bluuebunny/crossref_metadata_2025 huggingface dataset:
Enumerating combinatorial classes of the complex polynomial vector fields in ℂ
Authors: DIAS KEALEY
Published: February 2012

In order to understand the parameter space Ξd of monic and centered complex polynomial vector fields in ℂ of degree d, decomposed by the combinatorial classes of the vector fields, it is interesting to know the number of loci in parameter space consisting of vector fields with the same combinatorial data (corresponding to topological classification with fixed separatrices at infinity). This paper answers questions posed by Adam L. Epstein and Tan Lei about the total number of combinatorial classes and the number of combinatorial classes corresponding to loci of a specific (real) dimension q in parameter space, for fixed degree d; these numbers are denoted by cd and cd,q, respectively. These results are extensions of a result by Douady, Estrada, and Sentenac, which shows that the number of combinatorial classes of the structurally stable complex polynomial vector fields in ℂ of degree d is the Catalan number Cd−1. We show that enumerating the combinatorial classes is equivalent to a so-called bracketing problem. Then we analyze the generating functions and find closed-form expressions for cd and cd,q, and we furthermore make an asymptotic analysis of these sequences for d tending to ∞. These results are also applicable to special classes of quadratic and Abelian differentials and singular holomorphic foliations of the plane.
Informal research statement
Authors: RUDOLPH DANIEL J.
Published: February 2012

The editors are reproducing here an informal research statement that Dan wrote in one of his last years at the University of Maryland. It provides a rare insight into how he viewed his own work and as usual he did an excellent job in setting forth the main points in a clear way. The summary was retyped, lightly edited to correct typos, and provided with references by Ayşe Şahin. One of the editors (B.W.) added a brief appendix to cover some of the highlights of Dan’s work during the last years of his life. Following the research summary is a complete list of Dan’s publications as well as a second list for the other references cited.
A critical review of recommendations to increase dietary protein requirements in the habitually active
Authors: Lamont Linda S.
Published: February 2012

Some scientists and professional organisations have called for an increase in dietary protein for those who reach a threshold level of exercise, i.e. endurance athletes. But there are individual scientists who question this recommendation. Limitations in the procedures used to justify changing the recommended daily allowance (RDA) are at issue. N balance has been used to justify this increase; but it is limiting even when measured in a well-controlled clinical research centre. Experimental shortcomings are only exacerbated when performed in a sports or exercise field setting. Another laboratory method used to justify this increase, the isotope infusion procedure, has methodological problems as well. Stable isotope infusion data collected during and after exercise cannot account for fed-state gains that counterbalance those exercise losses over a 24 h dietary period. The present review concludes that an adaptive metabolic demand model may be needed to accurately study the protein health of the active individual.
Change in methodology for collection of drinking water intake in What We Eat in America/National Health and Nutrition Examination Survey: implications for analysis
Authors: Sebastian Rhonda S , Wilkinson Enns Cecilia , Goldman Joseph D , Moshfegh Alanna J
Published: February 2012

Objective

To provide updated estimates of drinking water intake (total, tap, plain bottled) for groups aged ≥1 year in the USA and to determine whether intakes collected in 2005–2006 using the Automated Multiple-Pass Method for the 24 h recall differ from intakes collected in 2003–2004 via post-recall food-frequency type questions.

Design

Cross-sectional, observational study.

Setting

What We Eat in America (WWEIA), the dietary intake component of the US National Health and Nutrition Examination Survey (NHANES).

Subjects

Individuals aged ≥1 year in 2003–2004 (n 8249) and 2005–2006 (n 8437) with one complete 24 h recall.

Results

The estimate for the percentage of individuals who reported total drinking water in 2005–2006 was significantly (P < 0·0000) smaller (76·9 %) than that for 2003–2004 (87·1 %), attributable to a lower percentage reporting tap water (54·1 % in 2005–2006 v. 67·0 % in 2003–2004; P = 0·0001). Estimates of mean tap water intake differed between the survey cycles for men aged ≥71 years.

Conclusions

Survey variables must be examined before combining or comparing data from multiple WWEIA/NHANES release cycles. For at least some age/gender groups, drinking water intake data from NHANES cycles prior to 2005–2006 should not be considered comparable to more recent data.
What Is the Relationship between Inequity in Family Law and Violence against Women? Approaching the Issue of Legal Enclaves
Authors: Hudson Valerie M. , Bowen Donna Lee , Nielsen Perpetua Lynne
Published: February 2012

“Family law” is the term applied to the legal regulation of marriage and parenthood within a society, and may serve to express a society's accepted ideals concerning male–female relations. Adopting a feminist evolutionary analytic (FEA) approach, we hypothesize that nation-states with higher degrees of inequity in family law favoring men, codifying an evolutionary legacy of male dominance and control over female reproduction, will experience higher rates of violence against women. This hypothesis is borne out in conventional statistical analysis, both bivariate and multivariate, suggesting that policy attention to family law so as to make it more concordant with norms of the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) may have salutatory effects on women's physical security over time. These results may also have policy implications for societies with, or contemplating, enclaves of inequitable family law.

Where, after all, do universal human rights begin? In small places, close to home.

