水文过程的基流分割方法研究进展

基流分割研究是水文学、生态水文学研究的重点和难点之一,一直以来在其概念与方法上都缺乏统一的标准.本文详细介绍了基于不同基流组成定义的基流分割理论,并分析了各基流分割方法的发展历程.对不同分割方法进行对比发现：直接分割法简单、适用,却有任意性;水量平衡法实施起来困难,但符合水文规律;时间序列分析法和同位素法能克服手工图解分割方法的主观性和随意性,可以快速有效地得到连续基流过程.近年来,水文模拟、数字滤波、同位素法成为基流分割的主要方法.     

The terminology and use of species–area relationships: a response to Dengler (2009)

Dengler ( Journal of Biogeography , 2009, 36 , 728–744) addresses issues regarding species–area relationships (SARs), but fails to settles those issues. He states that only certain types of sampling schemes should be used to construct SARs, but is not consistent in the criteria that he uses to include some sampling schemes but not others. He argues that a sampling scheme of contiguous plots will be more accurate in extrapolating beyond the sampled area, but logic tells us that a dispersed sampling scheme is likely to be more accurate. Finally, he concludes that the 'true' SAR is a power function, but this conclusion is inconsistent with his results and with the results of others. Rather than defining a narrow framework for SARs, we need to recognize that the relationship between area and species richness is scale- and system-dependent. Different sampling schemes serve different purposes, and a variety of functional relationships are likely to hold. Further theoretical and empirical work is needed to resolve these issues fully.     

Rec2 interplay with both Brh2 and Rad51 balances recombinational repair in Ustilago maydis

Rec2 is the single Rad51 paralog in Ustilago maydis. Here, we find that Rec2 is required for radiation-induced Rad51 nuclear focus formation but that Rec2 foci form independently of Rad51 and Brh2. Brh2 foci also form in the absence of Rad51 and Rec2. By coprecipitation from cleared extracts prepared from Escherichia coli cells expressing the proteins, we found that Rec2 interacts physically not only with Rad51 and itself but also with Brh2. Transgenic expression of Brh2 in rec2 mutants can effectively restore radiation resistance, but the frequencies of spontaneous Rad51 focus formation and allelic recombination are elevated. The Dss1-independent Brh2-RPA70 fusion protein is also active in restoring radiation sensitivity of rec2 but is hyperactive to an extreme degree in allelic recombination and in suppressing the meiotic block of rec2. However, the high frequency of chromosome missegregation in meiotic products is an indicator of a corrupted process. The results demonstrate that the importance of Rec2 function is not only in stimulating recombination activity but also in ensuring that recombination is properly controlled.     

Anonymat et compensation financière du don de gamètes et d’embryons en Belgique

Belgian law concerning medically assisted procreation (MAP) and use of gametes and supernumerary embryos was adopted in 2007 and entered into force at the end of July 2007. It has only a limited impact on routine clinical practice, but dramatically limits the number of pregnancies that can be achieved by gamete donation. In Belgium, sperm donation is theoretically anonymous, but anonymity is not mandatory: when the donor and recipient attend the clinic together, request direct donation and sign an agreement, this procedure is acceptable. Sperm donation is free but it is permitted to provide reasonable compensation to the donor for any expenses and loss of income. Ooocyte donation is also free and theoretically anonymous, but directed (non-anonymous) donation is not prohibited when all parties sign an agreement. In this case, the donor and recipient attend the clinic together. It is also permitted to provide compensation to the donor, but no agreement has been reached concerning the acceptable amount. By taking into account the need for treatment, it would be reasonable to provide for 10 to 15 days off work and therefore an equivalent loss of income that could be compensated by 500 to 1000 euros, travel expenses, or even accommodation close to the MAP clinic during this period, which could also represent 500 to 1000 euros. Justified compensation would therefore represent 1000 or even 2000 euros. This amount appeared to be excessive up until now, but opinions tend to change. It is nevertheless true that spontaneous volunteer donors for free and anonymous oocyte donation are rare. Some centres perform donor randomisation to ensure anonymity. Embryo donation is anonymous. Embryos cannot be sold, but the MAP clinic must ensure the health security of these embryos and their management after the 5-year legal storage period, which also has a certain cost.     

The Intelligent Egg, and How It Got That Way: from Genes to Genius in a Few Easy Lessons

A seed has no flowers or leaves, and an egg no fingers or lungs. Yet plants and animals not only have these things but they resemble their parents in detail throughout their bodies. Something is inherited, but what is it? Life is based on the activities of cells. An organism has large numbers of them—a human has trillions! Cells live as separate units, which enables them each to do its own thing within its particular organ, but to be an organism they must work together. A cell can only detect its immediate local environment, but that includes various kinds of signals or information from nearby or far away within the body—or even from the external environment. It is by being local but responding globally in this way that an egg becomes an organism, an organism manages its way through life, and organisms make up species and ecosystems that interact with each other. The evolution of these abilities has produced the glorious array of living forms that populate the world. In these ways, an egg may have no thoughts but is a highly intelligent being.     

