镇江圌山绍隆禅寺“活地”成因

"活地"是宗教的传奇,而由于以往知识与技术的限制以及宗教圣地的"不可侵犯性","活地"也成了大自然的千年未解之谜。通过现场考察和资料调研,明晰了"活地"所在地区的地质构造特征。采用高频率表面波监测、分析技术,通过现场试验,研究了"活地"附近地表浅层岩土体分布情况。采用图像分析技术,经室内试验研究得出了"活地"及周围地区出露岩石的矿物组成。最终,对于"活地"的成因提出以下看法:1.否定了地下深层生长性岩脉诱发"活地"现象的观点;2.膨胀岩及膨胀土吸水膨胀对"活地"的隆升有一定作用,但这不是"活地"的主要诱因;3.提出"活地"是岩石风化作用及特殊地理环境综合作用结果的观点:风化作用使岩体疏松、体积增大,地面隆起;两侧山体运动对其交界处岩石产生挤压作用,为"活地"的持续隆升提供动力源。     

Colorado’s Millennial Generation: Youth Perceptions and Experiences of Nature

Abstract

This study uses survey and focus group methods to explore attitudes toward and experiences of nature among millennial-aged students in northern Colorado. First, results confirm that young people possess a strong interest in the outdoors yet time, transportation, and new technologies hamper their ability to visit public lands and outdoor spaces. Second, respondents experience nature in ways more mediated by new technologies such as cell phones and nature DVDs. Third, citizen science and active learning show promise as techniques for returning young people to the outdoors. The challenge lies in teaching young people to reimagine the outdoors not as elsewhere or out there but as a backyard geographic space.     

Field Trips as Valuable Learning Experiences in Geography Courses

Abstract

Field trips have been acknowledged as valuable learning experiences in geography. This article uses Kolb’s (1984) experiential learning model to discuss how students learn and how field trips can help enhance learning. Using Kolb’s experiential learning theory as a guide in the design of field trips helps ensure that field trips contribute to internalizing relevant geographical theory and concepts. Three types of field trips are presented: an informal survey of a neighborhood, a more formal scavenger hunt, and a virtual field trip using Google Earth.

Learning is the process whereby knowledge is created through the transformation of experience.

—Kolb (1984)     

Lens on Climate Change: Making Climate Meaningful Through Student-Produced Videos

Learning about climate change is tangible when it addresses impacts that can be observed close to home. In this program, sixty-four diverse middle and high school students produced videos about locally relevant climate change topics. Graduate and undergraduate students provided mentorship. The program engaged students in research and learning about climate change, and sparked their interest in science careers. Evaluation results showed that students were highly motivated by the experience, developed a genuine interest in their science topic, learned about the scientific process, and developed twenty-first century skills. The program provided a unique and authentic approach to science learning and communication.     

Neutral hydrogen absorption observations of the central region of NGC 5929

We present 0.15-arcsec (25-pc) resolution MERLIN observations of neutral hydrogen absorption detected towards the nuclear region of the type 2 Seyfert galaxy NGC 5929. Absorption is detected only towards the north-eastern radio component with a column density of (6.5 ± 0.6) × 10²¹ cm⁻². Based on comparison with an HST WFPC2 continuum image, we propose that the absorption is caused by a 1.5-arcsec structure of neutral gas and dust offset 0.3 arcsec south-east of the nucleus and running NE–SW. A separate cloud of dust is apparent 1.5 arcsec to the south-west of the nucleus in the HST image. A comparison of the centroid velocity (2358 ± 5 km s⁻¹) and full width at half-maximum (43 ± 6 km s⁻¹) of the absorbing gas with previous [O  III ] observations suggests that both the neutral and ionized gas are undergoing galactic rotation towards the observer in the north-east and away from the observer in the south-west. The main structure is consistent with an inclined ring of gas and dust encircling the active galactic nucleus (AGN); alternatively it may be a bar or inner spiral arm. We do not detect neutral hydrogen absorption or dust obscuration against the radio nucleus (column density < 3.1 × 10²¹ cm⁻²) expected by a torus of neutral gas and dust in unified models of AGNs for a type 2 Seyfert galaxy.     

汶川地震区北西向断裂带遥感分析

利用北京一号小卫星遥感影像判读汶川地震区的断裂构造,发现了一系列100km左右等间距排列的北西向断裂,结果已部分地得到实地考察验证。龙门山断裂与北西向断裂的交汇部位发生强烈地震的几率较高。这些新发现将对汶川Ms8.0级地震发生机理、龙门山断裂带活动性分段、断裂同震位移自南西向北东、由右旋走滑逆断层向右旋走滑断层转变等重大问题提供了新的合理解释。     

Cloud radiative forcing in Asian monsoon region simulated by IPCC AR4 AMIP models

