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Compact radio sources exhibit scintillation, an interference pattern arising from propagation through inhomogeneous plasma, where scintillation patterns encode the relative distances and velocities of the source, scattering material, and Earth. In previous work, we showed that the scintillation velocity of the repeating fast radio burst FRB20201124A could be measured by correlating burst spectra pairs, with low values of the scintillation velocity and scattering timescale suggesting scattering nearby the Earth at $\sim0.4\,$kpc. In this work, we have measured the scintillation velocity at 10 epochs spanning a year, observing an annual variation which strongly implies the screen is within the Milky Way. Modelling the annual variation with a 1D anisotropic or 2D isotropic screen results in a screen distance $d_{l} = 0.40\pm0.04\,$kpc or $d_{l} = 0.46\pm0.06\,$kpc from Earth respectively, possibly associated with material outside of the Local Bubble or the edge of the Orion-Eridanus Superbubble. Additional measurements particularly at times of low effective velocity will help probe changes in screen properties, and distinguish between screen models. Where scintillation of an FRB originates in its host galaxy or local environment, these techniques could be used to detect orbital motion, and probe the FRB's local ionised environment., Comment: 5 pages, 5 Figures, accepted in MNRAS Letters. Replacement, fixed typo in abstract: 0.4kpc instead of 0.4pc

Globular clusters contain a unique pulsar population, with many exotic systems that can form only in their dense stellar environments. The leap in sensitivity of the upgraded Giant Metrewave Radio Telescope (uGMRT) in India, especially at low radio frequencies ($, 18 pages, 9 figures, 7 tables. Accepted for publication in Astronomy & Astrophysics

We report the observations of the highly active FRb20201124A with the upgraded Giant Metrewave Radio Telescope at 550-750~MHz. These observations in the incoherent array mode simultaneously provided an arcsecond localization of bursts from \rss, the discovery of persistent radio emission associated with the host galaxy, and the detection of 48 bursts. Using the brightest burst in the sample ($F= 108~{\rm Jy~ms}$) we find a structure-maximizing dispersion measure of $410.8 \pm 0.5~{\rm pc~cm}^{-3}$. We find that our observations are complete down to a fluence level of $10~{\rm Jy~ms}$, above which the cumulative burst rate scales as a power-law $R(>\!F) = 10~{\rm hr}^{-1} \left(F/10\mathrm{~Jy~ms}\right)^{\gamma}$ with $\gamma = -1.2 \pm 0.2$. We find that the bursts are on average wider than those reported for other repeating FRBs. We find that the waiting time between bursts is well approximated by an exponential distribution with a mean of $\sim 2.9$ min during our observations. We searched for periodicities using both a standard Fourier domain method and the Fast Folding Algorithm, but found no significant candidates. We measure bulk spectro-temporal drift rates between $-0.75$ and $-20~{\rm MHz~ms}^{-1}$. Finally, we use the brightest burst to set an upper limit to the scattering time of 11.1~ms at 550~MHz. The localization of FRB20201124A adds strength to the proof-of-concept method described in our earlier work and serves as a potential model for future localizations and follow-up of repeating FRBs with the uGMRT., Comment: 11 pages, 8 figures, accepted for publication in MNRAS

BACKGROUND Several ways of performing laparoscopic right hemicolectomy (RHC) have evolved. The vascular pedicle can be divided into extracorporeal (RHC-EC) or intracorporeal (RHC-IC). It is not known whether vessel ligation during RHC-EC is as central as during RHC-IC. We compare these approaches in terms of pathological and short-term clinical outcomes. METHODS Patients undergoing elective laparoscopic RHC in a single centre (July 2013-September 2016) were identified. Data collection included operative details, length of stay, complications, specimen parameters including number and involvement of lymph nodes and recurrence. RESULTS One hundred and sixty-nine patients were included (94 RHC-IC, 75 RHC-EC). For caecal and ascending colon cancers, mesocolic width was greater after RHC-IC than RHC-EC (7.9 cm versus 6.6 cm, P

We report the results of a study to investigate the effect of aluminium on the impact sensitiveness of a range of Ammonium Nitrate-Fuel Oil (ANFO) mixtures. The data obtained indicate that the impact sensitiveness of these mixtures depends on the quantity and type of aluminium, and on the ratio of ammonium nitrate to fuel oil. The magnitude of the dependences is relatively small, however, and all the aluminium-ANFO mixtures examined can be classed as “comparatively insensitive”. We have also shown that the sensitiveness of such mixtures to impact can increase if they contain small quantities of rust or grit as a contaminant.

