University of Massachusetts Boston

About: University of Massachusetts Boston is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Health care. The organization has 6541 authors who have published 12918 publications receiving 411731 citations. The organization is also known as: UMass Boston.

Surface currents in the Bransfield and Gerlache Straits, Antarctica

Abstract: We used 39 tracks of mixed layer drifters deployed during the period from November 1988 to January 1990 to study the surface flow characteristics in the Bransfield and Gerlache Straits, Antarctica. The results revealed both the Gerlache Strait Current and the Bransfield Strait Current, which flows along the deep channel of the Gerlache Strait, northeastward to the southern continental margin of the South Shetland Islands following the 750 m isobath. The observed strongest sustained daily mean current reached approximately 40 cm s � 1 in the Bransfield Strait and was confined to the shelf break south of the South Shetland Islands. The computed acceleration of drifters in the Bransfield Strait Current indicates the southward transversal component limits drifters from approaching isobaths shallower than 750 m. The southern side of the Current is rich in cyclonic eddies. Drifters spun off and circulated in cyclonic eddies over deep basins. The residence time of a water parcel in the current is approximately 10–20 days. Anticyclonic circulations were observed around Tower, Hoseason and Liege Islands, and long residence times were found for drifters in shallows and bays of up to 70 days. Results also indicate the Gerlache Strait water can extend along the shelf of the Antarctic peninsula to Tower Island, where it meets the southewestward Weddell Sea water. Most of the Gerlache Strait water exits northward and enters the Bransfield Strait Current. It Spins off and mixes with other waters in the Bransfield Strait. Several long tracks indicated the existence of a cyclonic large circulation gyre in the Bransfield Strait during the ice-free condition. The circulation patterns in both Bransfield and Gerlache Straits change seasonally. The analysis of force balance indicates that currents and eddies are geostrophic though the ageostrophic components are important to maintain currents and form eddies. This composition of eddies and currents provides ideal physical settings for zooplankton growth in eddies and bays and zooplankton dispersion in currents. r 2002 Elsevier Science Ltd. All rights reserved.

Optimizing the properties of the protein corona surrounding nanoparticles for tuning payload release.

Abstract: We manipulate the passive release rates of DNA payloads on protein coronas formed around nanoparticles (NPs) by varying the corona composition. The coronas are prepared using a mixture of hard and soft corona proteins. We form coronas around gold nanorods (NRs), nanobones (NBs), and carbon nanotubes (CNTs) from human serum (HS) and find that tuning the amount of human serum albumin (HSA) in the NR-coronas (NR-HS-DNA) changes the payload release profile. The effect of buffer strength, HS concentration, and concentration of the cetyltrimethylammonium bromide (CTAB) passivating the NP surfaces on passive release is explored. We find that corona properties play an important role in passive release, and concentrations of CTAB, HS, and phosphate buffer used in corona formation can tune payload release profiles. These advances in understanding protein corona properties bring us closer toward developing a set of basic design rules that enable their manipulation and optimization for particular biological applications.

Chemical composition and cycling of dissolved organic matter in the Mid-Atlantic Bight

Abstract: This study focuses on the chemical characterization of high molecular-weight dissolved organic matter (HMW DOM) isolated from the Middle Atlantic Bight in April 1994 and March 1996. Using proton nuclear magnetic resonance spectroscopy (1HNMR) and monosaccharide analysis we compared both spatial and temporal variations in the chemical structure of HMW DOM across this region. Our analyses support the presence of at least two compositionally distinct components to HMW DOM. The major component is acyl polysaccharide (APS), a biopolymer rich in carbohydrates, acetate and lipid, accounting for between 50% and 80% of the total high molecular-weight dissolved organic carbon (HMW DOC) in surface samples. APS is most abundant in fully marine, surface-water samples, and is a product of autochthonous production. Organic matter with spectral properties characteristic of humic substances is the second major component of HMW DOM. Humic substances are most abundant (up to 49% of the total carbon) in samples collected from estuaries, near the coast, and in deep water, suggesting both marine and perhaps terrestrial sources. Radiocarbon analyses of neutral monosaccharides released by the hydrolysis of APS have similar and modern (average 71‰) Δ14C values. Radiocarbon data support our suggestion that these sugars occur as part of a common macromolecule, with an origin via recent biosynthesis. Preliminary radiocarbon data for total neutral monosaccharides isolated from APS at 300 and 750 m show this fraction to be substantially enriched relative to total HMW DOC and DOC. The relatively enriched radiocarbon values of APS at depth suggest APS is rapidly transported into the deep ocean.