—Eleanor Roosevelt
Speaking for the Underrepresented in the House of Representatives: Voicing Women's Interests in a Partisan Era
Authors: Pearson Kathryn , Dancey Logan
Published: February 2012

We ask whether women's descriptive representation in Congress enhances women's substantive representation through speechmaking on the House floor. Much of the research on women's substantive representation has focused on members' votes for and sponsorship of “women's issues” legislation. We depart from this research by systematically analyzing how members' gender and partisan identities affect gendered rhetoric in their floor speeches. In an era marked by significant increases in the number of congresswomen and partisan polarization, understanding the interactive effect of gender and partisanship on women's representation is particularly important. In an analysis of more than 30,000 speeches from 1993 to 2008, we find that when members speak about issues of their choosing during one-minute speeches, and during specific legislative debates over the most important policies considered on the House floor, congresswomen in both parties are significantly more likely than men to discuss women, enhancing women's representation.
Tracking the Latino Gender Gap: Gender Attitudes across Sex, Borders, and Generations
Authors: Bejarano Christina E. , Manzano Sylvia , Montoya Celeste
Published: February 2012

Many cultural stereotypes exist regarding the “modernity” of values possessed by Latino immigrants, particularly in reference to gender norms. Common perceptions about Latin machismo and marianismo (the idea that women should be pure and moral) do not paint a portrait of gender egalitarian dispositions. These assessments are upheld by neomodernization theorists who specifically identify gender attitudes as a critical element of modernity. In applying a revised modernization theory to the issue of comparative gender values, Inglehart and Norris (2003, 10) hypothesize that development “brings about changed cultural attitudes toward gender equality in virtually any society that experiences the various forms of modernization linked with economic development.” The idea that gender equality norms develop gradually, as a function of modernization, gives rise to different expectations about accepted gender roles in developing countries as opposed to those in advanced industrial democracies. Another feature of this modernization process is the emergence of gender gaps in political behavior and attitudes. Inglehart and Norris (2000) distinguish between traditional gender gaps found in postcommunist and developing societies (in which women are more conservative in their behavior and cultural attitudes relative to men) and modern gender gaps evident in postindustrial societies (in which women are more progressive than men).
Baking at the Front Line, Sleeping with the Enemy: Reflections on Gender and Women's Peace Activism in Israel
Authors: Kotef Hagar
Published: February 2012

One day in the summer of 2004, a shift of activists from Checkpoint Watch (CPW) brought to the checkpoint some cookies that one of them had baked earlier that morning. Checkpoint Watch is an all-women Israeli organization that opposes the Israeli checkpoints in the occupied Palestinian territories and the Israeli 1967 occupation more broadly. Its members conduct routine tours to monitor changes in the deployment of checkpoints and stand in regular shifts at the larger, manned checkpoints in the West Bank. As they spend several hours weekly at specific checkpoints, some activists develop acquaintances with both the soldiers who operate them and the Palestinians who regularly pass through them. Many also stop for coffee at the local Palestinian “shacks,” conduct weekly political debates with soldiers, and try to pass the time in conversation. Therefore, it may have seemed trivial, for the activists, to share homemade cookies with the people they encounter weekly. This is precisely what happened on that morning in 2004: a trivial event that probably happened many times before and many times afterwards.
But Now Can See: One Academic's Journey to Feminist Security Studies
Authors: Hudson Valerie M.
Published: February 2012

This essay expresses my gratitude for the spirit of inclusiveness shown by the first generation of Feminist Security Studies (FSS) scholars. I would like to see FSS remain a large tent, for in constructing boundaries for FSS, we may unintentionally make it smaller than it really is. Indeed, I would like to explore the value of inclusiveness to FSS by undertaking a bit of autobiography. I was a poor candidate to wind up as part of this field; the story of how FSS insights upended my academic life may be instructive as we endeavor to help others in the academy see the connections between gender and security studies that we ourselves see.
Feminist Politics in Feminist Security Studies
Authors: Wibben Annick T. R.
Published: February 2012

Feminist Security Studies (FSS) is quickly becoming a recognized area of research. Recent articles in Security Studies (Sjoberg 2009) and International Security (Hudson et al. 2008/9) specifically address the contributions of FSS to the field of security studies, a network of scholars working in FSS is regularly represented at the Annual Convention of the International Studies Association, and the terminology has been used in many recent publications (e.g. Hansen 2009; Shepherd 2010; Sjoberg and Martin 2010; Wibben 2009, 2011). Given the proliferation of feminist security scholarship, which is based on a variety of feminisms, feminist scholars should begin to debate the content and scope of their research. Not only is there now enough material to do so, but there also are some real differences in feminist scholarship—and these differences matter.
“A Long Ways from Home?” Hampton Institute and the Early History of “Sometimes I Feel like a Motherless Child”
Authors: MIYAKAWA FELICIA M.
Published: February 2012

