bluuebunny/crossref_metadata_2025 huggingface dataset:
Network lifetime maximization for time‐sensitive data gathering in wireless sensor networks with a mobile sink
Authors: Liang Weifa , Luo Jun , Xu Xu
Published: August 2011

With the advances of more and more mobile sink deployments (e.g., robots and unmanned aerial vehicles), mobile sinks have been demonstrated to play an important role in the prolongation of network lifetime. In this paper, we consider the network lifetime maximization problem for time‐sensitive data gathering, which requires sensing data to be sent to the sink as soon as possible, subject to several constraints on the mobile sink. Because the mobile sink is powered by petrol or electricity, its maximum travel distance per tour is bounded. The mobile sink's maximum moving distance from its current location to the next must also be bounded to minimize data loss. As building a new routing tree rooted at each new location will incur an overhead on energy consumption, the mobile sink must sojourn at each chosen location at least for a certain amount of time. The problem, thus, is to find an optimal sojourn tour for the mobile sink such that the network lifetime is maximized, which is subject to a set of constraints on the mobile sink: its maximum travel distance, the maximum distance of each movement, and the minimum sojourn time at each sojourn location. In this paper, we first formulate this novel multiple‐constrained optimization problem as the distance‐constrained mobile sink problem for time‐sensitive data gathering. We then devise a novel heuristic for it. We finally conduct extensive experiments by simulation to evaluate the performance of the proposed algorithm. The experimental results demonstrate that the performance of the proposed algorithm is very promising, and the solution obtained is fractional of the optimal one. Copyright © 2011 John Wiley & Sons, Ltd.
Energy‐conserving data gathering by mobile mules in a spatially separated wireless sensor network
Authors: Wu Fang‐Jing , Tseng Yu‐Chee
Published: August 2011

This paper considers a spatially separated wireless sensor network, which consists of a number of isolated subnetworks that could be far away from each other in distance. We address the issue of using mobile mules to collect data from these sensor nodes. In such an environment, both data‐collection latency and network lifetime are critical issues. We model this problem as a bi‐objective problem, called energy‐constrained mule traveling salesman problem (EM‐TSP), which aims at minimizing the traversal paths of mobile mules such that at least one node in each subnetwork is visited by a mule and the maximum energy consumption among all sensor nodes does not exceed a pre‐defined threshold. Interestingly, the traversal problem turns out to be a generalization of the classical traveling salesman problem (TSP), an NP‐complete problem. With some geometrical properties of the network, we propose some efficient heuristics for EM‐TSP. We then extend our heuristics to multiple mobile mules. Extensive simulation results have been conducted, which show that our proposed solutions usually give much better solutions than most TSP‐like approximations. Copyright © 2011 John Wiley & Sons, Ltd.
Feline Urate Urolithiasis: A Retrospective Study of 159 Cases
Authors: Dear Jonathan D , Shiraki Ryojj , Ruby Annette L , Westropp Jodi L
Published: August 2011

The objective of the study was to characterize the signalment, clinicopathologic data, and diagnostic imaging of cats with urate urolithiasis, as well as the salts of uric acid present in the uroliths. A retrospective analysis of feline urate uroliths submitted to the GV Ling Urinary Stone Analysis Laboratory between 2000 and 2008 was included. From these data, records were assimilated from referring veterinarians (143); furthermore, all recorded cases from within the William R Pritchard Veterinary Medical Teaching Hospital (16) were included. Median values for the complete blood count and chemistry panels available were within the reference intervals, when provided, with only a few outliers present. Of all cases evaluated, seven had a portosystemic shunt (PSS). Cats with urate uroliths and a PSS were younger than cats without a PSS (2 years vs 7 years). The pathogenesis of urate uroliths in cats is poorly understood. Most cats were not completely evaluated for a PSS, however, clinicopathologic parameters indicating hepatic dysfunction were seldom noted; more sensitive diagnostics such as serum bile acids were rarely performed to confirm or negate the presence of a shunt. Studies are warranted to evaluate pathogenesis of urate uroliths to tailor proper management and breeding strategies.
Evaluation of the Effects of Hospital Visit Stress on Physiologic Parameters in the Cat
Authors: Quimby Jessica M , Smith Melissa L , Lunn Katharine F
Published: August 2011

Physiologic parameters such as blood pressure, rectal temperature, heart rate, and respiratory rate are an important part of the medical assessment of a patient. However, these factors can potentially be affected by stress. The purpose of this study was to compare physiologic parameter data gathered from cats in the home environment with those gathered in a veterinary hospital. Thirty healthy cats were evaluated both at home and at Colorado State University's Veterinary Medical Center. Doppler systolic blood pressure, temperature, heart rate, and respiratory rate were recorded, and the differences between the values obtained in the home and veterinary clinic environments were evaluated using the Wilcoxon sign rank test. A significant difference was found in blood pressure, heart rate, and respiratory rate between the home and veterinary hospital environments. This information may help practitioners recognize that physiologic abnormalities can sometimes be due to transportation or environmental stress rather than medical illness.
TWO APPROACHES TO MÖBIUS INVERSION
Authors: HUANG I-CHIAU
Published: August 2011

