A novel xylan degrading beta-D-xylosidase: purification and biochemical characterization

Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular beta-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. beta-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 A degrees C and 3.0-5.5, respectively. beta-xylosidase was stable in acidic pH (3.0-6.0) and 70 A degrees C for 1 h. The enzyme was activated by 5 mM MnCl2 (28 %) and MgCl2 (20 %) salts. The beta-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-beta-d-xylopyranoside, exhibiting apparent K-m and V-max values of 0.66 mM and 39 U (mg protein)(-1) respectively, and to a lesser extent p-nitrophenyl-beta-d-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources, suggesting a novel beta-d-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by beta-xylosidase. TLC confirmed the capacity of the enzyme in hydrolyzing xylan and larger xylo-oligosaccharides, as xylopentaose.

Active processes, morphology, and dynamics of icy debris fans: Landform evolution along rapidly degrading escarpments in alpine regions undergoing recent deglaciation

In the past few decades the impacts of climate warming have been significant in alpine glaciated regions. Many valley glaciers formerly linked as distributary glaciers to high-level icecaps have decoupled at their icefalls, exposing major escarpments and generating a suite of dynamic landforrns dominated by mass wasting. Ice-dominated landforms, here termed icy debris fans, develop rapidly by ice avalanching, rockfall, and icy debris flow. Field-based reconnaissance studies at two alpine settings, the Wrangell Mountains of Alaska and the Southern Alps of New Zealand, provide a preliminary morphogenetic model of spatial and temporal evolution of icy debris fans in a range of alpine settings. The influence of these processes on landform evolution is largely unrecognized in the literature dealing with post-glacial landform adjustment known as the paraglacial. A better understanding of these dynamic processes will be increasingly important because of the extreme geohazards characterizing these areas. Our field studies show that after glacier decoupling, icy debris fans begin to form along the base of bedrock escarpments at the mouths of catchments and prograde over valley glaciers. The presence of a distinct catchment, apex, and fan morphology distinguishes these landforms from other landforms common in periglacial hillslope settings receiving abundant clastic debris and ice. Ice avalanching is the most abundant process involved in icy debris fan formation. Fans developed below weakly incised catchments are dominated by ice avalanching and are composed primarily of ice with minor lithic detritus. Typically, avalanches fall into the fan catchments where sediments transform into grainflows that flow onto the fans. Once on the fans, avalanche deposits ablate rapidly, flattening and concentrating lithic fragments at the surface. Icy debris fans may become thick enough to become glaciers with splay crevasse systems. Fans developed below larger, more complex catchments are composed of higher proportions of lithic detritus resulting from temporary storage of ice and lithic detritus deposits within the catchment. Episodic outbursts of meltwater from the icecap may mix with the stored sediments and mobilize icy debris flows (mixture of ice and lithic clasts) onto the fans. Our observations indicate that the entire evolutionary cycle of icy debris fans probably occurs during an early paraglacial interval (i.e., decades to 100 years). Observations comparing avalanche frequency, volume, and fan morphologic evolution at the Alaska site between 2006 and 2010 illustrate complex response between icy debris fans even within the same cirque - where one fan may be growing while others are downwasting because of differences in ice supply controlled by their respective catchments and icecap contributions. As ice supply from the icecap diminishes through time, icy debris fans rapidly downwaste and eventually evolve into talus cones that receive occasional but ephemeral ice avalanches.

Review of Complete Crime and Punishment Series

Some examples of topics covered include undocumented immigrants, guns, and terrorism within Crime and Criminal Behavior, vigilantes, Miranda warnings, and zero-tolerance policing within Police and Law Enforcement; insanity laws, DNA evidence, and victims' rights within Courts, Law, and Justice; gangs and prison violence, capital punishment, and prison privatization within Corrections; and school violence, violent juvenile offenders, and age of responsibility within Juvenile Crime and Justice. Note that Sage offers numerous reference works that provide focused analysis of key topics in the field of criminal justice, such as the Encyclopedia of Crime and Punishment (2002), the Encyclopedia of Race and Crime (2009), the Encyclopedia of Victimology and Crime Prevention (2010), the Encyclopedia of White Collar & Corporate Crime (2004), and the Encyclopedia of Interpersonal Violence (2008), available in print or as e-books via Sage Reference online.

"Security Here is Not Safe": Violence, Punishment, and Space in the Contemporary US Penitentiary

The US penitentiary at Lewisburg, Pennsylvania, was retrofitted in 2008 to offer the country's first federal Special Management Unit (SMU) program of its kind. This model SMU is designed for federal inmates from around the country identified as the most intractably troublesome, and features double-celling of inmates in tiny spaces, in 23-hour or 24-hour a day lockdown, requiring them to pass through a two-year program of readjustment. These spatial tactics, and the philosophy of punishment underlying them, contrast with the modern reform ideals upon which the prison was designed and built in 1932. The SMU represents the latest punitive phase in American penology, one that neither simply eliminates men as in the premodern spectacle, nor creates the docile, rehabilitated bodies of the modern panopticon; rather, it is a late-modern structure that produces only fear, terror, violence, and death. This SMU represents the latest of the late-modern prisons, similar to other supermax facilities in the US but offering its own unique system of punishment as well. While the prison exists within the system of American law and jurisprudence, it also manifests features of Agamben's lawless, camp-like space that emerges during a state of exception, exempt from outside scrutiny with inmate treatment typically beyond the scope of the law