The history of the well-known spiritual “Sometimes I Feel like a Motherless Child,” is wrapped up in the legacy of the Hampton Students, an ensemble of African American students modeled after the Fisk Jubilee Singers. The song's inclusion in the 1901 edition ofCabin and Plantation Songs as Sung by the Hampton Studentssolidified its place in the growing canon of spirituals. Although the tune remained in Hampton Institute's repertoire through subsequent printings ofCabin and Plantation Songs, it also entered the art music world, quickly becoming a favorite of performers and arrangers. But even as the tune journeyed away from Hampton, it remained tightly bound to composers, performers, and choir directors affiliated with what is now Hampton University. The story of “Motherless Child's” entrance into Hampton's repertoire around the turn of the twentieth century, its move beyond Hampton, and its later return is the story of the complex racial, cultural, and geographical relationships that have characterized the Institute's history. The telling of this story reveals a networked cast of characters, all invested in the health and growth of African American music in the early twentieth century, crossing paths in Tennessee, Mississippi, Massachusetts, New York, Connecticut, London, and, of course, Virginia.
Journeys of an Immigrant Violinist: Jacques Oliveira in Civil War–Era New York and New Orleans
Authors: THOMPSON BRIAN C.
Published: February 2012

This article explores the U.S. career of the Dutch immigrant violinist Jacques Oliveira. Following successful performances in Britain, Oliveira sailed for the United States in the fall of 1859. Under P.T. Barnum's management, the twenty-three-year-old became a fixture on New York's theatrical scene, as an instrumental soloist with Tom Thumb's company, with the Drayton Parlor Opera troupe, and with Hooley and Campbell's Minstrels. After a year, he traveled south, settling in occupied New Orleans, where he had family connections. Despite the economic difficulties of the time, he soon became an important figure in the city's cultural life, only to die during an outbreak of cholera and yellow fever in the summer of 1867.

In the absence of letters or diaries, the article relies heavily on close examination of period newspapers, city directories and census data to reconstruct Oliveira's world. Oliveira's activities, his successes and struggles, offer insights into the place of the working musician, newly arrived in the Unites States in the late 1850s. Examining the events of his life enables us to contrast cultural life in New York and New Orleans at the time of the Civil War. The article illuminates the place of the instrumentalist in the theater, reveals how attitudes toward music were influenced by a cultural hierarchy, provides insights into the place of the violin in the musical life of the United States, and examines the impact of the Civil War on musical life in New Orleans.
The Spirit inside Each Object: John Cage, Oskar Fischinger, and “The Future of Music”
Authors: BROWN RICHARD H.
Published: February 2012

Late in his career, John Cage often recalled his brief interaction with German abstract animator Oskar Fischinger in 1937 as the primary impetus for his early percussion works. Further examination of this connection reveals an important technological foundation to Cage's call for the expansion of musical resources. Fischinger's experiments with film phonography (the manipulation of the optical portion of sound film to synthesize sounds) mirrored contemporaneous refinements in recording and synthesis technology of electron beam tubes for film and television. New documentation on Cage's early career in Los Angeles, including research Cage conducted for his father John Cage, Sr.'s patents, explain his interest in these technologies. Finally, an examination of the sources of Cage's 1940 essay “The Future of Music: Credo” reveals the extent of Cage's knowledge of early sound synthesis and recording technologies and presents a more nuanced understanding of the historical relevance and origins of this document.
Can Asian dust trigger phytoplankton blooms in the oligotrophic northern South China Sea?
Authors: Wang Sheng‐Hsiang , Hsu N. Christina , Tsay Si‐Chee , Lin Neng‐Huei , Sayer Andrew M. , Huang Shih‐Jen , Lau William K. M.
Published: February 2012

Satellite data estimate a high dust deposition flux (∼18 g m−2 a−1) into the northern South China Sea (SCS). However, observational evidence concerning any biological response to dust fertilization is sparse. In this study, we combined long‐term aerosol and chlorophyll‐a (Chl‐a) measurements from satellite sensors (MODIS and SeaWiFS) with a 16‐year record of dust events from surface PM10observations to investigate dust transport, flux, and the changes in Chl‐a concentration over the northern SCS. Our result revealed that readily identifiable strong dust events over this region, although relatively rare (6 cases since 1994) and accounting for only a small proportion of the total dust deposition (∼0.28 g m−2 a−1), do occur and could significantly enhance phytoplankton blooms. Following such events, the Chl‐a concentration increased up to 4‐fold, and generally doubled the springtime background value (0.15 mg m−3). We suggest these heavy dust events contain readily bioavailable iron and enhance the phytoplankton growth in the oligotrophic northern SCS.
Does a theoretical estimation of the dust size distribution at emission suggest more bioavailable iron deposition?
Authors: Ito Akinori , Kok Jasper F. , Feng Yan , Penner Joyce E.
Published: February 2012

