bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding capacity differences for antibodies and Fc‐fusion proteins on protein A chromatographic materials
Authors: Ghose Sanchayita , Hubbard Brian , Cramer Steven M.
Published: July 2006

A range of studies were carried out to investigate the underlying reason for differences in dynamic binding capacities observed with various antibodies and Fc‐fusion proteins during Protein A chromatography. Dynamic binding capacities were determined for these biomolecules using different protein A stationary phase materials. SEC was carried out to determine the relative sizes of the antibodies and fusion proteins. Pore diffusivities and static binding capacities were also determined on these Protein A resin materials. Trends in the dynamic binding capacities for these molecules did not correlate with differences in pore diffusion coefficients as might be expected for a mass transfer limited system. Instead, dynamic binding capacities were seen to follow the same trends as the static binding capacities and the apparent size of the molecules. Differences in static binding capacities were attributed to be due to differences in steric factor between the molecules. Solution binding stoichiometry studies were employed to estimate intra‐Protein A steric effects while binding to the various domains within a Protein A ligand. In addition, steric hindrance was also found to exist between adjacent immobilized Protein A ligands on the chromatographic surface. The combination of intra and inter Protein A steric hindrances can explain differences in binding capacities observed between various antibody and Fc fusion proteins. The effect of Protein A ligand density on these supports was also examined and the results indicate that increasing Protein A ligand density leads to a situation of diminishing returns for binding capacity due to increased steric hindrance on the resin surface. The results presented in this paper show that steric hindrances can dominate over mass transfer effects in causing capacity variation between different molecules on the same stationary phase. This can lead to the development of more cost‐efficient chromatographic stationary phases as well as provide information during the selection of Protein A media for preparative purification of monoclonal antibodies and Fc fusion proteins. Biotechnol. Bioeng. 2007;96:768–779. © 2006 Wiley Periodicals, Inc.
Further study of flickering auroral roar emission: 1. South Pole observations
Authors: Ye S. , LaBelle J. , Weatherwax A. T.
Published: July 2006

Hughes and LaBelle (2001) reported a single example of a new geophysical phenomenon: ∼10 Hz modulation of auroral radio emissions near twice the auroral ionospheric electron gyrofrequency. They called this phenomenon flickering auroral roar and suggested that it is related to flickering aurora, which results from ∼10 Hz modulation of the precipitating auroral electrons. Observations at South Pole Station during 2003 using a new high‐bandwidth receiving system have yielded 10 examples of flickering roar emissions. Although 10 examples is still a small number for statistics, these observations considerably extend previous knowledge of this phenomenon which was based on a single example. On the basis of the 2003 South Pole data set, flickering auroral roar accounts for only about 1–2% of auroral roar in number of seconds, but ∼20% of auroral roar events have some flickering feature. The observed modulation frequencies range from ∼3 to 30 Hz. The 10‐ to 20‐Hz modulations, which correspond to about 65% of the time when flickering roar occurs, are much more common than the higher‐frequency 20‐ to 30‐Hz modulations, which correspond to about 20% of the time when flickering roar occurs. These frequencies compare favorably with optical observations of auroral emissions, rocket observations of electron flux modulations, and modeling results. If these frequencies correspond to the oxygen gyrofrequency where electrons and ion cyclotron waves interact, the 3‐ to 30‐Hz frequency range would imply sources at altitudes of 1500–10,500 km. Six of the ten flickering roar examples occurred during substorm expansion phase as defined from local magnetometer data, in contrast to flickering aurora, which is usually observed after the onset of auroral breakup.
Relationships between rainfall anomalies over northeastern Brazil and the El Niño–Southern Oscillation
Authors: Kayano Mary T. , Andreoli Rita V.
Published: July 2006

In this paper, sea surface temperature (SST) and sea level pressure variability modes associated with climate extremes (droughts and floods) over northeastern Brazil (NEB) stratified according to the El Niño–Southern Oscillation (ENSO) phases (El Niño, La Niña, and neutral) are reexamined. The analyses indicate that only 36% of the time an ENSO‐based forecast for the NEB climate would be right. This relatively low percentage is mostly because the interannual variations of the NEB climate are more closely tied to the tropical South Atlantic SST variability modes than to the tropical Pacific variability mode. An interesting aspect revealed in the present analysis is that hints of the February–April SST anomaly patterns in the tropical Atlantic for dry and wet cases which are not directly related to the ENSO can be found months prior to the NEB rainy season. Since these hints are particularly strong in the tropical South Atlantic, the SST variations in this sector during months prior to the rainy season should be carefully monitored in the diagnostic activities.
Forward modeling and radiative transfer for the NASA EOS‐Aura High Resolution Dynamics Limb Sounder (HIRDLS) instrument
Authors: Francis G. L. , Edwards D. P. , Lambert A. , Halvorson C. M. , Lee‐Taylor J. M. , Gille J. C.
Published: July 2006

