On the Maximum Mass of Differentially Rotating Neutron Stars

The analysis of spectral lag between energy bands, which combines temporal and spectral analyses, can add strict constraints to gamma-ray burst (GRB) models. In previous studies, the lag analysis focused on the lags between channel 1 (25-57 keV) and channel 3 (115-320 keV) from the Burst and Transient Source Experiment (BATSE). In this Letter, we analyzed the cross-correlation average lags (including approximate uncertainties) between energy bands for two GRB samples: 19 events detected by Ginga and 109 events detected by BATSE. We paid special attention to the BATSE GRBs with known redshifts because there has been a reported connection between lag and luminosity. This extends our knowledge of spectral lags to lower energy ( approximately 2 keV). We found that lags between energy bands are small. The lag between the peak of approximately 50 keV photons and that of approximately 200 keV photons is approximately 0.08 s. The upper limit in the lag between approximately 9 and approximately 90 keV photons is approximately 0.5 s. Thus, there are not large shifts at low energy. We found that about 20% of GRBs have detectable lags between energy bands in the Ginga and BATSE samples. From the internal shock model, we found that there are three sources of time structure in GRB pulses: cooling, hydrodynamics, and angular effects. We argue that cooling is much too fast to account for our observed lags and that angular effects are independent of energy. Thus, only hydrodynamics can produce these lags. Perhaps the radiation process varies as the reverse shock moves through the shell.     

北美观测系统计划（NAOS）

北美观测系统计划（ＮＡＯＳ）是由加拿大、墨西哥及美国的政府组织和大学合作支持的计划,其目的是提出有关这些国家（及其相邻水域）的高空观测系统布局的建议,以满足今后几十年的社会需求。其要点是：①一种评估数值天气预报和局地预报服务中观测系统各种布局价值的科...     

Rapid increase in copper concentrations in a new marina, San Diego Bay

Concentrations of copper in water rose rapidly following the introduction of boats to a new marina in San Diego Bay. Two months after the marina reached half its capacity, a majority of water samples exceeded chronic and acute criteria for dissolved copper, and copper concentrations in several samples exceeded the highest concentrations observed in another marina that has been listed as an impaired water body. A box model suggested that a small fraction of the leached copper was sequestered in sediment. Copper concentrations in water entering the marina from the bay was more than half the chronic concentration limit, so only 50% of marina boat capacity could be accommodated without exceeding the chronic criterion more than 50% of the time. Copper concentrations in water may increase rapidly following boat introduction in small marinas, but could return to pre-introduction levels by controlling boat numbers or reducing use of copper-based paints.     

Development of a coral cDNA array to examine gene expression profiles in Montastraea faveolata exposed to environmental stress

The development of a cDNA array of coral genes and its application to investigate changes in coral gene expression associated with stressful conditions is described. The array includes both well-characterized and previously unidentified coral genes from Acropora cervicornis and Montastraea faveolata. Corals were exposed to either natural or anthropogenic stressors to elicit the expression of stress genes for isolation and incorporation onto the array. A total of 32 genes involved in protein synthesis, apoptosis, cell signaling, metabolism, cellular defense and inflammation were included on the array. Labeled cDNA from coral (Montastraea faveolata) exposed to elevated seawater temperature, salinity and ultraviolet light was tested against the microarray to determine patterns of gene expression associated with each stressor. Carbonic anhydrase, thioredoxin, a urokinase plasminogen activator receptor (uPAR) and three ribosomal genes demonstrated differential expression across all replicates on the array and between replicate colonies. Specific gene expression patterns produced in response to different stressors demonstrate the potential for gene expression profiling in characterizing the coral stress response.     

“竺可桢精神与西部大开发”座谈会在兰举行

今年恰逢我国一代宗师 ,杰出的气象学家、地理学家和教育家竺可桢先生诞辰 1 1 0周年 ,由中国地理学会冰川冻土分会和沙漠分会、甘肃省气象学会及甘肃省地理学会联合主办 ,“竺可桢精神与西部大开发”座谈会于 4月 1 7日下午在中科院寒区旱区环境与工程研究所冻土工程国家重点实验室学术厅举行 ,会议由施雅风院士主持。与会代表来自兰州分院 ,兰州大学及省气象局等 ,与会者既有年过半百的专家学者 ,也有年轻的师生 ,共一百余人。会上首先放映了有关竺可桢先生的文献记录片 ,然后施雅风院士介绍了竺老如何为国办学 ,如何呕心力血地为规划新中…     

Hypoxia in Manila Bay, Philippines during the northeast monsoon

Herein we present results from one of the first extensive bay-wide oceanographic surveys of Manila Bay, wherein 31 stations were sampled during the northeast monsoon (cold and dry season). A band of hypoxic bottom water (dissolved oxygen<2.8 mg/L) spanned the midsection of the bay from east to west. Bottom nitrate concentrations (5.7-16.8 μM; avg. 11.1 μM) and total organic carbon values in sediments (1.7-3.1%; avg. 2.4%) were high in the midsection, which coincided with the band of hypoxic bottom water. Physical processes and site-specific accumulation of organic material likely lead to hypoxic conditions in Manila Bay, even during the northeast monsoon period when the water column is relatively well mixed. The results of this study complement the previously reported widespread hypoxia that occurs during the rainy season. Thus, hypoxia may be pervasive in the bay throughout the year, although it varies in intensity and spatial extent.