More on the Narrowing of Impact Broadened Radio Recombination Lines at High Principal Quantum Number

Recently Alexander and Gulyaev have suggested that the apparent decrease in impact broadening of radio recombination lines seen at high principal quantum number n may be a product of the data reduction process, possibly resulting from the presence of noise on the telescope spectra that is not present on the calculated comparison spectra. This is an interesting proposal. However, there are serious problems with their analysis that need to be pointed out. Perhaps the most important of these is the fact that for principal quantum numbers below n = 200, where the widths are not in question, their processed generated profile widths do not fit the widths of the processed lines obtained at the telescope. After processing, the halfwidths of the generated and telescope profiles must agree below n = 200 if we are to believe that the processed generated linewidths above n = 200 are meaningful. Theirs do not. Furthermore, we find that after applying the linewidth reduction factors found by Alexander and Gulyaev for their noise added profiles to our generated profiles to simulate their noise adding effect, the processed widths we obtain still do not come close to explaining the narrowing seen in the telescope lines for n values in the range 200 < n < 250. It is concluded that what is needed to solve this mystery is a completely new approach using a different observing technique instead of simply a further manipulation of the frequency-switched data.Comment: Six pages with 4 figures. Accepted for publication in Astrophysics and Space Scienc

Effect of tillage and residue retention on maize productivity

In Bangladesh, maize is generally sown after extensive tilth and minimum residue retention. Conservation agriculture (CA) systems reduce the input costs, machinery use, CO2 emissions; and improve soil health (Raper et al., 1994). Crop residues are known to affect soil physical properties (Hulugalle et al., 1986), availability of nutrients (Wade and Sanchez, 1983; Asghar et al., 2006) and soil biological activity (Tian et al., 1993). Crop residue retention has been suggested to improve overall soil fertility and to support sustainable crop production. Crop residue retention under no tillage system reduce soil erosion, increase soil organic matter (SOM), and reduce requirement of labour and fuel under cereal grain and row crop culture (Salinas-Garcia et al., 1997). Kumar and Goh (2000) reported that incorporation of crop residues is essential for sustaining soil productivity through replenishing SOM that not only a key indicator of soil quality, but it also supplies essential nutrients upon mineralization (N, P, and S) and improves soil physical, chemical, and biological properties (Kumar et al., 2001). In our country, the crop residue is used mostly for cattle feed (Saadullah et al., 1991), fuel for stove and some cases burning. It is essential to estimate the amount of crop residue that should be retained in field to get the benefits. Therefore, the present research investigated to find out the minimum tillage with residue retention could be an effective element for maize production

Preterm nutritional intake and MRI phenotype at term age: a prospective observational study

Objective: To describe (1) the relationship between nutrition and the preterm-at-term infant phenotype, (2) phenotypic differences between preterm-at-term infants and healthy term born infants and (3) relationships between somatic and brain MRI outcomes. Design: Prospective observational study. Setting: UK tertiary neonatal unit. Participants: Preterm infants (<32 weeks gestation) (n=22) and healthy term infants (n=39) Main outcome measures: Preterm nutrient intake; total and regional adipose tissue (AT) depot volumes; brain volume and proximal cerebral arterial vessel tortuosity (CAVT) in preterm infants and in term infants. Results: Preterm nutrition was deficient in protein and high in carbohydrate and fat. Preterm nutrition was not related to AT volumes, brain volume or proximal CAVT score; a positive association was noted between human milk intake and proximal CAVT score (r=0.44, p=0.05). In comparison to term infants, preterm infants had increased total adiposity, comparable brain volumes and reduced proximal CAVT scores. There was a significant negative correlation between deep subcutaneous abdominal AT volume and brain volume in preterm infants (r=−0.58, p=0.01). Conclusions: Though there are significant phenotypic differences between preterm infants at term and term infants, preterm macronutrient intake does not appear to be a determinant. Our preliminary data suggest that (1) human milk may exert a beneficial effect on cerebral arterial vessel tortuosity and (2) there is a negative correlation between adiposity and brain volume in preterm infants at term. Further work is warranted to see if our findings can be replicated and to understand the causal mechanisms

The life of meaning: A model of the positive contributions to well-being from veterinary work

We present a veterinary model of work-derived well-being, and argue that educators should not only present a (potentially self-fulfilling) stress management model of future wellness, but also balance this with a positive psychology-based approach depicting a veterinary career as a richly generative source of satisfaction and fulfillment. A review of known sources of satisfaction for veterinarians finds them to be based mostly in meaningful purpose, relationships, and personal growth. This positions veterinary well-being within the tradition of eudaimonia, an ancient concept of achieving one's best possible self, and a term increasingly employed to describe well-being derived from living a life that is engaging, meaningful, and deeply fulfilling. The theory of eudaimonia for workplace well-being should inform development of personal resources that foster resilience in undergraduate and graduate veterinarians