Global models have been used to deduce atmospheric iron supply to the ocean, but the uncertainty remains large. We used a global chemical transport model to investigate the effect of the estimated size distribution of dust on the bioavailable iron deposition. Simulations are performed with six different size distributions for dust aerosols at emission using similar aerosol optical depths (AODs) to constrain the total emission flux of dust. The global dust emission rate using a recent theoretical estimate for the dust size distribution at emission (2116 Tg yr−1) is about two times larger than the average of estimates using the other four empirical size distributions (1089 ± 469 Tg yr−1). In contrast to the large differences in total emissions, the emission of fine dust (diameter < 2.5 μm) is relatively robust (176 ± 34 Tg yr−1), due to the strong constraint of AOD on fine dust emission. Our model results indicate that soluble iron (SFe) deposition is relatively invariant to the dust size distribution at emission in regions where most soluble iron is provided by acid mobilization of fine dust. In contrast, the use of the theoretical size distribution suggests a larger deposition of SFe (by a factor of 1.2 to 5) in regions where the concentration of acidic gases is insufficient to promote iron dissolution in dust particles, such as the South Atlantic. These results could have important implications for the projection of marine ecosystem feedbacks to climate change and highlight the necessity to improve the dust size distribution.
Severe 2011 ozone depletion assessed with 11 years of ozone, NO2, and OClO measurements at 80°N
Authors: Adams C. , Strong K. , Zhao X. , Bassford M. R. , Chipperfield M. P. , Daffer W. , Drummond J. R. , Farahani E. E. , Feng W. , Fraser A. , Goutail F. , Manney G. , McLinden C. A. , Pazmino A. , Rex M. , Walker Kaley A.
Published: February 2012

Unusually cold conditions in Arctic winter 2010/11 led to large stratospheric ozone loss. We investigate this with UV‐visible measurements made at Eureka, Canada (80.05°N, 86.42°W) from 1999–2011. For 8–22 March 2011, OClO was enhanced, indicating chlorine activation above Eureka. Ozone columns were lower than in any other year in the record, reaching minima of 237 DU and 247 DU in two datasets. The average NO2 column inside the vortex, measured at visible and UV wavelengths, was 46 ± 30% and 45 ± 27% lower in 2011 than the average NO2column from previous years. Ozone column loss was estimated from two ozone datasets, using a modeled passive ozone tracer. For 12–20 March 2011, the average ozone loss was 27% and 29% (99 DU and 108 DU). The largest percent ozone loss in the 11‐year record of 47% (250 DU and 251 DU) was observed on 5 April 2011.
Cloud ice water content retrieved from the CALIOP space‐based lidar
Authors: Avery Melody , Winker David , Heymsfield Andrew , Vaughan Mark , Young Stuart , Hu Yongxiang , Trepte Charles
Published: February 2012

Ice water content (IWC) profiles are derived from retrievals of optical extinction from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite lidar, using a parameterization derived from particle probe measurements acquired during several aircraft field campaigns. With more than five years of data now available, CALIOP IWC is well suited for characterization of the climate‐sensitive upper troposphere/lower stratosphere where reliable global IWC measurements are needed to reduce climate model uncertainty. We describe CALIOP IWC and compare it with global satellite‐based and regional airborne IWC measurements made during August 2007. IWC distributions in a convective cloud sampled during the Tropical Clouds, Chemistry, Composition and Climate experiment show temperature‐dependent differences betweenin situmeasured IWC, IWC retrieved from CloudSat and CALIOP, and IWC parameterized from the airborne Cloud Physics Lidar (CPL) 532 nm volume extinction coefficients. At temperatures above −50°C the CALIOP IWC retrieval indicates less cloud ice than the other instruments, due to signal attenuation and screening for horizontally‐oriented ice crystals. Above 12 km where temperatures drop below −50°C CALIOP compares well within situ IWC measurements. In situmeasurements are limited above 12 km, and more cold‐temperature comparisons are needed. Global zonal in‐cloud IWC averages at altitudes above 9 km show that CloudSat IWC is roughly an order of magnitude higher than CALIOP IWC, consistent with a higher detection threshold. When averaged to the vertical resolution characteristic of Microwave Limb Sounder (MLS), global zonal averages of CALIOP and MLS IWC were found to agree to about +/−50%.
Dramatic decrease in streamflow from the headwater source in the central route of China's water diversion project: Climatic variation or human influence?
Authors: Liu Xiaomang , Liu Changming , Luo Yuzhou , Zhang Minghua , Xia Jun
Published: February 2012

The Danjiangkou Reservoir is the headwater source of the central route of China's South to North Water Diversion Project (SNWDP). Average annual streamflow into the Reservoir was 40.97 km3 from 1951 to 1989, while it was 31.64 km3 from 1990 to 2006. Between the two periods, the average annual streamflow was reduced by 9.33 km3, accounting for 71.8% of the proposed amount of water diversion of the central route (13 km3 per year). The sharply decreasing streamflow would inevitably have negative impacts on the implementation of the SNWDP. The reasons for the decrease in streamflow should be investigated before developing any adaption strategies. In this study, the impacts of climatic variation and human activities on streamflow were evaluated by a climate elasticity method. The results show that the impact of climatic variation (indicated by precipitation and potential evapotranspiration) was responsible for 84.1–90.1% of the streamflow reduction, while human activities or other indentified uncertainties contributed 9.9–15.9% of the streamflow reduction. The observed 69.89 mm decrease in average annual precipitation contributed 81.6–87.3% of the decrease in streamflow. According to the observed data during the study period, the planned water diversion could lead to an ecological disaster of the downstream area of the Danjiangkou Reservoir in certain years. We suggest that the water diversion from the Danjiangkou Reservoir should be conducted in an adaptive manner to avoid such an adverse consequence, instead of the current plan of a fixed annual amount of water.
The influence of burn severity on postfire vegetation recovery and albedo change during early succession in North American boreal forests
Authors: Jin Yufang , Randerson James T. , Goetz Scott J. , Beck Pieter S. A. , Loranty Michael M. , Goulden Michael L.
Published: February 2012