The Möbius inversion formula for a locally finite partially ordered set is realized as a Lagrange inversion formula. Schauder bases are introduced to interpret Möbius inversion.
Karst development on a mobile substrate: Konarsiah salt extrusion, Iran
Authors: ZAREỊ MEHDI , RAEISI EZATOLAH , TALBOT CHRISTOPHER J.
Published: August 2011

Most karst terranes develop slowly on static limestone substrates as part of the global hydrological cycle. Here we introduce the novel concept of a karst morphology developing very rapidly on a more soluble substrate of salt (NaCl) that is moving through its own global cycle. We open with a reminder of karst features and processes in limestone. We then illustrate the global salt cycle using the 180 or so extrusions of Hormoz salt in the Zagros Mountains of Iran. After describing the geology of an example, we consider how it fits into the evolution of salt extrusions. This example, Konarsiah, was chosen for its simple hydrology. Konarsiah is covered by residual soils of the insoluble components that remain in place as the Hormoz salt is dissolved. Dolines in the surface of these soils enlarge and the soils thicken as the moving salt dissolves. The long-term rate of salt dissolution and soil production on Konarsiah are estimated using traditional methods. The calculated age of the thickest, most distal soil is used to constrain the average rate at which the underlying salt flows downslope after extruding from two vents. The average velocities constrained for salt flow are lower than rates of displacement of markers near the summit of Konarsiah measured at irregular intervals over five years. Salt extruding from recently truncated diapirs near the arid south coast of Iran exhibit all the features seen in classical karst terranes. In the more humid mountains inland, vegetated soils protect salt extrusions like Konarsiah from erosion and limit their salt karst features. Soil covers also probably even out salt flow velocities. Salt extrusions advance when such protective covers grow and thicken in humid conditions. They retreat when such protection is lost to erosion in drier conditions. These external signs complement internal recumbent folds in extruded salt that signal intervals of faster salt flow when wet than dry. They also add to the features that render salt extrusions records of climate change.
Impact of landrace germplasm, non-conventional habit and regional cultivar selection on forage and seed yield of organically grown lucerne in Italy
Authors: ANNICCHIARICO P. , PECETTI L. , TORRICELLI R.
Published: August 2011

Organically grown lucerne (Medicago sativa L.) should ensure sufficiently high forage and seed yields to sustain the profitability of organic production chains. Twenty lucerne populations were evaluated for forage dry matter (DM) yield over 3 years (2005–7), and for seed yield and its components in the third year, under organic management and a mowing regime in Lodi (sub-continental climate with sandy-loam soil) and Perugia (sub-Mediterranean climate with silty-clay soil). The objectives were to assess the impact on lucerne forage and seed yield of: (i) type of germplasm (landrace or commercial cultivar); (ii) plant growth habit (erect or non-conventional); (iii) area of germplasm origin or selection (northern Italy north of the Po river, NI-N; northern Italy south of the Po river, NI-S; central Italy, CI). The populations included seven cultivars selected under conventional management and one selected under organic management, seven landraces and five breeding selections, of which one was semi-erect and one was semi-prostrate. On average, cultivar and landrace germplasm types did not differ for forage or seed yield in any geographic set of populations (NI-N, NI-S or CI), except for the higher seed yield of landraces in one set. Compared with erect germplasm, semi-prostrate germplasm exhibited distinctly lower forage and seed yield, especially where weed competition was severe (Lodi) because of poor competitive ability. Semi-erect germplasm tended to have lower forage yield across locations. Specific adaptation was the main determinant of forage and seed yield responses of landraces and cultivars. Erect populations originated in NI-N were high yielding in the test site similar to NI-N environments (Lodi) and low yielding in the location representing CI environments (Perugia). Populations that originated in CI, including the cultivar selected under organic management, displayed the opposite adaptive response. Populations that originated in NI-S, whose major environmental characteristics were somewhat intermediate between NI-N and CI, tended to be mid-ranking for forage and seed yield in each site. The large cross-over population×location interaction was confirmed by the lack of genetic correlation for forage yield (rg=−0·25, P>0·20) and the negative genetic correlation for seed yield (rg=−0·68, P<0·05) of populations across locations. No genetic correlation across locations was found for density of fertile tillers and pod fertility. The association of population seed yield with its component traits was site-specific. Cropping and seed multiplication of locally adapted erect cultivars have paramount importance for mown organically grown lucerne in Italy.
Immune monitoring ofTrichuris suisegg therapy in multiple sclerosis patients
Authors: Benzel F. , Erdur H. , Kohler S. , Frentsch M. , Thiel A. , Harms L. , Wandinger K.-P. , Rosche B.
Published: August 2011

Initial clinical trials usingTrichuris suiseggs (TSO) in autoimmune diseases such as inflammatory bowel disease, revealed a striking suppressive effect on the autoimmune response. Here, we analysed the effect of TSO therapy on the course of multiple sclerosis (MS), as a Th1/Th17-associated autoimmune disease. Different immunological parameters in four patients with secondary progressive MS were surveyed during a 6-month therapy with TSO, focusing on the modulation of T-cell Th1–Th2 balance as well as on the innate immune response. We are able to show a slight downregulation of the Th1-associated cytokine pattern, especially relevant in interleukin (IL)-2 (P < 0.05 after 2 months of therapy), with a temporary increase of Th2-associated cytokines such as IL-4. Furthermore, mild eosinophily and changes in CD4+ and CD8+T cells and natural killer (NK) CD56 bright cell numbers were observed. The findings observed in this group of patients suggest that TSO therapy has a moderate immunomodulatory impact in MS.
Quality of rabbit vitrified/thawed transgenic embryos
Authors: Chrenek P. , Turanová Z. , Slamečka J. , Makarevich A. V.
Published: August 2011

