2BC and PtABCD compositions, and there is wide variability of chromophores. The most common ligands in addition to the C donor are PPh3 and chlorine. Platinum(II) is found only in a square-planar environment involving cis- as well as trans-configurations with a different degree of distortion, especially when bi- or terdentate ligands are present. The trans-effect decreases in the order of the atoms in which the effect dominates, H>C>P>Si>S. There are at least two types of isomerism, cis-trans and distortion. The data strongly suggest that distortion isomerism is, for platinum chemistry, more common than cis- and trans-isomerism.
Bericht vom GMA-Fachausschuss 1.40 “Theoretische Verfahren der Regelungstechnik”
Authors: Wahrburg Arne
Published: December 2012

Der Beitrag bietet einen Überblick über die inhaltlichen Schwerpunkte der diesjährigen Tagung des GMA-Fachausschusses 1.40 und fasst die Beschlüsse des Fachausschusses bezüglich seiner zukünftigen Arbeit zusammen.
Productivity and credit constraints: A firm-level propensity score evidence for agricultural farms in central and east European countries
Authors: Ciaian Pavel , Fałkowski Jan , Kancs D’Artis
Published: December 2012

Drawing on a unique farm level panel data set with 37,409 observations for period 2004–2005 and employing a matching estimator, this paper analyses how farm access to credit affects farm input allocation and farm efficiency in the CEE transition countries. We find that farms are asymmetrically credit constrained with respect to inputs. Farm use of variable inputs and capital investment increases up to 2.3% and 29%, respectively, per 1000 EUR of additional credit. Our estimates suggest also that farm access to credit increases the total factor productivity up to 1.9% per 1000 EUR of additional credit, indicating that an improved access to credit results in adjusting the relative input intensities on farms. This finding is further supported by a negative effect of better access to credit on labour, suggesting that these two are substitutes. Interestingly, farms are found not to be credit constrained with respect to land.
Determinants of sales rates at Turkish art auctions
Authors: Atukeren Erdal , Seçk.in Aylin
Published: December 2012

We examine the determinants of the overall sales rates at art auctions in Turkey. We use a unique dataset that covers 79 auctions that took place between January 2005 and February 2008. After controlling for auction house differences, seasonal factors and the price levels of the auctions, we find that the expectations about the economic developments and consumption patterns play an important role in explaining the sales rates differentials across different auctions taking place over time.
Coordinated distributed experiments: an emerging tool for testing global hypotheses in ecology and environmental science
Authors: Fraser Lauchlan H , Henry Hugh AL , Carlyle Cameron N , White Shannon R , Beierkuhnlein Carl , Cahill James F , Casper Brenda B , Cleland Elsa , Collins Scott L , Dukes Jeffrey S , Knapp Alan K , Lind Eric , Long Ruijun , Luo Yiqi , Reich Peter B , Smith Melinda D , Sternberg Marcelo , Turkington Roy
Published: December 2012

There is a growing realization among scientists and policy makers that an increased understanding of today's environmental issues requires international collaboration and data synthesis. Meta‐analyses have served this role in ecology for more than a decade, but the different experimental methodologies researchers use can limit the strength of the meta‐analytic approach. Considering the global nature of many environmental issues, a new collaborative approach, which we call coordinated distributed experiments (CDEs), is needed that will control for both spatial and temporal scale, and that encompasses large geographic ranges. Ecological CDEs, involving standardized, controlled protocols, have the potential to advance our understanding of general principles in ecology and environmental science.
Polyolefin‐Coated Urea Decreases Ammonia Volatilization in a Double Rice System of Southern China
Authors: Xu Minggang , Li Dongchu , Li Jumei , Qin Daozhu , Hosen Yasukazu , Shen Huaping , Cong Rihuan , He Xinhua
Published: December 2012

Field evaluations of slow‐release N fertilizers are needed to improve N use efficiency while reducing NH3 volatilization. Ammonia volatilization losses, floodwater NH4+, and aboveground rice (Oryza sativa L.) tissue N accumulation were compared between non‐coated urea (NCU) and polyolefin‐coated urea (POCU) applications in a double‐rice production system of subtropical China. A factorial treatment design included two urea sources such as POCU and NCU applied at 75 and 150 kg N ha−1, and a no‐N control. For early and late rice seasons, floodwater NH4+ and pH increased significantly within 7 to 10 d after NCU applications and then decreased rapidly. Nitrogen losses through NH3 volatilization accounted for 16 to 30% and 4 to 8% of the total N applied for NCU and POCU, respectively. Applications of POCU significantly increased N accumulation in aboveground rice biomass due to a slower N release and better synchrony between in‐season rice N demand and N supply from this fertilizer. Applications of POCU at a rate of 75 kg N ha−1 provided the optimal amounts of N for early and late rice crops and reduced NH3 volatilization losses. The use of slow release urea fertilizers should increase N use efficiency and maintain the high grain yield in the double rice production systems of subtropical China.
Phosphorus Fertilization Modes Affect Crop Yield, Nutrient Uptake, and Soil Biological Properties in the Rice–Wheat Cropping System
Authors: Guan Guan , Tu Shuxin , Li Hailan , Yang Juncheng , Zhang Jianfeng , Wen Shilin , Yang Li
Published: December 2012