Severity of burning can influence multiple aspects of forest composition, carbon cycling, and climate forcing. We quantified how burn severity affected vegetation recovery and albedo change during early succession in Canadian boreal regions by combining satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Canadian Large Fire Database. We used the MODIS‐derived difference Normalized Burn Ratio (dNBR) and initial changes in spring albedo as measures of burn severity. We found that the most severe burns had the greatest reduction in summer MODIS Enhanced Vegetation Index (EVI) in the first year after fire, indicating greater loss of vegetation cover. By 5–8 years after fire, summer EVI for all severity classes had recovered to within 90%–108% of prefire levels. Spring and summer albedo progressively increased during the first 7 years after fire, with more severely burned areas showing considerably larger postfire albedo increases during spring and more rapid increases during summer as compared with moderate‐ and low‐severity burns. After 5–7 years, increases in spring albedo above prefire levels were considerably larger in high‐severity burns (0.20 ± 0.06; defined by dNBR percentiles greater than 75%) as compared to changes observed in moderate‐ (0.16 ± 0.06; for dNBR percentiles between 45% and 75%) or low‐severity burns (0.13 ± 0.06; for dNBR percentiles between 20% and 45%). The sensitivity of spring albedo to dNBR was similar in all ecozones and for all vegetation types along gradients of burn severity. These results suggest carbon losses associated with increases in burn severity observed in some areas of boreal forests may be at least partly offset, in terms of climate impacts, by increases in negative forcing associated with changes in surface albedo.
Rift in Antarctic Glacier: A Unique Chance to Study Ice Shelf Retreat
Authors: Howat Ian M. , Jezek Ken , Studinger Michael , MacGregor Joseph A. , Paden John , Floricioiu Dana , Russell Rob , Linkswiler Matt , Dominguez Roseanne T.
Published: February 2012

It happened again, but this time it was caught in the act. During the last week of September 2011 a large transverse rift developed across the floating terminus of West Antarctica's Pine Island Glacier, less than 5 years after its last large calving event, in 2007 (Figure 1). Pine Island Glacier's retreat has accelerated substantially in the past 2 decades, and it is now losing 50 gigatons of ice per year, or roughly 25% of Antarctica's total annual contribution to sea level rise [Rignot et al., 2008]. The glacier's recent accelerated retreat is likely triggered by ocean warming and increased submarine melting. As such, it is of significant interest to glaciologists and of heightened societal relevance.
How Do Coronal Hole Storms Affect the Upper Atmosphere?
Authors: Mannucci A. J. , Tsurutani B. T. , Solomon S. C. , Verkhoglyadova O. P. , Thayer J. P.
Published: February 2012

The solar cycle, often described as an increase and decrease of solar activity with a period of about 11 years, can strongly affect Earth's thermosphere and ionosphere. Although the longest direct record of solar activity is based on sunspot number, a more quantifiable parameter is solar irradiance at extreme ultraviolet (EUV) wavelengths, which varies by more than a factor of 3 over the sunspot cycle. To first order, upper atmospheric variation is a result of changes in ionizing fluxes at EUV wavelengths. As the solar cycle passes its EUV peak and approaches minimum, the number of solar active regions declines, leading to a reduction and then a near absence of coronal mass ejections (CMEs)—episodic events of high‐energy bursts of solar plasma that cause geomagnetic storms at Earth. During the solar cycle's declining phase, coronal holes begin to occupy lower latitudes on the solar surface and fall in line with the ecliptic plane.
Scientists Provide Perspectives as Drilling Reaches Subglacial Antarctic Lake Vostok
Authors: Showstack Randy
Published: February 2012

Culminating decades of effort, researchers drilled to subglacial Lake Vostok on 5 February. The glacial drilling team of the 57th Russian Antarctic Expedition penetrated to the waters of the lake at a depth of 3769.3 meters through deep ice borehole 5G, according to a report sent to the Arctic and Antarctic Research Institute by the head of Vostok station and the head of the glacial drilling team. Researchers collected about 1.5 cubic meters of water while working to prevent contamination of the lake before a plug of frozen water sealed the lake again, as researchers had planned. The accomplishment culminates decades of effort to reach Lake Vostok—a freshwater lake roughly the size of Lake Ontario located near the middle of the continent—and it opens up a new era in investigating subglacial Antarctic lakes. Some scientists speculate that Lake Vostok, the largest of more than 280 known subglacial lakes on the continent, could harbor life forms in an environment that has been sealed off from light and air for possibly tens of millions of years. They also speculate that the Vostok environment could be analogous to that of some icy moons in the solar system.
Methane exceeds nitrous oxide in rivers' contribution to warming
Authors: Schultz Colin
Published: February 2012