The aim of our study was to investigate the influence of vitrification on developmental rate and quality (total number of cells, number of blastomeres in inner cell mass (ICM) area, apoptotic index and embryo diameter) of transgenic (carrying an endogenous–hFVIII or exogenous–enhanced green fluorescent protein (EGFP) gene) rabbit embryos. EGFP-positive rabbit embryos were produced under in vitro conditions by the microinjection of foreign genes into the pronucleus of fertilized eggs. The transgenic rabbit embryos with the hFVIII gene were produced by mating homozygous transgenic rabbits and flushing at the single-cell stage. Developmental rate of vitrified/thawed transgenic embryos that reached hatching blastocyst stage (68.00% and 69.00%) and differed significantly (p < 0.001) from those in control embryos (100.00%). Significant difference (p < 0.05) was found in total cell counts between control (117.00 ± 36.00) and vitrified (141.00 ± 34.80) hFVIII-positive embryos. The higher proportion of ICM cells (32.00%) and greatest embryo diameter (130.85 ± 10.90) were found in the control group compared with the transgenic. Ratio of apoptotic cells was significantly higher (p < 0.01) in the control group (2.50%) and vitrified EGFP-positive embryos (2.90%) compared with the vitrified, hFVIII-positive group of embryos (0.70%). Our results demonstrate that neither gene microinjection itself, nor exogenous (EGFP) and endogenous (hFVIII) gene expression interferes with developmental rate and quality of rabbit embryos. However, a combination of microinjection and vitrification significantly decreases (p < 0.001) the survival rate of rabbit embryos.
Structural analysis of oocytes, post-fertilization events and embryonic development of the Brazilian endangered teleost Brycon insignis (Characiformes)
Authors: Isaú Ziara A. , Rizzo Elizete , Amaral Thiciana B. , Mourad Natália M.N. , Viveiros Ana T.M.
Published: August 2011

The aim of this study was to evaluate the oocytes, post-fertilization events and embryonic development in Brycon insignis, under both scanning electron microscopy and stereomicroscopy. Oocytes and embryos were sampled from spawning up to hatching. Stripped oocytes were spherical, non-adhesive, greenish-brown, possessed a single micropyle, pore-canals and had a mean diameter of 1.46 mm. In 63% of oocytes the germinal vesicle was peripheric. The main post-fertilization events were the fertilization cone formation (20 s), micropyle closure (100–180 s) and agglutination of supernumerary spermatozoa (100–180 s). Embryonic development lasted 30 h at ~24 °C and was characterized by seven stages. Zygote, cleavage, blastula and gastrula stages were first observed at 0.25, 1, 3 and 6 h post-fertilization, respectively. Fertilization rate was determined at the moment of blastopore closure, 10–11 h post-fertilization. The segmentation stage began at 11 h post-fertilization and comprised the development of somites, notochord, optic, otic and Kupffer's vesicles, neural tube, primitive intestine, and development and release of the tail. The larval stage began 21 h post-fertilization and was characterized by the presence of somites, growth and elongation of the larvae. At the hatching stage, embryos presented vigorous contractions of the tail and body leading to chorion rupture (30 h). The morphological characteristics described for B. insignis were similar to that described for other teleost species, and such knowledge is important for a better understanding of reproductive features of a species and useful for ecological and conservational studies.
Effect of different culture systems on mRNA expression in developing rabbit embryos
Authors: Saenz-de-Juano M.D. , Naturil-Alfonso C. , Vicente J.S. , Marco-Jiménez F.
Published: August 2011

The rate of zygotes in vitro developed to hatched blastocyst stage was evaluated between two different commercial media (TCM-199 and Ham's F10) and two different culture systems (renewal and non-renewal single medium) to determine the effects of culture conditions on rabbit embryo preimplantation development. The relative transcript abundances of OCT4, vascular endothelial growth factor (VEGF) and epidermal growth factor receptor 3 (erbB3) of resultant blastocysts were also analysed and compared with in vivo developed blastocysts. Results showed an important divergence in mRNA expression between embryos developed under in vivo and in vitro conditions despite there being no significant difference in hatching blastocyst rates between different culture systems and different media. For OCT4, transcript abundance of in vitro culture embryos differs from their in vivo chronological counterparts, but, when the medium is renewed, mRNA expression seemed similar to in vivo developed 4-day-old embryos. In addition, VEGF and erbB3 expression showed marked variation between different in vitro conditions. Therefore, the study of specific transcript abundance in rabbit blastocyst provides a more detailed description of which alterations in gene expression occur due in vitro conditions, and further studies should be carried out to reduce current limitations of long-term culture of rabbit pre-implantation embryos.
THE LOCKEAN RIGHTS OF BEQUEST AND INHERITANCE
Authors: Kendrick Leslie
Published: August 2011