We describe the radiative transfer modeling developed for the High Resolution Dynamics Limb Sounder (HIRDLS) instrument on board the NASA EOS‐Aura satellite. HIRDLS is a 21‐channel broadband radiometer operating in the spectral region between 6 and 18 microns. It is designed to rapidly measure limb emission at tangent heights from the upper troposphere into the mesosphere on a global basis. Science products will include profiles of temperature and chemical constituents, aerosol estimates, the location of polar stratospheric clouds, and geopotential height gradients. We present the HIRDLS fast forward model, which must accurately and quickly estimate transmittances and channel radiances for use in the operational retrievals. The forward model uses a physically based approach that combines transmittance estimates from Curtis‐Godson and Emissivity‐Growth approximations with a statistical regression. Channel‐dependent radiance accuracies for an eleven‐member test ensemble are 0.5–1.0% or better, compared to a line‐by‐line reference, and satisfy the forward model design requirements. We also discuss the forward model hierarchy developed for HIRDLS which underlies the fast model and provides benchmark calculations, detailed spectroscopy, and access to the physics of the radiative transfer process for development work. Collectively, this framework provides an effective solution to the requirement for fast and accurate radiative transfer modeling for operational use.
Response of Hofsjökull and southern Vatnajökull, Iceland, to climate change
Authors: Aðalgeirsdóttir G. , Jóhannesson T. , Björnsson H. , Pálsson F. , Sigurðsson O.
Published: July 2006

(Possible changes in glacier mass balance are among the most important consequences of future climate change with both local and global implications, such as changes in the discharge of glacial rivers, changes in the vertical stratification in the upper layers of the Arctic Ocean, and a rise in global sea level. The response of the Hofsjökull and southern Vatnajökull ice caps in Iceland to climate change is analyzed with a vertically integrated, finite difference ice flow model coupled with a degree day mass balance model. Transient climate change simulations are forced with a climate change scenario for the Nordic countries, which for Iceland, specifies a warming rate of 0.15°C per decade in midsummer and 0.3°C per decade in midwinter, with a sinusoidal variation through the year starting from the baseline period 1981–2000. Precipitation is either held steady or is increased at 5% per °C of warming. Modeled ice volume is reduced by half within 100–150 years. About 2030, annual average runoff from the area that is presently covered by ice is projected to have increased by approximately 0.7 m yr−1 for Hofsjökull and by 1.4 m yr−1 for southern Vatnajökull. The sensitivity of the mass balance of the ice caps to climate change was found to be in the range 0.4–0.8 mw.e. yr−1 °C−1 for Hofsjökull and 0.8–1.3 mw.e. yr−1 °C−1 for southern Vatnajökull. The sensitivity remained within these ranges more than 150 years into the future.)
Paleomagnetism and tectonics of the southern Atacama Desert (25–28°S), northern Chile
Authors: Arriagada César , Roperch Pierrick , Mpodozis Constantino , Fernandez Rodrigo
Published: July 2006

We report paleomagnetic results for 131 sites from the modern forearc of northern Chile (25°S and 28°S). Remanent magnetization in volcanic and intrusive rocks is mostly primary, while a secondary magnetization is observed in sedimentary rocks. Comparison of locality‐mean directions with expected paleomagnetic directions indicates vertical axis rotations from −7.3° ± 21.6° counterclockwise to 52.7° ± 17° clockwise. Jurassic to Early Cretaceous rocks from the Coastal Cordillera and Cretaceous to Paleocene rocks from the Central Depression show similar magnitude (>30°) clockwise rotations, while more variable rotations occur in Mesozoic to Eocene rocks of the Precordillera. Clockwise rotations in Mesozoic and Paleogene rocks occur in the Chilean Frontal Cordillera south of 27°30′S. Paleomagnetic results in three large Miocene ignimbrite sheets overlying rotated and nonrotated older rocks in the Precordillera and Pre‐Andean Depression which show no relative rotation between sites indicate that most rotations within the study area occurred prior to 18 Ma (early Miocene) and likely during and after the “Incaic” tectonic event, which affected large tracts of the central Andes. The postulated onset of rotations in the north Chilean forearc was contemporaneous with the beginning of horizontal shortening and uplift of the Eastern Cordillera in Bolivia and northwestern Argentina. Rotation of the Chilean forearc, enhancement of the curvature of the central Andes, and the formation of the Bolivian Orocline seem to be, for the most part, closely linked to the evolution of the Eocene‐Oligocene tectonics of the Eastern Cordillera.
Some observations on the scale dependence of permeability by pumping tests
Authors: Raghavan Rajagopal
Published: July 2006

The dependence of scale in estimates of permeability or transmissivity in pumping tests is addressed in terms of internal architecture. The need for using geologic models that go beyond treating heterogeneity as a multinormal logarithmic field is noted. By using stratification as a vehicle and simulating flow, the role of the internal architecture of the aquifer is demonstrated. Specifically, transient data generated with the help of a stratified model are evaluated without consideration of internal architecture or geological imprint, and the consequences on estimates of aquifer properties are examined particularly in terms of scale. Evidence of scale effects should suggest the need for evaluating pumping tests with models that incorporate geologic considerations.
Crustal thinning between the Ethiopian and East African plateaus from modeling Rayleigh wave dispersion
Authors: Benoit Margaret H. , Nyblade Andrew A. , Pasyanos Michael E.
Published: July 2006