This study examines cloud radiative forcing (CRF) in the Asian monsoon region (0^o--50^oN,60^o--150^oE) simulated by Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) AMIP models. During boreal winter, no model realistically reproduces the larger long-wave cloud radiative forcing (LWCF) over the Tibet Plateau (TP) and only a couple of models reasonably capture the larger short-wave CRF (SWCF) to the east of the TP. During boreal summer, there are larger biases for central location and intensity of simulated CRF in active convective regions. The CRF biases are closely related to the rainfall biases in the models. Quantitative analysis further indicates that the correlation between simulated CRF and observations are not high, and that the biases and diversity in SWCF are larger than that in LWCF. The annual cycle of simulated CRF over East Asia (0^o--50^oN, 100^o--145^oE) is also examined. Though many models capture the basic annual cycle in tropics, strong LWCF and SWCF to the east of the TP beginning in early spring are underestimated by most models. As a whole, GFDL-CM2.1, MPI-ECHAM5, UKMO-HadGAM1, and MIROC3.2 (medres) perform well for CRF simulation in the Asian monsoon region, and the multi-model ensemble (MME) has improved results over the individual simulations. It is suggested that strengthening the physical parameterizations involved over the TP, and improving cumulus convection processes and model experiment design are crucial to CRF simulation in the Asian monsoon region.     

Rainfall yield characteristics of electrical storm observed in the Spanish Basque Country area during the period 1992–1996

This paper is focused on the study of rainfall yield characteristics of electrical storms observed over the Northern Iberian Peninsula during 1992–1996. To this aim Principal Components Analysis (PCA) and Self-Organizing Maps (SOM) method have been used. The SOM method is a group of artificial neural networks based on the topological properties of the human brain. Results clearly suggest that there exist three different meteorological patterns that are linked to the characteristics of electrical events found in the study area. In winter, most of the electrical events are formed under oceanic advection (NW air fluxes). On these cases, mean rainfall yield estimates reach values of 700 10⁴ m³ per cloud to ground lightning flash (CG flash). During summer most frequent electrical storms are associated to local instability shooting by surface heating with advection of humidity coming from the Iberian Peninsula. Under these meteorological situations, rain is scarcer if compared with oceanic events but lightning CG counts reach the maximum values found in the area (about 10 CG counts per 20 × 20 km² and day) giving this way the smallest rainfall yield with a mean value of 15 10⁴ m³ per CG flash. Iberian air fluxes associated with cold air in upper parts of the atmosphere represent the third meteorological pattern found. This pattern is most common in spring and autumn but is not unusual in the rest of the seasons. In those cases mean rainfall yield in the area is about 150 10⁴ m³ per CG flash. In all electrical episodes K instability index is greater than 15 °C but in the most lightning producing events, this index reaches in the area values greater than 24 °C. PCA results pointed out that there exists a relationship between rain and CG counts expressed by the first principal component computed from standardized data. However, we must notice that no event is solely linked to this axis, since a seasonal influence which decreases lightning production when rain increases is always present. Results found are of great interest for short term forecasting of flashfloods in mountainous areas like the Spanish Basque Country region.     

Halo masses for optically selected and for radio-loud AGN from clustering and galaxy–galaxy lensing

We compute two-point correlation functions and measure the shear signal due to galaxy–galaxy lensing for 80 000 optically identified and 5700 radio-loud active galactic nuclei (AGN) from Data Release 4 of the Sloan Digital Sky Survey. Halo occupation models are used to estimate halo masses and satellite fractions for these two types of AGN. The large sample size allows us to separate AGN according to the stellar mass of their host galaxies. We study how the halo masses of optical and radio AGN differ from those of the parent population at fixed   M _*  . Halo masses deduced from clustering and from lensing agree satisfactorily. Radio AGN are found in more massive haloes than optical AGN: in our samples, their mean halo masses are  1.6 × 10¹³  and  8 × 10¹¹  h ⁻¹ M_⊙  , respectively. Optical AGN follow the same relation between stellar mass and halo mass as galaxies selected without regard to nuclear properties, but radio-loud AGN deviate significantly from this relation. The dark matter haloes of radio-loud AGN are about twice as massive as those of control galaxies of the same stellar mass. This boost is independent of radio luminosity, and persists even when our analysis is restricted to field galaxies. The large-scale gaseous environment of the galaxy clearly plays a crucial role in producing observable radio emission. The dark matter halo masses that we derive for the AGN in our two samples are in good agreement with recent models in which feedback from radio AGN becomes dominant in haloes where gas cools quasi-statically.     

Non-thermal transient sources from rotating black holes

Rotating black holes can power the most extreme non-thermal transient sources. They have a long-duration viscous time-scale of spin-down, and produce non-thermal emissions along their spin-axis, powered by a relativistic capillary effect. We report on the discovery of exponential decay in Burst and Triensient Source Experiment (BATSE) light curves of long gamma-ray bursts (GRBs) by matched filtering, consistent with a viscous time-scale, and identify ultra-high energy cosmic rays (UHECRs) about the Greisen–Zatsepin–Kuzmin (GZK) threshold with linear acceleration of ion contaminants along the black hole spin-axis, consistent with black hole masses and lifetimes of Fanaroff–Riley type II (FR II) active galactic nuclei (AGN). We explain the absence of UHECRs from BL Lac objects due to UHECR emissions preferably at appreciable angles away from the black hole spin-axis. Black hole spin may be the key to unification of GRBs and their host environments, and to AGN and their host galaxies. Our model points to long-duration bursts in radio from long GRBs without supernovae and gravitational waves from all long GRBs.