Lawyers and philosophers have misunderstood the rights of bequest and inheritance within Locke's theory of property. While lawyers assume these are unqualified natural rights, philosophers find Locke's account of them so inadequate as to cast their existence into serious doubt. But on Locke's theory, the rights of bequest and inheritance are neither absolute nor incoherent. Locke treats inheritance as a form of imputed bequest, whereby natural law imputes to the intestate an intention to leave his goods to his closest family members. Both bequest and inheritance find their justification in the prerogatives of owners to dispose of their property. These prerogatives are not without limit, however. The needs of a decedent's dependents trump specific bequests, and both bequest and inheritance are subject to the duty of charity. Bequest and inheritance thus order the relative claims of owners and others so that they are consistent with Locke's more general theory of property.
Clergy-laity support and patients’ mood during serious illness: A cross-sectional epidemiologic study
Authors: Hays Judith C. , Wood Laura , Steinhauser Karen , Olson Maren K. , Lindquist Jennifer H. , Tulsky James A.
Published: August 2011

Objectives:

Religious participation is positively associated with mental health, but attendance at worship services declines during serious illness. This study assessed whether home visits by clergy or laity provide benefits to seriously ill patients who may have difficulty attending religious services.

Method:

A cross-sectional study design nested in an observational epidemiologic cohort study was used. The regionally representative sample of patients had metastatic lung, colorectal, breast, and prostate cancer (n = 70); Class III and IV congestive heart failure (n = 70); or chronic obstructive pulmonary disease with hypercapnea (n = 70) and were observed regarding clergy–laity support in their natural environments. Dependent variable: 10-item Center for Epidemiologic Studies – Depression Scale. Independent variable: A one-item question measuring how much helpful support patients received from clergy or other persons from church, temple, synagogue, or mosque. Covariates: demographic, health, social support, religiousness.

Results:

Depressed mood was negatively associated with clergy–laity support in a non-linear pattern. Depressed mood was also positively associated with functional deficits and a lifetime history of difficulties related to religious involvement.

Significance of results:

In lieu of worship attendance when people are sick, home visits by members of a patient's religious community may bolster mood by providing continuity of instrumental, emotional, and spiritual support.
An unusual cause of vomiting in a palliative care setting
Authors: Railsback Linda
Published: August 2011

Control of symptoms, including nausea and vomiting, is central to palliative care. Self-induced vomiting in a middle-aged male patient with a life-limiting abdominal malignancy provided a challenge in diagnosis and management. This case report discusses diagnostic and therapeutic considerations.
Greenland elders and high school students offer perspectives on climate change and science
Authors: Showstack Randy
Published: August 2011

KANGERLUSSUAQ, GREENLAND—This small town in central western Greenland, which has a population of about 650 and a major airstrip dating from World War II, is a center for scientific research and a starting point for scientists working in the region and on Greenland's ice sheet to study climate change and other issues. The town, just north of the Arctic Circle, sits at the edge of the 190‐kilometer‐long Kangerlussuaq Fjord and straddles the Qinnguata Kuussua River estuary, whose source water is the Russell Glacier, about 20 kilometers to the east. Between Kanger—as some refer to the town—and the glacier, some Eskimo‐Kalaallit elders held a traditional gathering last month and also offered their perspectives on climate change during an impromptu 14 July meeting with high school students and other visitors. The evening before that meeting, Ole Olsvig, Kurt Olsen, Avaruna Mathaeussen, and other high schoolers from Greenland were in a makeshift classroom at the back of a renovated former U.S. Army barracks in Kanger, which had served as a U.S. military base. The students, who said they care deeply about their traditional culture and also are very aware of recent changes in climate, were helping to make presentations about their summer science projects. A total of 16 high schoolers from Greenland, 3 from Denmark, and 5 from the United States were there, participating in Joint Science Education Project (JSEP) activities; JSEP is an international collaborative polar science education effort between Greenland, Denmark, and the United States that receives support from the U.S. National Science Foundation (NSF).
Fall Meeting abstract submission inspires science poetry
Authors: Balcerak Ernie
Published: August 2011

When the 4 August deadline for submitting Fall Meeting abstracts passed, AGU had received more than 20,000 abstracts, a record‐breaking number. The submission process had an unexpected by‐product: It inspired some scientists to write haiku on Twitter. (Haiku is a form of Japanese poetry typically having three lines, the first with five syllables, the second with seven, and the third with five.) The following are examples of the haiku tweets, with the hashtag #AGU11AbstractHaiku. (For those who want to keep updated about the Fall Meeting on Twitter, the hashtag is #AGU11.) For more information about the meeting, including registration and housing, visit http://sites.agu.org/fallmeeting/.
Determining critical open science questions regarding biosphere‐atmosphere interactions
Authors: Carlton Annmarie G.
Published: August 2011