The BAM Fallhammer test is one of the most widely used impact tests, but the results of the test rely on the subjective assessments of the test operator using the senses of hearing, smell and sight. The paper describes an investigation into the suitability of using a neural network for determining the outcome of BAM Fallhammer tests. The network utilises digital data from instrumentation installed around the BAM apparatus, including a microphone and a gas sensor. Selected examples are given to show that neural networks have the potential to distinguish between the test results of ‘no reaction’, ‘decomposition’, and ‘explosion’ for propellants, plastic and high explosives. The technique removes the possible operator dependence of assessments and the study in general may also lead to clarification of the categories involved in defining the test outcome.

Tephritid parasitoids reared from 26 different host fruit species showed remarkably little diversity across 21 Brazilian counties. The majority of the parasitoids (81.4%) belonged to the braconid subfamily Opiinae, with Doryctobracon areolatus (Szepligeti) the most commonly encountered species. Four other opiines, namely D. brasiliensis (Szepligeti), Opius bellus Gahan, Optus sp. and Utetes (Bracanastrepha) anastrephae (Viereck) were also reared, but in much smaller numbers. Asobara anastrephae (Muesebeck), an alysiine braconid parasitoid of tephritids, accounted for an additional 18–6% of the individuals reared from tephritids. The hosts and distribution patterns of the braconid parasitoids of Brazilian fruit‐infesting Tephritidae are summarized.

Leaf-mining Liriomyza spp. and their associated hymenopterous parasitoids were surveyed during the fall of 1980 and spring of 1981 on fresh market tomatoes in west-central Florida. L. sativae Blanchard was more abundant than L. tnfolii (Burgess) in both seasons, accounting for 85.7 and 54.3% of the total reared in 1980 and 1981, respectively. The parasitoids Diglyphus intermedius (Girault), D. begini (Ashmead), and Neochrysocharis punctiventris (Crawford) were the most abundant larval parasitoids reared from leafminer-infested foliage, accounting for 28.8, 26.3, and 15.6%, respectively. D. begini was not detected in 1980, but was nearly as abundant as D. intermedius in 1981. Opius dissitus (Muesebeck) was the most abundant larval-pupal parasitoid reared from leafminer-infested foliage, accounting for 51.8 and 12.6% of the total parasitoids reared in 1980 and 1981, respectively.

Muscle cell fiber types in gracilis, rectus femoris, and long head of triceps brachii muscles of ferrets and dogs were identified on serial sections stained for myosin ATPase after preincubation at pH values of 9.8, 4.6, and 4.3 and for NADH-tetrazolium reductase (NADH-TR) activity. Although fiber types I and II were identified, the ATPase stain did not demonstrate classic type IIA/IIB fiber differences in either species. However, two type II fiber subtypes could be distinguished in the ferret because they differed slightly in staining intensity with ATPase at pH 4.3 and markedly with NADH-TR. One ferret type II fiber (designated II dark or IID) was smaller, slightly darker on ATPase, more oxidative on NADH-TR, and comprised more muscle volume than the other type II fiber (designated II light IIL). The IID fibers of ferret may represent the IID/X fibers of other authors. Both ferret type II fiber subtypes stained darker at pH 4.3 than canine II fibers. The NADH-TR staining indicated high oxidative activity in canine and ferret type I fibers. In contrast, type II fibers in the dog and IIL fibers in the ferret were moderately oxidative. Canine type IIC fibers were intermediate between type I and type II, whereas in the ferret, type IIC fibers were highly oxidative, as were type IID fibers. Ferret muscles are more oxidative than canine muscles according to NADH-TR staining. Also, ferret muscles possess 40-100% higher citrate synthase activity as compared to canine muscles.

Several different test methods can be used to determine the sensitiveness of an explosive or energetic material to initiation by friction. In this paper we examine the results for seven explosives obtained using three commonly used friction test methods. The suitability of each method as a means of quantifying friction sensitiveness is discussed, and the advantages and disadvantages of the individual techniques are highlighted.