Effects of diamide and iodoacetamide on the expression of the glycoprotein IIb/IIIa complex on blood platelets

We have examined the effects of two agents that alter platelet thiol-disulphide status on platelet aggregation and on the ability of platelets to bind a monoclonal antibody (M148) that is directed toward an epitope on the glycoprotein IIb/IIIa complex. The immediate effect of both diamide and iodoacetamide is to enhance aggregation but after further incubation diamide, but not iodoacetamide, inhibits platelet aggregation. Incubation of platelets with diamide, but not iodoacetamide, is accompanied by a marked increase in the amount of M148 that binds to platelets. This is presumably a reflection of an altered distribution of glycoproteins on the platelet surface. It is known that diamide, but not iodoacetamide, leads to polymerisation of cytoskeletal proteins in platelets. Thus evidence is provided that agents that interact with the cytoskeleton inhibit platelet behaviour via an effect on surface glycoproteins.     

Cutting edge: antilisterial activity of CD8+ T cells derived from TNF-deficient and TNF/perforin double-deficient mice

The mechanisms by which CD8+ T cells mediate immunity against bacterial pathogens remain largely unknown. Perforin-dependent cytolysis plays a role, but is not required for CD8+ T cell-mediated immunity against Listeria monocytogenes. TNF is essential for CD8+ T cell immunity to L. monocytogenes, but the cellular source of TNF is undefined. TNF-deficient and TNF/perforin double-deficient mice were used to generate CD8+ T cells specific for an L. monocytogenes-derived Ag. Wild-type and TNF-deficient CD8+ T cells mediated antilisterial immunity in wild-type but not TNF-deficient host mice, revealing that CD8+ T cell-derived TNF is not required for CD8+ T cell-mediated antilisterial immunity, but demonstrating a role for TNF derived from other cell types. TNF/perforin double-deficient CD8+ T cells mediated antilisterial immunity in the liver, but not in the spleen, of wild-type recipient mice, suggesting that perforin-independent immunity in the spleen requires CD8+ T cell-derived TNF.     

论首都农村卫生室乡村医生的前世???? ? ——以政策与法律变迁为研究主线

赤脚医生始于1965年终于1985年，是中国医疗卫生历史上一个特殊的职业群体。综观这一时期，赤脚医生的身份在本质上仍是农民，其选拔的条件尽管不够严苛但却比较综合，其所接受的培训尽管不够系统但却务实多样，与其匹配的待遇尽管不够优厚但却足以优越，其所提供的服务尽管水平有限但却受益广泛。可以说，赤脚医生为解决建国初期缺医少药这一重大现实问题作出了卓越贡献。     

ROENTGEN THERAPY OF INTRATHORACIC NEOPLASMS

The results of treatment of carcinoma of the esophagus, whether by operation or radiation, are equally poor: At best 3 to 5 per cent 5-year survival in larger series. Likewise, the palliative results as judged from short-term survival after 1, 2, and 3 years are approximately the same. The cause of failure is usually that metastatic deposits are already present in the paraesophageal and mediastinal nodes by the time diagnosis is made. Control of these nodes is impossible either by surgical or by radiation therapy, but in about half of the patients adequate irradiation therapy will be palliative and will satisfactorily re-establish esophageal function, but entail less morbidity than surgical operation.Carcinoma of the lung yields little to radiotherapy. Cure is rare, but specific aims of palliation may be achieved. Anaplastic tumors can be controlled locally by irradiation, but they metastasize so rapidly that the chief aim of radiotherapy is to relieve pulmonary embarrassment due to rapid enlargement of mediastinal lymph nodes. Epidermoid carcinomas and adenocarcinomas may be treated at points of bronchial obstruction by intense irradiation, but diffuse thoracic pain is better palliated by sympathetic nerve block.     

Inflammatory peptides derived from adipose tissue

The low-grade inflammation seen with aging is noted particularly in subjects with the metabolic syndrome of aging. Insulin resistance, obesity/abdominal obesity, and risks for many age-related diseases characterize this common syndrome. It is becoming clear that this increased adipose tissue is not simply a reservoir for excess nutrients, but rather an active and dynamic organ capable of expressing several cytokines and other fat-derived peptides (FDP). Some, but not all, FDP may have a role in development of the metabolic syndrome but there is no evidence that these FDP are causing inflammation directly. We suggest that high levels of inflammatory peptides are markers for obesity/abdominal obesity seen with aging, but some may not necessarily have a causative role in the development of inflammation.     

Studies on the interaction between Cd(2+) ions and nucleobases and nucleotides

Cadmium is a potent carcinogen in rodents and has recently been accepted by the International Agency for Research on Cancer as a category 1 (human) carcinogen, but the molecular mechanism of its action remains largely unclear. It has however been suggested that cadmium-induced carcinogenesis may involve either direct or indirect interaction of Cd²⁺ with DNA. In this study it is found that when Cd²⁺ is allowed to interact with adenine and guanine, there is a marked change in the high performance liquid chromatography (HPLC) retention time for adenine but not for guanine. Since Cd²⁺ is believed to bind covalently to adenine and guanine, the changes in retention time but absence of any cadmium in the peak fraction point to the following: (i) lability of cadmium-nucleobase adducts, and (ii) introduction of some kind of chemical modification in adenine but not in guanine as a result of covalent binding. This result is different from that for Ni²⁺ in which case a change in retention time was observed for guanine but not for adenine.     