Measuring and Modeling at the Interface of Air Quality and Climate to Understand Biosphere‐Atmosphere Interactions; New Brunswick, New Jersey, 26–27 May 2011 The southeastern United States has not warmed like other U.S. regions in response to global climate change. This anomaly may be related to aerosols derived from biogenic volatile organic compounds (BVOCs) and the related aerosol direct and indirect radiative effects. To understand the causal relationships that result in this trend, the scientific community must ask, What sources and processes control the fate of biogenic compounds in anthropogenically influenced environments? What are the climate‐relevant properties and air quality impacts? Approximately 30 atmospheric scientists with experimental (field and laboratory) and modeling backgrounds met to discern the most critical open science questions regarding biosphere‐atmosphere interactions. An objective of the meeting was to formulate targeted science questions and broadly discuss the tools, approaches, and measurements needed to answer them.
Thomson Reuters to release Book Citation Index later this year
Authors: Aldred Maxine
Published: August 2011

Thomson Reuters will launch its new Book Citation Index later this year. Projected to include 25,000 volumes from major publishers and university presses in science, social science, and the humanities, the Book Citation Index will cover scholarly books (both series and nonseries) that present original research or literature reviews. The current effort regarding the science section is focused on books published from 2005 to the present. AGU has sent copies of its catalog for inclusion in the Book Citation Index, but the final selection will be made by Thomson Reuters, using its internal selection criteria, which may be found at http://wokinfo.com/wok/media/pdf/BKCI‐SelectionEssay_web.pdf.
Ozone depletion leading force for Southern Ocean change
Authors: Schultz Colin
Published: August 2011

Previous studies have suggested that key aspects of the Southern Ocean are affected by elevated atmospheric carbon dioxide levels. Increasing greenhouse gas (GHG) concentrations, which strengthen surface winds over much of the Southern Ocean, may increase flow rates in the Antarctic Circumpolar Current (ACC), induce a temperature disparity between the northern and central Southern Ocean, and affect the strength of the meridional ocean circulation (MOC). But GHGs are not the only set of compounds arising from human activity that can trigger these changes. Stratospheric ozone depletion due to such ozone‐depleting substances (ODSs) as chlorofluorocarbons, whose production and use were heavily regulated by the 1987 Montreal Protocol, results in similar changes. Using an atmosphere‐ocean coupled general circulation model that allows for detailed calculations of stratospheric chemistry, Sigmond et al. simulated past and future changes for the Southern Ocean due to both GHGs and ODSs. Their model calculations suggest that ODSs, which peaked in concentration in 1995, will be the dominant driver of changes in ACC until the second quarter of the 21st century, at which point the monotonically increasing GHG levels will take over. Further, they found that the peak impact of ODSs on ACC will occur a few decades after their peak concentration. The authors suggest that future research needs to take into account the effects of ozone depletion—something not ordinarily done in investigations of Southern Ocean behavior. (Geophysical Research Letters, doi:10.1029/2011GL047120, 2011)
Miniature detector measures deep space radiation
Authors: Schultz Colin
Published: August 2011

The 1972 journey of Apollo 17 marked not only the last time a human walked on the Moon but also the most recent manned venture beyond the outer reaches of the Earth's atmosphere. With preparations being made for humans to once again explore deep space, important steps are under way to quantify the hazards of leaving low‐Earth orbit. One significant risk for long‐distance missions is the increased exposure to ionizing radiation—energetic particles that can strip electrons off of otherwise neutral materials, affecting human health and the functioning of spacecraft equipment. The deep space probes that are being sent to measure the risks from ionizing radiation and other hazards can be costly, so maximizing the scientific value of each launch is important. With this goal in mind, Mazur et al. designed and developed a miniature dosimeter that was sent into lunar orbit aboard NASA's Lunar Reconnaissance Orbiter (LRO) in 2009. Weighing only 20 grams, the detector is able to measure fluctuations in ionizing radiation as low as 1 microrad (equivalent to 1.0 × 10‐8 joules of energy deposited into 1 kilogram) while requiring minimal power and computer processing. The postage stamp—sized detector tracked radiation dosages for the first year of LRO's mission, with the results being confirmed by other onboard and near‐Earth detectors. (Space Weather, doi:10.1029/2010SW000641, 2011)
Statistics of GPS scintillations over South America at three levels of solar activity
Authors: Akala A. O. , Doherty P. H. , Valladares C. E. , Carrano C. S. , Sheehan R.
Published: August 2011

This study characterizes low‐latitude scintillations at L‐band frequency in South America on daily, monthly, and seasonal time scales at three levels of solar activity: high, moderate and low levels. Three years (November 2001–October 2002, 2004 and 2008) of amplitude scintillation data from GPS receivers at three locations: Cuzco (14.0°S, 73.0°W, dip 1.0°S), Iquitos (3.8°S, 73.2°W, dip 7.0°N), and Bogota (4.4°N, 74.1°W, dip 16.0°N) were used for the investigation. These data were grouped into daily, monthly, and seasonal sets. We introduced tests on the data to reject signal fluctuations from non‐ionospheric sources, such as multipath from terrestrial objects. The scintillation events from the data were further classified into three levels: weak (0.3 ≤ S4 < 0.4), moderate (0.4 ≤ S4 < 0.7), and intense (S4 ≥ 0.7) scintillations and their monthly percentage of occurrences and durations were determined. We also used the seasonal averages of daily (1900 LT–2000 LT) TEC values to observe the variability of the equatorial anomaly using a chain of ten GPS receivers that are located at a latitudinal span of 10°N–40°S along the west coast of South America. This study concludes that GPS scintillations in this longitude sector are post‐sunset events and decay before or around local midnight, with intense activity and longer durations in the months of March and January. On seasonal time scales, the highest frequencies and longest durations of events were recorded during March Equinox and December Solstice. The months of May–July (June Solstice) had the least frequencies of occurrence and durations of events. Scintillation activity also increases with solar activity. Finally, scintillations increase in frequencies of occurrence and durations from Cuzco (near the magnetic equator) toward Bogota (near the crest of the equatorial anomaly) during solar maximum. However, a gradual collapse of the anomaly crest, away from Bogota toward Iquitos was observed as solar activity decreases, and as a result, the occurrence frequencies of scintillations at Iquitos increase relative to those at Bogota.
The existence of species rests on a metastable equilibrium between inbreeding and outbreeding
Authors: Joly Etienne
Published: August 2011