A 500‐km wide region separating the East African and Ethiopian plateaus is one of the few places within the African Superswell with elevations below 1 km. The region encompasses much of southeastern Sudan and northern Kenya and experienced both Mesozoic and Cenozoic rifting. Crustal and uppermost mantle structure is investigated in the region by modeling Rayleigh wave dispersion measurements. Modeling results give Sn velocities of 4.1–4.3 km/s and average crustal thickness of 25 ± 5 km, some 10–15 km thinner than the crust beneath the East African and Ethiopian Plateaus. The isostatic response from 10 to 15 km of crustal thinning is sufficient to account for the low elevations between the plateaus.
Rapid variations in polar motion during the 2005–2006 winter season
Authors: Lambert S. B. , Bizouard C. , Dehant V.
Published: July 2006

The terrestrial motion of the Earth's rotation pole shows mainly two large oscillations: the Chandler and the annual wobbles driven by mass redistributions in surface geophysical fluids. These contributions interfere destructively every 6.4 years, slowing down the pole at that period of time. This is the case for the recent period from November 2005 till February 2006. Due to the high precision of Earth orientation data of these days and for the first time in the history of polar motion observation, very small structures of the motion are observed. We compared the observed polar motion with the contribution of atmosphere and oceans predicted from global atmospheric and oceanic analyses and models. We clearly see that centimeter level polar motion displacements during the 2005–2006 winter season are almost fully explained by major pressure events on the continents and on the ocean, especially a depression over Northern Europe in‐phase with similar events over North America.
On the assignment of prior errors in Bayesian inversions of CO2 surface fluxes
Authors: Chevallier Frédéric , Viovy Nicolas , Reichstein Markus , Ciais Philippe
Published: July 2006

For the estimation of surface CO2 fluxes from atmospheric concentration measurements, most often Bayesian approaches have been adopted. As with all Bayesian techniques the definition of prior probability distributions is a critical step in the analysis. However, practical considerations usually guide the definition of prior information rather than objective criterions. In this paper, in situ CO2 flux pointwise measurements made by the eddy‐covariance technique are used to estimate the errors of prior fluxes provided by the prognostic carbon‐water‐energy model ORCHIDEE. The results contradict the usual convenient assumption of a multivariate Gaussian distribution. The errors of ORCHIDEE have a heavier‐tail distribution with a linear temporal dependency after the second lag day and no particular spatial structure. Such error distribution significantly complicates the inversion of CO2 surface fluxes.
Cirrhotic cardiomyopathy: Indian scenario
Authors: Alexander Jacob , Mishra Peeyush , Desai Nutan , Ambadekar Shekhar , Gala Bharat , Sawant Prabha
Published: July 2006

Background:  Cirrhotic cardiomyopathy has been reported to be a major cause of morbidity and mortality in liver transplant recipients. However, there is scant data from Asia. With liver transplantation programs gradually being established in the region, Asian hepatologists are bound to face this entity.

Methods:  Thirty patients with alcoholic cirrhosis and 30 with cirrhosis of nonalcoholic etiology were enrolled, after excluding those with recent bleeding, gross ascites, severe anemia and other conditions which could alter cardiovascular status. Thirty healthy subjects without cardiovascular risk factors were enrolled as controls. Hepatic function status was assessed by biochemical tests and prothrombin time. Cardiac structural and functional assessment was performed non‐invasively using transthoracic echocardiography.

Results:  Deceleration time was significantly (P < 0.05) prolonged in both the cirrhotic groups (235.03 ± 44.23 ms and 255.87 ± 46.16 ms) compared to controls (185.83 ± 25.04 ms), indicative of diastolic dysfunction in cirrhotic patients. Other parameters, viz. ejection fraction, E : A ratio, left ventricular relative wall thickness, interventricular septal thickness and left ventricular systolic as well as diastolic chamber dimensions did not show statistically significant difference between any of the groups. Cardiac structural and functional parameters were not correlated with the severity of liver dysfunction. There was no statistically significant difference between the alcoholic and nonalcoholic groups.

Conclusions:  Asian patients with cirrhosis do have evidence of diastolic dysfunction. Cardiac structural and functional parameters did not correlate with the severity of liver dysfunction. Cardiac dysfunction seemed to be the consequence of cirrhosis itself, rather than of alcohol.
Cimetidine inhibits epidermal growth factor‐induced cell signaling
Authors: Fujikawa Tatsuya , Shiraha Hidenori , Nakanishi Yutaka , Takaoka Nobuyuki , Ueda Naoki , Suzuki Mayumi , Shiratori Yasushi
Published: July 2006

Background:  Cimetidine, a histamine‐2 (H2) receptor antagonist, has been demonstrated to have anticancer effects on colorectal cancer, melanoma and renal cell carcinoma. In the current study, we clarified that cimetidine inhibits both epidermal growth factor (EGF)‐induced cell proliferation and migration in hepatocellular carcinoma (HCC) cell lines.

Method:  HCC cell lines (Hep3B, HLF, SK‐Hep‐1, JHH‐2, PLC/PRF/5 and HLE) were used and cell proliferation was assessed by [3H]‐thymidine incorporation assay. Cell migration was measured by in vitro cell migration assay. Biological effects of cimetidine were assessed with human EGF receptor (EGFR)‐expressing mouse fibroblast cells (NR6‐WT). The autophosphorylation of EGFR and the activation of other downstream effectors were analyzed by immunoprecipitation and immunoblotting. The concentration of intracellular cyclic AMP (cAMP) was measured by competitive enzyme immunoassay.