Nitrous oxide emissions have been the leading area of concern for scientists investigating the role of streams and rivers in global climate change for the past decade. Nitrous oxide, a potent greenhouse gas, is produced in riverbed sediments through nitrification and denitrification. Efforts to understand the rate at which nitrous oxide diffuses through the water to the atmosphere have dominated the field, yet diffusion is not the only relevant mechanism, nor is nitrous oxide the only relevant gas. Observations by Baulch et al. suggest that the global warming potential of methane gas, which they measured bubbling up from several riverbeds, exceeded that of nitrous oxide.
New record of climate history in central Asia
Authors: Balcerak Ernie
Published: February 2012

The climate in Central Asia, currently a semiarid region, has varied over the past 500,000 years. An accurate record of the past climate can help scientists understand current climate and better predict how the climate may change in the future. Previous studies with paleoclimate records, such as lake sediments and ice cores, show changes in moisture in the region, but climate history in Central Asia is debated, as some of those records are not high resolution or not well dated. Cheng et al. describe a new high‐resolution, well‐dated record of oxygen isotopes in stalagmites from the Kesang cave in western China. The researchers dated the stalagmites using radioactive thorium dating and then looked at the oxygen isotope record, which provides information on past atmospheric circulation and precipitation.
Continuous observations of North Atlantic heat transport
Authors: Balcerak Ernie
Published: February 2012

The Atlantic meridional overturning circulation (AMOC), which transports warm water northward and cold water back southward, is important in transferring heat to the North Atlantic Ocean. Some models predict that AMOC will slow down as Earth's temperatures rise due to anthropogenic warming, which could have serious climate consequences for the Northern Hemisphere. However, the response of AMOC to global warming is uncertain—different models predict different rates of slowdown—and there have been few continuous observations of AMOC heat transport. Hobbs and Willis used temperature, salinity, and displacement data measured from foats in the Argo array, combined with sea surface heights measured by satellites, to estimate a continuous time series of Atlantic meridional heat transport from 2002 to 2010 at 41°N latitude. They found that the mean heat transport was about 0.5 petawatt. The authors note that this estimate is consistent with previous studies in similar latitudes based on atmospheric flux data but is lower than most hydrographic estimates. Heat transport varied on an annual cycle as well as on shorter time scales, with atmospheric variability explaining most of the short‐term variance. The researchers note that the period of study was too short to infer any long‐term trends, and they emphasize the need for continued monitoring of AMOC. (Journal of Geophysical Research‐Oceans, doi:10.1029/2011JC007039, 2012)
Formation of single and double‐headed streamers in sprite‐halo events
Authors: Qin Jianqi , Celestin Sebastien , Pasko Victor P.
Published: February 2012

Sprite streamers initiate from electron inhomogeneities in the lower ionosphere and undergo significant acceleration and expansion growth before their optical emissions become observable. It is shown that electron inhomogeneities located at high altitudes in the region of sprite halo, which may be sub‐visual, only transform into single‐headed downward streamers, and corresponding upward streamers quickly merge into the sprite halo due to fast relaxation of lightning‐induced electric field. In contrast, the inhomogeneities located at and below the lower edge of the sprite halo, where a high field region persists significantly longer, can transform into double‐headed streamers. The upward negative streamer heads start from the existing bright structures in the channel of previous downward streamers as observed by Cummer et al. (2006), McHarg et al. (2007), and Stenbaek‐Nielsen and McHarg (2008) because at low altitudes, electron density enhancements associated with these channels are much stronger than in preexisting inhomogeneities in the ambient ionosphere.
Anatomical and Functional Assessment of Brown Adipose Tissue by Magnetic Resonance Imaging
Authors: Chen Y. Iris , Cypess Aaron M. , Sass Christina A. , Brownell Anna‐Liisa , Jokivarsi Kimmo T. , Kahn C. Ronald , Kwong Kenneth K.
Published: February 2012

Brown adipose tissue (BAT) is the primary tissue responsible for nonshivering thermogenesis in mammals. The amount of BAT and its level of activation help regulate the utilization of excessive calories for thermogenesis as opposed to storage in white adipose tissue (WAT) which would lead to weight gain. Over the past several years, BAT activity in vivo has been primarily assessed by positron emission tomography‐computed tomography (PET‐CT) scan using 2‐[18F]‐fluoro‐2‐deoxy‐D‐glucose (18F‐FDG) to measure glucose utilization associated with BAT mitochondrial respiration. In this study, we demonstrate the feasibility of mapping and estimating BAT volume and metabolic function in vivo in rats at a 9.4T magnetic resonance imaging (MRI) scanner using sequences available from clinical MR scanners. Based on the morphological characteristics of BAT, we measured the volume distribution of BAT with MRI sequences that have strong fat‐water contrast. We also investigated BAT volume by utilizing spin‐echo MRI sequences. The in vivo MRI‐estimated BAT volumes were correlated with direct measurement of BAT mass from dissected samples. Using MRI, we also were able to map hemodynamic responses to changes in BAT metabolism induced pharmacologically by β3‐adrenergic receptor agonist, CL‐316,243 and compare this to BAT activity in response to CL‐316,243 assessed by PET 18F‐FDG. In conclusion, we demonstrate the feasibility of measuring BAT volume and function in vivo using routine MRI sequences. The MRI measurement of BAT volume is consistent with quantitative measurement of the tissue ex vivo.
Induction of NANOG expression by targeting promoter sequence with small activating RNA antagonizes retinoic acid-induced differentiation
Authors: Wang Xiaoling , Wang Ji , Huang Vera , Place Robert F. , Li Long-Cheng
Published: February 2012

