340 research outputs found
A case of epigastric heteropagus twinning with other congenital abnormalities in a Chihuahua puppy
A two-year-old Chihuahua was presented on day 58 of pregnancy due to very marked abdominal distension. A cesarean section was performed and five normal and one clearly abnormal puppy were delivered. Examination of the abnormal puppy revealed a combination of congenital anomalies including epigastric heteropagus twinning. The autosite showed focal cranial aplasia cutis, anasarca, lissencephaly, palatoschisis, sternal agenesis and eventeratio (gastroschisis/schistocoelia). The partly formed parasitic twin was attached at the sternal region of the autosite and demonstrated four formed limbs, atresia rectum, atresia ani, a single kidney, tail agenesis and atresia vulvae. To the authors' knowledge, this is only the third reported case of heteropagus conjoined twinning in the dog and the first reported case of canine epigastric heteropagus twinning. In addition, there appear to be no reports in the veterinary literature noting an association with conjoined twinning in the dog with focal cranial aplasia cutis, eventeratio, lissencephaly, palatoschisis and anasarca. An in-depth literature review was hampered by the lack of a uniform nomenclature to identify this type of conjoined twinning
Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)
The Torngat Mountains National Park, northern Labrador, Canada, contains more
than 120 small glaciers: the only remaining glaciers in continental northeast
North America. These small cirque glaciers exist in a unique topo-climatic
setting, experiencing temperate maritime summer conditions yet very cold and
dry winters, and may provide insights into the deglaciation dynamics of
similar small glaciers in temperate mountain settings. Due to their size and
remote location, very little information exists regarding the health of these
glaciers. Just a single study has been published on the contemporary
glaciology of the Torngat Mountains, focusing on net mass balances from 1981
to 1984. This paper addresses the extent to which glaciologically relevant
climate variables have changed in northern Labrador in concert with
20th-century Arctic warming, and how these changes have affected Torngat Mountain
glaciers. Field surveys and remote-sensing analyses were used to measure
regional glacier area loss of 27 % from 1950 to 2005, substantial rates of
ice surface thinning (up to 6 m yr<sup>−1</sup>) and volume losses at Abraham,
Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances
appear to be controlled by variations in winter precipitation and,
increasingly, by strong summer and autumn atmospheric warming since the
early 1990s, though further observations are required to fully understand
mass balance sensitivities. This study provides the first comprehensive
contemporary assessment of Labrador glaciers and will inform both regional
impact assessments and syntheses of global glacier mass balance
Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)
The Torngat Mountains National Park, northern Labrador, Canada, contains more
than 120 small glaciers: the only remaining glaciers in continental northeast
North America. These small cirque glaciers exist in a unique topo-climatic
setting, experiencing temperate maritime summer conditions yet very cold and
dry winters, and may provide insights into the deglaciation dynamics of
similar small glaciers in temperate mountain settings. Due to their size and
remote location, very little information exists regarding the health of these
glaciers. Just a single study has been published on the contemporary
glaciology of the Torngat Mountains, focusing on net mass balances from 1981
to 1984. This paper addresses the extent to which glaciologically relevant
climate variables have changed in northern Labrador in concert with
20th-century Arctic warming, and how these changes have affected Torngat Mountain
glaciers. Field surveys and remote-sensing analyses were used to measure
regional glacier area loss of 27 % from 1950 to 2005, substantial rates of
ice surface thinning (up to 6 m yr−1) and volume losses at Abraham,
Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances
appear to be controlled by variations in winter precipitation and,
increasingly, by strong summer and autumn atmospheric warming since the
early 1990s, though further observations are required to fully understand
mass balance sensitivities. This study provides the first comprehensive
contemporary assessment of Labrador glaciers and will inform both regional
impact assessments and syntheses of global glacier mass balance
Future evolution and uncertainty of river flow regime change in a deglaciating river basin
The flow regimes of glacier-fed rivers are sensitive to climate change due to
strong climate–cryosphere–hydrosphere interactions. Previous modelling
studies have projected changes in annual and seasonal flow magnitude but
neglect other changes in river flow regime that also have socio-economic and
environmental impacts. This study employs a signature-based analysis of
climate change impacts on the river flow regime for the deglaciating Virkisá
river basin in southern Iceland. Twenty-five metrics (signatures) are derived from 21st century projections of river flow time series to evaluate changes in
different characteristics (magnitude, timing and variability) of river flow
regime over sub-daily to decadal timescales. The projections are produced by
a model chain that links numerical models of climate and glacio-hydrology.
Five components of the model chain are perturbed to represent their
uncertainty including the emission scenario, numerical climate model,
downscaling procedure, snow/ice melt model and runoff-routing model. The
results show that the magnitude, timing and variability of glacier-fed river
flows over a range of timescales will change in response to climate change.
For most signatures there is high confidence in the direction of change, but
the magnitude is uncertain. A decomposition of the projection uncertainties
using analysis of variance (ANOVA) shows that all five perturbed model chain
components contribute to projection uncertainty, but their relative
contributions vary across the signatures of river flow. For example, the
numerical climate model is the dominant source of uncertainty for projections
of high-magnitude, quick-release flows, while the runoff-routing model is
most important for signatures related to low-magnitude, slow-release flows.
The emission scenario dominates mean monthly flow projection uncertainty, but
during the transition from the cold to melt season (April and May) the
snow/ice melt model contributes up to 23 % of projection uncertainty.