Results:  Cimetidine inhibited both EGF‐induced cell proliferation and migration in Hep3B, HLF, SK‐Hep‐1 and JHH‐2, while cimetidine did not affect EGF‐induced cell proliferation and migration in PLC/PRF/5 and HLE. Cimetidine was revealed to disrupt the EGF‐induced autophosphorylation of EGFR and its downstream effectors, mitogen activated protein kinases and phospholipase C‐γ. To define the molecular basis of this negative regulation, we identified that cimetidine significantly decreased intracellular cAMP levels and that decrement of cAMP inhibited autophosphorylation of EGFR. The cell permeable cAMP analog, CPT‐cAMPS reversed the cimetidine‐induced inhibition of EGF‐induced cell proliferation and cell migration by restoring autophosphorylation of EGFR.

Conclusion:  Cimetidine inhibited EGF‐induced cell proliferation and migration in HCC cell lines by decreasing the concentration of intracellular cAMP levels. Cimetidine may be a candidate chemopreventive agent for HCC.
Effect of tegaserod on colonic transit time in male patients with constipation‐predominant irritable bowel syndrome
Authors: Harish Kareem , Hazeena Kizhekkan , Thomas Varghese , Kumar Sunil , Jose Tony , Narayanan Puthiyaveetil
Published: July 2006

Background and Aims: Tegaserod is approved for the treatment of constipation‐predominant irritable bowel syndrome (C‐IBS) in females. The aim of this study was to evaluate the effect of tegaserod on colonic transit time (CTT) and symptoms in male patients with C‐IBS.

Methods: Forty‐four males with C‐IBS (Rome II) were enrolled. After a baseline washout period of 2 weeks, 40 patients were randomized to 6 mg twice daily of tegaserod or placebo for 12 weeks. Daily bowel habits and weekly satisfactory relief of symptoms were recorded. Total and segmental CTT were measured using radiopaque markers at baseline and after treatment.

Results: The mean ± SD for the total colonic, right colonic, left colonic and rectosigmoid transit time (in hours) were 18.96 ± 3.92, 7.74 ± 1.55, 5.64 ± 1.51 and 5.58 ± 2.2 in the tegaserod group compared to 22.47 ± 3.73, 9.69 ± 2.33, 6.6 ± 1.32 and 6.18 ± 2.22 in the placebo group at the end of 12 weeks. There was a statistically significant difference in the total, right and left CTT in the tegaserod group (P < 0.05) at the end of treatment. Global satisfactory relief at the end of 12 weeks was 75% in the tegaserod group and 50% in the placebo group (P > 0.05). Greater stool frequency occurred in the tegaserod group (P > 0.05). There was a significant decrease in the stool consistency at the end of 12 weeks in patients treated with tegaserod (P < 0.05).

Conclusions: Tegaserod causes significant acceleration of CTT in male patients with C‐IBS. Although there was a trend towards improvement in bowel symptoms in the treated group, this effect was not statistically significant.
Analysis of clinical features of acute pancreatitis in Shandong Province, China
Authors: Gao Yan Jing , Li Yan Qing , Wang Qing , Li Shen Lin , Li Guo Qing , Ma Ji , Zeng Xian Zhong , Huang Liu Ye , Yuan Sheng An , Liu Chun An , Wang Fu Xian
Published: July 2006

Aim:  To investigate and obtain a more comprehensive view of the etiology and clinical features of acute pancreatitis in China.

Method:  The study comprised 1471 patients in 10 cites of China who were admitted to hospitals for acute pancreatitis from January 1992 to December 2002. Data for each patient were collected on a standardized form.

Results:  Of the 1471 patients (854 men, 617 women; mean age 43.3 years; range 13–82 years), 1280 had mild pancreatitis and 191 had the severe form. Cholelithiasis (20.2%), alcohol (17.3%) and diet‐induced (12.4%) were the most frequent etiological factors, followed by biliary tract infections (5.6%), hyperlipidemia (2.3%) and other factors (5.1%). However, in about 36.1% of cases, the etiology of acute pancreatitis still remained unexplained. In coastal regions, cholelithiasis was the most frequent factor but alcohol ranked first in interior regions. In males, a small predominance of alcohol over cholelithiasis was seen (27.4%vs 14.3%) and there was a clear predominance of cholelithiasis over alcohol (28.4%vs 3.2%) in females. The differences in the frequency of cholelithiasis and alcohol between coastal regions and interior regions and males and females were statistically significant (P < 0.01). According to their frequency, complications of acute pancreatitis were pancreatic pseudocyst, pancreatic ascities and bacterial peritonitis, pulmonary infections, multiple organ failure, diabetes mellitus type 2 and shock.