Long‐term application of P fertilizer has resulted in P overabundance in farmland and environmental pollution in the middle and lower reaches of the Yangtze River in China. Field experiments were performed to investigate the effects of different P fertilizer application modes on crop yield, nutrient uptake, soil enzyme activity, number of microbes (bacteria, actinomycetes, and fungi), and diversity of microbes in rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotation system. The results showed that a 20% reduction of the traditional application amount of P fertilizer did not cause decreases in crop yield, amount of nutrient uptake, soil enzyme activity, or the number of soil microbes. In addition, both the 20% reduction in applied P and the mixed application of organic manure and chemical P fertilizer increased not only the activity of neutral phosphatase, sucrase, protease and urease, but also the number of soil microbes, as well as the Shannon's microbial diversity index (H), although they had no impact on crop yield and nutrient uptake. A 20% reduction of P fertilizer could be a possible agricultural measure for reducing farmland pollution, and the combined application of organic manure and chemical P fertilizer could be recommended for improving soil fertility in the study areas.
Comparing Methods to Determine Hydraulic Conductivities on Stony Soils
Authors: Verbist K.M.J. , Cornelis W.M. , Torfs S. , Gabriels D.
Published: December 2012

Determination of the field‐saturated hydraulic conductivity (Kfs) can result in very high variability due to soil heterogeneity, the measurement method, the number of replications, and the Kfs calculation method used. Especially for dryland soils, stoniness can influence infiltration rates significantly. To identify this variability as well as its source, six widely used measurement methods were compared: single‐ring (SR) and double‐ring (DR) infiltrometers, the constant‐head well infiltrometer (CH), the inverse auger hole method (IA), the tension infiltrometer (TI), and the rainfall simulator (RFS). The six methods were applied at three locations in a semiarid part of Chile that showed moderate (15%) to high (55%) stoniness. Additionally, Kfs variations due to different calculation techniques for the same measurement method were thoroughly investigated. Results showed that different calculation techniques sometimes gave significantly different estimates of Kfs when using the same data set, and those relative differences were conserved among measurement locations. The borehole methods (IA and CH) showed high discard rates due to stoniness, making these methods less appropriate. The SR and DR methods gave considerably higher Kfs estimates, while the RFS and TI proved good candidates as reference methods for stony soils, with low failure rates and coefficients of variation.
Soil Properties Controlling Infiltration in Volcanic Soils (Tenerife, Spain)
Authors: Tejedor Marisa , Neris Jonay , Jiménez Concepción
Published: December 2012

Soil water infiltration is an important process whose behavior depends on external factors and soil properties, which vary depending on the type of soil. The present paper aims to establish which soil parameters determine the steady‐state infiltration rate of six Soil Orders, all formed on volcanic materials—Andisols (nonallophanic, allophanic, vitric), Inceptisols (typic, andic, vertic), Alfisols, Vertisols, Aridisols, and Entisols (psamments, fluvents), and contribute to the differences between them. The study was conducted at 108 sites on the island of Tenerife (Spain). The steady‐state infiltration rate was measured using a double‐ring infiltrometer. The relationship between the soil properties and infiltration was studied using Principal Components Analysis and a multiple regression model. The research concludes that texture, bulk density, and structural stability play decisive roles. Clay content is the most influential factor across all the soils. It is of greatest importance for infiltration in Vertisols, vertic Inceptisols, and Alfisols and of least importance in vitric Andisols and Entisols. Bulk density is the second most decisive factor and determines infiltration principally in vitric Andisols and Entisols (high ρb values) and in non‐vitric Andisols (low values). Structural stability mainly influences non‐vitric Andisols, although texture is the factor that determines the biggest changes in this type of soil. Structural stability is also found to influence infiltration in Entisols, vitric Andisols, and Aridisols, although in these cases owing to their low values.