Background:

Speciation corresponds to the progressive establishment of reproductive barriers between groups of individuals derived from an ancestral stock. Since Darwin did not believe that reproductive barriers could be selected for, he proposed that most events of speciation would occur through a process of separation and divergence, and this point of view is still shared by most evolutionary biologists today.

Results:

I do, however, contend that, if so much speciation occurs, it must result from a process of natural selection, whereby it is advantageous for individuals to reproduce preferentially within a group and reduce their breeding with the rest of the population, leading to a model whereby new species arise not by populations splitting into separate branches, but by small inbreeding groups “budding” from an ancestral stock. This would be driven by several advantages of inbreeding, and mainly by advantageous recessive phenotypes, which could only be retained in the context of inbreeding. Reproductive barriers would thus not arise passively as a consequence of drift in isolated populations, but under the selective pressure of ancestral stocks. Most documented cases of speciation in natural populations appear to fit the model proposed, with more speciation occurring in populations with high inbreeding coefficients, many recessive characters identified as central to the phenomenon of speciation, with these recessive mutations expected to be surrounded by patterns of limited genomic diversity.

Conclusions:

Whilst adaptive evolution would correspond to gains of function that would, most of the time, be dominant, the phenomenon of speciation would thus be driven by mutations resulting in the advantageous loss of certain functions since recessive mutations very often correspond to the inactivation of a gene. A very important further advantage of inbreeding is that it reduces the accumulation of recessive mutations in genomes. A consequence of the model proposed is that the existence of species would correspond to a metastable equilibrium between inbreeding and outbreeding, with excessive inbreeding promoting speciation, and excessive outbreeding resulting in irreversible accumulation of recessive mutations that could ultimately only lead to the extinction.
Novel NIR Spectroscopy Correlation Approach to Amino Acid Analysis of Soybean Proteins for Composition Improvements. (Version 2.0)
Authors: Prisecaru Valentin , Baianu I.
Published: August 2011

Amino acid NIR calibrations were developed in our Physical Chemistry of Foods Laboratory of the University of Illinois at Urbana for three selected amino acid groups that include essential amino acids for identified soybean accessions. Conventional “wet chemistry” analytical methods are time-consuming and costly. As a result, soybean breeders and researchers have an imperative need to utilize faster and less expensive methods. NIR Spectroscopy is a rapid and inexpensive method for composition analysis for academia and industry. Recent advancements in instrumentation design, such as the application of the Diode Array (DA) technique and the Fourier Transform (FT) IR and NIR techniques, have significantly improved overall instrument performance and advancement in the field of grain analysis.Novel results are presented for amino acid calibrations for US soybean accessions relevant to the food and agricultural industry.
BioMed Central - open data guidance for authors
Authors: Attar Naomi
Published: August 2011

All research articles published by BioMed Central are open access. In keeping with the spirit of open access publishing, we aim to maximize the availability of data associated with these articles.
Prediction of Soil Organic Properties in a Diverse Population of Ohio Soils Using Near Infrared Reflectance Spectroscopy Analysis
Authors: Dick Warren , Sengupta Aditi
Published: August 2011

A Near Infrared Spectroscopy (NIRS) method was used to predict soil organic carbon and amino sugar concentrations, and β-Glucosidase and β-Glucosaminidase activity in 184 diverse soils of Ohio. The measured variable values were calibrated to NIR spectral data with partial least squares regression analysis. The multivariate models developed were validated using the full cross validation method and the test set method with a test set size of 50 samples. Statistical analysis of the spectral data was done using the multivariate analysis software Unscrambler 8.0 (CAMO Inc). The first differential transformation of the NIR region (1100-2498 nm) gave good results. The NIRS method predicted well the organic carbon (OC) and amino sugar concentrations in soil (R2 was 0.91 for OC and 0.90 for amino sugar). The enzyme activity values were also well predicted (R2 was 0.82 for soil β-glucosidase and β-glucosaminidase enzyme activity). Thus, the NIRS method has the potential to rapidly and accurately predict values of carbon-related variables, including the carbon enzymes β-Glucosidase and β-Glucosaminidase, in soils. The equipment needed is not expensive and the NIRS method can be used where very large numbers of environmental samples need to be rapidly analyzed. Indeed, the prediction equations can be constantly improved as more data points are entered into the correlations between laboratory measured values and NIRS values.
High-temperature and high-pressure pulsed synthesis apparatus for supercritical production of nanoparticles
Authors: Eltzholtz Jakob R. , Iversen Bo B.
Published: August 2011