Conclusion:  Cholelithiasis, alcohol and diet‐induced factors were the main etiological factors seen in China, whereas cholelithiasis alone predominated in females and alcohol ranked first in males. In about 36.1% of cases, the etiology of acute pancreatitis remained unknown. More attention should be paid to studying the etiologies of acute pancreatitis that remain unknown.
Determination of mutations of the 23S rRNA gene of Helicobacter pylori by allele specific primer‐polymerase chain reaction method
Authors: Nakamura Akiko , Furuta Takahisa , Shirai Naohito , Sugimoto Mitsushige , Kajimura Masayoshi , Soya Yoshihiro , Hishida Akira
Published: July 2006

Background and Aims:  Susceptibility to clarithromycin of Helicobacter pylori (H. pylori) is caused by single nucleotide polymorphisms (SNPs) of the 23SrRNA gene. Allele specific primer‐polymerase chain reaction (ASP‐PCR) is one of the methods for determining SNPs, which can measure SNPs easily within a short period by PCR amplification alone without digestion with restriction enzymes. The aim of the present study was to develop the ASP‐PCR assay for determining SNPs at positions 2142 and 2143 of the 23S rRNA gene of H. pylori.

Methods:  In total, 112 patients with H. pylori infection based on positive results of a rapid urease test (RUT) were enrolled in the study. Thirty‐five had failed to eradicate H. pylori by a clarithromycin‐based regimen. DNA was extracted from the RUT‐positive gastric tissue samples. SNPs from adenine to guanine at positions 2142 and 2143 of the 23S rRNA of H. pylori (A2142G and A2143G) were determined by the ASP‐PCR method. Minimum inhibitory concentrations (MICs) of clarithromycin for H. pylori were also measured.

Results:  Forty‐nine of 112 patients were infected with wild‐type strains of H. pylori. Thirty‐nine patients were infected with strains with A2143G mutations. Twenty‐three patients were infected with both wild‐type strains and those with A2143G mutations. Only one patient was infected with the strain with A2142G mutation. H. pylori strains with A2143G or A2142G mutation had significantly higher MICs for clarithromycin.

Conclusion:  The ASP‐PCR assay for 23S rRNA mutation of H. pylori is a useful method to detect clarithromycin‐resistant strains of H. pylori easily.
Species Protection, the Changing Informal Economy, and the Politics of Access to the Bushmeat Trade in the Democratic Republic of Congo
Authors: De MERODE EMMANUEL , COWLISHAW GUY
Published: July 2006

Abstract:  Our understanding of the linkages between the bushmeat trade and the wider informal economy is limited. This lack of knowledge is particularly problematic for conservation under conditions of political instability, when the informal economy can be highly dynamic and impacts on wildlife populations can be severe. To explore these interlinked processes, we conducted a study of the bushmeat trade in Garamba National Park, Democratic Republic of Congo, through a combination of market surveys, semistructured interviews, and direct observation. We focused on the sale of protected and unprotected species in urban and rural markets, and the bushmeat commodity chains that supplied these markets, under conditions of political stability and armed conflict. During peacetime, protected species from the park (predominantly elephant and buffalo) rarely appeared in the rural markets, but they comprised more than half of all bushmeat sales in the urban markets. This pattern reflected differences in the rural and urban commodity chains. Automatic weapons were required to hunt large protected species and were supplied to hunters by the military officers who controlled the urban trade. The use of such weapons was discouraged by the traditional chiefs, who administered the village markets. During wartime, the sales of protected species in the urban markets increased fivefold because the military officers fled, leaving behind an open‐access system that led to a massive increase in the exploitation of protected species. In contrast, the rural markets remained relatively stable because of the continued authority of the village chiefs. Our results indicate that sociopolitical factors can be an important determinant of species offtake and, therefore, that knowledge of the bushmeat commodity chain can be vital to controlling the processes that drive species extraction. In addition, our findings suggest that traditional authorities can be potentially valuable partners for bushmeat management.
Long‐Term Landscape Change and Bird Abundance in Amazonian Rainforest Fragments
Authors: STOUFFER PHILIP C. , BIERREGAARD RICHARD O. , STRONG CHERYL , LOVEJOY THOMAS E.
Published: July 2006

Abstract: The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km2/year, leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1–100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist‐netting program in 1– to 100‐ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (≤10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10‐ and 100‐ha fragments connected to continuous forest by 20‐year‐old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into “forest” and “nonforest” misses essential information about the matrix.
Remarkable Amphibian Biomass and Abundance in an Isolated Wetland: Implications for Wetland Conservation
Authors: GIBBONS J. WHITFIELD , WINNE CHRISTOPHER T. , SCOTT DAVID E. , WILLSON JOHN D. , GLAUDAS XAVIER , ANDREWS KIMBERLY M. , TODD BRIAN D. , FEDEWA LUKE A. , WILKINSON LUCAS , TSALIAGOS RIA N. , HARPER STEVEN J. , GREENE JUDITH L. , TUBERVILLE TRACEY D. , METTS BRIAN S. , DORCAS MICHAEL E. , NESTOR JOHN P. , YOUNG CAMERON A. , AKRE TOM , REED ROBERT N. , BUHLMANN KURT A. , NORMAN JASON , CROSHAW DEAN A. , HAGEN CRIS , ROTHERMEL BETSIE B.
Published: July 2006