RNAa (RNA activation) is a mechanism by which small dsRNA (double-stranded RNA), termed saRNA (small activating RNA), target promoter sequences to induce gene expression. This technique represents a novel approach to gene overexpression without the use of exogenous DNA. In the present study, we investigated whether RNAa can modulate expression of the development-related gene NANOG and manipulate cell fate. Using a lentivirus-based reporter system as a screening tool, we identified synthetic saRNAs that stimulate NANOG expression in human NCCIT embryonic carcinoma cells. Mismatch mutations to saRNA duplexes define sequence requirement for gene activation. Functional analysis of NANOG induction reveals saRNA treatment predictably modulates the expression of several known downstream target genes, including FOXH1 (forkhead box H1), REST (RE1-silencing transcription factor), OCT4 (octamer-binding protein 4) and REX1 (reduced expression protein 1). Treatment with RA (retinoic acid) triggers NCCIT cell differentiation, reducing NANOG and OCT4 expression and up-regulating several neural markers [i.e. ASCL1 (achaete-scute complex homologue 1), NEUROD1 (neuronal differentiation 1) and PAX6 (paired box 6)]. However, co-treatment with saRNA antagonizes NANOG down-regulation and RA-induced differentiation. Ectopic overexpression of NANOG via lentiviral transduction further recapitulates saRNA results, providing proof-of-concept that RNAa may be utilized to activate development-related genes and manipulate cell fate.
CS055 (Chidamide/HBI-8000), a novel histone deacetylase inhibitor, induces G1 arrest, ROS-dependent apoptosis and differentiation in human leukaemia cells
Authors: Gong Ke , Xie Jia , Yi Hong , Li Wenhua
Published: February 2012

CS055 (Chidamide/HBI-8000) is a novel benzamide-type HDACi (histone deacetylase inhibitor), which has entered Phase I clinical trials in the U.S. and Phase II/III in China. In the present study, we investigated the effects of CS055 on proliferation, differentiation and apoptosis in human leukaemia cell lines and primary myeloid leukaemia cells. The results showed that at low concentrations (<1 μM), CS055 induced G1 arrest. At moderate concentrations (0.5 μM–2 μM), CS055 induced differentiation, as determined by the increased expression of the myeloid differentiation marker CD11b. At relatively high concentrations (2 μM–4 μM), CS055 potently induced caspase-dependent apoptosis. Co-treatment with the ROS (reactive oxygen species) scavengers N-acetyl-L-cysteine or Tiron blocked CS055-induced cell differentiation and apoptosis, suggesting an essential role for ROS in these effects. Cytochrome c release and ROS-mediated mitochondrial dysfunction are involved in CS055-induced apoptosis of leukaemia. In addition to cell lines, CS055 also exhibits therapeutic effects in human primary leukaemia cells. Moreover, daily oral CS055 treatment of nude mice bearing HL60 cell xenografts suppressed tumour growth, induced tumour cell apoptosis and prolonged the survival of tumour-bearing mice. In conclusion, our findings demonstrate that CS055 is a novel HDACi with potential chemotherapeutic value in several haematological malignancies, especially leukaemia.
Records of vagrant phocid seals (family Phocidae) in South Australia
Authors: Shaughnessy Peter D. , Kemper Catherine M. , Ling John K.
Published: February 2012

Five species of phocid seal of the Southern Ocean and Antarctica come ashore occasionally on the southern Australian coast but do not breed there. We document records (specimens and sightings) of visits to South Australia (SA) by southern phocids from 1883 until August 2011. We used records from the SA Museum, reports from coastal officers of SA Department of Environment and Natural Resources (DENR), the DENR fauna database, information from the public, the literature and newspapers. Thirty-six southern elephant seal records included two births, in November 1932 and October 1986. The latter pup suckled for 20 days and then stayed ashore for eight weeks; both are similar to average durations at Macquarie Island. Of 33 dated records, 31 were between August and April, when elephant seals at Macquarie Island (the closest breeding site) are ashore to breed or moult. A recognisable male on Kangaroo Island has been sighted often over 10 years to 2010. Of the ice-breeding species, there were 54 leopard seal records. All of 40 dated records were between June and December, with the maximum (12) in August, similar to the seasonal distribution in Tasmania. There were five records of crabeater seals, one of a Ross seal, and one of a Weddell seal.
Plastic limits of agricultural soils as functions of soil texture and organic matter content
Authors: Keller Thomas , Dexter Anthony R.
Published: February 2012