Impact of Versatile Multi-crop Planter on service providers’ livelihood in some selected areas of Bangladesh

The cropping intensity of Bangladesh is increasing year after year because most small holders start growing three or more crops in a year. Over a 5-year cycle due to changing profitability of crops, farmers cultivate 4-6 crops with diverse seed sizes, seed rate, row spacing, fertilizer rates, and seed depth. Hence a planter for such diverse cropping systems needs to have multi-functional capabilities. Service providers also need to be able to hire out their planter for business all year round to justify the investment cost. There are a number of other criteria and challenges that would need to be satisfied by potential purchasers of a planter. The VMP (Versatile Multi-crop Planter) is such a unique machine for two-wheel tractor which can meet the above criteria and successfully establish a diverse range of crops since 2008 (Haque et al., 2011). It has designed with capability for seeding and fertilizing with fluted roller or vertical plate meters in lines for single-pass shallow-tillage, strip planting, zero tillage and bed planting. The service providers remove seeding unit from VMP and convert only for high speed rotary tiller (HSRT). Most of the grain seeds like wheat, paddy, maize, jute, pulses, oilseeds etc. can be sown in line using VMP. It owners are using this device for their own land cultivation and earning cash income through custom hiring to other farmers and could improve their livelihood through this machine. Therefore, an attempt was made to assess the profitability of VMP operations at farm level and the impacts of its operations on service providers’ livelihood

Development and validation of unpuddled riding-type rice transplanter for wet land rice establishment

Manual transplanting is tedious and time consuming which often the causes of delayed planting resulting yield loss of rice in Bangladesh. Mechanized rice transplanting is seen as a solution of labor problems. Likewise, using mechanized rice transplanting ensures uniform plant spacing as well as fast and efficient planting that contributes to high productivity (Manjunatha et al., 2009). Transplanters have been developed for rice seedling planting into puddled soils to alleviate labour shortages and reduce costs of rice establishment (Adhikari et al., 2006). Although, tillage for rice establishment has significantly mechanized in Bangladesh, 16-18 % of total production cost are involved in tillage and land leveling (BRRI, 2013). Development of a rice transplanter suitable for unpuddled transplanting under minimum tillage conditions could further minimize the land preparation cost, which will be of interest to the farmers. No significant work to date has been conducted in Bangladesh to develop a rice transplanter for minimum tillage unpuddled soil conditions. Therefore, the following development and validation study was conducted during 2013-15 with modifying and evaluating a riding-type, 6-row mechanical rice transplanter for unpuddled soil conditions

Non-puddling practice for rice-based cropping system increases carbon sequestration in soil

In Indo-Gangetic Plains, intensive rice-based cropping systems with conventional crop establishment practices has been followed for many years. Contradictory results are reported about the effect of rice monoculture or rice-upland crop rotations on soil properties. While CA practices may sequester C into the soil organic C pool and improve soil health, in most cases, the practice of CA in rice-upland rotations is only partial; conservation tillage and residues retention are followed for upland crops only but not for rice. So, whatever benefits may accrue from CA practices followed for upland crops are lost by several wet tillage operations followed by puddling. In the EGP, rice-upland crop growers are now adopting CA increasingly, namely non-puddling of rice, in the intensive triple cropping systems (Alam et al. 2016; Haque et al. 2016). The incorporation of minimum tillage and retention of more residues in these systems of the EGP will change the dynamics of C in soil but nature of these changes has not been explored yet. The study was, therefore, conducted to determine the C cycling in soils of rice-upland triple cropping systems under CA practices

Sensitive Observations of Radio Recombination Lines in Orion and W51: The Data and Detection of Systematic Recombination Line Blueshifts Proportional to Impact Broadening

Sensitive spectral observations made in two frequency bands near 6.0 and 17.6 GHz are described for Orion and W51. Using frequency switching we were able to achieve a dynamic range in excess of 10,000 without fitting sinusoidal or polynomial baselines. This enabled us to detect lines as weak as T$_{A} ~1mK in these strong continuum sources. Hydrogen recombination lines with$\Delta n$ as high as 25 have been detected in Orion. In the Orion data, where the lines are stronger, we have also detected a systematic shift in the line center frequencies proportional to linewidth that cannot be explained by normal optical depth effects.Comment: 22 pages, 13 figures. Accepted for publication in Astrophysics and Space Scienc

Generation of spatially-separated spin entanglement in a triple quantum dot system

We propose a novel method for the creation of spatially-separated spin entanglement by means of adiabatic passage of an external gate voltage in a triple quantum dot system.Comment: 10 pages, 6 figure