Abstract:  Despite the continuing loss of wetland habitats and associated declines in amphibian populations, attempts to translate wetland losses into measurable losses to ecosystems have been lacking. We estimated the potential productivity from the amphibian community that would be compromised by the loss of a single isolated wetland that has been protected from most industrial, agricultural, and urban impacts for the past 54 years. We used a continuous drift fence at Ellenton Bay, a 10‐ha freshwater wetland on the Savannah River Site, near Aiken, South Carolina (U.S.A.), to sample all amphibians for 1 year following a prolonged drought. Despite intensive agricultural use of the land surrounding Ellenton Bay prior to 1951, we documented 24 species and remarkably high numbers and biomass of juvenile amphibians (>360,000 individuals; >1,400 kg) produced during one breeding season. Anurans (17 species) were more abundant than salamanders (7 species), comprising 96.4% of individual captures. Most (95.9%) of the amphibian biomass came from 232095 individuals of a single species of anuran (southern leopard frog[Rana sphenocephala]). Our results revealed the resilience of an amphibian community to natural stressors and historical habitat alteration and the potential magnitude of biomass and energy transfer from isolated wetlands to surrounding terrestrial habitat. We attributed the postdrought success of amphibians to a combination of adult longevity (often >5 years), a reduction in predator abundance, and an abundance of larval food resources. Likewise, the increase of forest cover around Ellenton Bay from <20% in 1951 to >60% in 2001 probably contributed to the long‐term persistence of amphibians at this site. Our findings provide an optimistic counterpoint to the issue of the global decline of biological diversity by demonstrating that conservation efforts can mitigate historical habitat degradation.
A Mechanistic Approach to Evaluation of Umbrella Species as Conservation Surrogates
Authors: OZAKI KENICHI , ISONO MASAHIRO , KAWAHARA TAKAYUKI , IIDA SHIGEO , KUDO TAKUMA , FUKUYAMA KENJI
Published: July 2006

Abstract: Although species with large area requirements are sometimes used as umbrella species, their general utility as conservation tools is uncertain. We surveyed the species diversity of birds, butterflies, carabids, and forest‐floor plants in forest sites across an area (1600 km2) in which we delineated large breeding home ranges of Northern Goshawk (Accipiter gentilis). We tested whether protection of the home ranges could serve as an effective umbrella to protect sympatric species of the four taxa. We also used an empirical habitat model of occupancy of home range to examine mechanisms by which the Northern Goshawk acts as an umbrella species. Among species richness, abundance, and species composition of the four taxa, only abundance and species composition of birds differed between sites located inside and outside home ranges, which was due to greater abundance of bird species that were prey of Northern Goshawks inside the home ranges. Thus, although home range indicated areas with high abundance of certain bird prey species, it was not effective as an indicator of the species diversity of all four taxa. We also did not find any difference in species richness, abundance, and species composition between sites predicted as occupied and unoccupied using the habitat model. In contrast, when we selected sites on the basis of each habitat variable in the model, habitat variables that selected sites either in agricultural or forested landscapes encompassed sites with high species richness or particular species composition. This result suggests that the low performance of the Northern Goshawk as an umbrella species is due to this species' preference for habitat in both agricultural and forested landscapes. Species that can adjust to changes in habitat conditions may not act as effective umbrella species despite having large home ranges.
Achieving Integrative, Collaborative Ecosystem Management
Authors: KEOUGH HEATHER L. , BLAHNA DALE J.
Published: July 2006

Abstract: Although numerous principles have been identified as being important for successfully integrating social and ecological factors in collaborative management, few authors have illustrated how these principles are used and why they are effective. On the basis of a review of the ecosystem management and collaboration literature, we identified eight factors important for integrative, collaborative ecosystem management—integrated and balanced goals, inclusive public involvement, stakeholder influence, consensus group approach, collaborative stewardship, monitoring and adaptive management, multidisciplinary data, and economic incentives.We examined four cases of successful ecosystem management to illustrate how the factors were incorporated and discuss the role they played in each case's success. The cases illustrate that balancing social and ecosystem sustainability goals is possible. Collaborative efforts resulted in part from factors aimed at making plans economically feasible and from meaningful stakeholder participation in ongoing management. It also required participation in monitoring programs to ensure stakeholder interests were protected and management efforts were focused on agreed‐upon goals. Data collection efforts were not all‐inclusive and systematic; rather, they addressed the ecological, economic, and social aspects of key issues as they emerged over time. Economic considerations appear to be broader than simply providing economic incentives; stakeholders seem willing to trade some economic value for recreational or environmental benefits. The cases demonstrate that it is not idealistic to believe integrative, collaborative ecosystem management is possible in field applications.
Conservation as Virtue: a Scientific and Social Process for Conservation Ethics
Authors: VAN HOUTAN KYLE S.
Published: July 2006