The plastic limits (lower plastic limit, PL; and liquid limit, LL) are important soil properties that can yield information on soil mechanical behaviour. The objective of this paper is to study the plastic limits of agricultural soils as functions of soil texture and organic matter (OM) content. The plastic limits were highly related to the clay content. The LL was more strongly correlated with clay than was PL, but the reasons are unclear. Interestingly, PL was virtually unaffected by clay content for soils with clay contents below ~35%. The OM had a strong effect on the plastic limits. This effect was clearly demonstrated when analysing soils of similar texture with a range of OM. We present equations (pedotransfer functions) for estimation of PL, LL, and plasticity index (PI) from soil texture and OM. Finally, we predict that the clay content must be ≥10% for soils without OM to be plastic; however, soils with <10% clay can be plastic if OM is present. More research is needed to investigate OM effects on soil consistency.
Solubilisation of soil carbon following treatment with cow urine under laboratory conditions
Authors: Lambie S. M. , Schipper L. A. , Balks M. R. , Baisden W. T.
Published: February 2012

There have been reported losses of soil carbon (C) under intensively grazed pastures, and soil C solubilisation following cow urine deposition was identified as a possible mechanism. We measured potential soil C solubilisation in pasture and plantation pine soils following treatment of soil with cow urine. Soils from five paired pasture and pine sites were collected. Adsorption of urine-C and desorption of soil C was determined by shaking air-dried soil with cow urine for 4 h at 4°C, decanting the urine, and then extracting the soil with water. Soil C solubilisation was the difference between adsorption of urine-C and desorption of soil C. Solubilisation of soil C in the pine soils including the organic layers was 21.6 ± 2.6 mg/g (10.5 ± 1.1% of soil C concentration), in the pine soils excluding the organic layers 7.5 ± 2.2 mg/g (18.7 ± 5.8%), and in the pasture soils 12.4 ± 5.3 mg/g (27.8 ± 7.3%). There was no significant difference with respect to soil C solubilisation between the pine (with and without organic layers) and pasture soils. Soil C lower in the profile may be as susceptible to solubilisation as C in topsoils. Adsorption of urine-C was minimal. Solubilisation of soil C under urine patches may contribute to losses of soil C under intensively grazed pastures, and this hypothesis would benefit from further testing under field conditions.
The role of fire severity, distance from fire perimeter and vegetation on post-fire recovery of small-mammal communities in chaparral
Authors: Diffendorfer Jay , Fleming Genie M. , Tremor Scott , Spencer Wayne , Beyers Jan L.
Published: February 2012

Chaparral shrublands in southern California, US, exhibit significant biodiversity but are prone to large, intense wildfires. Debate exists regarding fuel reduction to prevent such fires in wildland areas, but the effects of these fires on fauna are not well understood. We studied whether fire severity and distance from unburned fire perimeter influenced recovery of the small-mammal community from 13 to 39 months after the large (1134.2 km2) Cedar fire in San Diego County. In general, neither factor influenced small-mammal recovery. However, vegetation characteristics, distance to riparian habitat and the prevalence of rocky substrate affected recovery in species-specific patterns. This indicates the effects of fire severity and immigration from outside the fire perimeter, if they occur, do so within 1 year, whereas longer-term recovery is largely driven by previously known relationships between small mammals and habitat structure. Our results, when combined with results from other studies in southern California, suggest where human lives or infrastructure are not at risk, efforts to preserve chaparral biodiversity should focus on maintaining the native plant community. Doing so may require novel management strategies in the face of an increasing human population, ignition sources and the spread of invasive exotic plants.
Meta‐analyses from a collaborative project in mobile lifelong learning
Authors: Arrigo Marco , Kukulska‐Hulme Agnes , Arnedillo‐Sánchez Inmaculada , Kismihok Gábor
Published: February 2012

This paper focuses on the use of mobile technologies in relation to the aims of the European Union's Lifelong Learning programme. First, we explain the background to the notion of mobile lifelong learning. We then present a methodological framework to analyse and identify good practices in mobile lifelong learning, based on the outcomes of the MOTILL project (‘Mobile Technologies in Lifelong Learning: Best Practices’). In particular, we give an account of the methodology adopted to carry out meta‐analyses of published literature and accounts of mobile learning experiences. Furthermore, we present the results of an implementation of our Evaluation Grid and the implications arising from it in terms of management, pedagogy, policies and ethical issues. Finally, we discuss lessons learnt and future work.
Sergio Grinstein: Phagocytosis step by step
Authors: Sedwick Caitlin
Published: February 2012

Grinstein studies how phagocytes clean up pathogens and the mess left behind by cell death.
Caspase levels and execution efficiencies determine the apoptotic potential of the cell
Authors: Florentin Anat , Arama Eli
Published: February 2012

Essentially, all metazoan cells can undergo apoptosis, but some cells are more sensitive than others to apoptotic stimuli. To date, it is unclear what determines the apoptotic potential of the cell. We set up an in vivo system for monitoring and comparing the activity levels of the two main effector caspases in Drosophila melanogaster, Drice and Dcp-1. Both caspases were activated by the apoptosome after irradiation. However, whereas each caspase alone could induce apoptosis, Drice was a more effective inducer of apoptosis than Dcp-1, which instead had a role in establishing the rate of cell death. These functional differences are attributed to their intrinsic properties rather than merely their tissue specificities. Significantly, the levels of the procaspases are directly proportional to their activity levels and play a key role in determining the cell’s sensitivity to apoptosis. Finally, we provide evidence for the existence of a cellular execution threshold of caspase activity, which must be reached to induce apoptosis.