In materials science continuous flow supercritical fluid reactors are widely used for highly controlled synthesis of nanoparticles. The major limitation of continuous flow reactors is that the inherent distribution of residence times leads to broadening of the corresponding size distribution of the nanoparticles, and in addition it is not possible to carry out synthesis with very short or very long reaction times. Here, we report a new synthesis concept that we call pulsed synthesis, which removes the limitations of flow synthesis at the expense of a more complex reactor design and extensive computer control. Another limitation of flow synthesis is that it is largely a black box, where limited direct information is available of the specific chemical reactions taking place, the particle nucleation, the particle growth, etc. Such information is commonly obtained from in situ synchrotron and neutron scattering studies, but transfer of information from in situ studies with static reactors to laboratory flow reactor conditions is highly non-trivial. The new pulse reactor provides superior heating rates, arbitrary residence times with narrow distribution limited only by the pulse duration, and the ability of using the same reactor both for nanoparticle production and in situ synchrotron studies; thus eliminating the need for transfer of in situ information to laboratory reactor designs.
Manifold electronic structure transition of BNC biribbons
Authors: Fan Yingcai , Zhao Mingwen , Zhang Xuejuan , Wang Zhenhai , He Tao , Xia Huihao , Liu Xiangdong
Published: August 2011

Using first principles calculations, we investigate the electronic and magnetic properties of BNC biribbons, a laterally-heterostructured nanoribbon constructed by joining a graphene nanoribbon (GNR) and a BN nanoribbon (BNNR) with zigzag edges. We find that the spin-polarization and electronic structures of the biribbons can be well-tuned by changing the width of the GNR, undergoing manifold transitions from semiconducting to half-metal and ferromagnetic metal. The critical points of GNR width to induce the transitions depend on the interface type (B/C or C/N) rather than the BNNR width. The ground states of metallic BNC biribbons are spin-polarized, forming non-zero magnetic moments. The tunable electronic structures and ferromagnetic ground states make the BNC biribbons promising candidate nanomaterials for building nanoscaled spintronic devices.
Computational study of the Seebeck coefficient of one-dimensional composite nano-structures
Authors: Kim Raseong , Lundstrom Mark S.
Published: August 2011

The Seebeck coefficient (S) of composite nano-structures is theoretically explored within a self-consistent electro-thermal transport simulation framework using the non-equilibrium Green’s function method and a heat diffusion equation. Seebeck coefficients are determined using numerical techniques that mimic experimental measurements. Simulation results show that, without energy relaxing scattering, the overall S of a composite structure is determined by the highest barrier within the device. For a diffusive, composite structure with energy relaxation due to electron-phonon scattering, however, the measured S is an average of the position-dependent values with the weighting factor being the lattice temperature gradient. The results stress the importance of self-consistent solutions of phonon heat transport and the resulting lattice temperature distribution in understanding the thermoelectric properties of a composite structure. It is also clarified that the measured S of a composite structure reflects its power generation performance rather than its cooling performance. The results suggest that the lattice thermal conductivity within the composite structure might be engineered to improve the power factor over the bulk by avoiding the conventional trade-off between S and the electrical conductivity.
Alignment of high-aspect ratio colloidal gold nanoplatelets in nematic liquid crystals
Authors: Evans Julian S. , Beier Corinne N. , Smalyukh Ivan I.
Published: August 2011

We study elasticity-mediated alignment of anisotropic gold colloids in liquid crystals. Colloidal gold particles of controlled shapes (spheres, rods, and polygonal platelets) and sizes are prepared using well-established biosynthesis techniques with varying solvent conditions. When introduced into liquid crystalline structured solvents, these gold particles impose tangential or vertical surface boundary conditions for the liquid crystal molecules or building blocks such as chromonic molecular aggregates. This allows for multiple types of their controlled alignment in both lyotropic and thermotropic liquid crystals and is of interest for self-assembly-based fabrication of tunable nanostructured composite materials.
CL study of blue and UV emissions in β-Ga2O3 nanowires grown by thermal evaporation of GaN
Authors: Guzmán-Navarro G. , Herrera-Zaldívar M. , Valenzuela-Benavides J. , Maestre D.
Published: August 2011

We report a cathodoluminescence (CL) study of β-Ga2O3 nanowires grown by thermal evaporation of GaN on Si(100) and Au/Si(00) substrates. Condensation and subsequent oxidation of metallic Ga is suggested as the growth mechanism of β-Ga2O3 nanowires. The β-Ga2O3 nanowires grown on Si(100) show multiple bends or undulations, together with a strong UV emission at 3.31 eV and a weak blue emission centered at 2.8 eV as a band component. The β-Ga2O3 nanowires grown on Au/Si(100) substrates recorded a lower CL intensity of a well-defined blue emission of 2.8 eV. A thermal treatment on these samples produced an increase of the UV emission and quenching of the blue band. Thermal annealing of oxygen vacancies is proposed as the responsible mechanism for the observed behavior of these samples.
Effect of cap layer thickness on the perpendicular magnetic anisotropy in top MgO/CoFeB/Ta structures
Authors: Cheng Chih-Wei , Feng Wuwei , Chern G. , Lee C. M. , Wu Te-ho
Published: August 2011

