182 research outputs found
Guidelines for Equivalent Instruction Through Home-Schooling
Guidelines for Equivalent Instruction Through Home-Schooling
Dr. Robert E. Boose, Commissioner, Department of Educational and Cultural Services, Augusta, Maine, September 13, 1984
Contents: Part I - Rules for Equivalent Instruction Programs / Part II - Guidelines for Implementation of Equivalent Instruction Programs by School Boardshttps://digitalcommons.usm.maine.edu/me_collection/1154/thumbnail.jp
Human or Natural Disturbance: Landscape-Scale Dynamics of the Tropical Forests of Puerto Rico
The Horizontal Ice Nucleation Chamber (HINC) : INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch
In this work we describe the Horizontal Ice Nucleation Chamber (HINC) as a new instrument to measure ambient ice-nucleating particle
(INP) concentrations for conditions relevant to mixed-phase
clouds. Laboratory verification and validation experiments confirm
the accuracy of the thermodynamic conditions of temperature (T)
and relative humidity (RH) in HINC with uncertainties in T
of ±0.4 K and in RH with respect to water
(RHw) of ±1.5 %, which translates
into an uncertainty in RH with respect to ice
(RHi) of ±3.0 % at T > 235 K. For further validation of HINC as a field
instrument, two measurement campaigns were conducted in winters 2015
and 2016 at the High Altitude Research Station Jungfraujoch (JFJ;
Switzerland, 3580 m a. s. l. ) to sample ambient INPs. During
winters 2015 and 2016 the site encountered free-tropospheric
conditions 92 and 79 % of the time, respectively. We measured
INP concentrations at 242 K at water-subsaturated conditions
(RHw = 94 %), relevant for the formation of
ice clouds, and in the water-supersaturated regime
(RHw = 104 %) to represent ice formation
occurring under mixed-phase cloud conditions. In winters 2015 and
2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At
RHw = 104 %, INP concentrations were an
order of magnitude higher, with median concentrations in winter 2015
of 2.8 per standard liter (std L−1; normalized to
standard T of 273 K and pressure, p, of
1013 hPa) and 4.7 std L−1 in winter 2016. The
measurements are in agreement with previous winter measurements
obtained with the Portable Ice Nucleation Chamber (PINC) of
2.2 std L−1 at the same location. During winter 2015,
two events caused the INP concentrations at RHw = 104 % to significantly increase above the campaign
average. First, an increase to 72.1 std L−1 was measured
during an event influenced by marine air, arriving at the JFJ from
the North Sea and the Norwegian Sea. The contribution from
anthropogenic or other sources can thereby not be ruled out. Second,
INP concentrations up to 146.2 std L−1 were observed
during a Saharan dust event. To our knowledge this is the first time
that a clear enrichment in ambient INP concentration in remote
regions of the atmosphere is observed during a time of marine air
mass influence, suggesting the importance of marine particles on ice
nucleation in the free troposphere
The Horizontal Ice Nucleation Chamber (HINC): INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch
Abstract. In this work we describe the Horizontal Ice Nucleation Chamber, HINC as a new instrument to measure ambient ice nucleating particle (INP) concentrations for conditions relevant to mixed-phase clouds. Laboratory verification and validation experiments confirm accuracy of the thermodynamic conditions of temperature (T) and relative humidity (RH) in HINC with uncertainties in temperature of ±0.4 K and in RH with respect to water (RHw) of ±1.5 %, which translates to an uncertainty in RH with respect to ice (RHi) of ±3.0 % at T > 235 K. For further validation of HINC as a field instrument, two measurement campaigns were conducted in winters 2015 and 2016 at the High Altitude Research Station Jungfraujoch (JFJ; Switzerland, 3580 m a.s.l.) to sample ambient INPs. During winters 2015 and 2016 the site encountered free tropospheric conditions 92 % and 79 % of the time respectively. We measured INP concentrations at 242 K at water sub-saturated conditions (RHw = 94 %), relevant for the formation of ice clouds, and in the water supersaturated regime (RHw = 103–104 %) to represent ice formation occurring under mixed-phase cloud conditions. In winter 2015 and 2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At RHw = 104 %, INP concentrations were an order of magnitude higher, with median concentrations in winter 2015 of 2.8 per standard liter (stdL−1; normalized to standard temperature T = 273 K and pressure p = 1013 hPa) and 4.7 stdL−1 in winter 2016. The measurements are in agreement with previous winter measurements obtained with the Portable Ice Nucleation Chamber, PINC, of 2.2 stdL−1 at the same location. During winter 2015, two events caused the INP concentrations at RHw = 103–104 % to significantly increase above the campaign average. First, an increase to 72.1 stdL−1 was measured during an event influenced by marine air, coming from the Northern Sea and the Norwegian Sea. Second, INP concentrations up to 146.2 stdL−1 were observed during a Saharan dust event. To our knowledge this is the first time that a clear enrichment in ambient INP concentration is observed during a time of marine air mass influence, indicating the importance of marine particles on ice nucleation in the free troposphere.
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Semiclassical cross section correlations
We calculate within a semiclassical approximation the autocorrelation
function of cross sections. The starting point is the semiclassical expression
for the diagonal matrix elements of an operator. For general operators with a
smooth classical limit the autocorrelation function of such matrix elements has
two contributions with relative weights determined by classical dynamics. We
show how the random matrix result can be obtained if the operator approaches a
projector onto a single initial state. The expressions are verified in
calculations for the kicked rotor.Comment: 6 pages, 2 figure
Modelling Hurricane Exposure and Wind Speed on a Mesoclimate Scale: A Case Study from Cusuco NP, Honduras
High energy weather events are often expected to play a substantial role in biotic community dynamics and large scale diversity patterns but their contribution is hard to prove. Currently, observations are limited to the documentation of accidental records after the passing of such events. A more comprehensive approach is synthesising weather events in a location over a long time period, ideally at a high spatial resolution and on a large geographic scale. We provide a detailed overview on how to generate hurricane exposure data at a meso-climate level for a specific region. As a case study we modelled landscape hurricane exposure in Cusuco National Park (CNP), Honduras with a resolution of 50 m×50 m patches. We calculated actual hurricane exposure vulnerability site scores (EVVS) through the combination of a wind pressure model, an exposure model that can incorporate simple wind dynamics within a 3-dimensional landscape and the integration of historical hurricanes data. The EVSS was calculated as a weighted function of sites exposure, hurricane frequency and maximum wind velocity. Eleven hurricanes were found to have affected CNP between 1995 and 2010. The highest EVSS's were predicted to be on South and South-East facing sites of the park. Ground validation demonstrated that the South-solution (i.e. the South wind inflow direction) explained most of the observed tree damage (90% of the observed tree damage in the field). Incorporating historical data to the model to calculate actual hurricane exposure values, instead of potential exposure values, increased the model fit by 50%
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