Abstract:  Most scientists take ethical arguments for conservation as given and focus on scientific or economic questions. Although nature conservation is often considered a just cause, it is given little further consideration. A lack of attention to ethical theory raises serious concerns for how conservation scientists conceive and practice ethics. I contrast two common ways scientists approach ethics, as demonstrated in the writings of Stephen Jay Gould and E. O. Wilson. Gould casts severe doubt as to whether any ethics are possible from science, whereas Wilson proposes science as the only path to ethics. I argue these two methods ultimately limit popular support for conservation and offer Alasdair MacIntyre's “virtue ethics” as an alternative. Unlike Gould and Wilson, MacIntyre provides an ethical theory that reconciles scientific inquiry and social traditions. Recent studies of the Civil Rights Movement in the United States affirm MacIntyre's claims and provide important insights for conservation today. These accounts argue that social solidarity and political success against segregation were possible only as rooted in the particular language, logic, and practices of a robust cultural tradition. If correct, conservation science should attend to several questions. On what basis can conservation achieve widespread cultural legitimacy? What are the particular social currencies for a conservation ethic? What role does science play in such a scheme? MacIntyre's careful positioning of scientific and social traditions provides a hopeful ethical direction for conservation.
Using Scalar Models for Precautionary Assessments of Threatened Species
Authors: DUNHAM AMY E. , AKÇAKAYA H. RESIT , BRIDGES TODD S.
Published: July 2006

Abstract: Scalar population models, commonly referred to as count‐based models, are based on time‐series data of population sizes and may be useful for screening‐level ecological risk assessments when data for more complex models are not available. Appropriate use of such models for management purposes, however, requires understanding inherent biases that may exist in these models. Through a series of simulations, which compared predictions of risk of decline of scalar and matrix‐based models, we examined whether discrepancies may arise from different dynamics displayed due to age structure and generation time. We also examined scalar and matrix‐based population models of 18 real populations for potential patterns of bias in population viability estimates. In the simulation study, precautionary bias (i.e., overestimating risks of decline) of scalar models increased as a function of generation time. Models of real populations showed poor fit between scalar and matrix‐based models, with scalar models predicting significantly higher risks of decline on average. The strength of this bias was not correlated with generation time, suggesting that additional sources of bias may be masking this relationship. Scalar models can be useful for screening‐level assessments, which should in general be precautionary, but the potential shortfalls of these models should be considered before using them as a basis for management decisions.
Understanding Barriers to Implementation of an Adaptive Land Management Program
Authors: JACOBSON SUSAN K. , MORRIS JULIE K. , SANDERS J. SCOTT , WILEY EUGENE N. , BROOKS MICHAEL , BENNETTS ROBERT E. , PERCIVAL H. FRANKLIN , MARYNOWSKI SUSAN
Published: July 2006

Abstract: The Florida Fish and Wildlife Conservation Commission manages over 650,000 ha, including 26 wildlife management and environmental areas. To improve management, they developed an objective‐based vegetation management (OBVM) process that focuses on desired conditions of plant communities through an adaptive management framework. Our goals were to understand potential barriers to implementing OBVM and to recommend strategies to overcome barriers. A literature review identified 47 potential barriers in six categories to implementation of adaptive and ecosystem management: logistical, communication, attitudinal, institutional, conceptual, and educational. We explored these barriers through a bureau‐wide survey of 90 staff involved in OBVM and personal interviews with area managers, scientists, and administrators. The survey incorporated an organizational culture assessment instrument to gauge how institutional factors might influence OBVM implementation. The survey response rate was 69%. Logistics and communications were the greatest barriers to implementing OBVM. Respondents perceived that the agency had inadequate resources for implementing OBVM and provided inadequate information. About one‐third of the respondents believed OBVM would decrease their job flexibility and perceived greater institutional barriers to the approach. The 43% of respondents who believed they would have more responsibility under OBVM also had greater attitudinal barriers. A similar percentage of respondents reported OBVM would not give enough priority to wildlife. Staff believed that current agency culture was hierarchical but preferred a culture that would provide more flexibility for adaptive management and would foster learning from land management activities. In light of the barriers to OBVM, we recommend the following: (1) mitigation of logistical barriers by addressing real and perceived constraints of staff, funds, and other resources in a participatory manner; (2) mitigation of communication barriers through interpersonal and electronic communication channels; (3) development of an OBVM external advisory committee; and (4) adoption of characteristics of an organizational culture that promotes flexibility and learning.
Planting History and Propagule Pressure as Predictors of Invasion by Woody Species in a Temperate Region
Authors: KŘIVÁNEK MARTIN , PYŠEK PETR , JAROŠÍK VOJTĚCH
Published: July 2006

Abstract: We studied 28 alien tree species currently planted for forestry purposes in the Czech Republic to determine the probability of their escape from cultivation and naturalization. Indicators of propagule pressure (number of administrative units in which a species is planted and total planting area) and time of introduction into cultivation were used as explanatory variables in multiple regression models. Fourteen species escaped from cultivation, and 39% of the variance was explained by the number of planting units and the time of introduction, the latter being more important. Species introduced early had a higher probability of escape than those introduced later, with more than 95% probability of escape for those introduced before 1801 and <5% for those introduced after 1892. Probability of naturalization was more difficult to predict, and eight species were misclassified. A model omitting two species with the largest influence on the model yielded similar predictors of naturalization as did the probability of escape. Both phases of invasion therefore appear to be driven by planting and introduction history in a similar way. Our results demonstrate the importance of forestry for recruitment of invasive trees. Six alien forestry trees, classified as invasive in the Czech Republic, are currently reported in nature reserves. In addition, forestry authorities want to increase the diversity of alien species and planting area in the country.
Effectiveness of Protected Areas in Mitigating Fire within Their Boundaries: Case Study of Chiapas, Mexico
Authors: ROMÁN‐CUESTA ROSA MARÍA , MARTÍNEZ‐VILALTA JORDI
Published: July 2006