Plasmid-associated bacteriocin production by a strain of Carnobacterium piscicola from meat.

Carnobacterium piscicola LV17 isolated from vacuum-packed meat produces bacteriocin(s) that is active against closely related lactic acid bacteria, Enterococcus spp., and a strain of Listeria monocytogenes but not against gram-negative bacteria. The bacteriocin has a bactericidal mode of action, is heat resistant, and is stable over a wide range of pH but is inactivated by proteolytic enzymes. Sensitive and resistant cells were shown to adsorb the bacteriocin, but cell death depended on contact of the bacteriocin with the cell membrane. Bacteriocin production is detected early in the growth cycle of the organism in APT broth, but it is not produced in APT broth adjusted to pH 5.5. Bacteriocin production and resistance to the bacteriocin produced are associated with two plasmids of 40 and 49 megadaltons. The possibility that two bacteriocins are produced is indicated because the inhibitory substances of the mutant strains containing either the 40- or 49-megadalton plasmids have different antimicrobial spectra.     

Plasmid-associated bacteriocin production by a strain of Carnobacterium piscicola from meat

Carnobacterium piscicola LV17 isolated from vacuum-packed meat produces bacteriocin(s) that is active against closely related lactic acid bacteria, Enterococcus spp., and a strain of Listeria monocytogenes but not against gram-negative bacteria. The bacteriocin has a bactericidal mode of action, is heat resistant, and is stable over a wide range of pH but is inactivated by proteolytic enzymes. Sensitive and resistant cells were shown to adsorb the bacteriocin, but cell death depended on contact of the bacteriocin with the cell membrane. Bacteriocin production is detected early in the growth cycle of the organism in APT broth, but it is not produced in APT broth adjusted to pH 5.5. Bacteriocin production and resistance to the bacteriocin produced are associated with two plasmids of 40 and 49 megadaltons. The possibility that two bacteriocins are produced is indicated because the inhibitory substances of the mutant strains containing either the 40- or 49-megadalton plasmids have different antimicrobial spectra.     

An intracellular pathway is required for ABA-tyrosine presentation to T cells

Although tyrosine-azobenzenearsonate (ABA-Tyr) is not degraded by proteolytic enzymes, its presentation by accessory cells is inhibited by lysosomotropic agents such as chloroquine. Presentation of ABA-poly-L-glutamic, alanine, tyrosine (ABA-GAT) is similarly inhibited by chloroquine, but in contrast to ABA-Tyr it is also inhibited by leupeptin. Finally formaldehyde fixation of accessory cells after pulsing with ABA-Tyr but not before permits successful stimulation of ABA-specific hybridoma cells. These results suggest that a lysosomal pathway but not digestion is necessary for the association of ABA-Tyr and la molecules for presentation.     

SOME PROPERTIES OF THREE VIRUSES ISOLATED FROM A DISEASED PLANT OF SOLANUM JASMINOIDES PAXT. FROM INDIA

Three mechanically transmissible viruses were isolated from a diseased Solanum jasminoides plant obtained from India. One is a strain of potato virus Y , which in some potato varieties produces symptoms resembling those caused by potato virus C , but unlike potato virus C it is readily transmitted by Myzus persicae. The second, named tobacco wilt virus, is also transmitted by M. persicae but much less readily, whereas the third, named datura necrosis virus, is not. All three have a wide host range, but neither tobacco wilt nor datura necrosis viruses infects potato plants. All three have long flexuous particles and similar general properties.
Simultaneous infection with datura necrosis virus usually decreases the concentration reached by potato virus Y in tobacco plants but not in Nicotiana glutinosa.     

Staining Myelin, Elastic Fibers and Nuclei with Iron Hematoxylin

Two iron hematoxylin staining procedures were developed. Both use stable stock solutions and can be prepared volumetrically. The nuclear stain is progressive but differentiation is required for myelin sheath and elastic tissue staining. Histochemical procedures demonstrated that acid, hydroxyl, and aldehyde groups play no role in the staining but amine groups are essential. With both types of stains neither electrostatic bonding nor hydrogen bonding is essential but the nature of the union between tissue and the iron hematoxylin complex was not determined.     

Pollinator limitation and position dependent fruit set in the high Andean orchidMyrosmodes cochleare (Orchidaceae)

Myrosmodes cochleare is a terrestrial orchid restricted to high elevations of the northern Andes. It is self-compatible but not autogamous. Flowering begins at the apex of the inflorescence, but flower size increases steadily towards the base. Fruit set of selfed flowers was found to increase significantly from the apex to the base of the inflorescence. Open-pollinated fruit set was significantly lower than hand-pollinated fruit set overall, but the highest levels occurred in the middle of the inflorescence. Eumenid wasps and a calliphorid fly were observed to pollinate the flowers, but visits were rare and occurred only during infrequent warm periods.