Identifying Conservation-Priority Areas in the Tropics: a Land-Use Change Modeling Approach

Abstract: Most quantitative methods for identifying conservation-priority areas require more detailed knowledge about the extent and distribution of biodiversity than is currently available. Accelerated and irreversible losses of biodiversity call for the development of alternative methods to identify priority sites for biodiversity inventory and protection. We focused on the state of Arunachal Pradesh, a biodiversity-rich region in northeast India. We used a geographic information system and spatially explicit modeling to examine the correlation of land-cover and land-use patterns with biogeophysical characteristics and to project future patterns of land-use change. In 1988, 70% of Arunachal Pradesh was covered by forest. We project that 50% of the state's 1988 forest will be lost by 2021, based on anticipated growth of the human population and resulting resource use. Of the total simulated deforestation, 76% occurs in areas that have no legal state protection. We developed a map of threats to biodiversity that divides areas that were forested in 1988 into four categories: (1) susceptible to future deforestation and currently unprotected; (2) susceptible to future deforestation but currently within the protected-area network; (3) not susceptible to future deforestation and protected; and (4) neither susceptible to future deforestation nor currently protected. We make the following recommendations based on our analyses. Areas in category 1 should be a high priority for biodiversity inventory and conservation action. Areas in category 2 should have rigid enforcement of protection. Areas in category 3 are locations of relatively low priority for enforcement. Areas in category 4 that have a high conservation potential are politically the easiest to include in the protected-area network and should be protected before they become targets of future land-use change. Reserve forests—forests managed by the state forest department for a variety of purposes, including selective logging for timber harvesting—are predominantly located in areas susceptible to land-use change and are prime candidates for upgrading of protection status. Resumen: La mayoria de los metodos cuantitativos para identificar areas prioritarias de conservacion requieren de conocimiento mas detallado que el que actualmente se tiene acerca de la magnitud y distribucion de la biodiversidad. La perdida acelerada e irreversible de biodiversidad exige el desarrollo de metodos alternativos para identificar sitios prioritarios para inventariar y proteger la biodiversidad. Enfocamos el estado de Arunachal Pradesh, una region rica en biodiversidad del noreste de India. Utilizamos SIG y modelos espacialmente explicitos para examinar la correlacion de superficie y patrones de uso del suelo con caracteristicas biogeofisicas y para proyectar patrones futuros de cambio en el uso del suelo. En 1988, el 70% de Arunachal Pradesh estaba cubierto por bosques. Proyectamos que 50% de los bosques de 1988 se perdera para 2021 con base en el crecimiento esperado de la poblacion humana y la resultante utilizacion de recursos. Del total de deforestacion simulada, 76% ocurre en areas que no tienen ninguna proteccion legal. Elaboramos un mapa de amenazas a la biodiversidad que divide en cuatro categorias a las areas boscosas en 1988: 1) susceptible a deforestacion en el futuro y no protegida actualmente; 2) susceptible a deforestacion en el futuro pero actualmente en la red de areas protegidas; 3) no susceptible a deforestacion en el futuro y protegida y 4) ni susceptible a deforestacion en el futuro ni protegida actualmente. Hacemos las siguientes recomendaciones basadas en nuestros analisis. Las areas en la categoria 1 deben tener una prioridad alta para inventarios y acciones de conservacion. En las areas de la categoria 2 la proteccion debe ser de observancia forzosa. Las areas en la categoria 3 son de baja prioridad relativa para la observancia forzosa. Las areas en la categoria 4, que tienen un alto potencial de conservacion, son politicamente las mas faciles de incluir en la red de areas protegidas, lo cual debe hacerse antes de que se conviertan en blanco de cambios futuros en el uso del suelo. Las reservas de bosque (manejadas por el departamento forestal del estado para diversos propositos, incluyendo la tala selectiva para madera) se localizan predominantemente en areas susceptibles a cambios en el uso del suelo y son candidatas selectas para elevar su estatus de proteccion.