The family Braconidae is one of the largest in the Hymenoptera, containing more than 15,000 valid species (87). Together with the Ichneumonidae, it forms a distinctive superfamily among the assemblage of hymenopterans known as the parasitic wasps (39). Adult braconids oviposit almost exclusively in, on, or near other insects, with the immature stages completing their development at the host's expense. The terms parasitoid and protelean parasite are frequently applied to the various wasps, flies, and beetles that develop in this fashion. Many parasitoids are closely attuned to their hosts and have thus been of primary importance in the biological control of insect pests. Braconids are among the foremost of these beneficial insects. In classical biological­ control programs, their success rate is exceeded only by that of aphelinids (43, 60). Braconids are also widely used as models for the study of host-parasitoid interactions, and in this regard, an impressive number of recent contributions have encompassed the broad disciplines of physiology, behavior, and evolutionary biology. Clausen's book (19) includes a detailed review of the older literature on braconid biology, and this classic text still serves as an excellent source for general information on parasitic Hymenoptera. More recent volumes (39, 45, 136) provide additional insights into braconid biology and illustrate the diversity of research now being conducted on parasitoids. Several works (9, 87, 121) summarize braconid host relationships by subfamily, and a handbook on braconid classification and biology is now available (94). The exhaustive treatment of braconid biology contained in this handbook is an excellent review of the subject and will undoubtedly become the standard introductory reference for this family. The term bionomics is ideally suited for this review, which focuses on the

by us in comparative tests with antigens of different dilutions. The particular features of our test as finally recommended and the conditions under which it was conducted were that: (1) a dose of 0.02 ml of a 1:100,000 dilution of Dirofilaria immitis antigen was employed; (2) a corresponding concentration of dog serum was used as a control; (3) early and doubtful cases of filariasis, and individuals who had been in endemic areas, constituted the test group; and (4) a large number of persons, most of whom were allergic to various substances, but none of whom had ever lived in an endemic area, constituted the control group. It was concluded that a dilution of 1:100,000 of D. immitis in saline, in a dose of 0.02 ml, was a suitable antigen for the diagnostic test for filariasis.

Weeds adjacent to commercial tomato production fields on the west coast of Florida were surveyed during 1982–1983 to determine which species serve as reservoirs of Agromyzidae leaf miners and their parasitoids. About 95% of the leafminer larvae were observed in foliage of seven weed genera ( Solanum americanum Mill., Erechtites hieracifolia (L.), Bidens alba (L.), Gnaphalium spp., Physalis spp., Sonchus spp., and Rumex obtusifolius L.) and volunteer tomato even though these species accounted for only about 13–42% of the weed canopy. Liriomyza trifolii (Burgess) and L. sativae Blanchard accounted for 45 and 40%, respectively, of the leafminer adults reared from infested foliage and were most prevalent from S. americanum and B. alba . The larval–pupal parasitoids Optus dissitus Muesebeck, Oenonogastra microrhopalae (Ashmead), and Halticoptera circulus (Walker) were the most abundant leafminer parasitoid adults reared from leafminer infested foliage, accounting for 37.8, 15.1, and 15.8%, respectively, of the total reared. The larval parasitoids Neochrysocharis punctiventris (Crawford), Diglyphus begini (Ashmead), and D. intermedius (Girault) accounted for 8, 5, and 2.5%, respectively.

The electrokinetic and flotation behavior of the green alga Chlorella vulgaris was studied in the absence and presence of Pb(II), Al(III) and flotation collectors. It was found that the presence of Al(III) is necessary for good flotation of the organism, whether or not Pb(Il) is present, when dodecylammonium chloride or sodium dodecylsulfate is used as collector. Best flotation using dodecylamine is at about pH 8, and best flotation when using sodium dodecylsulfate is at about pH 4. It appears because of the small size of the organisms that the Al(III) is necessary for flocculation to enhance bubble-cell contact and C. vulgaris removal from water. When N-dodecyl-2-aminopropionic acid is used as collector, good flotation occurs at about pH 4 without the addition of Al(III).

There is direct geomorphological evidence that in the past Mars had large amounts of liquid water on its surface. Atmospheric models would suggest that this early period of hydrological activity was due to the presence of a thick atmosphere and the resulting warmer temperatures. From a biological perspective the existence of liquid water, by itself, motivates the question of the origin of life on Mars. From studies of the Earth's earliest biosphere we know that by 3.5 billion years ago, life had originated on Earth and reached a fair degree of biological sophistication. Surface activity and erosion on Earth make it difficult to trace the history of life before the 3.5 billion years ago timeframe. If Mars did maintain a clement environment for longer than it took for life to originate on Earth, then the question of the origin of life on Mars follows naturally.