Signature-based decompositions of projection uncertainty can be used to
better design impact studies to provide more robust projections.</p
Trends in Antarctic Peninsula surface melting conditions from observations and regional climate modeling
Multidecadal meteorological station records and microwave backscatter time-series from the SeaWinds scatterometer onboard QuikSCAT (QSCAT) were used to calculate temporal and spatial trends in surface melting conditions on the Antarctic Peninsula (AP). Four of six long-term station records showed strongly positive and statistically significant trends in duration of melting conditions, including a 95% increase in the average annual positive degree day sum (PDD) at Faraday/Vernadsky, since 1948. A validated, threshold-based melt detection method was employed to derive detailed melt season onset, extent, and duration climatologies on the AP from enhanced resolution QSCAT data during 1999–2009. Austral summer melt on the AP was linked to regional- and synoptic-scale atmospheric variability by respectively correlating melt season onset and extent with November near-surface air temperatures and the October–January averaged index of the Southern Hemisphere Annular Mode (SAM). The spatial pattern, magnitude, and interannual variability of AP melt from observations was closely reproduced by simulations of the regional model RACMO2. Local discrepancies between observations and model simulations were likely a result of the QSCAT response to, and RACMO2 treatment of, ponded surface water, and the relatively crude representation of coastal climate in the 27 km RACMO2 grid
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Technology Enhanced Learning in UK higher education - 2022 pulse survey
This 2022 Technology Enhanced Learning (TEL) Survey was developed as a short ‘pulse survey’ to focus on key areas that might have been impacted by the COVID-19 pandemic and the rapid shift to online learning. The survey retained and adapted 16 questions from the 2020 Survey to enable longitudinal analysis to be undertaken with previous TEL surveys. The Survey provides an invaluable insight of provision within institutions and the emerging patterns of learning technology usage across the UK HE sector. The 2022 findings report an increased provision of centrally supported TEL tools, an increase in outsourcing of TEL provision and an increase in TEL staffing. The findings also show that the sector is undergoing a continuous review cycle for TEL services, note a small growth in fully online delivery and the limited impact of new forms of delivery such as hybrid or HyFlex learning
Changing distributions of sea ice melt and meteoric water west of the Antarctic Peninsula
The Western Antarctic Peninsula has recently undergone rapid climatic warming, with associated decreases in sea ice extent and duration, and increases in precipitation and glacial discharge to the ocean. These shifts in the freshwater budget can have significant consequences on the functioning of the regional ecosystem, feedbacks on regional climate, and sea-level rise. Here we use shelf-wide oxygen isotope data from cruises in four consecutive Januaries (2011–2014) to distinguish the freshwater input from sea ice melt separately from that due to meteoric sources (precipitation plus glacial discharge). Sea ice melt distributions varied from minima in 2011 of around 0 % up to maxima in 2014 of around 4–5%. Meteoric water contribution to the marine environment is typically elevated inshore, due to local glacial discharge and orographic effects on precipitation, but this enhanced contribution was largely absent in January 2013 due to anomalously low precipitation in the last quarter of 2012. Both sea ice melt and meteoric water changes are seen to be strongly influenced by changes in regional wind forcing associated with the Southern Annular Mode and the El Niño–Southern Oscillation phenomenon, which also impact on net sea ice motion as inferred from the isotope data. A near-coastal time series of isotope data collected from Rothera Research Station reproduces well the temporal pattern of changes in sea ice melt, but less well the meteoric water changes, due to local glacial inputs and precipitation effects
Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula
The northern Antarctic Peninsula is currently undergoing rapid atmospheric warming. Increased glacier-surface melt during the twentieth century has contributed to ice-shelf collapse and the widespread acceleration, thinning and recession of glaciers. Therefore, glaciers peripheral to the Antarctic Ice Sheet currently make a large contribution to eustatic sea-level rise, but future melting may be offset by increased precipitation. Here we assess glacier-climate relationships both during the past and into the future, using ice-core and geological data and glacier and climate numerical model simulations. Focusing on Glacier IJR45 on James Ross Island, northeast Antarctic Peninsula, our modelling experiments show that this representative glacier is most sensitive to temperature change, not precipitation change. We determine that its most recent expansion occurred during the late Holocene a Little Ice Age' and not during the warmer mid-Holocene, as previously proposed. Simulations using a range of future Intergovernmental Panel on Climate Change climate scenarios indicate that future increases in precipitation are unlikely to offset atmospheric-warming-induced melt of peripheral Antarctic Peninsula glaciers
Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula
The northern Antarctic Peninsula is currently undergoing rapid atmospheric warming1. Increased glacier-surface melt during the twentieth century2, 3 has contributed to ice-shelf collapse and the widespread acceleration4, thinning and recession5 of glaciers. Therefore, glaciers peripheral to the Antarctic Ice Sheet currently make a large contribution to eustatic sea-level rise6, 7, but future melting may be offset by increased precipitation8. Here we assess glacier–climate relationships both during the past and into the future, using ice-core and geological data and glacier and climate numerical model simulations. Focusing on Glacier IJR45 on James Ross Island, northeast Antarctic Peninsula, our modelling experiments show that this representative glacier is most sensitive to temperature change, not precipitation change. We determine that its most recent expansion occurred during the late Holocene ‘Little Ice Age’ and not during the warmer mid-Holocene, as previously proposed9. Simulations using a range of future Intergovernmental Panel on Climate Change climate scenarios indicate that future increases in precipitation are unlikely to offset atmospheric-warming-induced melt of peripheral Antarctic Peninsula glaciers
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