The perpendicular magnetic anisotropy of a series of top MgO/CoFeB/Ta layers is studied. Similar to the bottom Ta/CoFeB/MgO structure, the critical thickness of CoFeB is limited in a range of 1.1–1.7 nm. However, the cap layer shows much sensitive effect. Not only the type of material is crucial, but the thickness of the cap layer also affects the magnetic anisotropy. The perpendicular anisotropy of a 1.2 nm-thick CoFeB can only exist with the capping Ta thickness less than 2 nm. The magnetic characterizations, including the magnetic remanence and coercivity, also show strong dependence on the Ta thickness. The diffusion of Ta into CoFeB layer is considered to play an important role, which could explain changes in perpendicular anisotropy and related magnetic responses. In addition, the asymmetric role of Ta layer in the top structure and bottom structures is also discussed.
Exchange bias and ferromagnetic coercivity in heterostructures with antiferromagnetic Cr2O3
Authors: Borisov P. , Kleemann W.
Published: August 2011

The perpendicular exchange bias effect in multilayer systems Cr2O3(0001)/[Co/Pt]n, n ≥ 1, is strongly correlated with the temperature dependence of the antiferromagnetic order parameter in Cr2O3 in the vicinity of its Néel temperature. A crossover between surface and 3D bulk critical behavior is found for the interface moments of Cr2O3. In addition, for the first time, a specific exchange bias-related contribution to the ferromagnetic coercive field could be separated.
To what extent the four-probes transport measurements allow to neglect a role of current leads?
Authors: Agrinskaya N. V. , Kozub V. I.
Published: August 2011

We demonstrate—both experimentally and theoretically—that the finite size of the current leads does not allow neglecting the role of these leads in the four-probes transport measurements if the properties of these leads are modified in the course of the experiment. We also give a short critical review of other publications, where, to our opinion, a possible role of the current leads was underestimated.
New photoacoustic cell design for studying aqueous solutions and gels
Authors: Kottmann J. , Rey J. M. , Sigrist M. W.
Published: August 2011

A new photoacoustic (PA) cell design, which is particularly suitable for investigations of liquids, gels, and outgassing samples is presented. The setup is based on a PA cell of only 78.5 mm3 volume, which is sealed on the sample side with either a 163 μm thick chemical vapor deposition diamond window or a 3.91 μm thin diamond membrane. This design offers great advantages compared to traditionally used open-ended PA cells especially when investigating volatile compounds. The new PA cell design is particularly interesting in the studies of biological samples characterized by a high water content. The performance was demonstrated with mid-infrared PA measurements of glucose in aqueous solutions using a tunable quantum-cascade laser as a light source. A detection limit of 100 mg/dl (SNR = 3) has been achieved. Furthermore, the spectral changes of glucose dissolved in water caused by mutorotation have been monitored time-resolved.
Structural evolution and the kinetics of Cu clustering in the amorphous phase of Fe-Cu-Nb-Si-B alloy
Authors: Gupta P. , Gupta A. , Shukla A. , Ganguli Tapas , Sinha A. K. , Principi G. , Maddalena A.
Published: August 2011

An attempt has been made to investigate the evolution of the structure of the amorphous phase of Fe73.9 Cu0.9 Nb3.1 Si13.2 B8.9 (finemet) alloy by a combination of wide-angle x-ray scattering, small angle x-ray scattering (SAXS), Mössbauer spectroscopy and X-ray absorption near edge spectroscopy on the supposition that they would provide complementary information. Before the onset of nanocrystallization, the amorphous phase undergoes a structural relaxation resulting in small increase in the hyperfine field and a decrease in the width of the first diffraction maxima. There is an increase in the topological ordering in the system, though chemical inhomogeneity sets-in due to the clustering of Cu atoms in the pure amorphous state of this alloy. Annealing at 400 °C (well below the crystallization temperature) for different time durations results in occurrence of Cu clusters having fcc structure. Kinetics of Cu clustering is studied using SAXS. The incubation time for the clustering at 400 °C is ∼120 min. With further annealing, the average cluster size gradually increases from the initial value of ∼0.4 nm, reaching a value of ∼0.6 nm after annealing for 720 min. Cluster size exhibits a t1/2 dependence, suggesting a diffusion controlled growth.
Rheological properties of alumina nanofluids and their implication to the heat transfer enhancement mechanism
Authors: Kim Seokwon , Kim Chongyoup , Lee Wook-Hyun , Park Seong-Ryong
Published: August 2011

Nanofluid is a novel heat transfer fluid prepared by dispersing nanometer-sized solid particles in a traditional heat transfer fluid for heat transfer enhancement. The microstructure investigation of nanofluids by rheological techniques shows that the particles do not exist as individual particles and nanofluids of rodlike alumina nanoparticles have a sol- or weakly flocculated gel-structure depending on particle concentration. The rate of thermal conductivity increase with concentration is faster in the sol state than in the weakly flocculated gel state. When the nanofluid becomes a strongly flocculated gel thermal conductivity remains almost the same as the pure liquid value. It is concluded that the Brownian motion plays a key role in enhancing thermal conductivity. The present study is the first report on the thermal conductivity of nanofluids with the characterized dispersion status.