Dans ce bref article, on fait etat de la relation entre les donnees de sensibilite a la friction d'explosifs a hautes performances obtenues avec les tests de friction BAM et ROTARY. Meme si les deux methodes peuvent etre utilisees pour evaluer la securite du transport, seul le test BAM est indique pour d'autres etudes de securite. Les resultats de la presente etude pourraient jouer un role important en vue de reduire la contrainte d'etudes complementaires, si l'on dispose deja des resultats du test ROTARY.

We assessed whether circulating cell positivity using RT-PCR for carcinoembryonic antigen (CEA) cDNA was affected by venesection via a needle compared with a pre-aspirated venous cannula, and by increased PCR cycles. Systemic blood was sampled by needle and pre-aspirated cannula in 101 healthy individuals with no cancer history. After erythrocyte removal, samples were subjected to RT-PCR using specific primers for CEA, with 29 or 35 RT-PCR cycles. There was a significant difference between the number of subjects whose samples were negative when collected via needle venesection and positive when collected via pre-aspirated cannula, compared with positive by needle venesection and negative by pre-aspirated cannula for both 29 (P = 0.016) and 35 (P = 0.0111) RT-PCR cycles. Venesection technique (P = 0.01) and number of cycles (P = 0.003) were significant predictors of a positive result. Positive results in healthy subjects were reduced to less than 3% when an aspirated cannula was used for venesection and29 PCR cycles were avoided.

Circulating tumor cells could provide a relatively noninvasive and repeatable source of information about tumor cell genotype that might influence treatment and estimation of prognosis. We developed a technique for identifying p53 mutations in tumor cells isolated from the peripheral venous blood of colorectal cancer patients and compared the prevalence and position of these mutations with multiple solid tumor samples from the same patient. We used immunomagnetic beads to isolate tumor cells, reverse transcriptase-nested polymerase chain amplification of the coding region between exons 4 and 9 within the p53 gene, and automated gene sequencing. Nineteen p53 mutations were detected in solid tumor samples from 19 of 41 colorectal carcinoma patients. An identical p53 mutation was invariably present in all samples from primary and metastatic colorectal tumor biopsies within the same patient. p53 mutations were detected in peripheral blood from 8 of these 19 patients with p53-mutated solid tumors. Where identified, the pattern of mutation in peripheral blood samples was invariably the same as in matching solid tumor samples. A single colorectal carcinoma biopsy provided reliable p53 gene mutational information in colorectal carcinoma. Detection of this p53 mutation in tumor cells from peripheral blood was achieved with an approach based on cell selection for epithelial characteristics, reverse transcription-PCR, and gene sequencing.

The objectives of this study were to assess whether the use of two reverse transcription-PCR (RT-PCR) cDNA assays and multiple blood sampling increased circulating tumor cell detection in colorectal cancer patients. Systemic blood was sampled three times at 1-min intervals in 100 colorectal cancer patients (50 primary tumors only and 50 liver metastases), and in 70 control patients without known cancer. After removal of the erythrocytes, samples were subjected to separate RT-PCR reactions using specific primers for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20). Statistical analysis was performed by the two-sample binomial test and the one-sided McNemar test. There were significant increases in circulating tumor cell positivity when CEA and CK20 assays were used together as compared with either CEA or CK20 assay used alone. There were also significant increases in circulating tumor cell positivity for either CEA or CK20 assay used alone when the results from two blood samples were compared with the results from one sample. Circulating colorectal cancer cell positivity rose from 48% (CEA) and 34% (CK20) with one assay of one sample to 74% when both assays of three samples were used to identify circulating tumor cells. Three non-cancer control patients (4.3%) were positive for either CEA (two patients) or CK20 (one patient). Tumor cells were identified more frequently in the circulation of colorectal cancer patients than had been suggested previously. RT-PCR-based studies of the clinical significance of circulating cancer cells in colorectal cancer should involve multiple blood samples with identification of multiple tumor-related cDNA products.