Abstract: Since the severe 1982–1983 El Niño drought, recurrent burning has been reported inside tropical protected areas (TPAs). Despite the key role of fire in habitat degradation, little is known about the effectiveness of TPAs in mitigating fire incidence and burned areas. We used a GPS fire database (1995–2005) (n= 3590 forest fires) obtained from the National Forest Commission to compare fire incidence (number of fires) and burned areas inside TPAs and their surrounding adjacent buffer areas in Southern Mexico (Chiapas). Burned areas inside parks ranged from 2% (Palenque) to 45% (Lagunas de Montebello) of a park's area, and the amount burned was influenced by two severe El Niño events (1998 and 2003). These two years together resulted in 67% and 46% of the total area burned in TPAs and buffers, respectively during the period under analysis. Larger burned areas in TPAs than in their buffers were exclusively related to the extent of natural habitats (flammable area excluding agrarian and pasture lands). Higher fuel loads together with access and extinction difficulties were likely behind this trend. A higher incidence of fire in TPAs than in their buffers was exclusively related to anthropogenic factors such as higher road densities and agrarian extensions. Our results suggest that TPAs are failing to mitigate fire impacts, with both fire incidence and total burned areas being significantly higher in the reserves than in adjacent buffer areas. Management plans should consider those factors that facilitate fires in TPAs: anthropogenic origin of fires, sensitivity of TPAs to El Niño‐droughts, large fuel loads and fuel continuity inside parks, and limited financial resources. Consideration of these factors favors lines of action such as alternatives to the use of fire (e.g., mucuna‐maize system), climatic prediction to follow the evolution of El Niño, fuel management strategies that favor extinction practices, and the strengthening of local communities and ecotourism.
Toward Meaningful Snag‐Management Guidelines for Postfire Salvage Logging in North American Conifer Forests
Authors: HUTTO RICHARD L.
Published: July 2006

Abstract: The bird species in western North America that are most restricted to, and therefore most dependent on, severely burned conifer forests during the first years following a fire event depend heavily on the abundant standing snags for perch sites, nest sites, and food resources. Thus, it is critical to develop and apply appropriate snag‐management guidelines to implement postfire timber harvest operations in the same locations. Unfortunately, existing guidelines designed for green‐tree forests cannot be applied to postfire salvage sales because the snag needs of snag‐dependent species in burned forests are not at all similar to the snag needs of snag‐dependent species in green‐tree forests. Birds in burned forests have very different snag‐retention needs from those cavity‐nesting bird species that have served as the focus for the development of existing snag‐management guidelines. Specifically, many postfire specialists use standing dead trees not only for nesting purposes but for feeding purposes as well. Woodpeckers, in particular, specialize on wood‐boring beetle larvae that are superabundant in fire‐killed trees for several years following severe fire. Species such as the Black‐backed Woodpecker (Picoides arcticus) are nearly restricted in their habitat distribution to severely burned forests. Moreover, existing postfire salvage‐logging studies reveal that most postfire specialist species are completely absent from burned forests that have been (even partially) salvage logged. I call for the long‐overdue development and use of more meaningful snag‐retention guidelines for postfire specialists, and I note that the biology of the most fire‐dependent bird species suggests that even a cursory attempt to meet their snag needs would preclude postfire salvage logging in those severely burned conifer forests wherein the maintenance of biological diversity is deemed important.
Preemptive and Salvage Harvesting of New England Forests: When Doing Nothing Is a Viable Alternative
Authors: FOSTER DAVID R. , ORWIG DAVID A.
Published: July 2006

Abstract: One unexpected consequence of natural disturbances in forested areas is that managers often initiate activities that may impose greater ecosystem impacts than the disturbances themselves. By salvage logging areas affected by windstorms or other impacts, by harvesting host trees in advance of insect infestation or disease, or by preemptively harvesting forests in an attempt to improve their resilience to future disturbances and stresses, managers initiate substantial changes in the ecosystem structure and function. Much of this activity is undertaken in the absence of information on the qualitative and quantitative differences between disturbance impacts and harvesting. To provide insight for such decisions we evaluated the ecosystem consequences of two major disturbance processes in New England (U.S.A.)—intense windstorms and invasive pests and pathogens—and contrasted them with impacts from preemptive and salvage harvesting. Despite dramatic physical changes in forest structure resulting from hurricane impacts and insect infestation, little disruption of biogeochemical processes or other ecosystem functions typically follows these disturbances. Indeed, the physical and organic structures produced by these disturbances are important natural features providing habitat and landscape heterogeneity that are often missing due to centuries of land use. From an ecosystem perspective there are strong arguments against preemptive and salvage logging or the attempt through silvicultural means to improve the resistance or resilience of forests to disturbance and stress. There are often valid motivations for salvage or preemptive logging including financial considerations, human safety, and a desire to shape the long‐term composition and resource‐production characteristics of forests. Nonetheless, there are many ecological benefits derived from leaving forests alone when they are affected or threatened by disturbances and pest and pathogen outbreaks.