SIVsmmPBj14 is a highly pathogenic lentivirus which causes acute diarrhea, rash, massive lymphocyte proliferation predominantly in the gastrointestinal tract, and death within 7 to 14 days. In cell culture, the virus has mitogenic effects on resting macaque T lymphocytes. In contrast, SIVmac239 causes AIDS in rhesus macaques, generally within 2 years after inoculation. In a previous study, replacement of amino acid residues 17 and 18 of the Nef protein of SIVmac239 with the corresponding amino acid residues of the Nef protein of SIVsmmPBj14 yielded a PBj-like virus that caused extensive activation of resting T lymphocytes in cultures and acute PBj-like disease when inoculated into pig-tailed macaques. This study suggested that nef played a major role in both processes. In this study, we replaced the nef/long terminal repeat (LTR) region of a nonpathogenic simian-human immunodeficiency virus (SHIV), SHIVPPc, with the corresponding region from SIVsmmPBj14 and examined the biological properties of the resultant virus. Like SIVsmmPBj14, SHIVPPcPBjnef caused massive stimulation of resting peripheral blood mononuclear cells (PBMC), which then produced virus in the absence of extraneous interleukin 2. However, when inoculated into macaques, the virus failed to replicate productively or cause disease. Thus, while these results confirmed that the nef/LTR region of SIVsmmPBj14 played a major role in the activation of resting PBMC, duplication of the cellular activation process in macaques may require a further interaction between nef and the envelope glycoprotein of simian immunodeficiency virus because SHIV, containing the envelope of human immunodeficiency virus type 1, failed to cause activation in vivo.

Eighty-one patients suffering from neck pain and tension-type headaches were treated by the application of a unique physical therapy device combining transcutaneous electrical nerve stimulation (TENS), traction, massage, vibration, and acupressure applied to the forehead, posterior cervical spine, and scapula. The device employed eight silver silicone electrodes for modality application. Its safety and effectiveness were assessed by evaluating patients before and after treatment. No complication ensued. Statistical analysis of visual analog scales for neck pain and headache yielded p values0.0001. Analysis of fibromyalgia neck and shoulder trigger points with three controls gave nonsignificant results. Conclusions were that 1) the device is safe and effective as judged by subjective patient input and 2) fibromyalgia trigger points are unaffected by the treatments. More objective measures are needed to provide evidence of efficacy.

We divide the history of water on the Martian surface into four epochs based upon the atmospheric temperature and pressure. In Epoch 1, during which a primordial CO2 atmosphere was actively maintained by impact and volcanic recycling, we presume the mean annual temperature to have been above freezing, the pressure to have exceeded one atmosphere, and liquid water to have been widespread. Under such conditions, similar to early Earth, life could have arisen and become abundant. After this initial period of recycling, atmospheric CO2 was irreversibly lost due to carbonate formation and the pressure and temperature declined. In Epoch II, the mean annual temperature fell below freezing but peak temperatures would have exceeded freezing. Ice covered lakes, similar to those in the McMurdo Dry Valleys of Antarctica could have provided a habitat for life. In Epoch III, the mean and peak temperatures were below freezing and there would have been only transient liquid water. Microbial ecosystems living in endolithic rock "greenhouses" could have continued to survive. Finally, in Epoch IV, the pressure dropped to near the triple point pressure of water and liquid water could no longer have existed on the surface and life on the surface would have become extinct.

Introduction: A positive circumferential resection margin (CRM) is associated with local recurrence and poor oncological outcome. Studies highlight that positive CRMs occurs more often following abdominoperineal excisions (APER), compared to anterior resections (AR). However a bias towards performing APERs in patients with locally advanced tumours, or down staging prior to sphincter preserving surgery may underlie the difference. Aims: Determine (1) positive CRM rates following APER and low ARs (2) if pre-operative decision making accounts for the difference. Methods: The last 100 low AR and 100 APERs within our unit were reviewed. Data collected included 1) Tumour distance from the anal verge, 2) Pre-operative staging (CT / MRI) (Early stage cancers T1-2N0, Intermediate stage – T3N0-1, and Advanced stage – CRM threatened by tumour or involved nodes) 3) Neo-adjuvant therapy use 4) positive CRMs. Results: One hundred Low AR were performed Between Jan 2008 – June 2004, while 100 APER were performed between Jan 2008 – Jan 2003. Average tumour distance from anal verge: APERs 3.4 cm vs. AR 5.2 cm. There was no significant difference in the pre-operative stage (Early 28 vs. 27, Intermediate 51 vs. 58, and advanced 21 vs. 15), or the use of chemo-radiotherapy (APER 9 vs. AR 13). There was a significant increase in CRMs in the APER group 15 vs. 7. Conclusion: A positive CRM occurred twice as often following APERs vs. low AR. This difference could not be accounted for by early cancers undergoing AR, or the use of down staging chemo-radiotherapy.

Introduction: The NHS Bowel Cancer Screening Programme (NHSBCSP) has been running since September 2006. Its impact on the workload of colorectal units has not currently been assessed. Aims: To determine the initial increased in workload resulting from screen detected cancers detected by the NHSBCSP. Methods: Cancers detected by the local NHSBCSP were reviewed with respect to: operative intervention, Dukes’ stage, post operative complications, and neo-adjuvant therapy. Results: Between September 2006 to Jan 2008 100 screen detected cancers were identified. Twenty eight were located in the rectum, 38 sigmoid colon, 2 descending colon, 9 transverse colon, 10 ascending colon, and 13 within the caecum. Of the 100 cases 18 were polyp cancers, 3 of which proceed to a subsequent resection, (2 anterior resections and 1 right hemicolectomy). Of the remaining 82 cases 38 patients had an anterior resection, 26 right hemicolectomy, 5 abdominal perineal resection, 3 sigmoid colectomy and 1 subtotal colectomy. Nine patients had no operative intervention; 5 due to metastatic disease and 4 as a result of patient choice. Thirty five patients had Dukes’ stage A, 31 Dukes’ B, 17 Dukes’ C, and 5 Dukes’ D. There were 8 major post operative complications: 6 anastomotic leaks, 1 colo-pouch-vaginal fistula, and one death. Two patients who underwent resections for polyp cancers failed to have the polyp scar removed at the time of surgery. Conclusion: The local NHS colorectal cancer screening programme has resulted in a significant shift towards Dukes’ stage A and B cancers at time of presentation. However it has resulted in a dramatic increase in the number of colorectal resections, 76 between September 06 to Jan 2008.

The combinations of ciprofloxacin plus ceftazidime, ciprofloxacin plus aztreonam, and ciprofloxacin plus azlocillin were evaluated for the presence of synergy against multiresistant isolates of Pseudomonas aeruginosa. The frequency of synergy was dependent on antibiotic susceptibilities. If the organism was resistant to ciprofloxacin, synergy was observed in more than 50% of the isolates; however, if the organism was resistant to the beta-lactam (with the exception of ceftazidime), synergy was generally observed in less than 10% of the isolates. Antagonism was not observed with any of the combinations. These results may be helpful in making clinical decisions in treating P. aeruginosa infections.

During the next 50 years, human civilization may well begin expanding into the solar system. This colonization of extraterrestrial bodies will most likely begin with the establishment of small research outposts on the Moon and/or Mars. In all probability these facilities, designed primarily for conducting exploration and basic science, will have international participation in their crews, logistical support and funding. High fidelity Earth-based simulations of planetary exploration could help prepare for these expensive and complex operations. Antarctica provides one possible venue for such a simulation. The hostile and remote dry valleys of southern Victoria Land offer a valid analog to the Martian environment but are sufficiently accessible to allow routine logistical support and to assure the relative safety of their inhabitants. An Antarctic research outpost designed as a planetary exploration simulation facility would have great potential as a testbed and training site for the operation of future Mars bases and represents a near-term, relatively low-cost alternative to other precursor activities. Antarctica already enjoys an international dimension, an aspect that is more than symbolically appropriate to an international endeavor of unprecedented scientific and social significance--planetary exploration by humans. Potential uses of such a facility include: 1) studying human factors in an isolated environment (including long-term interactions among an international crew); 2) testing emerging technologies (e.g., advanced life support facilities such as a partial bioregenerative life support system, advanced analytical and sample acquisition instrumentation and equipment, etc.); and 3) conducting basic scientific research similar to the research that will be conducted on Mars, while contributing to the planning for human exploration. (Research of this type is already ongoing in Antarctica).

In this paper we review recent research undertaken with the aim of developing a compression test apparatus that simulates the application of mechanical forces to which initiator devices may be typically subjected during handling. This resulted in the development of two different apparatuses, one supplied pressure by means of a weighted beam and the other by using a pneumatic piston. The latter unit has also been used to study the response of initiator devices to impact. Additionally, we discuss some of the key information that would be required in order to develop a safety-in-handling hazard index.

Snow plays a key role in the ecology of much of Earth's surface, especially in circumpolar and high-altitude regions where ecosystems are under increasing stress from global changes in climate and human development. Until recently, our knowledge of snow has been restricted to areas of study associated with specific physical, chemical, and biological disciplines. Although this research has significantly increased our understanding of snowpack dynamics, the results of these studies have not been integrated to further our knowledge of snow as a life-support system and as a component of larger terrestrial ecosystems.

Algal mats comprised primarily of the blue-green algae (cyanobacteria) Phormidium frigidum and Lyngbya martensiana, several species of pennate diatoms and heterotrophic bacteria occur abundantly th...